Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA.
Theor Appl Genet. 2013 Jan;126(1):93-9. doi: 10.1007/s00122-012-1962-z. Epub 2012 Aug 21.
Sunflower production in North America has recently suffered economic losses in yield and seed quality from sunflower rust (Puccinia helianthi Schwein.) because of the increasing incidence and lack of resistance to new rust races. RHA 464, a newly released sunflower male fertility restorer line, is resistant to both of the most predominant and most virulent rust races identified in the Northern Great Plains of the USA. The gene conditioning rust resistance in RHA 464 originated from wild Helianthus annuus L., but has not been molecularly marked or determined to be independent from other rust loci. The objectives of this study are to identify molecular markers linked to the rust resistance gene and to investigate the allelism of this gene with the unmapped rust resistance genes present in HA-R6, HA-R8 and RHA 397. Virulence phenotypes of seedlings for the F(2) population and F(2:3) families suggested that a single dominant gene confers rust resistance in RHA 464, and this gene was designated as R(12). Bulked segregant analysis identified ten markers polymorphic between resistant and susceptible bulks. In subsequent genetic mapping, the ten markers covered 33.4 cM of genetic distance on linkage group 11 of sunflower. A co-dominant marker CRT275-11 is the closest marker distal to R(12) with a genetic distance of 1.0 cM, while ZVG53, a dominant marker linked in the repulsion phase, is proximal to R(12) with a genetic distance of 9.6 cM. The allelism test demonstrated that R(12) is not allelic to the rust resistance genes in HA-R6, HA-R8 and RHA 397, and it is also not linked to any previously mapped rust resistance genes. Discovery of the R(12) novel rust resistance locus in sunflower and associated markers will potentially support the molecular marker-assisted introgression and pyramiding of R(12) into sunflower breeding lines.
向日葵生产在北美最近遭受了经济损失，产量和种子质量下降，因为向日葵锈病（Puccinia helianthi Schwein.）的发病率增加，而且缺乏对新锈病的抗性。RHA 464 是一种新发布的向日葵雄性育性恢复系，对美国大北方平原最主要和最毒力的锈病菌株均有抗性。RHA 464 中控制锈病抗性的基因来源于野生向日葵 Helianthus annuus L.，但尚未进行分子标记，也没有确定其与其他锈病基因座无关。本研究的目的是鉴定与锈病抗性基因连锁的分子标记，并研究该基因与 HA-R6、HA-R8 和 RHA 397 中未定位的锈病抗性基因的等位性。F2 群体和 F2:3 家系的幼苗毒力表型表明，一个显性基因赋予 RHA 464 锈病抗性，该基因被命名为 R(12)。混池分离分析在抗性和感病混池之间鉴定出 10 个多态性标记。在随后的遗传作图中，这 10 个标记覆盖了向日葵第 11 连锁群上 33.4cM 的遗传距离。一个共显性标记 CRT275-11 是与 R(12)最近的标记，遗传距离为 1.0cM，而 ZVG53 是一个与 R(12)连锁的显性标记，遗传距离为 9.6cM。等位性测试表明，R(12)与 HA-R6、HA-R8 和 RHA 397 中的锈病抗性基因不是等位基因，也与任何已定位的锈病抗性基因无关。在向日葵中发现 R(12)的新锈病抗性基因座及其相关标记，将有助于分子标记辅助导入和将 R(12)导入向日葵育种系。
