A predicted NEDD8 conjugating enzyme gene identified as a Capsicum candidate Rf gene using bulk segregant RNA sequencing

Bingqiang Wei; Paul W Bosland; Zhenghai Zhang; Yongfu Wang; Gaoyuan Zhang; Lanlan Wang; Jihua Yu

doi:10.1038/s41438-020-00425-7

A predicted NEDD8 conjugating enzyme gene identified as a Capsicum candidate Rf gene using bulk segregant RNA sequencing

Hortic Res. 2020 Dec 1:7:210. doi: 10.1038/s41438-020-00425-7. eCollection 2020.

Authors

Bingqiang Wei¹, Paul W Bosland², Zhenghai Zhang³, Yongfu Wang¹, Gaoyuan Zhang¹, Lanlan Wang⁴, Jihua Yu¹

Affiliations

¹ College of Horticulture, Gansu Agricultural University, 1 Yingmeng Village, Anning District, 730070 Lanzhou, China.
² Plant and Environmental Sciences Department, New Mexico State University, P.O. Box 30003, Las Cruces, 88001 NM USA.
³ Key Laboratory of Vegetable Genetics and Physiology of Ministry of the Agriculture, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 12 Zhongguancun Nandajie, 100081 Beijing, China.
⁴ Vegetable Institute, Gansu Academy of Agricultural Sciences, 1 Nongkeyuan New Village, 730070 Lanzhou, China.

Abstract

Cytoplasmic male sterility (CMS) is an important tool for producing F₁ hybrids, which can exhibit heterosis. The companion system, restorer-of-fertility (Rf), is poorly understood at the molecular level and would be valuable in producing restorer lines for hybrid seed production. The identity of the Rf gene in Capsicum (pepper) is currently unclear. In this study, using bulked segregant RNA sequencing (BSR-seq), a strong candidate Rf gene, Capana06g002866, which is annotated as a NEDD8 conjugating enzyme E2, was identified. Capana06g002866 has an ORF of 555 bp in length encoding 184 amino acids; it can be cloned from F₁ plants from the hybridization of the CMS line 8A and restorer line R1 but is not found in CMS line 8A. With qRT-PCR validation, Capana06g002866 was found to be upregulated in restorer accessions compared to sterile accessions. The relative expression in flower buds increased with the developmental stage in F₁ plants, while the expression was very low in all flower bud stages of the CMS lines. These results provide new insights into the Rf gene in pepper and will be useful for other crops utilizing the CMS system.

Keywords: Plant breeding; Plant sciences.