Tissue lignification, cell wall <em>p</em>-coumaroylation and degradability of maize stems depend on water status

International audienceWater supply and valorization are two urgent issues in the utilization of maize biomass in the context of climate change and replacement of fossil resources. Maximizing maize biomass valorization is of interest to make biofuel conversion competitive, and to increase forage energetic value for animal fodder. One way to estimate biomass valorization is to quantify cell wall degradability. In this study, we evaluated the impact of water supply on cell wall degradability, cell wall contents and structure, and distribution of lignified cell types in maize internodes using dedicated high-throughput tools to effectively phenotype maize internodes from 11 inbred lines under two contrasting irrigation scenarios in field trials over three years. Overall, our results clearly showed that water deficit induced significant changes in lignin content and distribution along with a reduction in lignin p-coumaroylation, thereby impacting cell wall degradability. Additionally, we also observed that responses to a water deficit vaned between the lines examined, underscoring biochemical and histological target traits for plant breeding

Custom methods to identify conserved genetic modules applied to novel transcriptomic data from Amborella trichopoda

International audienceAbstract We have devised a procedure for the inter-species comparison of transcriptomic data and used this to reconstruct the expression dynamics of major genetic modules that were present at least 149 million years ago in the most recent common ancestor (MRCA) of living angiosperms. We begin by using Laser-Assisted Microdissection to generate novel transcriptomic data from female flower tissues of Amborella trichopoda, the likely sister to all other living angiosperms. We then employ a gene-expression clustering method, followed by a custom procedure to compare genetic modules on the basis of gene-orthology between Amborella and the molecular-genetic model angiosperm Arabidopsis thaliana (Arabidopsis). Using this protocol, we have succeeded in identifying nine major genetic modules that appear to have conserved their expression dynamics from an early stage in angiosperm evolution. The genes of these modules, representing over 5000 orthogroups, include around a third of those known to control female reproductive development in Arabidopsis. Our study constitutes a proof-of-concept for the comparison of transcriptomic data between widely diverged plant species and represents a first step in the large-scale analysis of gene expression dynamics in a macro-evolutionary context

GDP-L-fucose is required for boundary definition in plants

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