Natural variation at qHd1 affects heading date acceleration at high temperatures with pleiotropism for yield traits in rice.
Natural variation at qHd1 affects heading date acceleration at high temperatures with pleiotropism for yield traits in rice.
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qHd1 的自然变异影响高温下抽穗期的加速，对水稻产量性状具有多效性
DOI：
10.1186/s12870-018-1330-5
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发表时间：
2018-06-07
影响因子：
5.3
通讯作者：
Zhuang JY
中科院分区：
文献类型：
--
作者：
Chen JY;Zhang HW;Zhang HL;Ying JZ;Ma LY;Zhuang JY
背景：水稻对温度波动高度敏感。近年来，高温胁迫频繁发生，严重影响了水稻生产。在特定的环境条件下，选择适宜的抽穗期，可保证高产。水稻抽穗在很大程度上取决于对环境变化的准确测量，特别是在日照长度和温度方面。与光周期途径的详细理解相反，很少有人知道温度如何调节水稻抽穗的遗传控制。结果：从籼稻品种珍汕97（珍汕97）和密阳46（MY 46）之间的杂交中分离出qHd 1的近等基因系。利用5个播期的水稻田间试验，观察了qHd 1基因对温度反应的影响。从试验Ⅰ到试验Ⅴ，随着温度的逐渐升高，MY 46纯合子的抽穗期从76 d到58 d，每次试验持续下降约5 d，而MY 97纯合子的抽穗期从试验Ⅰ到试验Ⅲ以相同的速度提高，然后稳定在69 d。在人工气候室中进行的温度梯度实验证实了这种热响应。研究还发现，该等位基因对高温加速抽穗的耐受性与较高的粒重相关，从而导致较高的籽粒产量。然后，通过qRT-PCR和RNA-seq技术，我们发现了qHd 1介导的花对温度反应的OsMADS 51-Ehd 1-RFT 1/Hd 3a途径。通过序列比较，与MY 46等位基因相比，OsMADS 51的qHd 1在MY 97等位基因的第1内含子中显示9.5-kb的插入。此外，这种大插入普遍存在于主要的早籼稻品种，但不是在中，晚季的，这对应于高温耐性的要求在抽穗期和灌浆期的早籼稻。结论：有益等位基因qHd 1赋予高温耐性在抽穗期和灌浆期，发挥了重要作用，在生态地理适应早籼稻在现代育种。这些结果与OsMADS 51-Ehd 1-RFT 1/Hd 3a花发育途径的相关研究结果为深入理解水稻抽穗期和产量性状温度响应调控的分子机制提供了有价值的信息。
Background:Rice is highly sensitive to temperature fluctuations. Recently, the frequent occurrence of high temperature stress has heavily influenced rice production. Proper heading date in specific environmental conditions could ensure high grain yield. Rice heading greatly depends on the accurate measurement of environmental changes, particularly in day length and temperature. In contrary to the detailed understanding of the photoperiod pathway, little has been known about how temperature regulates the genetic control of rice heading.Results:Near isogenic lines that were segregated for qHd1, were developed from a cross between indica rice varieties Zhenshan 97 (ZS97) and Milyang 46 (MY46). Using a five sowing-date experiment in the paddy field, we observed the involvement of qHd1 in temperature responses. With the gradual increase of temperature from Trial I to V, heading date of MY46 homozygotes continued to decrease for about 5 d per trial from 76 to 58 d, while that of ZS97 homozygotes was promoted at the same rate from Trial I to III and then stabilized at 69 d. This thermal response was confirmed in a temperature-gradient experiment conducted in the phytotron. It is also found that tolerance of the ZS97 allele to heading acceleration at high temperature was associated with higher grain weight that resulted in higher grain yield. Then, by qRT-PCR and RNA-seq, we found the pathway OsMADS51-Ehd1-RFT1/Hd3a underlying the qHd1-mediated floral response to temperature. By sequence comparison, OsMADS51 for qHd1 displayed a 9.5-kb insertion in the 1st intron of the ZS97 allele compared to the MY46 allele. Furthermore, this large insertion is commonly found in major early-season indica rice varieties, but not in the middle- and late-season ones, which corresponds to the requirement for high-temperature tolerance during the heading and grain-filling stages of early-season rice.Conclusions:Beneficial alleles at qHd1 confer tolerance to high temperatures at the heading and grain-filling stages, playing a significant role in the eco-geographical adaptation of early-season indica rice during modern breeding. These results, together with the underlying OsMADS51-Ehd1-RFT1/Hd3a floral pathway, provide valuable information for better understanding the molecular mechanism of temperature responsive regulation of heading date and yield traits in rice.