Inheritance of fertility restorer gene for cytoplasmic male-sterility in B. napus and identification of closely linked molecular markers to it

Abstract

Here we report identification and inheritance of a restorer gene for the restoration of cytoplasmic male sterility in Brassica napus. Analysis of 373 plants in F2 segregating population resulted from the crosses of cms PI-ARIT121 with four different restorer inbred lines found 288 male fertile and 85 male sterile progeny in the expected 3–1 ratio indicating a single dominant gene controlling fertility restoration. This observation has also been confirmed in a back cross population of 136 individuals with 66 male fertile and 70 male sterile with the expected 1–1 ratio. Analysis of two F2 populations with SRAP molecular marker revealed that two primer combinations, Me2Em5 and Me1Mo1 were linked to the restorer gene with 1 % recombination frequency. Sequencing of the linked SRAP markers from the polyacrylamide gel and blast search revealed no significant match with the known restorer gene found in B. napus. By designing new primers in the direction of the restorer gene doing chromosome walk, we found 100 % linked marker to the restorer gene and named as PPR121. Sequencing of this gene indicated to be in the same locus with other restorer genes found in B. napus, but a little different sequence may indicates evolution of new restorer gene for the cms-ARIT121. NCBI searches indicate close similarity to genes encoding the pentatricopeptide proteins that have functions in almost all stages of gene expression, including messenger RNA transcription, splicing, processing, editing, translation and stability.