芦笋茎枯病的生物防治及机理研究

Antagonistic inhibition analysis and biocontrol of asparagus stem blight Phomopsis asparagi

利用拮抗芽孢杆菌菌株B96-II对芦笋茎枯病菌进行了室内抑菌试验和田间防治及机理研究,结果表明:B96-II对芦笋茎枯病菌有明显抑制作用。稀释50～1600倍后平皿试验,生长速率抑制率为97.37%～92.98%;离体组织培养对菌斑的抑制率为94.40%;田间防治效果为93.40%。显微观察发现,B96-II处理后可导致菌丝和孢子严重破损,使细胞内容物外渗。处理后24h,菌液电导率(μs·cm-1)和总溶解固体(TDS)比不处理的对照明显提高,处理中B96-II培养液浓度从1%升到10%时,电导率增加量从47.50%提高到518.33%,总溶解固体增加量从176.10%提高到797.60%。经测定,B96-II可抑制病原菌菌丝呼吸,处理中B96-II培养液浓度从1%升到10%时呼吸抑制率从25.00%升至196.40%。生物测定表明,B96-II的主要抑菌物为拮抗蛋白。

The inhibition effects of an antagonistic Bacillus strain B96-II on asparagus stem blight （Phomopsis asparagi Sacc.） were investigated under laboratory in vitro and field conditions. The results demonstrate that B96-II effectively inhibits the pathogen. Inhabitation rates on P. asparagi growth rate are between 97.37% and 92.98%, when the cultures treated with 50 to 1 600 times dilution of B96-II fermentation brew. Under in vitro conditions, colonial growth on asparagus stem reduces by 94.40% compared with the control samples, and under field trials by 93.40%. Microscopic observation reveals that the mycelia and spore walls of P. asparagi are destroyed and cell contents released after B96-II treatment. Conductivity of the inoculum liquid of P. asparagi increases significantly 24 h after treatments. As B96-II inoculum liquid concentration increases from 1% to 10%, its conductivity increment increases from 47.50% to 518.33% and total dissolved solids （TDS） increment increases from 176.10% to 797.60%. B96-II also restricts P. asparagi mycelial respiration at an inhibition rate of 25.00% by addition of 1% B96-II and 196.40% by addition of 10% B96-II. Based on the analysis, the main active substances in B96-II are antagonistic proteins.