菜豆种子普通细菌性疫病菌检测

 由Xanthomonas axonopodis pv. phaseoli和Xanthomonas fuscans subsp. fuscans引起的菜豆普通细菌性疫病是严重影响菜豆生产的限制因子之一,可造成严重的产量和品种损失。染菌种子是病原菌传播的主要途径。本研究对5个菜豆主要产区的60份菜豆种子样品进行普通细菌性疫病菌检测。在MT选择性培养基上有36份种子样品浸提液检测到目标病原菌, 种子样品带菌量为2.49×10²~5.20×10⁷ CFU/粒。选择36个分离物接种感病品种“英国红”植株,所有分离物均引起接种植株发病。特异PCR检测结果表明,有20个分离物为X. fuscans subsp. fuscans,16个分离物为X. axonopodis pv. phaseoli。试验结果表明,我国一些菜豆主产区商业种植和研究用种子多数污染普通细菌性疫病菌,建议建立无菌种子生产区和加强种子管理,以有效控制病害发生。

Detection of Xanthomonas axonopodis pv.phaseoli and Xanthomonas fuscans subsp.fuscans on common bean seeds

Common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli and Xanthomonas fuscans subsp. fuscans, is one of the major constraints to common bean production and causes heavy yield losses and reduces the commercial value of seeds. Contaminated seeds are the primary mean of disease dissemination. This study aimed to detect the pathogens of common bacterial blight on seeds of 60 common bean samples collected from five main production regions. The pathogen colonies of common bacterial blight were isolated from seed extracts of 36 samples on MT medium by dilution-plating method, and the bacteria populations were from 2.49×10² to 5.20×10⁷ CFU per seed. The 36 representative strains were pathogenic on bean cultivar “Yingguohong” by stem inoculation. Based on PCR detection with specific primer pairs, 20 isolates were identified as X. fuscans subsp. fuscans, while 16 were identified as X. axonopodis pv. phaseoli. The results of seed detection showed that common bean seeds used in commerce and research had been contaminated with pathogens of common bacterial blight, it suggests that it is necessary to establish pathogen-free seeds production base and strengthen seed regulation.