禾谷丝核菌拮抗真菌的鉴定及抗菌活性研究

利用从小麦茎叶组织中分离的内生真菌,进行平板对峙试验,从中筛选出2株对禾谷丝核菌有明显抑制效果的菌株(RF5和RF6)。采用改良的真菌基因组DNA提取方法,提取内生真菌RF5和RF6的基因组DNA,运用ITS序列通用引物(ITS4、ITS5)进行扩增,分别得到约600 bp的特异条带。对PCR产物进行测序,根据序列比对分析结果,将拮抗真菌RF5和RF6分别鉴定为:肉座菌(Hypoc-reales sp.)和杂色曲霉(Aspergillus versicolor)。进一步研究这2株拮抗真菌的抗菌活性大小,结果显示,2株真菌对病原菌都能产生明显的抑菌圈,抑菌圈直径分别为23 mm和19 mm;其液体发酵产物对病原菌的生长也有显著抑制作用,抑制率分别为63.3%和60.8%。

Identification of the Endophytic Fungi Antagonistic to Rhizoctonia cerealis and Study on Antifungal Activity

Endophytic fungi were isolated from wheat stem and leaf tissues with PDA medium.Forty eight endophytic fungi strains were isolated from PDA medium which included 2 strains(RF5 and RF6) antagonistic to Rhizoctonia cerealis.Genomic DNA of the two antagonistic strains were extracted withimproved method and amplified by ITS primers(ITS4 and ITS5).The specific PCR fragments around 600 bp were obtained from each genomic DNA and sequenced.Based on ITS sequences alignment,RF5 and RF6 were identified as Hypocreales sp.and Aspergillus versicolor.The antifungal activity of antagonistic strains showed that both antagonistic strains could produce inhibition zone and RF5 showed stronger antibacterial activity with inhibition zone of 23 mm compared to RF6 of 19 mm.Fermentation filtrate of the strain RF5 and RF6 also had inhibitive activity against Rhizoctonia cerealis.The growth of Rhizoctonia cerealis after 7 days showed that the inhibition rate of fermentation filtrate were 63.3% and 60.8%,respectively.The results showed that the isolated endophytic fungi had potential biocontrolfunction and they played important roles in wheat sharp eyespot biocontrol.