Добірка наукової літератури з теми "Plant terrestrialization"

Abstract It is generally accepted that land plants evolved from streptophyte algae. However, there are also many chlorophytes (a sister group of streptophyte algae and land plants) that moved to terrestrial habitats and even resemble mosses. This raises the question of why no land plants evolved from chlorophytes. In order to better understand what enabled streptophyte algae to conquer the land, it is necessary to study the chlorophytes as well. This review will introduce the freshwater filamentous chlorophyte alga Draparnaldia sp. (Chaetophorales, Chlorophyceae) as a model for comparative analyses between these two lineages. It will also focus on current knowledge about the evolution of morphological complexity in chlorophytes versus streptophytes and their respective morphological/behavioural adaptations to semi-terrestrial habitats, and will show why Draparnaldia is needed as a new model system.

Symbiosis with arbuscular mycorrhizal fungi (AMF) improves plant nutrition in most land plants, and its contribution to the colonization of land by plants has been hypothesized. Here, we identify a conserved transcriptomic response to AMF among land plants, including the activation of lipid metabolism. Using gain of function, we show the transfer of lipids from the liverwort Marchantia paleacea to AMF and its direct regulation by the transcription factor WRINKLED (WRI). Arbuscules, the nutrient-exchange structures, were not formed in loss-of-function wri mutants in M. paleacea, leading to aborted mutualism. Our results show the orthology of the symbiotic transfer of lipids across land plants and demonstrate that mutualism with arbuscular mycorrhizal fungi was present in the most recent ancestor of land plants 450 million years ago.

Plants evolved an impressive arsenal of multifunctional specialized metabolites to cope with the novel environmental pressures imposed by the terrestrial habitat when moving from water. Here we examine the multifarious roles of flavonoids in plant terrestrialization. We reason on the environmental drivers, other than the increase in UV-B radiation, that were mostly responsible for the rise of flavonoid metabolism and how flavonoids helped plants in land conquest. We are reasonably based on a nutrient-deficiency hypothesis for the replacement of mycosporine-like amino acids, typical of streptophytic algae, with the flavonoid metabolism during the water-to-land transition. We suggest that flavonoids modulated auxin transport and signaling and promoted the symbiosis between plants and fungi (e.g., arbuscular mycorrhizal, AM), a central event for the conquest of land by plants. AM improved the ability of early plants to take up nutrients and water from highly impoverished soils. We offer evidence that flavonoids equipped early land plants with highly versatile “defense compounds”, essential for the new set of abiotic and biotic stressors imposed by the terrestrial environment. We conclude that flavonoids have been multifunctional since the appearance of plants on land, not only acting as UV filters but especially improving both nutrient acquisition and biotic stress defense.

La colonisation réussie et durable des terres par les plantes a nécessité l'apparition de certains traits afin de survivre aux nouvelles contraintes telles que l'accès limité aux nutriments et à l'eau, la gravité, l'environnement oxydatif et les radiations UV. Chez les plantes terrestres existantes, les polymères hydrophobes déposés à la surface de différents tissus, tels que la sporopollénine, la cuticule, la subérine et la lignine, sont connus pour contribuer à la limitation de la perte d'eau et à la résistance à d'autres stress abiotiques, ce qui en fait des "innovations de terrestrialisation" potentielles. Comment et quand ces traits ont évolué chez les plantes restent insaisissables. Les données fossiles et l'analyse phylogénétique des gènes impliqués dans la biosynthèse de ces polymères chez les plantes ont proposé la cutine, la partie hydrophobe et polymérisée de la cuticule, comme le meilleur candidat pour la terrestrialisation des plantes. Cette thèse décrit des recherches menées pour déterminer la distribution de la cutine dans les plantes, l'évolution des gènes nécessaires à sa biosynthèse et la fonction de deux d'entre eux chez la Bryophyte modèle, Marchantia polymorpha. La présence de la cutine dans les espèces de Zygnematophyceae, qui sont les algues les plus proches des plantes terrestres, et dans diverses plantes terrestres a été surveillée par des observations microscopiques et des analyses biochimiques. La cutine n'a été détectée que dans les plantes terrestres, de même qu'une enzyme terminale de la biosynthèse des monomères de cutine, les glycérol-phosphates acyle transférases (GPATs). Pour confirmer l'origine de la cutine chez les Embryophytes, nous avons étudié les GPATs chez M. polymorpha. Tout d'abord, le pattern d'expression des GPATs de M. polymorpha a été étudié en utilisant la fusion promoteur:GUS. Les activités de ces promoteurs ont été principalement détectées là où la cutine est formée. Ensuite, une lignée mutante GPAT de M. polymorpha a été isolée. Des analyses macroscopiques de ce mutant ont montré que, comme chez les autres Embryophytes, les gènes liés à la cutine de Marchantia sont impliqués dans le développement des organes aériens. L'analyse biochimique, la génétique inverse et la phylogénétique ont été combinées pour parvenir à la conclusion selon laquelle la cutine a évolué dans les premières plantes terrestres avec une classe d'enzymes de biosynthèse de la cutine, les GPATs, et joue probablement une fonction dans le développement chez les Bryophytes
The successful and long-lasting colonization of lands by plants required the evolution of innovations in order to survive to the novel constraints such as limited nutrient and water access, gravity, oxidative environment and UV radiations. In extant land plants, hydrophobic polymers deposited on the surface of different tissues, such as sporopollenin, cuticle, suberin and lignin, are known to contribute to the limitation of water loss, and resistance to other abiotic stresses, making them potential "terrestrialization innovations". How and when these traits evolved in plants remains elusive. Fossils data and phylogenetical analysis of genes involved in cutin biosynthesis in plants proposed cutin as the best candidate for plant terrestrialization. However, works testing this hypothesis are actually scares and the evidence limited. This thesis describes conducted investigations to determine the distribution of cutin in plants, the evolution of the genes required for its biosynthesis and the function of two of them in the model bryophyte, Marchantia polymorpha. The presence of cutin in species from the zygnematophyceae, which are the closest algal relatives to land plants, and in diverse land plants was monitored through microscopic observations and biochemical analyses. Cutin was only detected in land plants, as was one terminal enzyme in the biosynthesis of the cutin monomer, the Glycerol-Phosphate Acyl Transferases (GPATs). To confirm the origin of cutin in Embryophytes we have studied GPAT in the Bryophyte M. polymorpha. First, the expression pattern of M. polymorpha GPAT were studied using promoter:GUS fusion. The M. polymorpha GPATs promoter activities were mainly detected where cutin is formed. Then a mutant line of M. polymorpha GPAT was isolated. Macroscopic analysis of this mutant have shown that such as in Embryophytes, Marchantia cutin-related genes are involved in development of aerial organs. Biochemical analysis, reverse-genetics and phylogenetics were combined to reach the conclusion that cutin evolved in the first land plants together with one class of cutin-biosynthesis enzymes, the GPATs, and likely play a function in development in Bryophytes. This works indicates that cutin evolution in Embryophytes played a role in the terrestrialization event

With climate change and the massive extinction of biodiversity, this chapter seeks to address the ecological and economic significance of bryophytes. The objective of this chapter is to contribute to the general knowledge of this plant group to spur research and interest in conservation efforts. Ecologically, this chapter x-rays their habit, habitat, distribution, ecophysiology, and reproduction. Bryophytes terrestrialization begun several millions of years ago but is currently threatened by climate change and poor conservation efforts. Economically, this chapter highlights the multifarious uses and applications of bryophytes with a view to promoting diversification, sustainable utilization, and innovative application.