Jiajia Wang, Jing Xu, Li Wang, Mengyu Zhou, Jinqiang Nian, Minmin Chen, Xueli Lu, Xiong Liu, Zian Wang, Jiangsu Cen, Yiting Liu, Zhihai Zhang, Dali Zeng, Jiang Hu, Li Zhu, Guojun Dong, Deyong Ren, Zhenyu Gao, Lan Shen, Qiang Zhang, Qing Li, Longbiao Guo, Sibin Yu, Qian Qian, Guangheng Zhang.

Plant Biotechnol J.; 2023 Apr; 21(4):819-838. doi: 10.1111/pbi.13999.

Abstract

Plant architecture and stress tolerance play important roles in rice breeding. Specific leaf morphologies and ideal plant architecture can effectively improve both abiotic stress resistance and rice grain yield. However, the mechanism by which plants simultaneously regulate leaf morphogenesis and stress resistance remains elusive. Here, we report that SRL10, which encodes a double-stranded RNA-binding protein, regulates leaf morphology and thermotolerance in rice through alteration of microRNA biogenesis. The srl10 mutant had a semi-rolled leaf phenotype and elevated sensitivity to high temperature. SRL10 directly interacted with catalase isozyme B (CATB), and the two proteins mutually increased one other's stability to enhance hydrogen peroxide (H₂ O₂ ) scavenging, thereby contributing to thermotolerance. The natural Hap3 (AGC) type of SRL10 allele was found to be present in the majority of aus rice accessions, and was identified as a thermotolerant allele under high temperature stress in both the field and the growth chamber. Moreover, the seed-setting rate was 3.19 times higher and grain yield per plant was 1.68 times higher in near-isogenic line (NIL) carrying Hap3 allele compared to plants carrying Hap1 allele under heat stress. Collectively, these results reveal a new locus of interest and define a novel SRL10-CATB based regulatory mechanism for developing cultivars with high temperature tolerance and stable yield. Furthermore, our findings provide a theoretical basis for simultaneous breeding for plant architecture and stress resistance.

See https://pubmed.ncbi.nlm.nih.gov/36597711/

Figure 4

Map‐based cloning of SRL10. (a) Mapping of SRL10. (b–d) Complementation tests of SRL10. Representative images of WYJ7, srl10 and SRL10‐COM (T₂‐generation) plants (b) and leaves (c) under standard growth conditions. Scale bars = 20 cm and 7 cm respectively. (d) WYJ7, srl10 and SRL10‐COM plants under standard growth conditions (upper) and heat stress (lower). Scale bar = 5 cm. (e) Chromatograms showing the sequences of WYJ7, srl10 and SRL10‐COM in the relevant region of LOC_Os10g33970. (f) Volcano plot of differentially expressed miRNAs between WYJ7 and srl10. (g) Heat map of differentially expressed miRNAs between WYJ7 and srl10. (h) Leaf rolling index (LRI) values of WYJ7, srl10 and SRL10‐COM. Data are given as mean ± standard deviation. Significant differences between groups are marked with different letters (Duncan's multiple range test, P < 0.05). (i) Survival rate of WYJ7, srl10 and SRL10‐COM after heat stress. Data are given as mean ± standard deviation. Significant differences between groups are marked with different letters (Duncan's multiple range test, P < 0.05). (j) Relative expression level of miR166m in leaves of WYJ7 and srl10. Data are given as mean ± standard deviation. Asterisks indicate significant difference based on the Student's t test: ** for P < 0.01.