Downy mildew (Pl 8 and Pl 14 ) and rust (R Adv ) resistance genes reside in close proximity to tandemly duplicated clusters of non-TIR-like NBS-LRR-encoding genes on sunflower chromosomes 1 and 13

Abstract

Nucleotide binding site-leucine rich repeat (NBS-LRR) proteins are encoded by a ubiquitous gene family in sunflower and frequently harbor disease resistance genes. We investigated NBS-LRR-encoding resistance gene candidates (RGCs) flanking the downy mildew resistance genes Pl ( 8 ) and Pl ( 14 ) and the rust resistance gene R ( Adv ), which map on the NBS-LRR clusters of linkage groups 1 and 13 in sunflower genome. We shotgun sequenced bacterial artificial chromosome (BAC) clones proximal to Pl ( 8 ), Pl ( 14 ) , and R ( Adv ) and identified seven novel non-Toll/interleukin-1 receptor (TIR)-like NBS-LRR RGCs, which clustered with previously identified RGCs of linkage group 13 but were phylogenetically distant from the TIR- and non-TIR-NBS-LRR-encoding superfamilies of sunflower. Six of the seven predicted RGCs have intact open reading frames and reside in genomic segments with abundant transposable elements. The genomic localization and sequence similarity of the novel non-TIR-like predicted RGCs suggests that they originated from tandem duplications. RGCs in the proximity of Pl ( 8 ) and R ( Adv ) were likely introgressed from silverleaf sunflower genome, where the RGC cluster of linkage group 13 is duplicated in two independent chromosomes that have different architecture and level of recombination from the respective common sunflower chromosomes.

Genetic mapping of rust resistance genes in confection sunflower line HA-R6 and oilseed line RHA 397

“…To further narrow down the region harboring the R-genes, five resistance gene candidate (RGC) markers around the region of interest (Bachlava et al 2011;Radwan et al 2008) and six HA SSR markers previously mapped to the linkage group 13 (Talia et al 2010) were selected in the present study (Table 2). In addition, a 125.6-kb BAC clone (Genebank accession HQ222361) which corresponded to NBS-LRR locus RGC251 closely linked to downy mildew R-gene Pl 8 (Bachlava et al 2011), was used to design five new primer pairs (Table 3).…”

“…In addition, a 125.6-kb BAC clone (Genebank accession HQ222361) which corresponded to NBS-LRR locus RGC251 closely linked to downy mildew R-gene Pl 8 (Bachlava et al 2011), was used to design five new primer pairs (Table 3). Two primer pairs, SUN11 and SUN12, were developed from sequences in the two ends of the BAC clone.…”

“…The results revealed 13 lines resistant to both races, among which the breeding line HA-R6 is the only confection sunflower with high levels of resistance. Previously, 10 rust resistance genes, R 1 -R 5 , R 10 -R 12 , P u6 , and R adv , were documented in sunflower (Putt and Sackston 1963;Miah and Sackston 1970;Miller et al 1988;Yang et al 1989;Goulter 1990;Lambrides and Miller 1994;Lawson et al 1998;Radwan 2010;Bachlava et al 2011;Qi et al 2012b;Gong et al 2013). None of these genes, however, are present in public confection germplasm.…”

Monitoring Three Plasmopara halstedii Resistance Genes in Iranian Sunflower Inbred Lines

“…Pl 13 was also identified as a locus conferring resistance to races300, 700, 730, and 770 (20). The recent identified resistance gene, Pl 14 , confers resistance to race 730 (14). Although, several lines of evidence shows that Pl genes might have the coiled coils-nucleotide binding site-leucinerich repeat (CC-NBS-LRR) signature, so far none of the Pl genes are cloned (21,13,22).…”

“…Pl 1 was the first resistance gene identified in sunflower that provides resistancetorace100 (11). Several otherresistance genes have been identified and introduced to sunflower cultivars conferring resistance against different physiological races (12,13,14). Pl 2 confers resistance to race 300 (15).…”