OsRH52A, a DEAD-Box protein, is required for embryo sac development by regulating functional megaspore specification in rice

Jinghua Huang; Zhengping Qiao; Hang Yu; Zijun Lu; Weibin Chen; Junming Lu; Jinwen Wu; Yueming Bao; Muhammad Qasim Shahid; Xiangdong Liu

doi:10.1093/jxb/erae180

OsRH52A, a DEAD-Box protein, is required for embryo sac development by regulating functional megaspore specification in rice

J Exp Bot. 2024 Apr 20:erae180. doi: 10.1093/jxb/erae180. Online ahead of print.

Authors

Jinghua Huang^{1

2

3}, Zhengping Qiao^{1

2

3}, Hang Yu^{1

2

3}, Zijun Lu^{1

2

3}, Weibin Chen^{1

2

3}, Junming Lu^{1

2

3}, Jinwen Wu^{1

2

3}, Yueming Bao^{1

2

3}, Muhammad Qasim Shahid^{1

2

3}, Xiangdong Liu^{1

2

3}

Affiliations

¹ State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
² Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
³ Guangdong Base Bank for Lingnan Rice Germplasm Resources, College of Agriculture, South China Agricultural University, Guangzhou 510642, China.

PMID: 38642102
DOI: 10.1093/jxb/erae180

Abstract

The development of the embryo sac is an important factor affecting seed setting in rice. Numerous genes associated with embryo sac (ES) development have been identified in plants. However, the function of the DEAD-box RNA helicase family genes on ES is poorly known in rice. Here, we characterized a rice DEAD-box protein, OsRH52A, which was localized in the nucleus and cytoplasm and highly expressed in the floral organs in rice. The knockout mutant, rh52a, displayed partial ES sterility, including degenerated ES (21.0%) and the presence of double-female-gametophyte (DFG) structure (11.8%). The DFG developed from two functional megaspores (FM) near the chalazal end in one ovule, and 3.4% of DFG could fertilize via the sac near the micropylar pole in rh52a. OsRH52A was found to interact with OsMFS1 and ZIP4, both of which play a role in homologous recombination in rice meiosis. RNA-seq identified 234 down-regulated differentially expressed genes (DEGs) associated with reproductive development, including the two genes, OsMSP1 and HSA1b, required for female germline cell specification. Taken together, our study demonstrated that OsRH52A is essential for the development of the embryo sac and provided cytological evidence regarding the formation of DFG.

Keywords: Oryza sativa L; DEAD-Box RNA helicase; cell specification; chalazal functional megaspore; double-female-gametophyte; embryo sac.