Artykuły w czasopismach na temat „Petunia Reproduction”

In an effort to modify and study leaf senescence, we have produced several different transgenic petunia lines with altered leaf senescence phenotypes. Using two promoters from senescence-associated genes (sag12 & sag13) fused to the isopentenyl transferase (IPT) gene, which catalyzes the rate-limiting step of cytokinin production, we have produced transgenic petunia plants with delayed lower leaf senescence. We have observed that apparent “leaky” expression of IPT gives rise to plants with other morphological alterations such as increased branching habit and decreased root formation. Plants with delayed leaf senescence phenotypes were selected and bred to produce progeny that were evaluated in greenhouse experiments. Breeding characteristics, horticultural performance and reproduction of these plants will be discussed in terms of potential commercial benefits and limitations. Using the sag12 promoter to drive expression of the knotted (KN1) gene, we have also been able to engineer petunia plants with delayed lower leaf senescence. Initial progeny evaluations of sag12-KN1 petunias will also be discussed.

We are studying the horticultural performance of two model plant systems that carry a mutant gene that confers ethylene-insensitivity: Never Ripe tomatoes and petunia plants transformed with the mutant etr1-1 gene isolated from Arabidopsis thaliana. Having two model systems to compare side-by-side allows us to determine with greater certainty ethylene's role at different developmental stages. Presence of the mutant etr1-1 gene in transgenic petunias was determined using three techniques: PCR analysis, the seedling triple response assay (inhibition of stem elongation, radial swelling of stem and roots, and an exaggerated apical hook when grown in the dark and in the presence of ethylene), and the flower wilting response to pollination, which is known to be induced by ethylene. Flowers from ethylene-insensitive petunias took almost four times as long to wilt after pollination as wild-type plants. It is well known that fruit ripening in Never Ripe tomato is inhibited, and a similar delayed fruit ripening phenotype is observed in petunia plants transformed with etr1-1. In an effort to maintain ethylene-insensitive petunia plants by vegetative propagation, we observed that the rate of adventitious root formation was much lower with transgenic plants than in wild-type plants. In subsequent experiments on adventitious root formation in Never Ripe tomato, we observed the same result. Therefore, while ethylene-insensitive tomato and petunia plants appear phenotypically normal for many characters, other factors are altered by the presence of this mutation. The fact that these changes are present in two model systems helps to define the role of ethylene perception in plant growth and reproduction.

A series of experiments on ethylene-insensitive (EI) petunia plants (Petunia ×hybrida Hort. Vilm.-Andr.) generated in two genetic backgrounds were conducted to determine the involvement of ethylene in horticultural performance. Experiments examined various aspects of horticultural performance: days to flower, flower senescence after pollination and without pollination, fruit set and ripening, and adventitious root formation on vegetative stem cuttings. The development of EI plants was altered in several ways. Time from seed sowing to first flower anthesis was decreased by a week for EI plants grown at 26/21 °C. Flower senescence in nonpollinated and self-pollinated flowers was delayed in all EI plants compared to wild-type plants. Fruit set percentage on EI plants was slightly lower than on wild-type plants and fruit ripening on EI plants was delayed by up to 7 days. EI plants produced fewer commercially acceptable rooted cuttings than wild-type plants. There was a basic difference in the horticultural performance of the two EI lines examined due to a difference in the genetic backgrounds used to generate the lines. EI plants displayed better horticultural performance when grown with day/night temperatures of 26/21 °C than 30/24 °C. These results suggest that tissue-specific ethylene insensitivity as well as careful consideration of the genetic background used in transformation procedures and growth conditions of etr1-1 plants will be required to produce commercially viable transgenic floriculture crops. EI petunias provide an ideal model system for studying the role of ethylene in regulating various aspects of plant reproduction.

Calibrachoa mottle virus (CbMV), a tentative carmovirus, was first isolated and reported by Liu et al. (1) from infected Calibrachoa plants. During the spring of 2003, petunia samples from Florida and California sent to testing services at Agdia, Inc (Elkhart IN) tested positive for CbMV by enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay (ImmunoStrips). These samples also tested positive by carmovirus group-specific polymerase chain reaction (PCR) primers and by immunocapture PCR (2). RNA extracted from these samples with the RNeasy Plant Kit (Qiagen Inc., Valencia, CA) hybridized with a digoxigenin labeled probe derived from purified CbMV viral RNA. All plant samples that tested positive for CbMV were symptomless except one symptomatic sample that also tested positive for Tobacco mosaic virus. From samples that tested positive for CbMV only, mechanical inoculations were made to Chenopodium quinoa at a USDA-ARS greenhouse in Salinas, CA. Representative single, local lesions were used to inoculate additional C. quinoa plants. The resulting local lesions from these inoculations were freeze-dried and further used as virus inoculum (CbMV petunia). Similar inoculum was made with CbMV isolated from Calibrachoa plants (CbMV calibrachoa). Virus-free Petunia hybrida cultivars Surfinia ‘Baby Pink’ and Surfinia ‘Violet’ (Jackson and Perkins Inc., Somis, CA) were mechanically inoculated with CbMV petunia and CbMV calibrachoa. Four weeks postinoculation, all plants were tested using ELISA for the presence of CbMV. In greenhouse conditions, 14.3% of ‘Baby Pink’ plants were positive for CbMV petunia, whereas none were positive for CbMV calibrachoa. ‘Violet’ plants were 64.3 and 33.3% positive for CbMV petunia and CbMV calibrachoa, respectively. None of the positive plants expressed virus-like symptoms. Virus particles resembling those of CbMV were observed from infected petunia plants with transmission electron microscopy in leaf-dip preparations. To our knowledge, this is the first report of CbMV infecting petunia. Commercial reproduction of petunia plants and maintenance of genetic mother stock are usually by vegetative propagation. CbMV can be transmitted mechanically and is readily propagated along with its host. To produce healthy petunia plants, virus-free mother stock should be used, which requires regular screening of mother stock for CbMV. Reference: (1) H.-Y. Liu et al. Plant Dis. 87:167, 2003. (2) A. M. Harness et al. (Abstr.) Phytopathology 92:S34, 2002.

Plants synthesize a diversity of volatile molecules that are important for reproduction and defense, serve as practical products for humans, and influence atmospheric chemistry and climate. Despite progress in deciphering plant volatile biosynthesis, their release from the cell has been poorly understood. The default assumption has been that volatiles passively diffuse out of cells. By characterization of aPetunia hybridaadenosine triphosphate–binding cassette (ABC) transporter, PhABCG1, we demonstrate that passage of volatiles across the plasma membrane relies on active transport.PhABCG1down-regulation by RNA interference results in decreased emission of volatiles, which accumulate to toxic levels in the plasma membrane. This study provides direct proof of a biologically mediated mechanism of volatile emission.

Flowering is the first committed step of plant sexual reproduction. While the developing flower is a strong sink requiring large quantity of sugars from photosynthetic source tissues, this process is under-temper-spatially controlled via hormone signaling pathway and nutrient availability. Sugar transporters SUT/SUC and SWEET mediate sugars movement across membranes and play a significant role in various physiological processes, including reproductive organ development. In Petunia axillaris, a model ornamental plant, 5 SUT/SUC and 36 SWEET genes are identified in the current version of the genome. Analysis of their gene structure and chromosomal locations reveal that SWEET family is moderately expanded. Most of the transporter genes are abundantly expressed in the flower than in other organs. During the five flower developmental stages, transcript levels of PaSUT1, PaSUT3, PaSWEET13c, PaSWEET9a, PaSWEET1d, PaSWEET5a and PaSWEET14a increase with the maturation of the flower and reach their maximum in the fully open flowers. PaSWEET9c, the nectar-specific PhNEC1 orthologous, is expressed in matured and fully opened flowers. Moreover, determination of sugar concentrations and phytohormone dynamics in flowers at the five developmental stages shows that glucose is the predominant form of sugar in young flowers at the early stage but depletes at the later stage, whereas sucrose accumulates only in maturated flowers prior to the corolla opening. On the other hand, GA3 content and to a less extent IAA and zeatin decreases with the flower development; however, JA, SA and ABA display a remarkable peak at mid- or later flower developmental stage.

Previous works indicated a considerable variation in the pathogenicity, virulence, and host range of Oidium neolycopersici isolates causing tomato powdery mildew epidemics in many parts of the world. In this study, rDNA internal transcribed spacer (ITS) sequences, and amplified fragment length polymorphism (AFLP) patterns were analyzed in 17 O. neolycopersici samples collected in Europe, North America, and Japan, including those which overcame some of the tomato major resistance genes. The ITS sequences were identical in all 10 samples tested and were also identical to ITS sequences of eight previously studied O. neolycopersici specimens. The AFLP analysis revealed a high genetic diversity in O. neolycopersici and indicated that all 17 samples represented different genotypes. This might suggest the existence of either a yet unrevealed sexual reproduction or other genetic mechanisms that maintain a high genetic variability in O. neolycopersici. No clear correlation was found between the virulence and the AFLP patterns of the O. neolycopersici isolates studied. The relationship between O. neolycopersici and powdery mildew anamorphs infecting Aquilegia vulgaris, Chelidonium majus, Passiflora caerulea, and Sedum alboroseum was also investigated. These anamorphs are morphologically indistinguishable from and phylogenetically closely related to O. neolycopersici. The cross-inoculation tests and the analyses of ITS sequences and AFLP patterns jointly indicated that the powdery mildew anamorphs collected from the above mentioned plant species all represent distinct, but closely related species according to the phylogenetic species recognition. All these species were pathogenic only to their original host plant species, except O. neolycopersici which infected S. alboroseum, tobacco, petunia, and Arabidopsis thaliana, in addition to tomato, in cross-inoculation tests. This is the first genome-wide study that investigates the relationships among powdery mildews that are closely related based on ITS sequences and morphology. The results indicate that morphologically indistinguishable powdery mildews that differed in only one to five single nucleotide positions in their ITS region are to be considered as different taxa with distinct host ranges.

We have identified a novel petunia MADS box gene, PETUNIA FLOWERING GENE (PFG), which is involved in the transition from vegetative to reproductive development. PFG is expressed in the entire plant except stamens, roots and seedlings. Highest expression levels of PFG are found in vegetative and inflorescence meristems. Inhibition of PFG expression in transgenic plants, using a cosuppression strategy, resulted in a unique nonflowering phenotype. Homozygous pfg cosuppression plants are blocked in the formation of inflorescences and maintain vegetative growth. In these mutants, the expression of both PFG and the MADS box gene FLORAL BINDING PROTEIN26 (FBP26), the putative petunia homolog of SQUAMOSA from Antirrhinum, are down-regulated. In hemizygous pfg cosuppression plants initially a few flowers are formed, after which the meristem reverts to the vegetative phase. This reverted phenotype suggests that PFG, besides being required for floral transition, is also required to maintain the reproductive identity after this transition. The position of PFG in the hierarchy of genes controlling floral meristem development was investigated using a double mutant of the floral meristem identity mutant aberrant leaf and flower (alf) and the pfg cosuppression mutant. This analysis revealed that the pfg cosuppression phenotype is epistatic to the alf mutant phenotype, indicating that PFG acts early in the transition to flowering. These results suggest that the petunia MADS box gene, PFG, functions as an inflorescence meristem identity gene required for the transition of the vegetative shoot apex to the reproductive phase and the maintenance of reproductive identity.

Transmitting tissue-specific proteins (TTS proteins) are abundant in the extracellular matrix of Nicotiana pistils, and vital for optimal pollen tube growth and seed set. We have identified orthologs from several species in the Solanaceae, including Petunia axillaris axillaris and Petunia integrifolia. We refer to TTS proteins and their orthologs as histidine domain-arabinogalactan proteins (HD-APGs). HD-AGPs have distinctive domains, including a small histidine-rich region and a C-terminal PAC domain. Pairwise comparisons between HD-AGPs of 15 species belonging to Petunia, Nicotiana, and Solanum show that the his-domain and PAC domain are under purifying selection. In contrast, a proline-rich domain (HV2) is conserved among cross-hybridizing species, but variant in species-pairs that are reproductively isolated by post-pollination pre-fertilization reproductive barriers. In particular, variation in a tetrapeptide motif (XKPP) is systematically correlated with the presence of an interspecific reproductive barrier. Ka/Ks ratios are not informative at the infrageneric level, but the ratios reveal a clear signature of positive selection on two hypervariable domains (HV1 and HV2) when HD-AGPs from five solanaceous genera are compared. We propose that sequence divergence in the hypervariable domains of HD-AGPs reinforces sympatric speciation in incipient species that may have first diverged as a consequence of pollinator preferences or other ecological factors.

Scientific relevance. The garden petunia, Petunia hybrida, is a popular and wide spread ornamental crop from the family Solanaceae. It is a promising model plant for molecular and genetic research. In vitro micropropagation plays an important role in the distribution of the garden petunia because the survivability and quality of seed material decreases significantly in every subsequent generation. Besides, micropropagation reduces the cost of production substantially. Considering that very few researchers addressed this question in the Russian Federation, this direction of research is still worthy of attention.Materials and methods. The experiments were conducted by the Laboratory of Breeding and Genetic Research on Field Crops at FSBSI “Federal Scientific Center of Agricultural Biotechnology of the Far East named after A.K. Chaiki”. Seeds of Petunia hybrida (double-flowered) were used as primary explants. Liquid bleacher ACE diluted with distilled water in the proportion 1:9 was used as a sterilizing agent (the working solution contained 0.50% NaOCl). The total time of exposure was 15 minutes. The primary explants were subcultured onto a hormone-free Murashige and Skoog basal medium containing 20 g/L sucrose and 6 g/L agar. Isolated in vitro objects were cultured in test tubes with cotton-gauze plugs at an illuminance of 4000 lx, a temperature of 22–25 °C, and a 16h photoperiod in a culture room. The duration of one passage was 60 days. Micropropagation was carried out using 7- 10 mm cuttings with one or two nodes. The pot culture of the regenerants was established under controlled conditions in a light room (photoperiod was 16 hours, temperature was 23°С).Results. The optimal method for introducing Petunia hybrida into cell culture is the use of seeds treated with the solution of bleacher ACE that was diluted with distilled water in the proportion 1:9. The optimal time of exposure is 15 minutes. Petunia hybrida demonstrated a high regeneration rate on the hormone-free MS medium – it had a fast growth and development rate, and good rhizogenesis; the reproductive rate was 8.77. For the micropropagation of the garden petunia, it is advisable to use cuttings of test tube plants, which should be placed onto a hormone-free MS medium. The test tube plants of Petunia hybrida acclimatized successfully on a soil substrate. This shows the high plasticity of the culture.

A major innovation in angiosperms is the recruitment of animal pollinators as a means to enhance the efficiency and specificity of pollen transfer. The implementation of this reproductive strategy involved the rapid and presumably coordinated evolution of multiple floral traits. A major question concerns the molecular identity of the genetic polymorphisms that specify the phenotypic differences between distinct pollination syndromes. Here, we report on our work with Petunia , an attractive model system for quantitative plant genetics and genomics. From interspecific crosses, we obtained F2 plants that differed in the length of the floral tube or the size of the limb. We used these plants to study the behaviour of the hawkmoth pollinator, Manduca sexta . Plants with larger limbs were preferentially visited, consistent with the notion that flower size affects visibility under low light conditions. The moths also displayed an innate preference for shorter tubes. However, in those cases that flowers with long tubes were chosen, the animals fed for equal time. Thus, the perception of tube length may help the moths, early on, to avoid those plants that are more difficult to handle.

Phytophthora cryptogea was consistently isolated from diseased tissue taken from the crown and necrotic roots of grandiflora type petunia (Petunia × hybrida) that were collected in gardens in five public parks in Santiago, Chile in 2004 and 2005. Symptoms included leaf wilting and foliar chlorosis, followed by partial necrosis, and extensive dark-brown to reddish cankers in the crown. Disease incidence was over 50% and infected plants died within 7 to 10 days after transplanting. This pathogen was identified on the basis of colony morphology, morphological characterization of the sexual and asexual reproductive structures, and temperature range. The identification of Phytophthora cryptogea was further corroborated by the internal transcribed spacer sequence analysis (GenBank accession number EF093534). Isolates of P. cryptogea were pathogenic on 10-week-old white grandiflora petunia plants that were inoculated on the roots or on the crown using mycelium fragments, or via soil inoculation using zoospores. A rapid decline was observed after soil inoculations with zoospores. Root fresh weight decreased significantly and the root rot index and severity of foliage symptoms increased significantly (P ≤ 0.05), relative to noninoculated plants after 14 days of incubation. Two isolates (Ph-1 and Ph-2) were pathogenic on bell pepper and one isolate (Ph-1) was pathogenic on tomato after root inoculation. Two isolates (Ph-2 and Ph-3) were pathogenic on the fruit of avocado, bell pepper, cherry tomato, cucumber, kiwifruit, lemon, pear, pepino, and potato tubers, demonstrating the pathogen's ability to cause postharvest infection of fruit of a wide range of host plants. The efficacy of mefenoxam at 0.1 mg/ml mixed with either chlorothalonil at 1.0 mg/ml or mancozeb at 1.6 mg/ml was demonstrated in this study, whereas chlorothalonil and mancozeb alone did not control disease development. No significant differences were obtained between foliage and soil drench applications. This study demonstrated that P. cryptogea is the cause of the rapid decline found on petunia in Santiago, Chile and, to our knowledge, this is the first report giving a detailed description of a disease caused by P. cryptogea on petunia.

Embryo infection is important for efficient seed transmission of viroids. To identify the major pattern of seed transmission of viroids, we used in situ hybridization to histochemically analyze the distribution of Potato spindle tuber viroid (PSTVd) in each developmental stage of petunia (flowering to mature seed stages). In floral organs, PSTVd was present in the reproductive tissues of infected female × infected male and infected female × healthy male but not of healthy female × infected male before embryogenesis. After pollination, PSTVd was detected in the developed embryo and endosperm in all three crosses. These findings indicate that PSTVd is indirectly delivered to the embryo through ovule or pollen during the development of reproductive tissues before embryogenesis but not directly through maternal tissues as cell-to-cell movement during embryogenesis.

The floral perianth, comprising sepals and petals, conceals the sexual organs and attracts pollinators. The coordination of growth and scent emission is not fully understood. We have analyzed the effect of knocking down CHANEL (PhCHL), the ZEITLUPE ortholog in petunia (PhCHL) by hairpin RNAs. Plants with low PhCHL mRNA had overall decreased size. Growth evaluation using time lapse image analysis showed that early leaf movement was not affected by RNAi:PhCHL, but flower angle movement was modified, moving earlier during the day in knockdown plants than in wild types. Despite differences in stem length, growth rate was not significantly affected by loss of PhCHL. In contrast, petal growth displayed lower growth rate in RNAi:PhCHL. Decreased levels of PhCHL caused strongly modified scent profiles, including changes in composition and timing of emission resulting in volatile profiles highly divergent from the wild type. Our results show a role of PhCHL in controlling growth and development of vegetative and reproductive organs in petunia. The different effects of PhCHL on organ development indicate an organ-specific interpretation of the down regulation of PhCHL. Through the control of both timing and quantitative volatile emissions, PhCHL appears to be a major coordinator of scent profiles.

The decrease of fertility and improving public health are the main objectives to improve family welfare. The purpose of this study was to determine the fertility level of Kedampul Hamlet in Petung Sewu Village, Tumpang District, Malang Regency and to evaluate the success of family planning (KB) program of Couples of Reproductive Age (CRA) in that area. This research is a survey research with population of couples of reproductive ages in Kedampul Hamlet. The CRA sampling technique of the respondent is purposive, and interview as the main technique in data collection. The results showed that the fertility rate of CRA is higher in non-acceptor than the acceptor. The fertility of acceptor communities with non-acceptors are based on age of first marriage, span of reproduction period, wife's education, family income and infant mortality. There is a no significant difference in fertility based on the use of contraceptive. However, simultaneously the six independent variables have a significant relationship with fertility for acceptors and non-acceptors CRA. The largest contribution is given by the infant mortality variable and the smallest by the use of contraceptive.

Arrhenotokous and thelytokous populations of Thrips tabaci from tobacco or leek plants were evaluated for their ability to transmit Tomato spotted wilt virus (TSWV) and for their host preference. Transmission efficiencies were comparatively studied using leaf disks of Petunia hybrida, Datura stramonium, and Nicotiana tabacum cv. Basmas. Adults of arrhenotokous populations collected on infected tobacco plants in the field were efficient transmitters (up to 48.5% transmission) and remained so when maintained on tobacco for several generations. Arrhenotokous T. tabacipopulations from leek plants were poor transmitters (up to 3.1% transmission), whereas no transmission was obtained with thelytokous populations from leek. All populations could infest leek, however none of the arrhenotokous and thelytokous populations from leek plants was able to infest tobacco. TSWV could be acquired by both first and second larval instars of a T. tabacipopulation from tobacco. However, the transmission by adults decreased with the age at which the virus was acquired by larvae. The highest efficiencies (61% of males and 51% of females transmitted) were obtained when newborn (0- to 24-h old) larvae acquired the virus. The majority of thrips started to transmit after becoming adult and rates were positively correlated with the temperature at which the thrips were kept. The median latent period values found for adults decreased with increasing temperature. The median acquisition access period (AAP50) of the population was 41 min, whereas the AAP50 was 65 min for males and 35 min for females. The median inoculation access period of males was 246 and 365 min on tobacco and petunia, respectively, and 96 and 345 min for females. The results show that T. tabaci forms a complex in terms of host preference, reproductive strategy, and ability to transmit TSWV. The transmission parameters show that the thrips of arrhenotokous populations infesting tobacco are highly efficient vectors.

Antisense technology was successfully used to reduce flavonoid 3′-hydroxylase (F3′H) gene expression and enzyme activity and to promote the accumulation of monohydroxylated flavonols in petunia flower tissue. The hydroxylation pattern of specific flavonoid groups is a target for modification because of the possible associated changes in a range of factors including colour, stress tolerance and reproductive viability. Petunia (cv. Mitchell) plants were transformed to express in the antisense orientation the sequences encoding the F3′H (asF3′H). Transformants showed a range of responses, in terms of the level of endogenous F3′H gene expression and the relative proportion of the monohydroxylated flavonol (kaempferol) glycosides that accumulated. Kaempferol glycosides increased from 7% of the total flavonols in flower limb tissue of the wild type plants, to 45% in the flower limb tissue of line 114, the transgenic line that also showed the greatest decrease in F3′H expression in flower tissue. In leaf tissue, the trend was for a decrease in total flavonol concentration, with the relative proportion of kaempferol glycosides varying from ~40 to 80% of the total flavonols. The changes in leaf tissue were not consistent with the changes observed in flower tissue of the same lines. Endogenous F3′H activity in flower limb tissue was not completely shut down, although an 80% decrease in enzyme activity was recorded for line 114. The residual F3′H activity was still sufficient that quercetin glycosides remained as the major flavonol form. Alteration of F3′H activity appears to have affected overall flavonoid biosynthesis. A decrease in total flavonol concentration was observed in leaf tissue and two other flavonoid biosynthetic genes were down-regulated. No morphological changes were observed in the transgenic plants; however, up to a 60% decrease in pollen germination was observed in line 13. Thus, the relatively small change in flavonoid biosynthesis induced by the asF3′H transgene, correlated with several other effects beyond just the specific biosynthetic step regulated by this enzyme.

Vegetative annuals are increasing in popularity among greenhouse growers and consumers but little is known about their postharvest shelf life. Twenty-two cultivars from ten species of vegetative annuals were grown to marketability with optimum greenhouse culture. Plants were then subjected to one of three shipping durations (0, 1, or 2 days) in simulated shipping i.e., a growth chamber at 26.7 ± 0.3 °C, 0 μmol·m-2·s-1, and 50% relative humidity. The plants were then moved to simulated postharvest environment i.e., growth room at 21.1 ± 1.3 °C and 6 μmol·m-2·s-1 to evaluate shelf life. Flower number and plant quality rating were measured weekly in addition to observations of plant appearances. Some of the postharvest disorders noted on several species and cultivars were stem die back, leaf chlorosis, stem elongation, bud abortion, flower drop, and flower fading. The majority of the cultivars maintained their quality one-week postharvest although flower drop was common. After the first week of shelf life, decline in vegetative and reproductive tissues were noted in most plants. Cultivars from nine species: Argyranthemum frutescens (L.) Sch. Bip, Bracteantha bracteata (Vent.) Anderb. & Haegi, Calibrachoa hybrid Lave Lex, Diascia ×hybrida, Lantana camara L., Nemesia ×hybrida, Petunia ×hybrida, Sutera hybrida, and Sutera cordata showed decreased flower number and/or quality rating due to shipping duration, with increased shipping duration causing accelerated postharvest disorders. The only species unaffected by shipping duration was Angelonia angustifolia Benth.

SARS-CoV-2 rapidly spread worldwide and resulted in an unprecedented pandemic. Considering the novelty of this disease, its potential effects on the endocrine system remain elusive. This virus is known to utilize the extracellular domain of angiotensin-converting enzyme (ACE) and transmembrane protein TMPRSS2. Broad expression of ACE-2 and TMPRSS2 is a potential cause of extrapulmonary manifestations of SARSCoV- 2, including endocrine ones. The most common presentations are direct or indirect damage of the endocrine part of the pancreas, hypothalamicpituitary- adrenal and hypothalamic-pituitary-thyroid axes, and possible long-term effects on the reproductive system. It was demonstrated that obesity and diabetes increase the risk of severe course and death in COVID-19. Similarly, patients with transitory hyperglycemia have a higher risk of severe disease course. Primary and secondary adrenal insufficiency of various origins potentially accounts for severity. The most common thyroid complications of the COVID-19 infection are euthyroid sick syndrome and transient destructive thyroiditis, including subacute thyroiditis. KEYWORDS: SARS-CoV-2, COVID-19, endocrinopathies, diabetes, adrenal insufficiency. FOR CITATION: Petunina N.A., Shkoda A.S., Telnova M.E. et al. Effects of SARS-CoV-2 on the endocrine system. Russian Medical Inquiry. 2021;5(9):575–578 (in Russ.). DOI: 10.32364/2587-6821-2021-5-9-575-578.

<p><strong>Detección de partículas baciliformes asociadas con enfermedad de origen viral en piña (Ananas comosus L.).</strong></p><p>María Clemencia F. de La-Rotta, Helena Riechel , Thamara Gutiérrez Serrano, Jaime Morales .</p><p>En los municipios de Lebrrja y Cirón (Santader), el cultivo de piña "Perolera" constituye el principal renglón productivo de los agricultor que la cultivan en una extensión de 6000 ha. aproximadamente. Desde hace tres años se viene presentado en la región síntomas de una enfermedad ampliamente diseminada, sobre plantas aisladas o en focos de diferente tamaño. Los daños se presentan en los diferentes estados de desarrollo del cultivo, desde colinos que inician su proceso de enraizamiento, hasta plantas en producción. Inicialmente las hojas internas cambian su color verde, por tonalidades amarillas que dan a la hoja un aspecto anaranjado y finalmente se produce el debilitamiento y muerte de las plantas. En este trabajo se presentan algunos de los avances sobre los estudios que se adelantan para determinar la etiología de la enfermedad; por su posible relación con eI BSV (Banana Streak Virus), se realizó la prueba de ELISA y se obtuvieron reacciones positivas con tejidos de la corona y sistema de raíces de planta enfermas. Por observaciones al microscopio electrónico con el virus semipurificado y mediante las técnicas de ISEM y "Leaf dip", se encontraron partículas baciliformes de aproximadamente 27 mm de ancho por 150 mm de largo. Estos resultados concuerdan con los obtenidos por varios investigadores de Hawai y Australia para la enfermedad denominada "Mealbug wilt pineapple virus", asociada también con un closterovirus y transmitida por una cochinilla harinosa.</p><p><strong>Distribución, incidencia y severidad de las principales enfermedades de cebolla de rama (Allium fistulosum l.) en la cuenca del Lago de Tota (Boyacá)'.</strong></p><p>Armando Angarita , María Clemencia F. de La-Rotta<strong>.</strong></p><p>La cebolla de rama es el principal renglón agrícola de la cuenca del lago de Tota, con un área estimada de 3.500 ha. Dado el sistema de cultivo intensivo, las enfermedades se han constituido en el principal limitante en la producción. La región se estratificó según la topografía y caracterización de suelos ; se dividió en seis zonas y en cada una de ellas se llevó registro diario de precipitación, humedad relativa y temperatura. En dos parcelas ubicadas en cada una de las zonas, se evaluó semanalmente y durante un ciclo del cultivo, la incidencia y severidad de las enfermedades foliares mas limitantes: Secamiento causado por Cladosporium allii y mildeo velloso por Peronospora destructor. Los resultados obtenidos indican que las precipitaciones y alta humedad relativa inducen el desarrollo de epidemias del secamiento y amarillamiento y que la temperatura no posee ningún grado de asociación con la incidencia de la enfermedad. El mildeo velloso se presenta en los cultivos ubicado hacia -las zonas donde la humedad relativa es la mas baja para la región. En el sistema radical las poblaciones de los nematodos Ditylenchus dipsaci, Protylenchus sp, Aphelenchoides sp y Tylenchu sp, son muy altas; su incidencia está relacionada con el contenido de materia orgánica en el suelo.</p><p><strong><br /></strong></p><p><strong>Enfermedades de origen viral en cultivos de ajo (Allium Sativum l.) de la Sabana de Bogotá.</strong></p><p>Mercedes Losada, María Clemencia F. de La-Rotta.</p><p>El estudio se realizó para contribuir al conocimiento de las enfermedades de origen viral que afectan el cultivo de ajo. Frecuentemente se encuentran plantas con mosaicos, rayas o pecas cloróticas y necróticas en las hojas y en algunos casos enanismo. Sobre esta especie existen registros de enfermedades de origen viral en la mayoría de los países productores como los que pertenecen al grupo de los Potyvirus (OYDV, LYSV y CYSV) y Carlavirus (SLV), pero en Colombia, se desconoce cuales de ellos se encuentran establecidos. Este trabajo tuvo como objetivo identificar los virus que afectan el cultivo de ajo.</p><p>Con material vegetal enfermo recolectado en diferentes zonas productoras de la Sabana, se realizaron pruebas de transmisión mecánica sobre las indicadoras Allium cepa, A. puerrum, A. fistulosun, Chenopodium amaranticolor, C. quinoa, C. murali, Nicotiana occidentalis, N. glutínosa, N. tabacum var. White Burley, Petunia sp, Vicia faba y Datura stramonnium. Se adelantaron pruebas de ELISA e ISEM, con antisueros para Potyvirus y Carlavirus, Leaf dip y observaciones de inclusiones citoplasmáticas por microscopía electrónica. Sobre las plantas inoculadas de C. amaranticolor, C. quinoa, C. murali y Petunia sp se presentaron a los 6 evaluaron semanalmente las siguientes variable incidencia y severidad de la enfermedad y su efecto en la producción de grano seco, y los daños directos sobre la semilla (porcentaje de transmisión, número de semillas por vaina, peso de granos por planta y peso de 100 semillas). Los datos obtenidos se sometieron a un análisis de varianza y prueba de Tukey. Los resultados indican que en Calostra, el período vegetativo fue de 17 semanas y en las otras variedades, dos semanas más. Entre ellas el número se hojas varió de25 a 27 /planta/ variedad, siendo todos los materiales susceptible al ataque de Ascochyta spp. La producción de arveja en grano para Guatecana se afectó en 42.7 %, en Calostra 26.3 %, en ICA-Tominé 37,1% Y L 3661 MB, 36.1%. En el tratamiento sin aplicación de fungicidas, el porcentaje de transmisión por semilla fue de 18.2% en la variedad Guatecana, 11.7% en Calostra, 5.2% en ICA-Tominé y 4.2% en L3661 MB y en menor cantidad cuando se controló la enfermedad con fungicidas. Algunas de las variables de producción, como número de semillas por vaina peso de semillas por planta y peso de 100 semilla mostraron diferencias altamente significativas entre los tratamientos con y sin fungicida.</p><p><strong><br /></strong></p><p><strong>Análisis comparativo de escalas de severidad de la enfermedad rhizoctoniasis en el cultivo del arroz (oriza sativa L.)¹.</strong></p><p>Juan Carlos Gutiérrez, Andrés M. Meneses, José Roberto Jurado N.</p><p>El añublo de la vaina, causada por el hongo Rhizoctonia solani, es una de las principales enfermedades del cultivo del arroz. Para evaluar la severidad de esta enfermedad, se desarrolló una nueva escala denominada Colombiana, la cual se comparó con la escala lRRl. El estudio se realizó en el municipio de Saldaña durante los meses de abril y octubre de 1995. En un lote comercial de 12 hectáreas, se delimitó una hectárea y en ella se evaluó semanalmente la severidad, en 20 unidades experimentales. La escala Colombiana compromete l0 grados y para mayor especificidad y confiabilidad se aplica sobre cada uno de los tres tercios de Ia planta. Los datos obtenidos en campo se procesaron estadísticamente mediante análisis de varianza y regresión lineal Se encontraron diferencias altamente significativas en las lecturas de severidad obtenidas por las dos escalas. Se definió el siguiente modelo matemático Y=3,1636+0.6968X donde Y es el porcentaje de severidad esperado mediante la escala Colombiana y X es el porcentaje de severidad determinado por la escala lRRl. Con este modelo se ajusta la evaluación de la enfermedad a las condiciones de cultivo a través del tiempo.</p><p><strong><br /></strong></p><p><strong>Estudios básicos para el mane¡o de poblaciones de la chinche de los pastos Collaria scenica Sta. (Hemiptera: Miridae) en la Sabana de Bogotá.</strong></p><p>Nancy Barreto T, Edgar Martínez C, Darío Corredor.</p><p>Debido al daño que ocasiona la chinche de los pastos en las diferentes gramÍneas se afecta la calidad de las mismas, disminuyendo la productividad de la fincas lecheras. Con el incremento de sus poblaciones, los ganaderos se han visto en la obligación de recurrir a la utilización de insecticidas para el control de la plaga, sin tener en cuenta los riesgos que se corren por la aplicación de productos que aún no tienen estudios para dicho agroecosistema, presentándose casos de residuos en pasto y toxicidad al ganado. Con el fin de desarrollar estrategias sostenibles para el manejo de la plaga, se diseñó esta investigación para conocer el comportamiento de la plaga en condiciones comerciales y cuantificar el daño. El estudio se llevó a cabo en una finca de Tocancipá (Cund), durante un año a partir del segundo semestre de 1995. Para registrar la fluctuación poblacional, se realizaron muestreos en dos potreros. En cada uno, se tomaron 39 muestras al azar por hectárea cada ocho días. Se propuso una escala para evaluar el daño en pasto kikuyo, se analizó la calidad y producción del forraje afectado y se estableció el nivel de daño económico.</p><p>De acuerdo a la fluctuación de la plaga, se determinó que sus máximas poblaciones se presentan entre los 35-45 días después del pastoreo. Se estableció una escala de daño que incluye cuatro niveles. La producción de forraje en materia seca se reduce en 19.2%, 21.4% y 24.5%, respectivamente para los niveles 1,2 y3. Se encontró que la digestibilidad del pasto con el máximo daño se reduce a un 10% respecto al pasto sano, tanto en praderas fertilizadas como sin fertilizar. Hay reducción en productividad para cada nivel de daño en 19.4%, 26.7% y 34.4%, respectivamente.</p><p><strong><br /></strong></p><p><strong>Patrón de disposición espacial de la chinche de los pastos Collaria columbiensis (Hemiptera : Miridae) en la Sabana de Bogotá.</strong></p><p>Nancy Barreto T, Edgar Martínez C, Ricardo Galindo P, Darío Corredor.</p><p>La chinche de los pastos es una plaga que ataca con severidad las praderas dedicadas a la explotación lechera en algunas zonas de los departamentos de Cundinamarca y Antioquia. El daño lo causan las ninfas y adultos del insecto, provocando amarillamiento prematuro, debilitamiento, secamiento y muerte de las plantas. El pasto kikuyo es el más atacado, sin embargo, se reportan daños en otros pastos de clima frío.</p><p>Para el manejo de poblaciones de la plaga no existen métodos específicos. También se desconocen aspectos inherentes a su dinámica poblacional. De ahí, que los objetivos de esta investigación fueron establecer el patrón de disposición espacial y el tamaño de muestra.</p><p>El trabajo se inició en septiembre de 1994, en una finca lechera del municipio de Tenjo, Cundinamarca. Durante cinco meses consecutivos, cada ocho (8) días, se tomaron al azar 30 muestras/ha, en cada uno de dos potreros diferentes. Cada muestra la conformaron los individuos, adultos e inmaduros, colectados en 10 pases dobles de jama. Estos se colocaron en frascos plásticos para su posterior conteo en laboratorio.</p><p>Las observaciones obtenidas en veintidós muestreos (22), se analizaron estadísticamente y se encontró que el patrón de disposición espacial es agregado o contagioso y que 34 fue el número óptimo de muestras por hectárea.</p><p><strong><br /></strong></p><p><strong>Análisis de consumo diario de la especie Rhammatocerus schistocercoides en su estado adulto (orthoptera, acrididae, gomphocerinae).</strong></p><p>Juan Carlos Gutiérrez, Hugo Jiménez S.</p><p>Durante 1994 y 1995 se reportó en la región de los Llanos Orientales un fenómeno de invasión de la especie Rhammatocerus schistocercoides , insecto polífago que ataca a gran variedad de especies vegetales muy relacionadas, gramíneas y algunas cyperaceas. Este suceso migratorio amenazó cultivos de importancia económica como praderas, arroz, maíz y caña de azúcar. Cuantificar su consumo diario y observar su comportamiento individual y grupal, permite conocer en forma objetiva su impacto sobre éstas especies. El ensayo se realizó entre los meses de enero y abril de 1997 en las instalaciones del C.l. La Libertad, bajo condiciones de casa malla, temperatura promedio 26^0C y HR 70%. Se evaluaron diferentes sustratos alimenticios. Se desarrollaron observaciones diarias y se cuantificó el área de consumo mediante la utilización de un medidor de área foliar modelo Ll-3000 a LI-COR. Para el aislamiento de individuos por sexo y grupos se utilizaron jaulas de acetatos cuyo diámetro fue de 75 cm y 30 cm de altura, ésta fueron insertadas en suelo. Se evaluaron diez repeticiones para cada tratamiento: individuo macho, individuo hembra y grupo de tres parejas. Entre los sustratos evaluados el insecto mostró preferencia por caña de azúcar EI análisis esta dístico estableció que el consumo promedio por hembra diario fue de 0.586 g (22,78 cm²) y para machos fue de 0.3478 g (14,54 cm²). Se desarrollaron dos ecuaciones de regresión lineal sobre consumo acumulado diario por sexo. Y=0.1203 +0.5851 X para hembras y Y= -0.032 + 0.4182 X para machos; donde Y= consumo alcanzado por el insecto y, X= días de consumo. Su consumo grupal diario fue mayor en un l0l0 respecto al individual. Lo anterior permite predecir la magnitud del daño que puede causar una invasión de esta población insectil en áreas de explotación agropecuarias.</p><p><strong><br /></strong></p><p><strong>Aspectos biológicos de la chinche de los pastos Collaria columbiensis. Carvalho.</strong></p><p>Juan Carlos Gutiérrez, Nancy Barreto Triana.</p><p>La chinche es un hemíptero perteneciente a la familia Miridae, que cobró gran importancia en los últimos años en diferentes zonas del país. Debido al incremento de su población y distribución. Llegando al punto de convertirse en la principal plaga para la Sabana de Bogotá. De ahí la importancia del conocimiento de su biología, con miras a la implementación en técnicas adecuadas de manejo. EI objetivo principal del estudio fue el conocimiento de sus diferentes aspectos básicos de su biología partiendo del desarrollo de una metodología que permitiera la supervivencia y seguimiento de los diferentes estados. La investigación se inició en noviembre de 1995 en el C.l. Tibaitatá, bajo condiciones de laboratorio, temperatura promedio 18^0C y HR 70%. Se evaluaron diferentes técnicas para la cría del insecto, encontrando que las caja petri modificadas ofrecieron las mejores condiciones para el desarrollo y seguimiento del ciclo. Se cuantificó la duración de los diferentes estados: La incubación dura en promedio 12 días, su fase inmadura posee una duración promedio de 24 días divididos en cinco instares ninfales y su fase adulta promedia los 28 días. Todo su ciclo biológico alcanza 64 días aproximadamente. Las evaluación mostraron que posee capacidad reproductiva durante toda su fase adulta, sin embargo, las hembras presentan incapacidad de ovipación sin un aparente estimulo del macho. El porcentaje de fertilidad de sus posturas estuvo por encima de 80%.lntegrando los resultados desarrollados en el estudio, se define la dificultad en el manejo de la plaga, al considerar sus excelentes mecanismo biológicos de adaptabilidad y supervivencia.</p><p><strong><br /></strong></p><p><strong>Estudio sobre el incremento natural de Rhammatocerus schistocercoides (Orthoptea, Acrididae, Gomphocerinae).</strong></p><p>Juan Carlos Gutiérrez R.</p><p>La aparición de nuevos individuos de Rhammatocerus schistocercoides<strong> </strong>dependen<strong> </strong>de un proceso reproductivo discontinuo en el tiempo y no por migración. Conocer los aspectos básicos sobre reproducción y la influencia de factores abióticos sobre este fenómeno permiten entender en gran parte sus fluctuaciones poblacionales. El ensayos se realizó durante los meses de septiembre de 1996 hasta abril de 1997 en las instalaciones del C.l. La Libertad y C. L Carimagua bajo condiciones de cautiverio en casa malla, con temperaturas de 26^0C y H.R. del 80%; contrastando con evaluaciones continuas de poblaciones de campo. Los insectos fueron discriminados por sexo utilizan jaulas de piso (dimensiones: 1m X 0,70m X 0.50m.), aislados por grupos de una a cinco parejas. Las lecturas sobre madurez sexual de los insectos se hicieron mediante disección abdominal.</p><p>Los resultados obtenidos en el estudio muestran que la especie R. schistocercoides<strong> </strong>presenta un período de inmadurez sexual de 150 a 160 días medido en forma porcentual de acuerdo a su polimorfismo cromático, asociado con la maduración sexual. Hacia la semana 20, el 900/0 de la población presentó decoloración en la parte frontal y latera del tórax. Dos semanas después la totalidad de la población presentó coloración verde intensa. Presenta un período productivo de 35 días. Los resultados muestran un promedio de 185 días de vida. El número de posturas por hembra fue de 1, con un promedio de 32 huevos por postura, los cuales presentaron un porcentaje de eclosión del 93%. La relación de sexos encontrada fue 1:1. La profundidad de postura estuvo entre 5 y 7 cm. Se observó que las hembras presentaron incapacidad para ovipositar normalmente en suelos con alta humedad, contrario a lo sucedido en suelos de humedad moderada y textura arenosa. Según estos resultados, R. schistocercoides<strong> </strong>necesita un biotipo de condiciones muy específicas para el desarrollo se su proceso reproductivo.</p><p><strong><br /></strong></p><p><strong>Estudios preliminares sobre la gota de la papa. con relación a precipitación, nubosidad e incidencia y severidad para la región del Sumapáz.¹</strong></p><p>Consuelo Bobadilla, Jhon Wilmar Mejía, José Roberto Jurado N.</p><p>Con el fin de conocer los factores meteorológicos que favorecen el desarrollo de la enfermedad "gota de la papa" Phytophthora infestans y lograr predecir por días de nubosidad y precipitación, se realizó en la provincia del Sumapaz un estudio en fincas de agricultores ubicadas en las veredas de Costa Rica y Lázaro Fonte. Se escogieron dos lotes de 1 ha. cada uno y se evaluaron cada ocho días cien plantas por lote. Se tomaron dato de incidencia y severidad, lo mismo los datos de precipitación y nubosidad. En los lotes del agricultor se hicieron aplicaciones de fungicidas cada 8 días y en los lotes propuestos cada vez que se presentaban días nubosos o cuando se acumulaban 10 milímetros de precipitación. Los resultados obtenidos mostraron que en la finca de la vereda Costa Rica el número de aplicaciones de fungicidas se redujo, el agricultor realizó l2 aplicaciones y en el lote objeto de estudio solamente llegaron a 9. La incidencia y severidad fue menor en el lote manejado con base en las condiciones climáticas; la producción fue de 18 toneladas para ambos lotes pero la calidad del tubérculo y uniformidad fue mejor para el lote del ensayo. En la finca ubicada en Lázaro Fonte se obtuvo una mayor incidencia y severidad en el lote del agricultor, en el lote de estudio hubo reducción en dos aplicaciones ; y por el cambio en las condiciones del clima se presentó la enfermedad foliar ocasionada por Alternaria sp, patógeno que afectó el último periodo vegetativo de la papa. La producción fue de 15 toneladas para el lote con el manejo propuesto.</p><p><strong><br /></strong></p><p><strong>Resultados preliminares sobre la incidencia y severidad de la gota de la papa con relación a la climatología y épocas de siembra en el C.l. Tibaitatá.</strong></p><p>José Roberto Jurado N, Ricardo Galindo P.</p><p>La gota o tizón tardío es la enfermedad más importante de la papa en el mundo. En Colombia, el campesino sigue un plan tradicional para el manejo de la enfermedad, que consiste en hacer aspersiones de fungicidas cada 5 a 7 días, después de la emergencia del cultivo. El promedio en número de aspersiones está en 14, pero se ha podido determinar que puede haber reducción de ellas, si se correlaciona la climatología con la incidencia y severidad de la enfermedad. Por tal razón se desarrolló este trabajo en el centro de Investigaciones Tibaitatá. Mosquera, Cundinamarca. Se utilizó un diseño experimental de parcelas divididas, para cuatro tratamientos, tres repeticiones y tres épocas de siembra diferentes. Sin control desde la siembra, para el tratamiento 1;sin control desde los dos meses d.d.s. para el tratamiento 2; sin control desde los tres meses d.d.s. para el tratamiento 3; sin control desde los cuatro meses d.d.s, para el tratamiento 4. En Parcelas de 10 x 10 m cada una para un total de 250 plantas, se evaluaron cada ocho días 25 plantas por parcela y con aplicaciones cada ocho días según el tratamiento. Los resultados indican que los tratamientos 1 en todas las épocas de siembra presentaron los niveles más altos tanto en incidencia como en severidad, de igual manera la producción total disminuyó. La menor incidencia y severidad se encontró en la segunda época de siembra. La mayor incidencia fue para la tercera época. La mayor producción fue para el tratamiento 4 en la primera época de siembra. La mayor producción para clase de primera fue para el tratamiento 3 de Ia época 3. La temperatura y humedad relativa nocturnas favorecieron más que las diurnas en la incidencia y severidad de la gota. Se determina que las épocas de siembra influyen en la incidencia y severidad de la gota de papa como en su producción y calidad.</p><p><strong>Determinación de pérdidas originadas por Rhizoctonia solani Kuhn. en el cultivo del arroz Oryza sativa L. en la Meseta de lbagué.¹</strong></p><p>Hugo A. Herrera , Olga Quijano, José Roberto Jurado N.</p><p>EI cultivo de arroz en Colombia es importante desde el punto de vista de la producción y el consumo, constituyendo uno de los productos agrícolas fundamentales dentro de la economía del país. Los perfiles de pérdidas indican la contribución relativa de cada desorden o factor depresivo en la pérdida total del cultivo y permite la planeación de los sistemas de producción integrada de cultivos. El trabajo se llevó a cabo en el municipio de lbagué, durante el semestre B/96; se escogieron dos lotes, cada uno de 1 ha, en los cuales se sembró arroz de la variedad Oryzica 1 ; se manejó según las recomendaciones del asistente técnico de la finca; en uno de los lotes se realizó control de Rhizoctonia solani y en el otro no. Se llevó registro de incidencia y severidad de la enfermedad, a favés del ciclo del cultivo y se registraron los datos de rendimiento de cada uno de ellos. Se realizó la prueba de “t” de student para analizar el comportamiento de los dos sistemas de evaluación (con control y sin control de la enfermedad). Se complementó el estudio con regresiones múltiples de tipo lineal, para la predicción de las pérdidas originadas Dor Rizoctoniasis en arroz. Los resultados muestran que Rhizoctonia solani presenta un comportamiento siempre creciente y amerita control, en la época de los 90 días después de sembrado. De las regresiones múltiples se obtuvieron ecuaciones para la predicción del rendimiento de arroz, según la incidencia y la severidad de Rhizoctoniasis sp; con control: Y= 872.450-2.008X1-2.701X2. sin control : Y =860.524-2.049X1 -3.680X2. Donde: Y, rendimiento esperado de arroz en gramos/ m2 ; X1, porcentaje de incidencia de Rizoctoniasis; X2, porcentaje de severidad de Rizoctoniasis. AI final del periodo vegetativo se observó una incidencia de29.2% y 49.3% para los tratamientos con y sin control, respectivamente, y una severidad de 33.88% y 54.59% para los mencionados tratamientos, obteniendo una diferencia en rendimiento de 0.5 ton/ha, que representan pérdidas por $353.220.00/ha.</p><p><strong><br /></strong></p><p><strong>Determinación de la relación entre el rendimiento de arroz Oryza sativa L. y el grado de severidad de Rhizoctonia solani Kuhn.¹</strong></p><p>Olga Quijano, Guillermo Medina, José Roberto Jurado N.</p><p>La importancia económica que ha tomado Rhizoctonia soloni en el cultivo de arroz en Colombia es de consideración y más si se tiene en cuenta que el problema va en aumento, debido a las variedades de alto rendimiento que incrementan el follaje favorable al patógeno. Además éste con su producción de esclerocios o estructuras de gran resistencia y de largo período de viabilidad constituye una fuente de inóculo que se convierte en un serio problema para las zonas arroceras. Con el fin de determinar la relación existente entre el grado de severidad de Rhizoctonia solani y el rendimiento de arroz, se llevó a cabo un estudio en la meseta de lbagué, ubicada a 720 m.s.n.m. con una temperatura de 28 ⁰Cy una precipitación promedio de 1200 mm anuales.</p><p>Se escogieron para tal efecto dos lotes, con y sin control, cada uno de 1 has; se llevó registro de incidencia y severidad de la enfermedad, a través del ciclo del cultivo, y se registraron los datos de rendimiento de cada uno de ellos. Se recolectaron 100 espigas para cada grado de severidad, se tomaron 1000 granos, se pesaron y se determinaron los llenos, vanos y enfermos. Para el lote 1 con control se presentó una correlación altamente significativa entre el grado de severidad y las variables granos llenos y granos vanos. La correlación entre granos llenos y el grado de severidad es negativa, lo que nos indica que a mayor grado de severidad menos peso de granos llenos; para granos vanos, la relación es directa, a mayor grado de severidad mayor vaneamiento. Para el lote 2 sin control, se presentó correlación altamente significativa solamente entre el grado de severidad y granos vanos, la cual es directa. Los resultados indican que Rhizoctonia solani afecta el rendimiento de las plantas por el vaneamiento de la semilla; existe un considerable grado de correlación entre estas variables y el grado de severidad de la enfermedad. La variable granos enfermos no está influenciada directamente por la severidad de la enfermedad, pues no presentó un grado de correlación importante.</p><p><strong><br /></strong></p><p><strong>Estudios de dinámica poblacional del estado ninfal de Rhammatoceru schistocercoides. (Rehn, 1906) (Orthoptera: Acrididade) en la Altillanura Colombiana.</strong></p><p>Alba Janeth Flórez Garzón, Juan Carlos Gutiérrez Ramírez.</p><p>Las características específicas del estado ninfa de acrididos permiten generar bases técnicas de manejo integrado. El estudio enfatiza en: 1. Capacidad de desplazamiento. 2. Incidencia de enemigos naturales sobre la fluctuación poblacional; 3. Disposición y distribución de especies de sabana nativa El trabajo se realizó en tres fincas del municipio de Puerto Caitán; se tomó como sede de apoyo el Centro Experimental Carimagua. Esta región presenta temperatura de 26⁰C y precipitación de 2300 mm anuales con tendencia monomodal. Para su ejecución se geoposicionaron cinco focos marcados con banderines y separados por distancias mayores de un kilómetro, durante la fase el desarrollo ninfal de mayo a septiembre de 1997, abarcando toda la fase inmadura del insecto.</p><p>Se observó relación directa entre el área de foco y su desplazamiento. Los instares de mayor recorrido fueron el quinto y sexto, siendo los de mayor duración. Su periodo ninfal osciló entre 140 y 150 días, presentando un recorrido de 5 a 7 kilómetros. El desplazamiento promedio diario fue de 60 m, siendo su mínimo 30 m y máximo 270 m, sin encontrar correlación del movimiento con la dirección del viento. Se presentó alta incidencia de enemigos naturales causando disminución del área de foco, hasta en un 85% en especial por aves, mostrando los instares 7 y 8 la mayor susceptibilidad.</p>

Marie Monniaux is a permanent CNRS researcher in the ‘Evo-devo of the flower’ group at the Laboratory for Plant Reproduction and Development (RDP) at the École normale supérieure (ENS) in Lyon, France. Marie uses Petunia to understand the development and evolution of the flower petal. We met Marie over Teams for a virtual chat about her career path, finding a permanent position and her ideas for the future.

Abstract Background The ALOG (Arabidopsis LSH1 and Oryza G1) family of proteins, namely DUF640 (domain of unknown function 640) domain proteins, were found in land plants. Functional characterization of a few ALOG members in model plants such as Arabidopsis and rice suggested they play important regulatory roles in plant development. The information about its evolution, however, is largely limited, and there was no any report on the ALOG genes in Petunia, an important ornamental species. Results The ALOG genes were identified in four species of Petunia including P. axillaris, P. inflata, P. integrifolia, and P. exserta based on the genome and/or transcriptome databases, which were further confirmed by cloning from P. hybrida ‘W115’ (Mitchel diploid), a popular laboratorial petunia line susceptible to genetic transformation. Phylogenetic analysis indicated that Petunia ALOG genes (named as LSHs according to their closest Arabidopsis homologs) were grouped into four clades, which can be further divided into eight groups, and similar exon-intron structure and motifs are reflected in the same group. The PhLSH genes of hybrid petunia ‘W115’ were mainly derived from P. axillaris. The qPCR analysis revealed distinct spatial expression patterns among them suggesting potentially functional diversification. Moreover, over-expressing PhLSH7a and PhLSH7b in Arabidopsis uncovered their functions in the development of both vegetative and reproductive organs. Conclusions Petunia genome includes 11 ALOG genes that can be divided into eight distinct groups, and they also show different expression patterns. Among these genes, PhLSH7b and PhLSH7a play significant roles in plant growth and development, especially in fruit development. Our results provide new insight into the evolution of ALOG gene family and have laid a good foundation for the study of petunia LSH gene in the future.

Abstract In Petunia (Solanaceae family), self-incompatibility (SI) is regulated by the polymorphic S-locus, which contains the pistil-specific S-RNase and multiple pollen-specific S-Locus F-box (SLF) genes. SLFs assemble into E3 ubiquitin ligase complexes known as Skp1–Cullin1–F-box complexes (SCFSLF). In pollen tubes, these complexes collectively mediate ubiquitination and degradation of all nonself S-RNases, but not self S-RNase, resulting in cross-compatible, but self-incompatible, pollination. Using Petunia inflata, we show that two pollen-expressed Cullin1 (CUL1) proteins, PiCUL1-P and PiCUL1-B, function redundantly in SI. This redundancy is lost in Petunia hybrida, not because of the inability of PhCUL1-B to interact with SSK1, but due to a reduction in the PhCUL1-B transcript level. This is possibly caused by the presence of a DNA transposon in the PhCUL1-B promoter region, which was inherited from Petunia axillaris, one of the parental species of P. hybrida. Phylogenetic and syntenic analyses of Cullin genes in various eudicots show that three Solanaceae-specific CUL1 genes share a common origin, with CUL1-P dedicated to S-RNase-related reproductive processes. However, CUL1-B is a dispersed duplicate of CUL1-P present only in Petunia, and not in the other species of the Solanaceae family examined. We suggest that the CUL1s involved (or potentially involved) in the SI response in eudicots share a common origin.

Abstract Hybridization between closely related plant species is a widespread phenomenon with significant evolutionary consequences, so natural hybrid zones provide exciting opportunities to study the processes of genetic differentiation and species formation. In Petunia, genetics, ecology and evolution of pollination syndromes have been thoroughly studied and related to the development of prezygotic isolation barriers between species. However, to date, no studies have explored the importance of extrinsic post-zygotic barriers such as environmental selection as drivers of reproductive isolation. In this study, we applied a population genetics approach to understand the speciation of two partially sympatric taxa of Petunia Juss that hybridize in the wild despite having strong differences in pollination syndrome, mating system and environmental requirements. We evaluated 58 individuals from seven allopatric and two contact zones of Petunia axillaris and P. exserta with genomic data to study the population genetic structure and gene exchange between these species and scan for potential loci under natural selection related to the preservation of species barriers. We explicitly evaluated the time, intensity and direction of interspecific migration, testing for alternative demographic scenarios. The genetic structure showed well-differentiated species-level lineages, and poor differentiation among populations of P. axillaris; P. exserta populations were highly structured, with several well-differentiated intraspecific lineages. Our data provide evidence for admixture with low asymmetric gene flow from P. axillaris to P. exserta associated with recent secondary contact, suggesting that pollinator specificity is not the only trait responsible for species integrity in this system. Combining the results from FST outlier and genotype–phenotype association methods, we identified 54 non-synonymous candidate variants under natural selection. Those variants are found in 35 coding sequences from which we found genes related to light-response networks, supporting that extrinsic factors such as habitat preferences can also provide a mechanism of reproductive isolation between Petunia spp. We argue that a set of pre- and post-zygotic barriers in conjunction with demographic processes maintain the species integrity.