Rice (Oryza sativa L.) is a staple food for over half of the global population. Cold stress at the booting stage leads to serious yield losses and has become a major limiting factor for rice production in regions of higher altitude and latitude. Therefore, isolating cold tolerance genes to facilitate breeding cultivars with higher cold tolerance at the booting stage (CTB) remains an urgent concern. Rice cold tolerance is a complex trait that is controlled by multiple loci. Due to the difficulties in identifying CTB phenotypes, only a few genes regulating CTB have been functionally characterized thus far.

Recently, a research group led by Prof. BU Qingyun from the the Northeast Institute of Geography and Agroecology (IGA) of Chinese Academy of Sciences (CAS) revealed that the mechanism of OsWRKY53 negatively regulates rice CTB, which provide a target for improving CTB in rice.

The study was published in The plant cell.

The researchers characterize the function of the cold-induced transcription factor OsWRKY53 in rice. The oswrky53 mutant displays increased CTB, as determined by higher seed setting. Low temperature is associated with lower gibberellin (GA) contents in anthers in the wild type but not in the oswrky53 mutant, which accumulates slightly more GA in its anthers. OsWRKY53 directly binds to the promoters of GA biosynthesis genes and transcriptionally represses them in anthers.

The researchers uncover a possible mechanism by which GA regulates male fertility: SLENDER RICE1 (SLR1) interacts with and sequesters two critical transcription factors for tapetum development, UNDEVELOPED TAPETUM1 (UDT1) and TAPETUM DEGENERATION RETARDATION (TDR), and GA alleviates the sequestration by SLR1, thus allowing UDT1 and TDR to activate transcription.

Finally, knocking out OsWRKY53 in diverse varieties increases cold tolerance without a yield penalty, leading to a higher yield in rice subjected to cold stress. Therefore, OsWRKY53 is a valuable target for cold-tolerance breeding.

The study provides new insights into the rice breeding. OsWRKY53 negatively regulates resistance to Xanthomonas oryzae pv. oryzae sheath blight, striped stem borer, and CTB in rice. It is very interesting to evaluate the practical value of oswrky53 mutants by assessing their yield under multiple conditions, including pathogen infection, insect pests, and low temperature or other stresses in the field.

The full information of the article:

Jiaqi Tang^#, Xiaojie Tian^#, Enyang Mei, Mingliang He, Junwen Gao, Jun Yu, Min Xu, Jiali Liu, Lu Song, Xiufeng Li, Zhenyu Wang, Qingjie Guan, Zhigang Zhao, Chunming Wang, Qingyun Bu*. (2022). WRKY53 negatively regulates rice cold tolerance at the booting stage by fine-tuning anther gibberellin levels, The plant cell. https://doi.org/10.1093/plcell/koac253.

Contact:

Prof. BU Qingyun

Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, Chinese Academy of Sciences, Harbin 150081, China.

E-mail: buqingyun@iga.ac.cn