Biology subjects

Sechet, J.

Publications and source records attributed to Sechet, J..

3 recordsLinked to original sources

bioRxiv2023

Inositolphosphate glycans accumulate and suppress plant defense during Arabidopsis/Botrytis interaction

This study investigates the presence and significance of previously undiscovered oligosaccharides that accumulate during the interaction between Arabidopsis thaliana and Botrytis cinerea, a pathogenic fungus. Initially focused on characterizing cell wall-derived oligosaccharides, the research uncovered inositol phosphate glycans (IPGs) originating from plant sphingolipids, specifically glycosylinositol phosphorylceramides. Advanced chromatography, mass spectrometry techniques and molecular biology were employed to identify these IPGs, determine their origins, and study their role in the A. thaliana-B. cinerea interaction. Contrary to the conventional belief that oligosaccharides trigger plant defense, this research suggests that B. cinerea releases IPGs identical to those generated by host plant to actually downregulate plant defense mechanisms. This discovery offers insight into the dynamic strategies used by B. cinerea to evade plant defenses and establish successful infections. One-Sentence SummaryA plant pathogen releases products identical to those generated by host plant that aids in evasion of the plant defense.

plant biology↗

bioRxiv2021

Plant inositol-phosphate-glycans and fucosylated xyloglucan oligosaccharide are accumulated upon Arabidopsis thaliana/ Botrytis cinerea infection

In mammals, insulin is involved in controlling blood glucose levels and its role in modulating immunity is being more and more documented. This hormone promotes the release of inositolphosphate glycans (IPG) which act as mediators. In plants, one IG has already been identified in plant culture cells (Smith and Fry, 1999; Smith et al., 1999) but, to our knowledge, no IPG have been yet identified. Here, we discovered 7 IPG that are accumulated upon Arabidopsis thaliana-Botrytis cinerea interaction, concomitantly with oligogalacturonides and a fucosylated xyloglucan oligosaccharide. Further structural characterization showed that they come from the hydrolysis of polar heads of Serie A to H glycosylinositol phosphorylceramides presumably via a phospholipase C activity. Taken together with the emerging role of insulin as immune regulator, these results question the role of IPG as damage associated molecular pattern both in animal and plant kingdoms.

plant biology↗

bioRxiv2019

Xyloglucan homeostasis and microtubule dynamics synergistically maintain meristem geometry and robustness of phyllotaxis in Arabidopsis

The shoot apical meristem (SAM) gives rise to all aerial organs of the plant. The cell walls are supposed to play a central role in this process, translating molecular regulation into dynamic changes of growth rates and directions, although their precise role in morphogenesis during organ formation remains not well understood. Here we investigate the role of xyloglucans (XyGs), which form a major, yet functionally poorly characterized, wall component in the SAM. Using immunolabeling, biochemical analysis, genetic approaches, micro-indentation, laser ablations and live imaging, we show that XyGs are important for meristem shape and phyllotaxis, although no difference in cell wall stiffness could be observed when XyGs are perturbed. Mutations in enzymes required for XyG synthesis also affect other cell wall components such as cellulose content and the pectin methylation status. Interestingly, we show that the control of cortical microtubules dynamics by the severing enzyme KATANIN becomes vital when XyGs are perturbed or absent. This suggests an active role of the cytoskeleton in compensating for altered wall composition.

plant biology↗