National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.
National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.
Plant Physiol Biochem. 2020 Jun;151:659-672. doi: 10.1016/j.plaphy.2020.04.006. Epub 2020 Apr 14.
Grain filling is the final determinant of yield, and this process is susceptible to abiotic stresses. Salicylic acid (SA) regulates grain filling in rice plants. A comparative proteomic study was conducted to understand how SA mediates grain filling under soil drying (SD) condition. Zhefu802 and its near-isogenic line (NIL) were planted in pots in an artificial chamber. SA (100 mg L) was applied, followed by SD treatment (with a water potential of -30 to -35 kPa) at anthesis. The results showed that the grain yield and grain weight significantly decreased under SD in Zhefu802, but not in its NIL variety. SD also decreased expression of photosynthesis-related proteins in grains of Zhefu802, which resulted in its poorer drought resistance. Furthermore, the decreased grain filling rate rather than the grain size explained the observed decreased grain weight and grain yield under SD. Interestingly, these reductions were reversed by SA. Expression of proteins involved in glycolysis/TCA circle, starch and sucrose metabolism, antioxidation and detoxication, oxidative phosphorylation, transcription, translation, and signal transduction, were significantly down-regulated under SD and were significantly up-regulated in response to SA. The expression of these proteins was examined at transcriptional level and similar results were obtained. Inhibited expression of these proteins and related pathways contributed to the observed decrease in the grain filling rate of Zhefu802, and application of SA up-regulated expression of these proteins to improve grain weight. The findings of this study provide new insights into grain filling regulation by SA, and offer the scientific foundation for cultivation practice.
籽粒灌浆是产量的最终决定因素，而这一过程易受非生物胁迫的影响。水杨酸（SA）调控水稻籽粒灌浆。本研究采用比较蛋白质组学方法，解析干旱胁迫下 SA 调控水稻籽粒灌浆的分子机制。以籼稻品种浙辐 802 及其近等基因系（NIL）为材料，在人工气候箱中盆栽，开花期喷施 SA（100 mg/L），随后进行干旱胁迫处理（水势-30 至-35 kPa）。结果表明，干旱胁迫显著降低浙辐 802 的粒重和产量，但对其 NIL 无显著影响。干旱胁迫还降低了浙辐 802 籽粒中与光合作用相关蛋白的表达，导致其抗旱性降低。此外，干旱胁迫下浙辐 802 灌浆速率的降低而非粒型的改变是粒重和产量降低的主要原因。有趣的是，SA 处理可以逆转这些表型。进一步分析发现，与糖酵解/TCA 循环、淀粉和蔗糖代谢、抗氧化和解毒、氧化磷酸化、转录、翻译和信号转导相关的蛋白表达在干旱胁迫下显著下调，而在 SA 处理下显著上调。转录水平的检测结果与蛋白表达水平一致。这些蛋白及其相关途径表达的下调可能是导致浙辐 802 灌浆速率降低的原因，而 SA 处理则通过上调这些蛋白的表达来提高粒重。本研究结果为 SA 调控籽粒灌浆的分子机制提供了新的见解，为栽培实践提供了科学依据。
