Mapping Of Gene HtNB Conferring Non-lesion Resistance Before Heading To Exserohilum Turcica (Pass.) In A Maize Inbred Line Driving From "Bramadi"

Corn is an important crop for food and feed. Exseruhilum turcicum is the cause agent of northern corn leaf blight, which belongs to Helminthosporium. Northern corn leaf blight (NCLB), southern leaf blight and corn sheath blight are known as the three major corn diseases in China. The excessive promotion of singe gene cultivars and the evolution and variation of pathogen may result in an outbreak and expansion of disease in partial corn producing areas, and usally cause severse crop losses especially in low temperature area with high humidity.The mapping and cloning of disease genes of northern corn leaf blight, is benefit for understanding the mechanism of disease resistance, the co-evolution of plants and pathogens, and makes a foundation of crop improvement of disease resistance.In the previous study, Bramadi was confirmed to contain a singe dominant gene. In this study, two F2 populations were prepared with Huangzao 4 and B73 as susptible lines and P111 derivativing from bramadi as resistant one. The main results of this study are describled as followed:1,The linkage map of chromosome 8 was constructed, in which 25 SSR was involved in ZQ1 popluation, while 19 SSR in ZQ2 population.2,HtNB was located in the nearly same interval. In the ZQ1 population, HtNB was located between MAC216826-4 and umc2218 at distances of 3.3 and 3.4 cM, respectively. In the ZQ2 population, HtNB was located between MAC216826-4 and umc2218 at distances of 4.3 and 4.0 cM, respectively. The result indicates that HtNB is a new gene of northern corn leaf blight.3,Many efforts were taken to evaluate the phenotype of HtNB and field evaluation in flowering time was finally undertaken. In vitro disease evaluation was also performed and is considered to be a potential method for evaluation, though it needs to be verificated.4,Various information was taken into account and HtNB is considered to be distinct from HtN which located in 8.06bin. The prediction that HtNB is tightly linked to HtN in the previous study is denied.5,Bioinformatic analysis was taken and several genes in the interval were found to be related to NCLB and might be candidate genes for HtNB. The three most probable proteins are an ubiquitin-like protein, a Ser/Thr kinase protein, and a leaf senescence-like proteinIn this study, the preliminary mapping using molecular markers was taken. And the firstly mapping of HtNB may proceed the further fine mapping.