LRX Proteins play a crucial role in pollen grain and pollen tube cell wall development

Leucine-rich repeat extensins (LRXs) are proteins involved in cell wall growth and are therefore required for plant growth processes. Fabrice et al. use pollen tube development in Arabidopsis thaliana as a vegetative plant growth model to elucidate the role of LRXs in these cellular processes. All 4 LRX genes expressed in pollen (LRX8, LRX9, LRX10, and LRX11) are redundantly required for pollen tube development. Furthermore, LRX proteins appear to regulate pollen germination, pollen tube growth, composition, and even the ultrastructure of the pollen tube cell wall. Moreover, lrx mutants have altered pollen tube mechanics, showing disrupted vesicle dynamics. This vesicle dynamic phenotype was alleviated in some phenotypes by altering calcium availability. Finally, it appears that the N-terminal leucine-rich repeat domain of LRX proteins are associated with the plasma membrane. This study enhances our understanding of how LRX proteins may be involved in call wall-plasma membrane communication (Summary by Isabel Mendoza) Plant Phys. 10.1104/pp.17.01374.