Phenotypic, genetic, and molecular function of msc-2, a genic male sterile mutant in pepper (Capsicum annuum L.)

Theor Appl Genet. 2020 Mar;133(3):843-855. doi: 10.1007/s00122-019-03510-1. Epub 2019 Dec 20.

Abstract

Bulked segregant analysis and fine mapping delimited the pepper genic male sterile (msc-2) locus into a 336 kb region on chromosome 5. A strong candidate gene, Capana05g000766, a homolog of AtMS1, was indentified in this region. Genic male sterility (msc-2) is used to produce hybrid seeds in Northern China. However, no co-segregated markers have been reported or candidate genes controlling this trait have been cloned. Here, bulked segregant analysis and genotyping of an F2 population and a 18Q5431AB line were employed to fine map msc-2, which was delimited to a 336 kb region. In this region, Capana05g000766 was a homolog of AtMS1, which encodes a plant homeodomain finger involved in tapetum development. A "T" deletion in the Capana05g000766 locus leads to a premature stop codon, which may cause a loss-of-function mutation. Real-time PCR analysis revealed that Capana05g000766 was an anther-specific gene and down-regulation of the gene resulted in male sterility. Therefore, Capana05g000766 was identified as the strongest candidate gene for the msc-2 locus. Allelism tests showed that msc-1 and msc-2 were nonallelic, and bimolecular fluorescence complementation analysis indicated that the two genes did not interact directly with each other at the protein level. As msc-1 and msc-2 are homologs of AtDYT1 and AtMS1 in Arabidopsis, they may play similar roles in tapetum development in genic male sterile peppers, and Msc-1 might be up stream of Msc-2 in the regulation of other genes involved in tapetum development.

MeSH terms

  • Alleles
  • Arabidopsis Proteins / genetics
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Capsicum / genetics*
  • Chromosome Mapping
  • Codon, Nonsense
  • Down-Regulation
  • Flowers / genetics
  • Flowers / metabolism
  • Gene Expression Regulation, Plant / genetics*
  • Gene Silencing
  • Genes, Plant
  • High-Throughput Nucleotide Sequencing
  • Phenotype
  • Phylogeny
  • Plant Infertility / genetics*
  • Plant Leaves / genetics
  • Plant Leaves / metabolism
  • Polymorphism, Single Nucleotide
  • Sequence Deletion
  • Transcription Factors / genetics

Substances

  • Arabidopsis Proteins
  • Basic Helix-Loop-Helix Transcription Factors
  • Codon, Nonsense
  • DYT1 protein, Arabidopsis
  • MS1 protein, Arabidopsis
  • Transcription Factors