Biology subjects

Zivy, M.

Publications and source records attributed to Zivy, M..

8 recordsLinked to original sources

bioRxiv2024

A moderate water deficit induces profound changes in the proteome of developing maize ovaries

Water deficit is a major cause of yield loss for maize (Zea mays), leading to ovary abortion when applied at flowering time. To help understand the mechanisms involved in this phenomenon, the proteome response to water deficit has been analysed in developing ovaries at silk emergence stage and five days later. Differential analysis, abundance pattern clustering and coexpressions networks were performed in order to draw a general picture of the proteome changes all along ovary development and under the effect of water deficit. The results show that, even mild, water deficit has a major impact on ovary proteome, but that this impact is very different from a response to a stress. A part of the changes can be related to a slowdown of ovary development, while another part cannot. In particular, ovaries submitted to water deficit show an increase in proteins involved in protein biosynthesis and in vesicle transport together with a decrease in proteins involved in amino acid metabolism and proteolysis. According to the functions of increased proteins, the changes may be linked to auxin, brassinosteroids and jasmonate signalling, but not abscisic acid.

plant biology↗

bioRxiv2024

Molecular signatures and associated regulators of the pea leaf response to sulfur deficiency and water deficit as revealed by multi-omics analyses

Sulfur availability affects crop yield, seed quality, and tolerance to environmental constraints. To understand how pea (Pisum sativum) leaves respond to sulfur deficiency alone or combined with moderate water deficit during the early reproductive phase, we employed a multi-omics approach. Sulfur deficiency reduced plant height, biomass and leaf carbon, and increased the nitrogen-to-sulfur ratio. Under this condition, 38 genes were up-regulated at both transcript and protein levels, including genes involved in sulfur metabolism and antioxidant responses, suggesting coordinated molecular adjustments that may mitigate low leaf sulfur status. Moderate water deficit alone had limited effects, but markedly altered plant growth, gene regulation and metal accumulation when combined with sulfur deficiency. Among synergistically up-regulated genes, twenty were linked to reactive oxygen species responses and activated early, while seven genes with sustained activation encoded glutathione S-transferases. This was associated with higher GST activity and likely contributed to limiting H2O2 accumulation in double-stressed leaves. One-third of differentially accumulated proteins were encoded by genes showing no transcriptional change under stress, including temperature-induced lipocalins with potential protective roles under combined stress. These findings enhance our understanding of multilevel molecular responses to stress interactions, which is essential for improving crop resilience under multi-stress conditions. HighlightModerate water deficit amplifies molecular responses to sulfur deficiency in Pisum sativum, revealing synergistic responses at multiple layers of regulation under this stress combination.

plant biology↗

bioRxiv2022

The PROSCOOP10 gene encodes two extracellular hydroxylated peptides and impacts flowering time in Arabidopsis

AO_SCPLOWBSTRACTC_SCPLOWThe Arabidopsis PROSCOOP genes belong to a family predicted to encode secreted propeptides which undergo maturation steps to produce peptides named SCOOP. Some of them are involved in defence signalling through their perception by a receptor complex including MIK2, BAK1 and BKK1. Here, we focused on the PROSCOOP10 gene which is highly and constitutively expressed in the aerial organs. The MS/MS analyses of leaf apoplastic fluids allowed the identification of two distinct peptides, named SCOOP10#1 and SCOOP10#2, covering two different regions of PROSCOOP10. They both possess the canonical S-X-S family motif and have hydroxylated prolines. This identification in apoplastic fluids confirms for the first time the biological reality of SCOOP peptides. NMR and molecular dynamics studies showed that the SCOOP10 peptides, although largely unstructured in solution, tend to assume a hairpin-like fold exposing the two serine residues previously identified as essential for the peptide activity. Furthermore, PROSCOOP10 mutations led to an early flowering phenotype and an increased expression of the floral integrators SOC1 and LEAFY, consistent with the transcription of PROSCOOP10 in several mutants displaying an early or late flowering phenotype. These results suggest a role of PROSCOOP10 in flowering time, illustrating the functional complexity of the PROSCOOP family. HO_SCPLOWIGHLIGHTC_SCPLOWThe PROSCOOP10 gene encodes two post-translationally modified extracellular SCOOP10 peptides and acts upstream of SOC1 and LFY to delay flowering.

plant biology↗

bioRxiv2020

Bradyrhizobium diazoefficiens USDA110 nodulation of Aeschynomene afraspera is associated with atypical terminal bacteroid differentiation and suboptimal symbiotic efficiency

Legume plants can form root organs called nodules where they house intracellular symbiotic rhizobium bacteria. Within nodule cells, rhizobia differentiate into bacteroids, which fix nitrogen for the benefit of the plant. Depending on the combination of host plants and rhizobial strains, the output of rhizobium-legume interactions is varying from non-fixing associations to symbioses that are highly beneficial for the plant. Bradyrhizobium diazoefficiens USDA110 was isolated as a soybean symbiont but it can also establish a functional symbiotic interaction with Aeschynomene afraspera. In contrast to soybean, A. afraspera triggers terminal bacteroid differentiation, a process involving bacterial cell elongation, polyploidy and membrane permeability leading to loss of bacterial viability while plants increase their symbiotic benefit. A combination of plant metabolomics, bacterial proteomics and transcriptomics along with cytological analyses was used to study the physiology of USDA110 bacteroids in these two host plants. We show that USDA110 establish a poorly efficient symbiosis with A. afraspera, despite the full activation of the bacterial symbiotic program. We found molecular signatures of high level of stress in A. afraspera bacteroids whereas those of terminal bacteroid differentiation were only partially activated. Finally, we show that in A. afraspera, USDA110 bacteroids undergo an atypical terminal differentiation hallmarked by the disconnection of the canonical features of this process. This study pinpoints how a rhizobium strain can adapt its physiology to a new host and cope with terminal differentiation when it did not co-evolve with such a host. ImportanceLegume-rhizobium symbiosis is a major ecological process in the nitrogen cycle, responsible for the main input of fixed nitrogen in the biosphere. The efficiency of this symbiosis relies on the coevolution of the partners. Some legume plants, but not all, optimize their return-on-investment in the symbiosis by imposing on their microsymbionts a terminal differentiation program that increases their symbiotic efficiency but imposes a high level of stress and drastically reduce their viability. We combined multi-omics with physiological analyses to show that the non-natural symbiotic couple formed by Bradyrhizobium diazoefficiens USDA110 and Aeschynomene afraspera is functional but displays a low symbiotic efficiency associated to a disconnection of terminal bacteroid differentiation features.

microbiology↗

bioRxiv2020

Proteomic data from leaves of twenty-four sunflower genotypes underwater deficit

This article describes how the proteomic data were produced on sunflower plants subjected to water deficit. Twenty-four sunflower genotypes were selected to represent genetic diversity within cultivated sunflower. They included both inbred lines and their hybridsWater deficit was applied to plants in pots at the vegetative stage using the high-throughput phenotyping platform Heliaphen. Here, we provide proteomic data from sunflower leaves corresponding to the identification of 3062 proteins and the quantification of 1211 of them in these 24 genotypes grown in two watering conditions. These data differentiate both treatment and the different genotypes and constitute a valuable resource to the community to study adaptation of crops to drought and the molecular basis of heterosis.Competing Interest StatementThe authors have declared no competing interest.View Full Text

plant biology↗

bioRxiv2019

Integrating proteomics and genomics into systems genetics provides novel insights into the mechanisms of drought tolerance in maize

The effect of drought on maize yield is of particular concern in the context of climate change and human population growth. However, the complexity of drought-response mechanisms make the design of new drought-tolerant varieties a difficult task that would greatly benefit from a better understanding of the genotype-phenotype relationship. To provide novel insight into this relationship, we applied a systems genetics approach integrating high-throughput phenotypic, proteomic and genomic data acquired from 254 maize hybrids grown under two watering conditions. Using association genetics and protein co-expression analysis, we detected more than 22,000 pQTLs across the two conditions and confidently identified fifteen loci with potential pleiotropic effects on the proteome. We showed that even mild water deficit induced a profound remodeling of the proteome, which affected the structure of the protein co-expression network, and a reprogramming of the genetic control of the abundance of many proteins, notably those involved in stress response. Co-localizations between pQTLs and QTLs for ecophysiological traits, found mostly in the water deficit condition, indicated that this reprogramming may also affect the phenotypic level. Finally, we identified several candidate genes that are potentially responsible for both the co-expression of stress response proteins and the variations of ecophysiological traits under water deficit. Taken together, our findings provide novel insights into the molecular mechanisms of drought tolerance and suggest some pathways for further research and breeding.

systems biology↗

bioRxiv2019

Comparative proteomics of osmotic signal transduction mutants in Botrytis cinerea explain loss of pathogenicity phenotypes and highlight interaction with cAMP and Ca2+ signalling pathways

O_LISignal transduction (ST) is essential for rapid adaptive responses to changing environmental conditions through rapid post-translational modifications of signalling proteins and downstream effectors that regulate the activity of target proteins and/or the expression of downstream genes. C_LIO_LIWe have performed a comparative proteomics study of ST mutants in the phytopathogenic fungus Botrytis cinerea during axenic growth under non-stressed conditions to decipher the roles of two kinases of the hyper-osmolarity pathway in B. cinerea physiology. We studied the mutants of the sensor histidine kinase Bos1 and of the MAP kinase Sak1. C_LIO_LIMultiplex shotgun proteomics detected 628 differential proteins between mutants and wild-type, 280 common to both mutants, indicating independent and shared regulatory functions for both kinases. Gene ontology analysis showed significant changes in proteins related to plant infection (secondary metabolism enzymes, lytic enzymes, proteins linked to osmotic, oxidative and cell wall stress) that may explain the virulence defects of both mutants. Intracellular accumulation of secreted proteins in the{Delta} bos1 histidine-kinase mutant suggests a potential secretion defect. The proteome data also highlight a new link between Sak1 MAPK, cAMP and Ca2+ signalling. C_LIO_LIThis study reveals the potential of proteomic analyses of signal transduction mutants to decipher their biological functions. C_LI

microbiology↗

bioRxiv2017

The use of salivary α-amylase as an evolutionary solution to host selection in parasitoids

Foraging parasitoids use chemical signals in host recognition and selection processes. Thereby, chemicals from the herbivore hosts play a crucial role. When different herbivores are present in the same plant or field, the perception of specific volatiles and contact compounds emitted from the host itself enable the parasitoids both to differentiate between hosts and non-hosts and to estimate the health status of its host. During the host feeding process, contact between the parasitoid and its host is very crucial, and oral secretions from the host play a key role during the first contact for such evaluation by the parasitoid. Using an integration of behavioral observations, biochemical and sensory physiological approaches we demonstrate that female parasitoids of Cotesia flavipes recognize their host and oviposit in reaction to an -amylase, which is present in the oral secretions of the larvae of their host, Chilo partellus. This activity was also mediated by a purified -amylase synthetized from Drosophila melanogaster. Using this synthetized enzyme, we further demonstrate that the conformation of the enzyme rather than its catalytic site is responsible for this activity. This enzyme is activating gustatory neurons of the terminal antennal sensilla chaetica of C. flavipes females. -amylases are therefore good candidates for an evolutionary solution to host selection in parasitoids, thus opening new avenues for investigations in hosts-parasitoids interactions.

evolutionary biology↗