小麦4B染色体上LOX基因的等位变异及其区域分布

为了解中国不同麦区小麦种质资源籽粒脂肪氧化酶（lipoxygenase,LOX）活性相关基因TaLox-B1的差异和分布,利用小麦4B染色体上的功能标记LOX16和LOX18对7个麦区的436份种质资源进行分子检测。结果表明：在供试材料中共检测到3种TaLox-B1基因等位变异类型,分别为TaLox-B1a（与高LOX活性相关)、TaLox-B1b（与低LOX活性相关）和杂合型,其频率分别为19.0％、70.4％和10.6％。小麦LOX活性基因不同变异类型在各生态区的分布存在明显差异：基因型TaLox-B1a在黄淮冬麦区、北部冬麦区和长江中下游冬麦区分布较多,其比例分别为21.1%、19.8%和17.6%;基因型TaLox-B1b在西南冬麦区和长江中下游冬麦区分布较多,比例分别为87.9%、72.5%;杂合型仅存在于北部冬麦区、黄淮冬麦区与长江中下游冬麦区,比例分别为14.2%、12.4%和9.8%。利用标记LOX16和LOX18对53个自选高代品系进行分子检测,发现自选品系仅有TaLox-B1b与杂合型两种基因型,其中基因型TaLox-B1ab有32个,比例为60.4%。采用分子标记辅助选择,有利于快速鉴定小麦籽粒LOX活性,加速LOX的遗传改良和新品种选育。

Allelic Variations of Lipoxygenase(LOX) Activity Genes on Chromosome 4B and Distributions in Different Wheat Regions of China

In order to identify distributions of genes for the lipoxygenase (LOX) activity of grains in different wheat regions in China, 436 wheat cultivars (lines) from seven wheat regions were genotyped by the functional markers LOX16 and LOX18 on the chromosome of 4B. The results showed that: TaLox-B1 had three allelic variations detected by the LOX16 and LOX18: TaLox-B1a (related to higher LOX activity), TaLox-B1b (related to lower LOX activity) and heterozygous type (related to intermediate type, moderate LOX activity), with frequencies of 19.0%, 70.4% and 10.6%, respectively. There were significant differences in the distribution of LOX activity genes among genotypes in different wheat regions. Wheat germplasms with the genotype TaLox-B1a were mostly distributed in the Huang-huai winter wheat region (HHR), Northern winter wheat region (NR) and Yangtze River middle-lower reaches winter wheat region (YMR), with the ratios of 21.1%, 19.8% and 17.6%, respectively. Wheat germplasms with the genotype of TaLox-B1b were mostly distributed in the Southwestern winter wheat region (SWR) and YMR, with the ratios of 87.9% and 72.5%, respectively. Heterozygous type was only found in NR, HHR and YMR, with the ratios of 14.2%, 12.4% and 9.8%, respectively. The markers LOX16 and LOX18 were further used to test LOX genotypes of 53 lines from our breeding program. The results showed that there were only two genotypes of TaLox-B1b and heterozygous type in 53 lines. Among them, 32 lines with heterozygous type in a proportion of 60.4%. Molecular marker-assisted selection was beneficial to the genetic improvement of LOX activity and breeding new wheat varieties.