中国小麦贵州98-18中抗叶锈基因的分子定位

小麦(Triticum aestivum)品系贵州98-18对中国目前大多数叶锈菌(Puccinia triticina)生理小种表现抗性。基因推导表明,贵州98-18可能携带新的抗叶锈基因。为了有效利用这一抗源,将贵州98-18和感病小麦品种郑州5389杂交,获得F1、F2代群体,用我国叶锈菌优势小种THTT对双亲及其杂交后代进行接种鉴定。结果表明,贵州98-18对THTT的抗性由1对显性基因控制,暂命名为LrG98。采用SSR技术对贵州98-18携带的抗病基因进行分子标记,共筛选了1 274对SSR或STS引物,位于1BL染色体上的4对引物可在抗/感池和双亲中扩增出多态性DNA片段。遗传连锁分析结果表明,该抗病基因位于小麦1BL染色体上,与Xbarc582-1B和Lr26的STS标记ω-secali(Glu-B3)的遗传距离最近,均为3.8 cM。该基因与目前所有已知的抗叶锈基因不同,可能是1个新的抗病基因。

Molecular mapping of leaf rust resistance gene LrG98 in Chinese wheat line Guizhou98-18

Wheat line Guizhou 98-18 showed low infection types to most of Chinese current isolates of Puccinia triticina. Resistance gene postulation suggested that Guizhou 98-18 might carry a new leaf rust resistance gene. In order to make use of the new leaf rust resistance gene effectively, F₁ and F₂ populations from the cross Guizhou 98-18/Zhengzhou 5389 were tested with prevalent Chinese pathotype THTT in greenhouse. The results indicated that Guizhou 98-18 carried a single dominant resistance gene, temporarily designated LrG98. A total of 1 274 SSR and STS primers were selected to test the two parents, as well as resistant and susceptible bulks. Four polymorphic markers on chromosome 1BL were used to test genotype F₂ plants. Subsequent lin-kage analysis indicated that the resistance gene LrG98 was linked to SSR marker Xbarc582-1B and STS marker of Lr26 with genetic distances of 3.8 cM, respectively. The seedling reaction pattern of LrG98 was different from those of lines with Lr26, Lr33, Lr44 and LrZH84, all of which were located in chromosome 1B. It was concluded that LrG98 was likely to be a new leaf rust resistance gene.