Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka City, Shizuoka 422-8529, Japan.
Faculty of Agriculture, Tottori University, 4-101 Koyama Minami, Tottori 680-8550, Japan.
Int J Mol Sci. 2019 Oct 31;20(21):5442. doi: 10.3390/ijms20215442.
Genetic analysis of "InochinoIchi," an exceptionally large grain rice variety, was conducted through five continuous backcrosses with Koshihikari as a recurrent parent using the large grain F plant in Koshihikari × Inochinoichi as a nonrecurrent parent. Thorough the F and all BCnF generations, large, medium, and small grain segregated in a 1:2:1 ratio, indicating that the large grain is controlled by a single allele. Mapping by using simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers with small grain homozygous segregants in the F of Nipponbare × Inochinoichi, revealed linkage with around 7.7 Mb markers from the distal end of the short arm of chromosome 2. Whole-genome sequencing on a large grain isogenic Koshihikari (BCF) using next-generation sequencing (NGS) identified a single nucleotide deletion in gene, which is located 8.1 Mb from the end of chromosome 2, encoding a RING protein with E3 ubiquitin ligase activity. The -integrated isogenic Koshihikari showed a 34% increase in thousand kernel weight compared to Koshihikari, while retaining a taste score of 80. We further developed a large grain/semi-dwarf isogenic Koshihikari integrated with and the semidwarfing gene , which was found to be localized on chromosome 2. The combined genotype secured high yielding while providing robustness to withstand climate change, which can contribute to the New Green Revolution.
利用“越光×InochinoIchi”的大粒 F1 植株作为非轮回亲本，通过与“越光”连续 5 代回交，对特大粒水稻品种“InochinoIchi”进行了遗传分析。在 F1 和所有 BCnF 世代中，大、中、小粒分离比为 1:2:1，表明大粒由单个等位基因控制。利用“日本晴×InochinoIchi”的 F1 中小粒纯合子分离的简单重复序列（SSR）和单核苷酸多态性（SNP）标记进行作图，发现与 2 号染色体短臂末端约 7.7 Mb 的标记连锁。利用下一代测序（NGS）对大粒纯合“越光”（BCF）进行全基因组测序，在 2 号染色体末端 8.1 Mb 处发现一个基因的单个核苷酸缺失，该基因编码具有 E3 泛素连接酶活性的 RING 蛋白。与“越光”相比，-整合的纯合“越光”千粒重增加了 34%，而口感评分保持在 80 分。我们进一步开发了一个带有 和半矮秆基因 的大粒/半矮秆纯合“越光”，该基因定位于 2 号染色体上。综合基因型确保了高产，同时具有抵御气候变化的稳健性，为新绿色革命做出贡献。
