瓜列当致病真菌的鉴定及其发酵产物活性研究

Identification of the pathogenic fungus of Orobanche aegyptiaca and the activity of its fermentation products

为筛选对瓜列当具有良好防治效果的生防真菌,本研究从新疆加工番茄田自然发病的瓜列当茎基部分离病原真菌,采用盆栽瓜列当接种无菌发酵滤液原液,筛选对瓜列当具有强致病性的菌株;采用共培养法测定菌株不同浓度无菌发酵滤液及其发酵产物萃取物对瓜列当种子萌发的影响;利用形态学特征和分子生物学方法对其进行种类鉴定。结果表明:盆栽瓜列当接种无菌发酵滤液原液可使瓜列当植株伤口变褐,严重的可造成整株萎蔫死亡;菌株JTF001发酵原液对瓜列当种子萌发抑制率可达100%,25倍、50倍稀释液抑制率分别为92.88%和87.62%;浓度为5μg/mL和1μg/mL JTF001发酵产物对瓜列当种子萌发抑制率均达100%;浓度为0.5、0.25μg/mL和0.1μg/mL的JTF001发酵产物对瓜列当种子萌发的抑制率分别为91.03%、81.87%和60.04%;结合形态学和基于rpb2、tef 1和gapdh基因序列分析,将菌株JTF001鉴定为交链格孢Alternaria alternata。上述结果表明菌株JTF001有作为开发防治瓜列当生物农药的潜力。

The present study was to isolate fungi from the stem base of Orobanche aegyptiaca,which naturally occurred in processing tomato fields in Xinjiang,and screen the strong pathogenic strains against O.aegyptiaca by potting assay with the sterile fermentation filtrate of the strains stock solution.The activities of the sterile fermentation filtrate of the strains and extracts of its solid fermentation products against the seed germination of O.aegyptiaca were measured by using the co-cultivation method.The species of strong pathogenic strains were identified by using morphological characteristics and molecular biological method.The potting assay showed that the inoculated area turn brown after inoculation with the sterile fermentation filtrate,and the whole plant even wilted or died.The inhibition rate of the fermentation filtrate of strain JTF001 on the seed germination of O.aegyptiaca was 100%,and the 25-fold and 50-fold dilutions was 92.88%and 87.62%,respectively.The inhibition rate of the extracts of the solid fermentation products on seed germination of O.aegyptiaca was up to 100%at the concentration of 5μg/mL or 1μg/mL,and it was 91.03%,81.87%and 60.04%at 0.5μg/mL,0.25μg/mL or 0.1μg/mL,respectively.Strain JTF001 was identified as Alternaria alternata based on morphological characteristics and sequence analysis of rpb2,tef 1 and gapdh.In conclusion,the above results suggested that A.alternata JTF001 had the potential to be developed as a biopesticide for the prevention of O.aegyptiaca.