Dong Nana, Yin Wenchao, Liu Dapu, Zhang Xiaoxing, Yu Zhikun, Huang Wei, Liu Jihong, Yang Yanzhao, Meng Wenjing, Niu Mei, Tong Hongning
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Plant Sci. 2020 Dec 10;11:621859. doi: 10.3389/fpls.2020.621859. eCollection 2020.
The complex roles of the steroid hormone brassinosteroids (BRs) in many different yield- and stress-related traits make it difficult to utilize the hormones for crop improvement. Here, we show that SERK2 as a BR signaling component is a potentially useful candidate for BR manipulation in rice. We generated multiple mutant alleles of by CRISPR/Cas9 editing and show that knockout of results in a compact structure accompanied with increased grain size. SERK2 is localized on plasma membrane and can interact with OsBRI1, the BR receptor, suggesting its conserved role as co-receptor in BR signaling. Consistently, the mutant has impaired BR sensitivity compared to wild type. Notably, the mutant is highly sensitive to salt stress as evaluated by plant survival rate as well as transcriptome analysis, whereas has slightly increased sensitivity to ABA, the stress hormone. By contrast, overexpression of significantly enhances grain size and salt stress resistance, importantly, without affecting plant architecture. Furthermore, while salt suppresses transcription, the protein is greatly induced by salt stress. Taken together, we propose that the adverse condition induces SERK2 accumulation to enhance early BR signaling on plasma membrane in favor of the anti-stress response. Our results illustrate the great potentials of specific BR components such as SERK2 for crop improvement by utilizing flexible strategies.
类固醇激素油菜素内酯（BRs）在许多与产量和胁迫相关的不同性状中发挥着复杂作用，这使得利用这些激素来改良作物变得困难。在此，我们表明，作为BR信号成分的SERK2是水稻中进行BR调控的一个潜在有用候选基因。我们通过CRISPR/Cas9编辑产生了多个等位突变体，并表明敲除该基因会导致植株结构紧凑，同时籽粒大小增加。SERK2定位于质膜上，并且可以与BR受体OsBRI1相互作用，这表明它在BR信号传导中作为共受体具有保守作用。一致地，与野生型相比，该突变体的BR敏感性受损。值得注意的是，通过植株存活率以及转录组分析评估，该突变体对盐胁迫高度敏感，而对胁迫激素ABA的敏感性略有增加。相比之下，过表达该基因显著提高了籽粒大小和耐盐性，重要的是，不影响植株结构。此外，虽然盐胁迫抑制了该基因的转录，但盐胁迫能极大地诱导该蛋白的产生。综上所述，我们提出逆境条件会诱导SERK2积累，以增强质膜上早期BR信号传导，从而有利于抗逆反应。我们的结果说明了特定的BR成分（如SERK2）通过灵活策略改良作物的巨大潜力。
