qGW11a/OsCAT8, encoding an amino acid permease, negatively regulates grain size and weight in rice

Peng Gao#, Feifan Chen#, Haitang Liu#, Shijun Fan, Jierui Zeng, Xue Diao, Yang Liu, Wencheng Song, Shifu Wang, Jing Li, Xiaobo Zhu, Bin Tu, Weilan Chen, Ting Li, Yuping Wang, Bingtian Ma, Shigui Li, Hua Yuan, Peng Qin

The Crop Journal.Volume 12, Issue 4, August 2024, Pages 1150-1158(IF=6.6)

https://www.sciencedirect.com/science/article/pii/S2214514124001296

Abstract

Grain size is a key factor influencing grain weight in rice. In this study, a chromosome segment substitution line (CSSL9-17) was identified, that exhibits a significant reduction in both grain size and weight compared to its donor parent 93-11. Further investigation identified two quantitative trait loci (QTL) on chromosome 11, designated qGW11a and qGW11b, which contribute to 1000-grain weight with an additive effect. LOC_Os11g05690, encoding the amino acid permease OsCAT8, is the target gene of qGW11a. Overexpression of OsCAT8 resulted in decreased grain weight, while OsCAT8 knockout mutants exhibited increased grain weight. The 287-bp located within the OsCAT8 promoter region of 93-11 negatively regulates its activity, which is subsequently correlated with an increase in grain size and weight. These results suggest that OsCAT8 functions as a negative regulator of grain size and grain weight in rice.

Keywords: Rice; Grain size; Grain weight; QTL; OsCAT8