Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology Ministry of Education, Nanjing Forestry University, Nanjing 210037, China.
Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology Ministry of Education, Nanjing Forestry University, Nanjing 210037, China; Institute of Pomology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Plant Sci. 2022 Dec;325:111456. doi: 10.1016/j.plantsci.2022.111456. Epub 2022 Sep 8.
Adventitious root (AR) development is an ecologically and economically important biological process that maintains ecological balance, improves plant survivability, and allows for massive vegetative propagation, but its genetic mechanisms are not well understood. Here, eight Arabidopsis response regulator (ARR) genes were cloned and identified in poplar, most of which were detected in the AR, phloem, and xylem and showed remarkable induction at different time points during AR development. Subcellular localization indicated that most of these PeRR genes are in the nucleus. Based on qRT-PCR expression analysis of some genes related to AR development, we inferred that overexpression of PeRR12 (OE_PeRR12) may inhibited AR formation by suppressing the transcription of PeWOX11, PeWOX5, PePIN1 and PePIN3 in poplar while promoting type-A RR transcripts. Correspondingly, exogenous auxin partially restored the rooting of OE_PeRR12 poplar by inhibiting PeRR12 expression. Moreover, the activities of the antioxidant systems of OE_PeRR12 poplars were lower than those of wild-type poplars under salt stress conditions, indicating that PeRR12 may acts as a repressor that mediates salt tolerance by suppressing the expression of PeHKT1;1. Altogether, these results suggest that PeRR12 plays essential roles in mediating AR formation and salinity tolerance in poplar.
不定根（AR）的发育是一种生态和经济上都非常重要的生物学过程，它维持着生态平衡，提高了植物的生存能力，并允许进行大规模的营养繁殖，但它的遗传机制还不是很清楚。在这里，我们从杨树中克隆并鉴定了 8 个拟南芥反应调节因子（ARR）基因，其中大多数在 AR、韧皮部和木质部中都有检测到，并在 AR 发育的不同时间点表现出显著的诱导。亚细胞定位表明，这些 PeRR 基因中的大多数都在细胞核中。基于对一些与 AR 发育相关基因的 qRT-PCR 表达分析，我们推断过量表达 PeRR12（OE_PeRR12）可能通过抑制杨树中 PeWOX11、PeWOX5、PePIN1 和 PePIN3 的转录，从而抑制不定根的形成，同时促进类型-A RR 转录物的产生。相应地，外源生长素通过抑制 PeRR12 的表达，部分恢复了 OE_PeRR12 杨树的生根能力。此外，在盐胁迫条件下，OE_PeRR12 杨树的抗氧化系统活性低于野生型杨树，这表明 PeRR12 可能作为一种转录抑制子，通过抑制 PeHKT1;1 的表达来介导耐盐性。总之，这些结果表明 PeRR12 在介导杨树不定根形成和耐盐性方面发挥着重要作用。
