Qi L L, Ma G J, Long Y M, Hulke B S, Gong L, Markell S G
USDA-Agricultural Research Service, Northern Crop Science Laboratory, 1605 Albrecht Blvd N, Fargo, ND, 58102-2765, USA,
Theor Appl Genet. 2015 Mar;128(3):477-88. doi: 10.1007/s00122-014-2446-0. Epub 2015 Jan 11.
The rust resistance gene R 2 was reassigned to linkage group 14 of the sunflower genome. DNA markers linked to R 2 were identified and used for marker-assisted gene pyramiding in a confection type genetic background. Due to the frequent evolution of new pathogen races, sunflower rust is a recurring threat to sunflower production worldwide. The inbred line Morden Cross 29 (MC29) carries the rust resistance gene, R 2 , conferring resistance to numerous races of rust fungus in the US, Canada, and Australia, and can be used as a broad-spectrum resistance resource. Based on phenotypic assessments and SSR marker analyses on the 117 F2 individuals derived from a cross of HA 89 with MC29 (USDA), R 2 was mapped to linkage group (LG) 14 of the sunflower, and not to the previously reported location on LG9. The closest SSR marker HT567 was located at 4.3 cM distal to R 2 . Furthermore, 36 selected SNP markers from LG14 were used to saturate the R 2 region. Two SNP markers, NSA_002316 and SFW01272, flanked R 2 at a genetic distance of 2.8 and 1.8 cM, respectively. Of the three closely linked markers, SFW00211 amplified an allele specific for the presence of R 2 in a marker validation set of 46 breeding lines, and SFW01272 was also shown to be diagnostic for R 2 . These newly developed markers, together with the previously identified markers linked to the gene R 13a , were used to screen 524 F2 individuals from a cross of a confection R 2 line and HA-R6 carrying R 13a . Eleven homozygous double-resistant F2 plants with the gene combination of R 2 and R 13a were obtained. This double-resistant line will be extremely useful in confection sunflower, where few rust R genes are available, risking evolution of new virulence phenotypes and further disease epidemics.
抗锈病基因R 2被重新定位到向日葵基因组的第14连锁群。鉴定出与R 2连锁的DNA标记，并将其用于在一种食用型遗传背景下进行标记辅助基因聚合。由于新病原菌小种的频繁进化，向日葵锈病对全球向日葵生产构成反复威胁。自交系莫登杂交29（MC29）携带抗锈病基因R 2，对美国、加拿大和澳大利亚的多种锈菌小种具有抗性，可作为一种广谱抗性资源。基于对HA 89与MC29（美国农业部）杂交产生的117个F2个体的表型评估和SSR标记分析，R 2被定位到向日葵的第14连锁群（LG），而非先前报道的LG9上的位置。最接近的SSR标记HT567位于R 2下游4.3厘摩处。此外，从第14连锁群中选择的36个SNP标记用于使R 2区域饱和。两个SNP标记NSA_002316和SFW01272分别在R 2两侧，遗传距离为2.8和1.8厘摩。在三个紧密连锁的标记中，SFW00211在46个育种系的标记验证集中扩增出一个特定于R 2存在的等位基因，并且SFW01272也被证明对R 2具有诊断性。这些新开发的标记，连同先前鉴定的与基因R 13a连锁的标记，用于筛选来自一个携带R 13a的食用型R 2系与HA - R6杂交的524个F2个体。获得了11株具有R 2和R 13a基因组合的纯合双抗F2植株。这种双抗品系在食用型向日葵中将非常有用，因为在食用型向日葵中可用的抗锈病基因很少，存在新的毒性表型进化和进一步病害流行的风险。
