Abscisic acid regulates secondary cell-wall formation and lignin deposition in Arabidopsis thaliana through phosphorylation of NST1

第一作者：Chang Liu

第一单位：北德克萨斯大学

通讯作者：Richard A. Dixon

 Abstract 

背景回顾：Plant secondary cell-wall (SCW) deposition and lignification are affected by both seasonal factors and abiotic stress, and these responses may involve the hormone abscisic acid (ABA).

提出问题：However, the mechanisms involved are not clear.

主要发现：Here we show that mutations that limit ABA synthesis or signaling reduce the extent of SCW thickness and lignification in Arabidopsis thaliana through the core ABA-signaling pathway involving SnRK2 kinases.

结果1-物理互作：SnRK2.2. 3 and 6 physically interact with the SCW regulator NAC SECONDARY WALL THICKENING PROMOTING FACTOR 1 (NST1), a NAC family transcription factor that orchestrates the transcriptional activation of a suite of downstream SCW biosynthesis genes, some of which are involved in the biosynthesis of cellulose and lignin.

结果2-磷酸化：This interaction leads to phosphorylation of NST1 at Ser316, a residue that is highly conserved among NST1 proteins from dicots, but not monocots, and is required for transcriptional activation of downstream SCW-related gene promoters.

结果3-功能突变：Loss of function of NST1 in the snd1 mutant background results in lack of SCWs in the interfascicular fiber region of the stem, and the Ser316Ala mutant of NST1 fails to complement this phenotype and ABA-induced lignin pathway gene expression.

结论：The discovery of NST1 as a key substrate for phosphorylation by SnRK2 suggests that the ABA-mediated core-signaling cascade provided land plants with a hormone-modulated, competitive desiccation-tolerance strategy allowing them to differentiate water-conducting and supporting tissues built of cells with thicker cell walls.

 摘 要 

doi: https://doi.org/10.1073/pnas.2010911118

Journal: PNAS

Published date: Feb 02, 2021