小麦赤霉病菌拮抗菌XG-6的分离鉴定及其应用

Isolation,identification and application of antagonistic strain XG-6 of Fusarium head blight of wheat

小麦赤霉病是发生在禾谷类作物上十分严重的一类病害,对我国麦类作物的生产影响巨大。病原菌产生的有毒物质DON(脱氧雪腐镰刀菌烯醇)等危害人畜健康,导致小麦产品产量及质量都大幅度下降,进而导致巨大的经济损失。合理开发利用小麦内生菌是一种高效、实惠的赤霉病生物防治方法。研究旨在从小麦内生菌中鉴定得到小麦赤霉病拮抗菌,并对其生长条件进行优化。以湖北荆州市荆州区农高区小麦赤霉病发病地区扬花期健壮的小麦植株为试验材料,通过平板对峙法从小麦根、茎、叶中筛选出7株对禾谷镰刀菌具有拮抗性的内生菌株,其中拮抗能力较高的是XG-6菌株,抑菌圈直径达到31.19mm。XG-6菌株对火龙果炭疽病菌、棉花立枯病菌、白绢病菌、梨黑斑病菌4种常见病原菌均有抑制效果,表现为广谱拮抗活性,对火龙果炭疸病菌的抑制效果最好;在接种到营养琼脂培养液后的24h内为对数期,24~72h内为稳定期,72h后进入衰退期;菌株适宜生长温度为25~30℃,适宜生长pH为6~9;对氯霉素、氨苄西林钠2种抗生素表现出极强的耐药性;XG-6菌株的16S rDNA序列含有1509个碱基,根据BLAST比对结果,所分离得到的XG-6菌株认定为解淀粉芽胞杆菌Bacillus amyloliquefaciens。

Fusarium head blight of wheat is a serious disease in cereal crops,which has a huge impact on wheat crop production in China.The toxic substance DON produced by pathogenic bacteria is harmful to human and animal health,leading to asignificant decline in the yield and quality of wheat products and thus resulting in huge economic losses.The rational development and utilization of wheat endophytes to enrich the biocontrol bacteria bank of wheat scab is an efficient and economical biological control method of scab.The aim of this study is to identify wheat scab antagonistic bacteria from wheat endophytes and optimize its growth conditions.Seven endophytic strains with antagonistic resistance to Fusarium graminearum were screened from wheat roots,stems and leaves by plate confrontation method using the robust wheat plants affected by wheat scab at flowering stage in Nonggao district of Jingzhou district,Jingzhou city,Hubei province.The results show that the highest antagonistic strain in seven strains is XG-6,and the diameter ofinhibition zone reaches 31.19mm.XG-6 shows broad spectrum antagonistic activity to four common pathogenic bacteria,such as pitaya anthracnose,cotton damping-off,southern blight and black spot of pear,and shows the best inhibitory effect against pitaya anthracnose.The logarithmic phase is observed within 24h after inoculation with nutrient AGARculture medium,the stable phase is observed within 24~72h,and the recession phase is observed after 72h;Theoptimum growth temperature of the strain is 25~30℃,and the suitable growth pH is 6~9;XG-6 shows strongresistance to chloramphenicol and ampicillin sodium;The 16S rDNA sequence of strain XG-6 contains 1509 bases,and the isolated strain XG-6 is identified as Bacillus amyloliquefaciens according to the BLAST comparison results.