State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cytogenetics Institute, Nanjing Agricultural University, Nanjing, 210095, China.
Chromosome Res. 2011 Feb;19(2):225-34. doi: 10.1007/s10577-011-9192-9. Epub 2011 Feb 18.
Fusarium head blight (FHB), also called wheat scab, is an important disease in warm and humid regions worldwide, which not only reduces crop yield and grain quality, but also is a major safety concern in food and feed production due to mycotoxin contamination. Growing wheat cultivars with FHB resistance is one of the most economical and effective means to control the disease. Chinese wheat landrace Wangshuibai is an important resistant source from southern China. Several resistance QTLs in Wangshuibai were identified and mapped on chromosomes or chromosomal arms including 3BS, 4B, 6BS, 7AL, etc. In the present research, a mutant with increased FHB susceptibility, designated as NAUH117, was identified from the M(1) progenies of Wangshuibai irradiated by fast neutron. Genetic analysis of the F (1), F (2), and F (2:3) families from the reciprocal cross of Wangshuibai and NAUH117 indicated that NAUH117 was a recessive mutant. Genome-wide molecular marker analysis identified a deletion in the short arm of chromosome 3B of NAUH117, spanning the region of FL0.57 to FL1.00 that covers the locus of Fhb1 previously mapped on chromosome 3BS. Further molecular cytogenetics characterization by bi-color fluorescence in situ hybridization using three repetitive sequences, pSc119.2, pAs1 and GAA-satellite indicated that a multiple chromosome rearrangements occurred in chromosomes 3B, 6B, 3D, 4D, and 3A of the mutant. During these processes, a distal fragment of chromosome arm 3BS was eliminated, which is confirmed by molecular marker analysis. Four markers covered the deletion fragment were used for analysis of the F (2) population. The result showed that the 3BS deletion was only present in the susceptible plants, indicating that the deletion of 3BS fragment in NAUH117 increased susceptibility to FHB. The susceptible mutant will be valuable for the validation of the contribution of the resistant QTL located on 3BS, and for the characterization of the molecular mechanisms of FHB resistance in Wangshuibai.
镰刀菌穗腐病（FHB），又称小麦赤霉病，是一种在温暖潮湿地区普遍存在的重要病害，不仅会降低作物产量和籽粒品质，而且由于真菌毒素污染，也是食品和饲料生产的一个主要安全隐患。培育具有 FHB 抗性的小麦品种是控制该病害最经济有效的手段之一。中国小麦地方品种望水白是来自中国南方的一个重要抗性资源。已在 3BS、4B、6BS、7AL 等染色体或染色体臂上鉴定和定位了几个望水白的抗性 QTL。在本研究中，从经快中子辐照的望水白 M(1)代中鉴定出一个感病突变体，命名为 NAUH117。对望水白和 NAUH117 正反交 F(1)、F(2)和 F(2:3)群体的遗传分析表明，NAUH117 是一个隐性突变体。全基因组分子标记分析表明，NAUH117 的 3B 染色体短臂发生缺失，跨越 FL0.57 到 FL1.00 区域，该区域包含先前在 3BS 染色体上定位的 Fhb1 基因座。利用三个重复序列 pSc119.2、pAs1 和 GAA-卫星通过双色荧光原位杂交对突变体进行进一步的分子细胞遗传学特征分析表明，在 3B、6B、3D、4D 和 3A 染色体上发生了多个染色体重排。在此过程中，3BS 染色体臂的远端片段被消除，这通过分子标记分析得到了证实。用于分析 F(2)群体的四个覆盖缺失片段的标记表明，3BS 缺失仅存在于感病植株中，表明 NAUH117 中 3BS 片段的缺失增加了对 FHB 的敏感性。易感突变体对望水白中位于 3BS 的抗性 QTL 的验证和 FHB 抗性的分子机制的研究将具有重要价值。
