Biology subjects

AbdElgawad, H.

Publications and source records attributed to AbdElgawad, H..

3 recordsLinked to original sources

bioRxiv2023

A pectin-binding peptide with a structural and signaling role in the assembly of the plant cell wall

Pressurized cells with strong walls make up the hydrostatic skeleton of plants. Assembly and expansion of such stressed walls depend on a family of secreted RAPID ALKALINIZATION FACTOR (RALF) peptides which, curiously, bind both a membrane receptor complex and wall-localized LEUCINE-RICH REPEAT EXTENSINs (LRXs) in a mutually exclusive way. Here we show that, in root hairs, the RALF22 peptide has a dual structural and signaling role in cell expansion. Together with LRX1, it directs the compaction of charged pectin polymers at the root hair tip into periodic circumferential rings. Free RALF22 induces the formation of a complex with LORELEI-LIKE-GPI-ANCHORED PROTEIN 1 (LLG1) and FERONIA (FER), triggering adaptive cellular responses. These findings show how a peptide simultaneously functions as a structural component organizing cell wall architecture and as a signaling molecule that regulates this process. This mechanism may also underlie wall assembly and expansion in other plant cell types.

plant biology↗

bioRxiv2023

Cellular dynamics in the maize leaf growth zone during recovery from chilling depends on the leaf developmental stage

Zea mays, a major crop, is highly sensitive to chilling which frequently occurs during its seedling stage and negatively affects yields. Although the direct effect of chilling is well-studied, the mechanisms determining the subsequent recovery are still unknown. Our goal is to determine the cellular basis of the dynamic leaf growth response to chilling and during recovery of leaves exposed before or after their emergence. We first studied the effect of a 3-day cold spell on leaf growth at the plant level. Then, we performed a kinematic analysis to analyse the dynamics of cell division and elongation during recovery of the 4th leaf after exposure to cold before or after emergence. Our results demonstrate that cold more strongly reduced the final length of non-emerged than emerged leaves (-13 vs -18%). This was not related to growth differences during cold, but a faster and more complete recovery of the growth of emerged leaves. Kinematic analysis showed that this difference was due to a higher cell division rate on the 1st and a higher cell elongation rate on the 2nd-day of recovery, respectively. The dynamics of cell division and expansion during recovery determine developmental stage-specific differences in cold tolerance of maize leaves.

plant biology↗

bioRxiv2018

Interspecific plant competition mediates impact of climate change on the ecophysiology of a plant-herbivore interaction.

O_LIBiotic interactions shape community evolution, but we lack mechanistic insights on how metabolic and ecological processes under climate change are altered by biotic interactions.\nC_LIO_LIWe used a two-trophic model community consisting of the aphid Dysaphis plantaginea feeding on the forb Plantago lanceolata, and a grass competitor Lolium perenne that does not experience herbivory by the aphid. Monocultures and mixtures were exposed to the herbivory treatment and to three relevant simulated environmental changes as prevalent under current climate change (increased temperature, CO2, and increased temperature and CO2)\nC_LIO_LIElevated CO2 reduced the nitrogen content of P. lanceolata, while simultaneous increases of CO2 and temperature modified the plant metabolic component and the magnitude of these responses in different directions. Elevated CO2 enhanced defence systems in P. lanceolata, but these effects were not altered by warming. Interspecific plant competition did, however, neutralise these responses. There were no indirect effects of climate change on aphid population growth despite changes in plant defense, nutritional quality and biomass induced by our environmental change scenarios.\nC_LIO_LIWe thus demonstrate interactions between abiotic and biotic processes on plant metabolite profiles, but more importantly, that climate change effect on a selection of the metabolic pathways are altered by herbivory and competition. Our experiment under semi-natural conditions thus demonstrates the non-additive and often neutralizing effects of biotic interactions on plant metabolism and species performance under climate-associated environmental change.\nC_LI

ecology↗