The practice of hybridization has greatly contributed to the increase in crop productivity. A major component that exploits heterosis in crops is the cytoplasmic male sterility (CMS) / nucleus-controlled fertility restoration (Rf) system.

Dr. WANG Zhiwei from Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, professor XIANG Changping from Huazhong Agricultural University and researcher MEI Shiyong from Hubei Academy of Agricultural Sciences studied CMS and Rf in radish through positional cloning. Their results showed that heterozygous alleles ( RsRf3-1/RsRf3-2) encoding pentatricopeptide repeat (PPR) proteins were responsible for restoring fertility to cytoplasmic male-sterile radish (Raphanus sativus L.). Furthermore, it was found that heterozygous alleles (RsRf3-1/RsRf3-2) showed higher expression and RNA polymerase II occupancy in the CMS cytoplasmic background compared with their homozygous alleles (RsRf3-1/RsRf3-1 or RsRf3-2/RsRf3-2). These data provided new insights into the molecular mechanism of fertility restoration to cytoplasmic male-sterile plants and illustrate a case of overdominance.

This work was supported by the National Natural Science Foundation of China (31100231), the Natural Science Foundation of Hubei Province, China (2007ABA004, 2009CDB221, and 2011CDB408), the Youth Chenguang Project of Science and Technology of Wuhan, China (200850731402), and the fund of the CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture (Y152081t01). Relevant results were published in Journal of Experimental Botany (2013, 64:2041–2048, IF: 5.364) entitled “Heterozygous alleles restore male fertility to cytoplasmic male-sterile radish (Raphanus sativus L.): a case of overdominance”.

Article link: http://jxb.oxfordjournals.org/content/64/7/2041 

Comparative study of anthers through different developmental stages in the male-fertile and male-sterile plants from 9802A1 and 9802B1 (Image by WANG)