Fine mapping of a dominant thermo-sensitive genic male sterility gene (BntsMs) in rapeseed (Brassica napus) with AFLP- and Brassica rapa-derived PCR markers

Abstract

A new thermo-sensitive dominant genic male sterility (TSDGMS) line of Brassica napus was found and mapped in this paper. Our result will greatly accelerate the map-based cloning of the BntsMs gene. TE5A is a thermo-sensitive dominant genic male sterility line originating from spontaneous mutation of the inbred line TE5 in Brassica napus and provides a promising system for the development of hybrid cultivars. Genetic analysis has revealed that the BntsMs mutant is controlled by a single, dominant gene. Here, we describe the fine mapping of BntsMs using amplified fragment length polymorphism (AFLP) and intron polymorphism (IP) methodologies. We screened 1,024 primer combinations and then identified five AFLP markers linked to the BntsMs gene, two of which were successfully converted into sequence-characterised amplified region (SCAR) markers. The linkage of the markers was identified by analysing a large BC2 population of 700 recessive-fertility individuals. Two SCAR markers were found in the flanking region of the BntsMs gene at distance of 3.5 and 4.8 cm. Based on sequence information from the previously screened AFLP markers and on genome organisation comparisons of the A genome of Brassica rapa and Arabidopsis, seven IP markers linked to the BntsMs gene were developed. By analysing the 700 recessive-fertility individuals, two IP markers, IP004 and IP470, were localised to the flanking region of the BntsMs gene at a distance of 0.3 and 0.2 cm, respectively. A comparison of the B. rapa and Arabidopsis genomes revealed 27 genes of B. rapa in the flanking region of these two IP markers. It is likely that the molecular markers developed from these investigations will greatly accelerate the positional cloning of the BntsMs gene.

Identification and Analysis of MS5d: A Gene That Affects Double-Strand Break (DSB) Repair during Meiosis I in Brassica napus Microsporocytes

“…The MS5 d gene had been previously localized to a 103-kb region that is highly syntenic to the B. rapa linkage group A8, and 24 putative genes (from Bra018439 to Bra018465 ) were identified in the target region ( Figure 1a ) (Zeng et al, 2014). Based on homolog analyses in Arabidopsis , functional annotation of the B. rapa transcripts suggested that six of the 24 B. rapa genes ( Bra018457, Bra018451, Bra018449, Bra018446, Bra018443 , and Bra018441 ) were involved in anther development 2 .…”

“…The B. napus lines TE5A and TE5 were obtained from the Oil Crop Research Institute of the Chinese Academy of Agricultural Sciences; we described TE5A in a previous study (Zeng et al, 2014). Mutant lines were planted in a greenhouse under 25°C day/15°C night temperature conditions.…”

“…The thermosensitive genic male sterility line TE5A is a spontaneous mutant from the B. napus inbred line TE5 (Zeng et al, 2014). The fertility of TE5A is normal at low temperature, but it shows complete male sterility and partial female sterility at temperatures above 20°C.…”

“…The fertility of TE5A is normal at low temperature, but it shows complete male sterility and partial female sterility at temperatures above 20°C. Previous genetic analysis revealed that the male sterility of TE5A is controlled by a single dominant gene, BntsMs (equivalent to MS5 d ; Zeng et al, 2014). Using a map-based cloning approach, the MS5 d gene was successfully localized to a region containing 24 annotated genes (Zeng et al, 2014).…”

“…Previous genetic analysis revealed that the male sterility of TE5A is controlled by a single dominant gene, BntsMs (equivalent to MS5 d ; Zeng et al, 2014). Using a map-based cloning approach, the MS5 d gene was successfully localized to a region containing 24 annotated genes (Zeng et al, 2014). In the current study, MS5 d was successfully identified based on the microsynteny between Brassica and Arabidopsis and was confirmed by Agrobacterium tumefaciens -mediated genetic transformation assays.…”