Cytoplasmic male sterility (CMS) is a naturally occurring phenomenon in plants where pollen grains do not develop, making cross-pollination necessary for successful reproduction. CMS has been widely utilized in hybrid breeding, but the lack of well-validated fertility restorer genes has hindered its application in pepper cultivation. While previous research pinpointed potential restorer genes on chromosome 6 in peppers, functional validation had not been achieved. This gap created a clear need for further research to identify and confirm effective fertility restorer genes in peppers.
A new study (DOI: 10.1093/hr/uhae223) led by a team from Hunan Agricultural University, in collaboration with other leading institutions, was published in Horticulture Research on October 1, 2024. The team discovered the CaRf gene, which encodes a mitochondria-targeted protein essential for restoring fertility in CMS pepper lines. In addition, they introduced the PepperSNP50K breeding chip—a powerful high-throughput genotyping tool designed to accelerate the breeding process by enhancing precision in genetic analysis.
The research team used a multi-faceted approach to identify and validate the CaRf gene, which encodes a pentatricopeptide repeat (PPR) protein crucial for restoring male fertility in CMS pepper lines. Through bulked segregant analysis (BSA-seq) and fine mapping, the team localized CaRf to a specific region on chromosome 6. Virus-induced gene silencing (VIGS) experiments confirmed its function—when CaRf was downregulated in hybrid F1 plants, male sterility occurred, proving its essential role in fertility restoration. Additionally, the researchers developed the PepperSNP50K breeding chip, which includes 51,172 markers across the pepper genome. This chip enables breeders to select genetic backgrounds with high precision, significantly improving the efficiency of developing high-quality pepper hybrids with desirable traits like increased yield and disease resistance.
Dr. Bingqian Tang, the lead researcher on the project, commented, “The discovery of CaRf and the development of the PepperSNP50K chip mark a significant advancement in pepper breeding. These tools will not only streamline the breeding process but also reduce labor costs and improve genetic diversity in hybrid varieties.”
The implications of this research extend beyond scientific curiosity; it has the potential to transform the pepper breeding industry. The identification of the CaRf gene, combined with the high-throughput capabilities of the PepperSNP50K chip, provides practical, scalable strategies for molecular breeding in peppers. These advancements can expedite the creation of high-yielding, disease-resistant pepper varieties, offering both economic and environmental benefits. The integration of these innovations into breeding programs promises to significantly enhance pepper production, contributing to a more sustainable future for the industry.
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References
DOI
10.1093/hr/uhae223
Original Source URL
https://doi.org/10.1093/hr/uhae223
Funding information
This work was supported by the Construction of Innovative Provinces in Hunan Province (Grant No. 2021NK1006), the National Natural Science Foundation of China (Grant No. 32402571), the Hunan Provincial Natural Science Foundation of China (Grant No. 2024JJ6239), the China Postdoctoral Science Foundation (Grant No. 2023M741144), and the Postdoctoral Fellowship Program of CPSF (Grant No. GZC20230777).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2022. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.