Upregulation of the glycine-rich protein-encoding gene GhGRPL enhances plant tolerance to abiotic and biotic stressors by promoting secondary cell wall development

Abstract

Both abiotic and biotic stress factors adversely affect plant survival, biomass generation, and crop yields. As the global availability of arable land decreases and the impacts of global warming intensify, such stressors may have increasingly pronounced effects on agricultural productivity. Currently, researchers face the overarching challenge of comprehensively enhancing plant resilience to abiotic and biotic stressors. The secondary cell wall plays a crucial role in bolstering the stress resistance of plants. To increase plant resistance to stress through genetic manipulation of the secondary cell wall, we cloned a cell wall protein designated glycine-rich protein-like (GhGRPL) from cotton fibers, which is specifically expressed during the secondary cell wall-biosynthesis period. Notably, this protein differs from its ArabidopsishomologAtGRP in which its glycine-rich domain is deficient in glycine residues. GhGRPL is involved in secondary cell wall deposition. Upregulation of GhGRPL enhances lignin accumulation and, consequently, the thickness of secondary cell walls, thereby increasing plant resistance to abiotic stressors, such as drought and salinity, and biotic threats, including V. dahliae infection. Conversely, interference with GhGRPL expression in cotton reduces lignin accumulation and compromises this resistance. Taken together, our findings elucidate the role of GhGRPL in regulating secondary cell wall development through its influence on lignin deposition, which, in turn, reinforces cell wall robustness and impermeability. These findings underline the promising near-future prospect of adopting GhGRPL as a viable, effective approach to enhance plant resilience to abiotic and biotic stress factors.