橡胶树多主棒孢拮抗细菌BACYitc8-7的分离鉴定及其挥发性抑菌物质组分分析

多主棒孢菌（Corynespora cassiicola）是为害橡胶叶片的一种重要病原真菌,目前生产上普遍使用化学农药防治该病害,给植胶区的生态环境带来很多负面影响,从橡胶树根际土壤中筛选对橡胶树多主棒孢菌具有高拮抗活性的细菌,可为橡胶树棒孢霉落叶病生防药剂的研发提供理论依据。本研究通过稀释涂布、平板对峙法从发病橡胶树根际土壤中分离筛选到1株对橡胶树多主棒孢菌具有高拮抗活性的细菌,抑菌带为(57.68±0.66)mm,且该菌株对9种重要的植物病原真菌均具有抑制作用;经过形态观察、生理生化检测及16S rRNA基因序列分析,结果发现其与铜绿假单孢菌基本相符,命名为BACYitc8-7;以LB、NA、高氏、金氏B和PDA为营养来源,评定不同营养条件下菌株BACYitc8-7挥发性物质对多主棒孢菌的抑制作用,发现菌株BACYitc8-7在金氏B和LB培养基上的拮抗作用最强,抑菌率达43.47%~48.69%;利用顶空固相微萃取-气相色谱-质谱法（HS-SPME-GC-MS）收集并检测菌株BACYitc8-7挥发性物质的抑菌组分,获得包括胺类、醇类、烯类、酚类、酯类、吡嗪类等35种物质,其中含量前5的物质为胺、硼烷二甲硫醚络合物、异戊醇、1-十三烯和2-甲基-3-甲硫基呋喃。

Isolation and Identification of Antagonistic Bacteria BACYitc8-7 Against Deciduous Disease Pathogen (Corynespora cassiicola) and Analysis of Antibacterial Components of Volatile Organic Compounds from Rubber Tree

Corynespora cassiicola is an important pathogen causing Corynespora leaf fall disease of rubber trees. Chemical fungicides are widely used to prevent and control the disease at present, which brings severe ecological environmental issues in rubber planting areas. Isolating and screening bacteria strains with inhibitory activity against C. cassiicola from rhizosphere soil of rubber trees would provide theoretical foundation for researches and development of biological control agents on Corynespora leaf fall disease. Bacteria with high antagonistic activity was obtained from the rhizosphere soil of rubber trees with leaf fall disease by using dilution plate coating and plate-confrontation, its bacteriostatic diameter was (57.68±0.66)mm. It was observed that nine important plant pathogenic fungi could be inhibited by the strain as well. Based on morphological, physiological, biochemical characteristics and 16S rRNA gene sequence, the strain was basically consistent with Pseudomonas aeruginos, and was named BACYitc8-7. The activity of the volatile compounds of BACYitc8-7 against C. cassiicola was evaluated when LB, NA, Gause, Kim B and PDA were used as nutrition sources. The strongest antagonistic effects were found in Kim B and LB mediums, and the inhibition rate was 43.47%-48.69%. 35 substances, including amines, alcohols, alkenes, phenols, esters and pyrazines were obtained from the antimicrobial components of BACYitc8-7 collected and detected by headspace solid phase micro extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and the top five contents were amine, borane dimethyl sulfide complex, isoamyl alcohol, 1-triene and 2-methyl-3-methylthiofuran, respectively.