Cai Zeping, Dai Yinuo, Jin Xia, Xu Hui, Huang Zhen, Xie Zhenyu, Yu Xudong, Luo Jiajia
School of Tropical Agriculture and Forestry, Hainan University, Hainan, China.
Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan, China.
Front Plant Sci. 2024 Mar 8;15:1348295. doi: 10.3389/fpls.2024.1348295. eCollection 2024.
Plant roots are constantly prepared to adjust their growth trajectories to avoid unfavorable environments, and their ability to reorient is particularly crucial for survival. Under laboratory conditions, this continuous reorientation of the root tip is manifested as coiling or waving, which we refer to as root circumnutation. However, the effect of ambient temperature (AT) on root circumnutation remains unexplored. In this study, rice seedlings were employed to assess the impact of varying ATs on root circumnutation. The role of ethylene in mediating root circumnutation under elevated AT was examined using the ethylene biosynthesis inhibitor aminooxyacetic acid (AOA) and the ethylene perception antagonist silver thiosulfate (STS). Furthermore, transcriptome sequencing, weighted gene co-expression network analysis, and real-time quantitative PCR were utilized to analyze gene expressions in rice root tips under four distinct treatments: 25°C, 35°C, 35°C+STS, and 35°C+AOA. As a result, genes associated with ethylene synthesis and signaling ( and ), auxin synthesis and transport (, , and ), cell elongation (, , , and ), as well as the inhibition of root curling () were identified. Notably, the expression levels of these genes increased with rising temperatures above 25°C. This study is the first to demonstrate that elevated AT can induce root circumnutation in rice via the ethylene pathway and proposes a potential molecular model through the identification of key genes. These findings offer valuable insights into the growth regulation mechanism of plant roots under elevated AT conditions.
植物根系时刻准备调整其生长轨迹以避开不利环境，而其重新定向的能力对生存尤为关键。在实验室条件下，根尖的这种持续重新定向表现为卷曲或波动，我们将其称为根的回旋转头运动。然而，环境温度（AT）对根的回旋转头运动的影响仍未得到探索。在本研究中，使用水稻幼苗来评估不同环境温度对根的回旋转头运动的影响。利用乙烯生物合成抑制剂氨基氧乙酸（AOA）和乙烯感知拮抗剂硫代硫酸银（STS），研究了乙烯在高温下介导根的回旋转头运动中的作用。此外，利用转录组测序、加权基因共表达网络分析和实时定量PCR，分析了在25℃、35℃、35℃+STS和35℃+AOA这四种不同处理下水稻根尖中的基因表达。结果，鉴定出了与乙烯合成和信号传导（以及）、生长素合成和运输（、和）、细胞伸长（、、和）以及抑制根卷曲（）相关的基因。值得注意的是，这些基因的表达水平随着温度高于25℃而升高。本研究首次证明高温可通过乙烯途径诱导水稻根的回旋转头运动，并通过鉴定关键基因提出了一个潜在的分子模型。这些发现为高温条件下植物根系的生长调控机制提供了有价值的见解。
