小麦赤霉病菌拮抗菌的筛选及拮抗特性研究

Screening and antagonistic characteristics of antagonistic bacteria against Fusarium graminearum

  • 摘要: 【目的】从小麦根际土壤中分离对禾谷镰刀菌具有抑制作用的菌株,为防控小麦赤霉病及其毒素污染提供菌株资源。【方法】以小麦根际土壤为材料,通过平板对峙法筛选抑制禾谷镰刀菌生长的菌株;根据菌落形态、生理生化特性和16S rDNA系统发育分析对拮抗菌进行种类鉴定;通过PCR扩增抗菌脂肽基因、发酵条件试验、抑菌物质的抑菌特性分析探究拮抗菌的拮抗特性;通过接种小麦穗和小麦籽粒试验验证拮抗菌对小麦赤霉病的防治效果及对脱氧雪腐镰刀菌稀醇(Deoxynivalenol,DON)的抑制作用。【结果】从小麦根际土壤中分离出5株对禾谷镰刀菌具有拮抗作用的细菌,其中菌株XW-10的拮抗效果最好,经鉴定该菌株为解淀粉芽孢杆菌(Bacillus amyloliquefaciens),其具有合成伊枯草菌素、表面活性素和丰原素等抗菌脂肽的基因。菌株XW-10生长的最适条件为CM培养基中培养10~48 h,抑菌物质主要存在于发酵上清液中,使禾谷镰刀菌的菌丝生长受到明显抑制,使孢子萌发率下降,也使菌丝形态畸变;发酵无菌上清液在低于90℃下可保持高抗菌活性,中性pH时抑菌效果最好。菌株XW-10发酵无菌上清液中的有效成分为粗蛋白,但对木瓜蛋白酶、胰蛋白酶和蛋白酶K的作用不敏感。应用试验表明菌株XW-10发酵无菌上清液可促进小麦幼苗生长、通过抑制禾谷镰刀菌的生长降低小麦基质中DON毒素的含量和小麦穗赤霉病的发生率。【结论】筛选获得的菌株XW-10对小麦赤霉病有较好的防治效果,具有作为小麦赤霉病生防菌的潜质。

     

    Abstract: 【Objective】To isolate strains with inhibitory function against Fusarium graminearum from soil of wheat plant,and to provide bacterial strain resources for prevention and control of wheat scab and toxin contamination.【Method】Wheat rhizosphere soil was used as material to screen strains that could inhibit F. graminearum growth by plate confrontation method. Antagonistic bacteria were identified according to colony morphology,physiological and biochemical properties and 16S rDNA phylogenetic analysis.The antagonistic characteristics of antagonistic bacteria were investigated by PCR amplification of antibacterial lipopeptide gene,fermentation condition test and antibacterial property analysis of antibacterial substances. The control effect of antagonistic bacteria on wheat scab and the inhibitory effect on deoxynivalenol(DON) were verified by inoculation of wheat ears and wheat grains.【Result】Five strains of bacteria with antagonistic effect against F. graminearum were isolated from wheat rhizosphere soil,among which the strain XW-10 with the best antagonistic effect was identified as Bacillus amyloliquefaciens which had genes involved in biosynthetic pathways of lipopeptides such as iturin,surfactin and fengysin. The optimum condition for the growth of strain XW-10 was cultured in CM medium for 10-48 h. Antagonistic substances,mainly found in the fermentation supernatant could significantly inhibit mycelial growth,decrease spore germinationrate and distort hyphae morphology. The cell-free supernatant maintained stable antimicrobial activity at temperatures below 90 ℃,and the antimicrobial activity peaked at neutral pH. Antagonistic characteristics of antagonistic bacteria were determined by PCR amplification of the antibacterial lipopeptide gene,fermentation condition test and antibacterial properties analysis of bacteriostatic substance. According to wheat ear and wheat kernel inoculation test,the efficient component of cell-free supernatant was crude protein,but it was not sensitive to effects of papain,trypsin and protease K. The experiment showed that cell-free supernatant of strain XW-10 could promote wheat seedling growth,reduce DON toxin content in wheat matrix and wheat scab incidence by inhibiting F. graminearum growth.【Conclusion】The screened strain XW-10 can significantly prevent and control wheat scab and significantly inhibit DON toxin,showing its potential to be a wheat scab biocontrol bacterium.

     

/

返回文章
返回