云南地方稻种抗稻瘟病基因Pi-d3序列变异分析

Sequence Variation of Pi-d3 for Rice Blast Resistance in Yunnan Rice Landrace

对来自云南的80份地方稻种抗稻瘟病基因Pi-d3编码区序列进行了PCR扩增并测序分析。结果表明,与地谷相比,80份云南地方稻种的Pi-d3编码区序列(全长2775bp)存在39个变异位点,平均变异率为1.41%。所有材料可以归为37种单倍型,频率较高的单倍型是H8(28.8%)、H4(11.3%)、H23(5.0%),其他单倍型频率较低,显示了云南地方稻种Pid3基因变异丰富,单倍型类型多,但频率较低。37种单倍型中存在28个氨基酸差异位点,共编码33种蛋白,其中18种单倍型共计32份材料(包括12份籼稻品种)出现了假基因,假基因化的频率较高,可能是粳稻Pi-d3假基因化向籼稻渗透。除已发现的737位氨基酸假基因位点外,新发现32和467两个假基因位点。Pi-d3基因在籼稻、粳稻亚种,水稻、陆稻,黏稻、糯稻的单倍型类型及频率两方面均存在差异,表明亚种间或生态型间发生了一定的遗传分化。37种单倍型在云南的地理分布呈大分散、小聚居的特点,普洱、版纳、临沧的单倍型种类最丰富,并以之为中心向外扩展,单倍型种类随之减少。

The sequence variations of Pi-d3 for rice blast resistance in 80 Yunnan rice landraces were analyzed by resequencing open reading frame （ORF）. Compared with Pi-d3Digu ORF, a total of 39 nucleotide variations were found in 2775-bp ORFs of 80 rice accessions with the average mutation rate of 1.41Y00. The WTBXPi-d3ORF of 80 rice accessions was divided into 37 haplotypes based on the nucleotide variations. H8（28.8%）, H4（11.3M） and H23（5.0%） are high-frequency types, while other types occurred at low frequency. The results showed that the WTBXPi-d3 in Yunnan rice landraces was rich in genetic variations and haplotypes, but low frequency. A total of 28 amino acids variations were found in 33 translation proteins of 37 haplotypes. 18 haplotypes with 32 rice landraees including 12 indica accessions possessde the Pi-d3 pseudogenes. The frequency of pseudogene was high. It was possible due to that the Pi-d3 pseudo- gene permeated to indica. Terminators were newly founded at position 32 and 467 of protein except the published termi- nator at position 737. Pi-d3 differed in both type and frequency of haplotypes between the subspecies of indica and ja- ponica, the ecotypes of lowland and upland rice, no-waxy and waxy rice. It indicated that genetic differentiation occurred between subspecies or ecotypes. Geographical distribution showed that 37 haplotypes spread over a large area while concentrated in small areas. Puer, Banna and Lincang were the central area with abundant haplotypes, and based on this scale, the types of haplotypes decreased outward progressively.