An insertion mutation located on putative enhancer regions of the -like gene induces inhibition of anther dehiscence resulting in novel genic male sterility in radish ( L.).

Unlabelled: A novel male-sterility trait was identified in a radish ( L.) population. Although the size of male-sterile anthers was comparable to that of normal flowers, no pollen grain was observed during anther dehiscence. However, dissection of male-sterile anthers revealed an abundance of normal pollen grains. Analysis of segregating populations showed that a single recessive locus, designated , conferred male sterility. Based on two radish draft genome sequences, molecular markers were developed to delimit the genomic region harboring the . The region was narrowed down to approximately 24 kb after analyzing recombinants selected from 7511 individuals of a segregating population. Sequencing of the delimited region yielded six putative genes including four genes expressed in the floral tissue, and one gene with significant differential expression between male-fertile and male-sterile individuals of a segregating population. This differentially expressed gene was orthologous to the gene, which played a critical role in anther dehiscence. Excluding a synonymous single nucleotide polymorphism in exon3, no polymorphism involving coding and putative promoter regions was detected between alleles. A 955-bp insertion was identified 7.5 kb upstream of the recessive allele. Highly conserved motifs among four Brassicaceae species were identified around this insertion site, suggesting the presence of putative enhancer sequences. A functional marker was developed for genotyping of the based on the 955-bp insertion. A total of 120 PI accessions were analyzed using this marker, and 11 accessions were shown to carry the recessive allele.

Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-021-01254-9.