解淀粉芽孢杆菌B9601-Y2在玉米叶际定殖能力的研究

A study on the colonization of Bacillus amyloliquefaciens 9601-Y2 in maize phyllosphere

解淀粉芽孢杆菌B9601-Y2（Y2）是一株具有良好防病功能的菌株．为了明确Y2能否在玉米叶际有效定殖，采用喷雾接种法，考察了其在玉米叶际的定殖能力．结果表明，温室条件下，绿色荧光标记菌株Y2-pHAPⅡ悬浮剂在每天16：00接种时定殖能力最强；同时Y2-pHAPⅡ悬浮剂和Y2-pHAPⅡ菌液的活菌数、菌体数以及芽孢数的消长动态相一致，9天时前者的活菌数、菌体数以及芽孢数出现的峰值分别为5．13×10^6、3．10×10^5cfu／g和2．04×10^6cfu／g，后者峰值分别为3．90×10^6、2．65×10^6cfu／g和1．25×10^6cfu／g；田间条件下Y2悬浮剂和Y2菌液的3种菌落数值变化曲线相类似，5天时前者的活菌数和菌体数分别达4．59×10^5cfu／g和2．30×10^5cfu／g，后者数值为3．44×10^5cfu／g和1．72×10^5cfu／g，12天时二者芽孢数小幅增长至1．17×10^5cfu／g和4．03×10^4cfu／g；温室和田间条件下，40天时均能回收到目标菌株，且悬浮剂比菌液提高25％左右的定殖能力．这些结果说明该菌株的良好定殖能力是有效防病可能机制之一．

The strain of Bacillus amyloliquefaciens 9601-Y2 （Y2）is helpful in diseases prevention in plants. The colonization of Y2 on maize leaves by spraying was investigated in order to clarify whether the strain could colonize or not.The results showed that Y2-pHAP 11 suspensions were inoculated at 16：00 showed the strongest colonization in the greenhouse, while the number of viable strains, strains and spores of Y2-pHAP Ⅱ were dy- namic consistent with the Y2-pHAP II suspensions.The peaks of the number of viable cells, strains and spores of the suspensions were 5.13×10^6 cfu/g,3.10×l0^6 cfu/g and 2.04×10^6 cfu/g at the 9th day after inoculation,re- spectively, while the fermentation liquid （FL） were 3.90× 10^6 cfu/g, 2.65 × 10^6 cfu/g and 1.25 × 10^6 cfu/g.The 3 indices of Y2 suspensions and Y2 FL showed the similar curves and trends under the field conditions.At the 5th day, the number of viable cells and the strains reached 4.59×10^5 cfu/g and 2.30×10^5 cfu/g in Y2 suspension re- spectively,and 3.44× 10^5 efu/g and 1.72×10^5 efu/g in Y2 FL.At the 12th day,the number of spores slightly in- creased to i. 17×10^5 cfu/g and 4.03 ×10^4efu/g.Under the greenhouse and field conditions, target strains were re- covered in 40 days, while the colonization of Y2 suspension was improved by 25 % than Y2 FL. The results showed that a good colonization ability of the strains might be one of the effective disease prevention mechanisms.