Strategic Innovation Platform, International Rice Research Institute, Los Baños, Philippines.
Plant Cell Environ. 2021 Jul;44(7):2245-2261. doi: 10.1111/pce.14046. Epub 2021 Mar 25.
High night temperature (HNT) causes substantial yield loss in rice (Oryza sativa L.). In this study, the physiological processes related to flag leaf dark respiration (Rn) and grain filling under HNT were explored in a multi-parent advanced generation intercross population developed for heat tolerance (MAGIC ) along with selected high temperature tolerant breeding lines developed with heat-tolerant parents. Within a subset of lines, flag leaf Rn under HNT treatment was related to lower spikelet number per panicle and thus reduced yield. HNT enhanced the nighttime reduction of non-structural carbohydrates (NSC) in stem tissue, but not in leaves, and stem nighttime NSC reduction was negatively correlated with yield. Between heading and harvest, the major difference in NSC concentration was found for starch, but not for soluble sugar. HNT weakened the relationship between NSC remobilization and harvest index at both the phenotypic and genetic level. By using genome-wide association studies, an invertase inhibitor, MADS box transcription factors and a UDP-glycosyltransferase that were identified as candidate genes orchestrating stem NSC remobilization in the control treatment were lost under HNT. With the identification of physiological and genetic components related to rice HNT response, this study offers promising prebreeding materials and trait targets to sustain yield stability under climate change.
高温夜（HNT）会导致水稻（Oryza sativa L.）严重减产。在这项研究中，通过多亲本高级世代互交群体（MAGIC）和具有耐热亲本的高温耐性选育系，探讨了与 HNT 下旗叶暗呼吸（Rn）和籽粒灌浆相关的生理过程。在一些系中，HNT 处理下的旗叶 Rn 与小穗数减少有关，从而导致产量降低。HNT 增强了茎组织中非结构性碳水化合物（NSC）在夜间的减少，但在叶片中没有，茎组织夜间 NSC 的减少与产量呈负相关。从抽穗到收获期间，发现淀粉而非可溶性糖的 NSC 浓度差异最大。HNT 削弱了 NSC 再利用与收获指数在表型和遗传水平上的关系。通过全基因组关联研究，确定了在对照处理中协调茎 NSC 再利用的蔗糖转化酶抑制剂、MADS 盒转录因子和 UDP-糖基转移酶等候选基因，在 HNT 下这些基因的表达受到抑制。本研究鉴定了与水稻 HNT 响应相关的生理和遗传组成部分，为在气候变化下维持产量稳定性提供了有前途的预育材料和性状目标。
