National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
Int J Mol Sci. 2022 Aug 5;23(15):8715. doi: 10.3390/ijms23158715.
Grain size is a key determinant of both grain weight and grain quality. Here, we report the map-based cloning of a novel quantitative trait locus (QTL), (, ), which encodes the CCT motif family protein, GHD7. The QTL is located in a 53 kb deletion fragment in the cultivar Jin23B, compared with the cultivar CR071. Scanning electron microscopy analysis and expression analysis revealed that promotes the transcription of several cell division and expansion genes, further resulting in a larger cell size and increased cell number, and finally enhancing the grain size as well as grain weight. could also increase endogenous GA content by up-regulating the expression of GA biosynthesis genes. Yeast two-hybrid assays and split firefly luciferase complementation assays revealed the interactions of GHD7 with seven grain-size-related proteins and the rice DELLA protein SLR1. Haplotype analysis and transcription activation assay revealed the effect of six amino acid substitutions on GHD7 activation activity. Additionally, the NIL with showed reduced chalkiness and improved cooking and eating quality. These findings provide a new insight into the role of and confirm the great potential of the allele in simultaneously improving grain yield and quality.
粒型是决定粒重和粒质的关键因素。在这里，我们报道了一个新的数量性状位点（QTL）的图位克隆， （ ），其编码 CCT 基序家族蛋白 GHD7。该 QTL位于品种 Jin23B 与品种 CR071 相比的 53kb 缺失片段中。扫描电子显微镜分析和表达分析表明， 促进了几个细胞分裂和扩张基因的转录，进一步导致细胞尺寸增大和细胞数量增加，最终增加了粒型和粒重。 还可以通过上调 GA 生物合成基因的表达来增加内源 GA 含量。酵母双杂交试验和分裂萤火虫荧光素酶互补测定表明 GHD7 与七个粒型相关蛋白和水稻 DELLA 蛋白 SLR1 的相互作用。单倍型分析和转录激活试验揭示了六个氨基酸取代对 GHD7 激活活性的影响。此外，携带 的 NIL 表现出降低的垩白度和改善的蒸煮和食用品质。这些发现为 和确认 的等位基因在同时提高产量和品质方面的巨大潜力提供了新的见解。
