Liu Rui, Wen Shuang-Shuang, Sun Ting-Ting, Wang Rui, Zuo Wen-Teng, Yang Tao, Wang Chao, Hu Jian-Jun, Lu Meng-Zhu, Wang Liu-Qiang
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Chinese Academy of Forestry Research Institute of Forestry, Beijing 100091, China.
College of Horticulture, China Agricultural University, Beijing 100193, China.
J Exp Bot. 2022 Dec 8;73(22):7298-7311. doi: 10.1093/jxb/erac345.
Adventitious root (AR) development is an extremely complex biological process that is affected by many intrinsic factors and extrinsic stimuli. Some WUSCHEL-related homeobox (WOX) transcription factors have been reported to play important roles in AR development, but their functional relationships with auxin signaling are poorly understood, especially the developmental plasticity of roots in response to adversity stress. Here, we identified that the WOX11/12a-SMALL AUXIN UP RNA36 (SAUR36) module mediates AR development through the auxin pathway in poplar, as well as under salt stress. PagWOX11/12a displayed inducible expression during AR development, and overexpression of PagWOX11/12a significantly promoted AR development and increased salt tolerance in poplar, whereas dominant repression of PagWOX11/12a produced the opposite phenotype. PagWOX11/12a proteins directly bind to the SAUR36 promoter to regulate SAUR36 transcription, and this binding was enhanced during salt stress. Genetic modification of PagWOX11/12a-PagSAUR36 expression revealed that the PagWOX11/12a-PagSAUR36 module is crucial for controlling AR development via the auxin pathway. Overall, our results indicate that a novel WOX11-SAUR-auxin signaling regulatory module is required for AR development in poplar. These findings provide key insights and a better understanding of the involvement of WOX11 in root developmental plasticity in saline environments.
不定根（AR）发育是一个极其复杂的生物学过程，受到许多内在因素和外在刺激的影响。一些与WUSCHEL相关的同源异型盒（WOX）转录因子已被报道在不定根发育中发挥重要作用，但其与生长素信号传导的功能关系尚不清楚，尤其是根系在逆境胁迫下的发育可塑性。在这里，我们发现WOX11/12a-SMALL AUXIN UP RNA36（SAUR36）模块通过杨树中的生长素途径介导不定根发育，在盐胁迫下也是如此。PagWOX11/12a在不定根发育过程中表现出诱导表达，PagWOX11/12a的过表达显著促进了杨树不定根发育并提高了耐盐性，而PagWOX11/12a的显性抑制则产生相反的表型。PagWOX11/12a蛋白直接结合到SAUR36启动子上以调节SAUR36转录，并且这种结合在盐胁迫期间增强。PagWOX11/12a-PagSAUR36表达的基因改造表明，PagWOX11/12a-PagSAUR36模块对于通过生长素途径控制不定根发育至关重要。总体而言，我们的结果表明杨树不定根发育需要一个新的WOX11-SAUR-生长素信号调节模块。这些发现为深入了解WOX11在盐环境中根系发育可塑性中的作用提供了关键见解。
