Johannes Liesche等《Journal of Experimental Botany》2020年
论文题目：Reduced pectin content of cell walls prevents stress-induced root cell elongation in Arabidopsis.
论文作者：Liu X, Cui H, Zhang B, Song M, Chen S, Xiao C, Tang Y, Liesche J
论文摘要：The primary cell walls of plants provide mechanical strength while maintaining the flexibility needed for cell extension growth. Cell extension involves loosening the bonds between cellulose microfibrils, hemicelluloses and pectins. Pectins have been implicated in this process, but it remains unclear if this depends on the abundance of certain pectins, their modifications and/or structure. Here, cell wall-related mutants of the model plant Arabidopsis thaliana were characterized by biochemical and immunohistochemical methods and Fourier-transform infrared microspectroscopy. Mutants with reduced pectin or hemicellulose contents showed no root cell elongation in response to simulated drought stress, in contrast to wild-type plants or mutants with reduced cellulose content. While no association was found between the degrees of pectin methylesterification and cell elongation, cell wall composition analysis suggested an important role of the pectin Rhamnogalacturonan II (RGII) that was corroborated in experiments with the RGII-modifying chemical 2β-deoxy-Kdo. Results were complemented by expression analysis of cell wall synthesis genes and the microscopic analysis of cell wall porosity. It is concluded that a certain amount of pectin is necessary for stress-induced root cell elongation and hypotheses regarding the mechanistic basis of this result are formulated.