Phytopathology. 2006 Aug;96(8):885-9. doi: 10.1094/PHYTO-96-0885.
ABSTRACT Race 3 of the fungus Pyrenophora tritici-repentis, causal agent of tan spot, induces differential symptoms in tetraploid and hexaploid wheat, causing necrosis and chlorosis, respectively. This study was conducted to examine the genetic control of resistance to necrosis induced by P. tritici-repentis race 3 and to map resistance genes identified in tetraploid wheat (Triticum turgidum). A mapping population of recombinant inbred lines (RILs) was developed from a cross between the resistant genotype T. tur-gidum no. 283 (PI 352519) and the susceptible durum cv. Coulter. Based on the reactions of the Langdon-T. dicoccoides (LDN[DIC]) disomic substitution lines, chromosomal location of the resistance genes was determined and further molecular mapping of the resistance genes for race 3 was conducted in 80 RILs of the cross T. turgidum no. 283/Coulter. Plants were inoculated at the two-leaf stage and disease reaction was assessed 8 days after inoculation based on lesion type. Disease reaction of the LDN(DIC) lines and molecular mapping on the T. turgidum no. 283/Coulter population indicated that the gene, designated tsn2, conditioning resistance to race 3 is located on the long arm of chromosome 3B. Genetic analysis of the F(2) generation and of the F(4:5) and F(6:7) families indicated that a single recessive gene controlled resistance to necrosis induced by race 3 in the cross studied.
摘要 小麦叶枯病菌 3 号生理小种引起的叶斑病会导致四倍体和六倍体小麦产生不同的症状，分别表现为坏死和黄化。本研究旨在研究小麦叶枯病菌 3 号生理小种诱导的坏死抗性的遗传控制，并对四倍体小麦（Triticum turgidum）中鉴定出的抗性基因进行定位。利用抗性基因型 T. turgidum no. 283（PI 352519）和感病硬粒小麦品种 Coulter 构建了重组自交系（RIL）群体。基于 Langdon-T. dicoccoides（LDN[DIC]）二体代换系的反应，确定了抗性基因的染色体定位，并在 T. turgidum no. 283/Coulter 杂交的 80 个 RIL 中进一步对 3 号生理小种的抗性基因进行了分子定位。在二叶期对植株进行接种，接种后 8 天根据病变类型评估发病反应。LDN(DIC)系的发病反应和 T. turgidum no. 283/Coulter 群体的分子定位表明，该基因被命名为 tsn2，它是控制对 3 号生理小种抗性的基因，位于 3B 染色体的长臂上。对 F2 代和 F4:5 代和 F6:7 代的遗传分析表明，在研究的杂交中，单个隐性基因控制着对 3 号生理小种诱导的坏死的抗性。
