An uncharacterized protein NY1 targets EAT1 to regulate anther tapetum development in polyploid rice

Nabieu Kamara; Zijun Lu; Yamin Jiao; Lianjun Zhu; Jinwen Wu; Zhixiong Chen; Lan Wang; Xiangdong Liu; Muhammad Qasim Shahid

doi:10.1186/s12870-022-03976-0

An uncharacterized protein NY1 targets EAT1 to regulate anther tapetum development in polyploid rice

BMC Plant Biol. 2022 Dec 13;22(1):582. doi: 10.1186/s12870-022-03976-0.

Authors

Nabieu Kamara^#^{1

2

3

4

5}, Zijun Lu^#^{1

2

3

4}, Yamin Jiao^#^{1

2

3

4}, Lianjun Zhu^{1

2

3

4}, Jinwen Wu^{1

2

3

4}, Zhixiong Chen^{1

2

3

4}, Lan Wang^{1

2

3

4}, Xiangdong Liu^{1

2

3

4}, Muhammad Qasim Shahid^{6

7

8

9}

Affiliations

¹ State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China.
² Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
³ Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou, 510642, China.
⁴ College of Agriculture, South China Agricultural University, Guangzhou, 510642, China.
⁵ Sierra Leone Agricultural Research Institute (SLARI), Freetown, PMB 1313, Sierra Leone.
⁶ State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China. qasim@scau.edu.cn.
⁷ Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China. qasim@scau.edu.cn.
⁸ Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou, 510642, China. qasim@scau.edu.cn.
⁹ College of Agriculture, South China Agricultural University, Guangzhou, 510642, China. qasim@scau.edu.cn.

^# Contributed equally.

Abstract

Background: Autotetraploid rice is a useful germplasm for the breeding of polyploid rice; however, low fertility is a major hindrance for its utilization. Neo-tetraploid rice with high fertility was developed from the crossing of different autotetraploid rice lines. Our previous research showed that the mutant (ny1) of LOC_Os07g32406 (NY1), which was generated by CRISPR/Cas9 knock-out in neo-tetraploid rice, showed low pollen fertility, low seed set, and defective chromosome behavior during meiosis. However, the molecular genetic mechanism underlying the fertility remains largely unknown.

Results: Here, cytological observations of the NY1 mutant (ny1) indicated that ny1 exhibited abnormal tapetum and middle layer development. RNA-seq analysis displayed a total of 5606 differentially expressed genes (DEGs) in ny1 compared to wild type (H1) during meiosis, of which 2977 were up-regulated and 2629 were down-regulated. Among the down-regulated genes, 16 important genes associated with tapetal development were detected, including EAT1, CYP703A3, CYP704B2, DPW, PTC1, OsABCG26, OsAGO2, SAW1, OsPKS1, OsPKS2, and OsTKPR1. The mutant of EAT1 was generated by CRISPR/Cas9 that showed abnormal tapetum and pollen wall formation, which was similar to ny1. Moreover, 478 meiosis-related genes displayed down-regulation at same stage, including 9 important meiosis-related genes, such as OsREC8, OsSHOC1, SMC1, SMC6a and DCM1, and their expression levels were validated by qRT-PCR.

Conclusions: Taken together, these results will aid in identifying the key genes associated with pollen fertility, which offered insights into the molecular mechanism underlying pollen development in tetraploid rice.

Keywords: Meiosis; Pollen sterility; RNA-seq; Tapetum; Tetraploid rice.

MeSH terms

Gene Expression Profiling
Gene Expression Regulation, Plant
Oryza* / metabolism
Plant Breeding
Polyploidy
Tetraploidy