News

FR AIB
News
Article

06 June 2023

Redaction: MA

The long-term maintenance of a resistance polymorphism through diffuse interactions

Plant resistance (R) genes are a crucial component in plant defence against pathogens. Although R genes often fail to provide durable resistance in an agricultural context, they frequently persist as long-lived balanced polymorphisms in nature. Standard theory explains the maintenance of such polymorphisms through a balance of the costs and benefits of resistance and virulence in a tightly coevolving host–pathogen pair. However, many plant-pathogen interactions lack such specificity.
Know more
Article

06 June 2023

Redaction: MA

Microbiome affects reproduction and investment in the uropygial gland in Great tits

Microorganisms constitute the major part of the earth biomass. The host microbiome, defined as the whole community of microorganisms in contact with an organism, includes pathogenic and commensal microorganisms that are remarkable in their diversity and ubiquity. Parasites influence allocation trade-offs between reproduction and self-maintenance, and many beneficial microorganisms are essential for instance to host digestion and nutrient synthesis. The host microbiome is thus expected to shape the evolution of host life-history traits, although experimental studies from natural systems are still lacking.
Know more
Article

06 June 2023

Redaction: MA

Cell - An immune receptor pair with an integrated decoy converts pathogen disabling of defensive transcription factors into resistance

Microbial pathogens infect host cells by delivering virulence factors (effectors) that interfere with defenses. In plants, intracellular nucleotide-binding/oligomeriza- tion domain (NOD)-like receptors (NLRs) detect specific effector interference and trigger immu- nity by an unknown mechanism. The Arabidopsis interacting NLR pair, RRS1-R with RPS4, confers resistance to different pathogens including Ralstonia solanacearum bacteria expressing the acetyltransferase effector, PopP2. We show that PopP2 directly acetylates a key lysine within an additional C-terminal WRKY transcription factor DNA-binding domain of RRS1-R. This disrupts RRS1-R DNA association and activates RPS4-dependent immunity...
Know more
Tropical rain forest
Article

06 June 2023

Redaction: GE

Improved allometric models to estimate the aboveground biomass of tropical trees

Terrestrial carbon stock mapping is important for the successful implementation of climate change mitigation policies. Its accuracy depends on the availability of reliable allome- tric models to infer oven-dry aboveground biomass of trees from census data. The degree of uncertainty associated with previously published pantropical aboveground biomass allometries is large.
Know more
Hirondelle à front blanc
Article

06 June 2023

Redaction: G Esteve

Avoiding pitfalls in estimating heritability with the common options approach

Heritability (i.e. the heredity of differences) is a central parameter of evolutionary sciences, as evolution by natural selection or drift can only occur in traits that are heritable. However, in many circumstances, heritability estimates are subject to two potentially interacting pitfalls: the spatial and the regression to the mean (RTM) fallacies. The spatial fallacy occurs when the set of potential movement options differs among individuals according to where individuals depart.
Know more
Silene latifolia
Article

06 June 2023

Redaction: Gael Esteve

A Quantitative Genetic Signature of Senescence in a Short-Lived Perennial Plant

The evolution of senescence (the physiological decline of organisms with age) poses an apparent paradox because it represents a failure of natural selection to increase the survival and reproductive performance of organisms. The paradox can be resolved if natural selection becomes less effective with age, because the death of post-reproductive individuals should have diminished effects on Darwinian fitness. A substantial body of empirical work is consistent with this prediction for animals, which transmit their genes to progeny via an immortal germline. However, such evidence is still lacking in plants, which lack a germline and whose reproduction is diffuse and modular across the soma. Here, we provide experimental evidence for a genetic basis of senescence in the short-lived perennial plant Silene latifolia. Our pedigree-based analysis revealed a marked increase with age in the additive genetic variance of traits closely associated with fitness. This result thus extends to plants the quantitative genetic support for the evolutionary theory of senescence.
Know more
Article

06 June 2023

Redaction: Gael Esteve

High-throughput genetics and phenotyping, or how to unravel plant quantitative resistance to a root pathogen

The root parasite Aphanomyces euteiches is the main pathogen of pea in Europe and is also an important limiting factor of alfalfa production in USA. Since no chemical control is available against A. euteiches, genetic programs to improve crop resistance is the best hope to prevent the spread of this disease.
Know more
nodule
Article

06 June 2023

Redaction: C.Masson & G.Esteve

Transient Hypermutagenesis Accelerates the Evolution of Legume Endosymbionts following Horizontal Gene Transfer

Horizontal gene transfer has an extraordinary impact on microbe evolution and diversification, by allowing exploration of new niches such as higher organisms. This is the case for rhizobia, a group of phylogenetically diverse bacteria that form a nitrogen-fixing symbiotic relationship with most leguminous plants. While these arose through horizontal transfer of symbiotic plasmids, this in itself is usually unproductive, and full expression of the acquired traits needs subsequent remodeling of the genome to ensure the ecological success of the transfer. Here we uncover a mechanism that accelerates the evolution of a soil bacterium into a legume symbiont.
Know more
herbarium specimen
Article

06 June 2023

Redaction: M. Aizpuru

From museums to genomics: old herbarium specimens shed light on a C3 to C4 transition

Collections of specimens held by natural history museums are invaluable material for biodiversity inventory and evolutionary studies, with specimens accumulated over 300 years readily available for sampling. Unfortunately, most museum specimens yield low-quality DNA. Recent advances in sequencing technologies, so called next-generation sequencing, are revolutionizing phylogenetic investigations at a deep level.
Know more
Article

06 June 2023

Redaction: G. Esteve

An integrated analysis of plant and bacterial gene expression in symbiotic root nodules using laser-capture microdissection coupled to RNA sequencing

Rhizobium-induced root nodules are specialized organs for symbiotic nitrogen fixation. Indeterminate-type nodules are formed from an apical meristem and exhibit a spatial zonation which corresponds to successive developmental stages. To get a dynamic and integrated view of plant and bacterial gene expression associated with nodule development, we used a sensitive and comprehensive approach based upon oriented high-depth RNA sequencing coupled to laser microdissection of nodule regions.
Know more
modéalisation protéine
Article

06 June 2023

Redaction: G.Esteve

Lipo-chitooligosaccharidic Symbiotic Signals Are Recognized by LysM Receptor-Like Kinase LYR3 in the Legume Medicago truncatula

While chitooligosaccharides (COs) derived from fungal chitin are potent elicitors of defense reactions, structurally related signals produced by certain bacteria and fungi, called lipo-chitooligosaccharides (LCOs), play important roles in the establishment of symbioses with plants. Understanding how plants distinguish between friend and foe through the perception of these signals is a major challenge.
Know more
Sunflower cover
Article

06 June 2023

Redaction: G. Esteve

Tournesol : un nouvel outil pour mesurer le manque d’eau

Plant or soil water status is required in many scientic elds to understand plant responses to drought. Because the transcriptomic response to abiotic conditions, such as water decit, reects plant water status, genomic tools could be used to develop a new type of molecular biomarker.
Know more
Aphanomyces euteiches
Article

06 June 2023

Redaction: Gael Esteve

Aphanomyces euteiches Cell Wall Fractions Containing Novel Glucan-Chitosaccharides Induce Defense Genes and Nuclear Calcium Oscillations in the Plant Host Medicago truncatula.

N-acetylglucosamine-based saccharides (chitosaccharides) are components of microbial cell walls and act as molecular signals during host-microbe interactions. In the legume plant Medicago truncatula, the perception of lipochitooligosaccharide signals produced by symbiotic rhizobia and arbuscular mycorrhizal fungi involves the Nod Factor Perception (NFP) lysin motif receptor-like protein and leads to the activation of the so-called common symbiotic pathway. In rice and Arabidopsis, lysin motif receptors are involved in the perception of chitooligosaccharides released by pathogenic fungi, resulting in the activation of plant immunity.
Know more
Chabot
Article

06 June 2023

Redaction: Gael Esteve

Do stream fish track climate change ? Assessing distribution shifts in recent decades

Understanding the ability of species to shift their distribution ranges in response to climate change is crucial for conservation biologists and resources managers. Although freshwater ecosystems include some of the most imperilled fauna worldwide, such range shifts have been poorly documented in streams and rivers and have never been compared to the current velocity of climate change. Based on national monitoring data, we examined the distributional changes of 32 stream species in France and quantified potential time lags in species responses, providing a unique opportunity to analyse range shifts over recent decades of warming in freshwater environments.
Know more
Oiseau
Article

06 June 2023

Redaction: Gael Esteve

Timing and number of colonizations but not diversification rates affect diversity patterns in hemosporidian lineages on a remote oceanic archipelago

Parasite diversity on remote oceanic archipelagos is determined by the number and timing of colonizations, and in-situ diversification rate. In this study we compare intra-archipelago diversity of two hemosporidian parasite genera, Plasmodium and Leucocytozoon, infecting birds of the Mascarene archipelago. Despite the generally higher vagility of Plasmodium parasites, we report a much lower diversity of Plasmodium cytochrome-b haplotypes in the archipelago compared to Leucocytozoon.
Know more
Nodule
Article

06 June 2023

Redaction: GE

Experimental evolution of nodule intracellular infection in legume symbionts

Soil bacteria known as rhizobia are able to establish an endosymbiosis with legumes that takes place in neoformed nodules in which intracellularly hosted bacteria fix nitrogen. Intracellular accommodation that facilitates nutrient exchange between the two partners and protects bacteria from plant defense reactions has been a major evolutionary step towards mutualism. Yet the forces that drove the selection of the late event of intracellular infection during rhizobium evolution are unknown.
Know more
Logo COST
Article

06 June 2023

Redaction: G.Esteve

European COoperation in Science and Technology (COST) Action Food & Agriculture FA1106 – QualityFruit

How fleshy fruits grow, ripen and produce their sensory and nutritional characteristics that make them so popular with consumers? Are tomato and grape using common or different strategies and signaling pathways to initiate their maturation process? To answer these questions the Laboratory of Genomics and Biotechnology of Fruits coordinates since July 2012 the COST Action FA1106 “QualityFruit”. This network funded by the European Commission includes up to 47 laboratories, working on fruit, from 22 Euro- pean countries. The four year budget finance scientific conferences, workshops, thematic schools or inter-laboratory exchanges to foster cooperation between European researchers and promote new research initiatives that seek for the mechanism controlling fleshy fruit development and quality.
Know more
Feuille A.Thaliana
Article

06 June 2023

Redaction: GE

RSK1 : An atypical kinase under balancing selection confers broad-spectrum disease resistance in Arabidopsis

During the evolution of plant-pathogen interactions, plants have evolved the capability to defend themselves from pathogen infection by different overlapping mechanisms. Disease resistance is constituted by an elaborate, multilayered system of defense. Among these responses, quantitative resistance is a prevalent form of resistance in crops and natural plant populations, for which the genetic and molecular bases remain largely unknown.Thus, identification of the genes underlying quantitative resistance constitutes a major challenge in plant breeding and evolutionary biology, and might have enormous practical implications for human health by increasing crop yield and quality.
Know more
Mort cellulaire
Article

06 June 2023

Redaction: GE

Arabidopsis ubiquitin ligase MIEL1 mediates degradation of the transcription factor MYB30 weakening plant defence

One of the most efficient plant resistance reactions to pathogen attack is the hypersensitive response, a form of programmed cell death at infection sites. The Arabidopsis transcription factor MYB30 is a positive regulator of hypersensitive cell death responses. Here we show that MIEL1 (MYB30-Interacting E3 Ligase1), an Arabidopsis RING-type E3 ubiquitin ligase that interacts with and ubiquitinates MYB30, leads to MYB30 proteasomal degradation and downregulation of its transcriptional activity...
Know more
Olives (JP Roger)
Article

06 June 2023

Redaction: G Esteve

The complex history of the olive tree

The location and timing of domestication of the olive tree, a key crop in Early Mediterranean societies, remain hotly debated. Here, reseachers unravel the history of wild olives (oleasters), and then infer the primary origins of the domesticated olive.
Know more
vignette medicago
Article

06 June 2023

Redaction: GE

CML9, an Arabidopsis calmodulin-like protein, contributes to plant innate immunity through a flagellin-dependent signalling pathway

Comment les plantes perçoivent-elles leur environnement ? Certes, elles n’ont pas d’yeux ou de système nerveux mais n’en sont pas moins dénuées de systèmes de perception… Grâce à des senseurs, elles parviennent à s’informer mais aussi à répondre aux contraintes auxquelles elles sont confrontées, qu’il s’agisse d’une sècheresse comme de l’agression par des bactéries. Une équipe du LRSV (UPS / CNRS) dans laquelle travaille Didier Aldon vient d’identifier un nouvel acteur permettant aux plantes de mieux se défendre vis-à-vis d’agents pathogènes.
Know more