西瓜蔓枯病分子诊断技术研究

PCR technique for rapid diagnosis of Didymella bryoniae on watermelon

本文测定西瓜上的西瓜蔓枯病菌(D idym ella bryoniae)、西瓜炭疽病菌(Colletotrichum orbiculare)及西瓜枯萎病菌(Fu-sarium oxysporumf.sp.niveum)的rDNA的ITS序列,比对近缘种及西瓜上不同病菌的ITS序列同源性,设计出特异性上游引物XM-2和下游引物XM-R2。经过对XM-2/XM-R2引物的PCR扩增条件的优化,可以扩增出一条344bp的西瓜蔓枯病菌特异性DNA条带。上述方法可以检测到pg以上的蔓枯病菌基因组DNA,并且可以准确扩增出西瓜蔓枯病自然病样中特异性的DNA片段。本文建立了一项西瓜蔓枯病分子检测技术,该方法准确、快速、可靠,可用于西瓜蔓枯病田间的快速诊断。

rDNA ITS sequences of Didymella bryoniae, Colletotrichum orbiculare and Fusarium oxysporium f. sp. niveum were sequenced. A pair of specific primers XM-2 and XM-R2 was designed by homology comparison of ITS sequence of D. bryoniae with closely-related species and other pathogenic fungi from watermelon and other cucurbitaceous plants. Only a 344 bp DNA band specific to D. bryoniae was amplified with XM-2/XM-R2 primers under the optimized PCR parameters. Above pg level genomic DNA of D. bryoniae could be detected and specific DNA fragments were amplified in the samples of gummy stem blight. A rapid, accurate molecular detection method developed in the study will be useful in the future diagnosis of gummy stem blight of watermelon.