Zhang Qing, Deng Aiwen, Xiang Min, Lan Qiuyan, Li Xiaokun, Yuan Shuai, Gou Xin, Hao Shuang, Du Juan, Xiao Chaowen
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China.
Front Plant Sci. 2022 May 2;13:862171. doi: 10.3389/fpls.2022.862171. eCollection 2022.
Pectin, cellulose, and hemicellulose constitute the primary cell wall in eudicots and function in multiple developmental processes in plants. Root hairs are outgrowths of specialized epidermal cells that absorb water and nutrients from the soil. Cell wall architecture influences root hair development, but how cell wall remodeling might enable enhanced root hair formation in response to phosphate (P) deficiency remains relatively unclear. Here, we found that POLYGALACTURONASE INVOLVED IN EXPANSION 2 (PGX2) functions in conditional root hair development. Under low P conditions, a activation tagged line ( ) displays bubble-like root hairs and abnormal callose deposition and superoxide accumulation in roots. We found that the polar localization and trafficking of PIN2 are altered in roots in response to P deficiency. We also found that actin filaments were less compact but more stable in root hair cells and that actin filament skewness in root hairs was recovered by treatment with 1-N-naphthylphthalamic acid (NPA), an auxin transport inhibitor. These results demonstrate that activation tagging of affects cell wall remodeling, auxin signaling, and actin microfilament orientation, which may cooperatively regulate root hair development in response to P starvation.
果胶、纤维素和半纤维素构成双子叶植物的初生细胞壁，并在植物的多个发育过程中发挥作用。根毛是特化表皮细胞的突出物，从土壤中吸收水分和养分。细胞壁结构影响根毛发育，但细胞壁重塑如何响应磷（P）缺乏而促进根毛形成仍相对不清楚。在这里，我们发现参与扩张2的多聚半乳糖醛酸酶（PGX2）在条件性根毛发育中起作用。在低磷条件下，一个激活标签系显示出泡状根毛以及根中异常的胼胝质沉积和超氧化物积累。我们发现，响应磷缺乏，PIN2在该系根中的极性定位和运输发生改变。我们还发现，在该系根毛细胞中肌动蛋白丝不太紧密但更稳定，并且用生长素运输抑制剂1-N-萘基邻苯二甲酰胺（NPA）处理可恢复该系根毛中的肌动蛋白丝偏斜度。这些结果表明，对该系的激活标签影响细胞壁重塑、生长素信号传导和肌动蛋白微丝取向，它们可能协同调节响应磷饥饿的根毛发育。
