内生解淀粉芽孢杆菌CC09菌株在小麦叶部的定殖能力及其防治白粉病效果研究

Colonization of Bacillus amyloliquefaciens CC09 in Wheat Leaf and Its Biocontrol Effect on Powdery Mildew Disease

利用抗利福平标记及平板菌落计数法，研究了内生解淀粉芽孢杆菌Bacillus amyloliquefaciensCC09在小麦叶内和叶际的定殖能力，证明菌株CC09能够在小麦叶内和叶际以较高数量稳定定殖，叶际定殖量在喷雾后1 d达到最大（3.98×107cfu/g），之后稳定维持在1.58×104～3.16×105cfu/g；而叶内的定殖量7 d时达到最大（1.58×106 cfu/g）并维持稳定。另外，菌株CC09在小麦叶际和叶内的定殖受温度及其代谢产物的影响，温度越高，其叶际和叶内定殖量越高；菌体重悬液中添加相当于原发酵液中代谢产物含量1倍和4倍的浸膏能显著提高菌株CC09在小麦叶际和叶内的定殖；而接种量对菌株CC09的定殖无显著影响。琼脂培养法测定表明，菌株CC09发酵液及其无菌滤液对小麦白粉菌分生孢子萌发均有显著的抑制作用，导致孢子透明、变形甚至细胞破裂。室内盆栽试验表明，菌株CC09发酵液对小麦白粉病有很高的预防和治疗效果，15 d时防效为95%，是三唑酮的2.3倍，而其20倍稀释液的防效与化学农药三唑酮效果相当。以上研究结果表明菌株CC09是防治小麦白粉病的潜在生防菌株，具有良好的开发和应用价值。

Colonization ofBacillus amyloliquefaciens CC09 in both interior leaves and phyllosphere of wheat and its affecting factors were investigated by using the rifampin-resistant mutants and plate diluting method. Results showed that strain CC09 could stably colonize and maintained at higher population in both interior leaves and phyllosphere of wheat. The maximum density in phyllosphere was 3.98×107cfu/g at 1 d , and decreased to 1.58× 104-3.16×105cfu/g at 3 d after inoculation. However, the population of strain CC09 reached the highest density （1.58×106cfu/g） inside wheat leaves at 7 d after inoculation and maintained the same level thereafter. In addition, the higher the temperature, the greater the amount of colonization in wheat. And the metabolites produced by strain CC09 exhibited significant promotion for the strain’s colonization in both interior of leaves and phyllosphere of wheat. However, the inoculation density did not significantly influence the colonization. Both the fermentation broth and cell free filtrate of CC09 showed significant germination inhibition against the conidia of Blumeria graminisf. sp. tritici based on slide agar assay, and resulted in spores transparent, deformed or even lysis. The broth of CC09 exhibited both protective and therapeutic efficiencies, approximately 95% at 15 d after treatments, incontrol of wheat powdery mildew in pot assay under greenhouse condition, which was 2.3 fold as high as to that of the triadimefon treatment. However, the disease control efficiency of its 20 fold dilution was not significantly different from that of triadimefon. All these results suggested that strain CC09 was an excellent candidate for developing a biocontrol agent to control wheat powdery mildew.