广谱持久抗性基因的挖掘和育种利用对提高作物的适应性、稳产性和减少农药对环境的污染至关重要。我们的前期研究表明：小麦品种宁7840携带的隐性单基因lm很可能通过控制抽穗前后叶片上自发出现的过敏性类似反应介导广谱成株期抗病性，能够极显著降低锈病和白粉病危害，也能显著增强赤霉病扩展抗性。已将该基因定位于小麦1BL染色体的C1BL6-0.32区域，并找到了关联的SNP等标记。本项目基于RIL、NIL和次级分离大群体等材料，借助1BL的物理-遗传图谱等信息和通过对NIL等的转录本de novo测序及差异蛋白质谱分析，开发新的标记，结合表型鉴定和连锁作图，精细定位lm并筛选候选基因；从理化和分子水平剖析其可能的作用机理；分析目标基因在不同遗传背景中和大田条件下的遗传效应，并结合前期研究结果，提出目标基因的育种利用策略。该项研究对克隆目标基因、解析广谱抗病机制和培育广谱持久抗性小麦品种都具有重要意义。

Development of crops carrying the genes controlling broad-spectrum and durable resistance is economically important for improving eco-adpatability and yield stability of crops in diverse ecoregions, and also for benefiting surrounding environment by reducing fungicides application. Our previous investigations demonstrated that the resistance gene, designated lm, from Chinese wheat cv. Ning7840 confers high level of resistances, probably by mediating spontaneously occurring hypersensitive reaction-like lesion mimic (LM) phenotype at the adult plant stage, to both rust and powdery mildew diseases (caused by biotrophic pathogens),and to type II resistance to fusarium head blight(caused by hemi-biotrophic pathogen). We have mapped the gene lm to the long arm of 1B chromosome within the deletion bin of C1BL6-0.32 and have identified the associated molecular markers such as SNPs and SSRs etc. In the current study, we are going to further map the gene lm to a chromosomal region at a fine scale and to screen its candiate genes by association of genotypes with phenotypes in different genetic stocks such as recombinant inbred lines (RIL), near-isogenic lines (NIL) and the specially-designed segregating populations. More markers used for fine mapping of the gene of interest will be developed based on published 1BL-specific physical and genetic maps as well as survey sequences, and particularly on the differentially expressed genes screened both at RNA (by transcripts de novo sequencing approach) and proteomic levels (by 2-D gel electrophoresis and MALDI-TOF/TOF approaches) in the NILs and pools contrasting in LM phenotypes. The mechanisms underlying the occurrence of LM will be deciphered at physiological, biochemical, cellular and molecular levels, respectively.The genetic effects of the gene alone in the background of cv. Yangmai15 (susceptible to both powdery mildew and rust diseases) and the additive and epistatic effects in the genetic background of cv.Amadina (carrying resistance gene Lr46) will also evaluated under field conditions.The results of both our previous work on LM and the current investigations are promising to facilitate isolation of lm, to help understand the mechanisms underlying broad-spectrum and durable resistance, and will also be essentially useful in developing, by marker assisted breeding approach, wheat cultivars with a high level of resistances to a wide array of isolates of a pathogen or/and multiple pathogens.