Zhao Junliang, Zhang Shaohong, Dong Jingfang, Yang Tifeng, Mao Xingxue, Liu Qing, Wang Xiaofei, Liu Bin
Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China.
Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangdong Academy of Agricultural Sciences, Guangzhou, China.
Plant Biotechnol J. 2017 Sep;15(9):1141-1148. doi: 10.1111/pbi.12704. Epub 2017 Mar 30.
Identification and cloning of cold-tolerant genes that can stably express under different cold environments are crucial for molecular rice breeding for cold tolerance. In the previous study, we identified a cold-tolerant QTL at the seedling stage, qCTS-9 which could be detected under different cold environments using a recombinant inbred line (RIL) population derived from a cold-tolerant variety Lijiangxintuanheigu (LTH) and a cold-sensitive variety Shanhuangzhan 2 (SHZ-2). In this study, eight candidate genes within the qCTS-9 interval were identified through integrated analysis of QTL mapping with genomewide differential expression profiling of LTH. The qRT-PCR assay showed that only Os09g0410300 exhibited different expression patterns between LTH and SHZ-2 during cold stress, and significantly positive correlation was found between cold induction of Os09g0410300 and seedling cold tolerance in the RI lines. Five SNPs and one InDel in the promoters of Os09g0410300 were detected between LTH and SHZ-2, and the InDel marker ID410300 designed based on the insertion-deletion polymorphism in the promoter was significantly associated with seedling cold tolerance in RIL population. Further, Os09g0410300 over-expression plants exhibited enhanced cold tolerance at the seedling stage compared with the wild-type plants. Thus, our results suggest that Os09g0410300 is the functional gene underlying qCTS-9. To our knowledge, it is a novel gene contributed to enhance cold tolerance at the seedling stage in rice. Identification of the functional gene underlying qCTS-9 and development of the gene-specific marker will facilitate molecular breeding for cold tolerance at the seedling stage in rice through transgenic approach and marker-assisted selection (MAS).
鉴定和克隆能够在不同低温环境下稳定表达的耐寒基因，对于水稻耐寒分子育种至关重要。在之前的研究中，我们在苗期鉴定到一个耐寒QTL，即qCTS - 9，利用源自耐寒品种丽江新团黑谷（LTH）和冷敏感品种汕黄占2（SHZ - 2）的重组自交系（RIL）群体，该QTL在不同低温环境下均可被检测到。在本研究中，通过对QTL定位与LTH全基因组差异表达谱进行综合分析，在qCTS - 9区间鉴定出8个候选基因。qRT - PCR分析表明，在低温胁迫期间，仅Os09g0410300在LTH和SHZ - 2之间表现出不同的表达模式，并且在RI系中，Os09g0410300的冷诱导与幼苗耐寒性之间存在显著正相关。在LTH和SHZ - 2之间检测到Os09g0410300启动子区的5个单核苷酸多态性（SNP）和1个插入缺失（InDel），基于启动子区插入缺失多态性设计的InDel标记ID410300与RIL群体的幼苗耐寒性显著相关。此外，与野生型植株相比，Os09g0410300过表达植株在苗期表现出增强的耐寒性。因此，我们的结果表明Os09g0410300是qCTS - 9的功能基因。据我们所知，它是一个有助于提高水稻苗期耐寒性的新基因。鉴定qCTS - 9的功能基因并开发基因特异性标记，将通过转基因方法和标记辅助选择（MAS）促进水稻苗期耐寒性的分子育种。
