Association of nad7a Gene with Cytoplasmic Male Sterility in Pigeonpea

Abstract

Cytoplasmic male sterility (CMS) has been exploited in the commercial pigeonpea [ (L.) Millsp.] hybrid breeding system; however, the molecular mechanism behind this system is unknown. To understand the underlying molecular mechanism involved in A CMS system derived from (Haines) Maesen, 34 mitochondrial genes were analyzed for expression profiling and structural variation analysis between CMS line (ICRISAT Pigeonpea A line, ICPA 2039) and its cognate maintainer (ICPB 2039). Expression profiling of 34 mitochondrial genes revealed nine genes with significant fold differential gene expression at ≤ 0.01, including one gene, , with 1366-fold higher expression in CMS line as compared with the maintainer. Structural variation analysis of these mitochondrial genes identified length variation between ICPA 2039 and ICPB 2039 for (subunit of gene). Sanger sequencing of and genes in the CMS and the maintainer lines identified two single nucleotide polymorphisms (SNPs) in upstream region of and a deletion of 10 bp in in the CMS line. Protein structure evaluation showed conformational changes in predicted protein structures for between ICPA 2039 and ICPB 2039 lines. All above analyses indicate association of gene with the CMS for A cytoplasm in pigeonpea. Additionally, one polymerase chain reaction (PCR) based Indel marker () has been developed and validated for testing genetic purity of A derived CMS lines to strengthen the commercial hybrid breeding program in pigeonpea.