Kuraparthy Vasu, Chhuneja Parveen, Dhaliwal Harcharan S, Kaur Satinder, Bowden Robert L, Gill Bikram S
Wheat Genetic and Genomic Resources Center, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506-5502, USA.
Theor Appl Genet. 2007 May;114(8):1379-89. doi: 10.1007/s00122-007-0524-2. Epub 2007 Mar 14.
Leaf rust and stripe rust are important foliar diseases of wheat worldwide. Leaf rust and stripe rust resistant introgression lines were developed by induced homoeologous chromosome pairing between wheat chromosome 5D and 5M(g) of Aegilops geniculata (U(g)M(g)). Characterization of rust resistant BC(2)F(5) and BC(3)F(6) homozygous progenies using genomic in situ hybridization with Aegilops comosa (M) DNA as probe identified three different types of introgressions; two cytologically visible and one invisible (termed cryptic alien introgression). All three types of introgression lines showed similar and complete resistance to the most prevalent pathotypes of leaf rust and stripe rust in Kansas (USA) and Punjab (India). Diagnostic polymorphisms between the alien segment and recipient parent were identified using physically mapped RFLP probes. Molecular mapping revealed that cryptic alien introgression conferring resistance to leaf rust and stripe rust comprised less than 5% of the 5DS arm and was designated T5DL.5DS-5M(g)S(0.95). Genetic mapping with an F(2)population of Wichita x T5DL.5DS-5M(g)S(0.95) demonstrated the monogenic and dominant inheritance of resistance to both diseases. Two diagnostic RFLP markers, previously mapped on chromosome arm 5DS, co-segregated with the rust resistance in the F(2) population. The unique map location of the resistant introgression on chromosome T5DL.5DS-5M(g)S(0.95) suggested that the leaf rust and stripe rust resistance genes were new and were designated Lr57 and Yr40. This is the first documentation of a successful transfer and characterization of cryptic alien introgression from Ae. geniculata conferring resistance to both leaf rust and stripe rust in wheat.
叶锈病和条锈病是全球小麦重要的叶部病害。通过诱导小麦5D染色体与节节麦（U(g)M(g)）的5M(g)染色体进行部分同源染色体配对，培育出了抗叶锈病和条锈病的渐渗系。以粗山羊草（M）DNA为探针，利用基因组原位杂交技术对BC(2)F(5)和BC(3)F(6)纯合后代进行锈病抗性鉴定，确定了三种不同类型的渐渗；两种在细胞学上可见，一种不可见（称为隐秘外源渐渗）。所有三种类型的渐渗系对美国堪萨斯州和印度旁遮普邦最常见的叶锈病和条锈病致病型均表现出相似且完全的抗性。利用物理定位的RFLP探针鉴定了外源片段与受体亲本之间的诊断性多态性。分子图谱显示，赋予叶锈病和条锈病抗性的隐秘外源渐渗占5DS臂的比例不到5%，被命名为T5DL.5DS-�M(g)S(0.95)。用威奇托与T5DL.5DS-5M(g)S(0.95)的F(2)群体进行遗传图谱分析，证明了对两种病害的抗性由单基因显性遗传。先前定位在5DS染色体臂上的两个诊断性RFLP标记在F(2)群体中与锈病抗性共分离。抗性渐渗在染色体T5DL.5DS-5M(g)S(0.95)上的独特图谱位置表明，叶锈病和条锈病抗性基因是新的，被命名为Lr57和Yr40。这是首次成功转移和鉴定来自节节麦的赋予小麦叶锈病和条锈病抗性的隐秘外源渐渗的报道。
