一株生防木霉的鉴定及环境pH与对羟基苯甲酸对其防病效果的影响

Identification of Biocontrol Trichoderma Strain and Effect of Environment pH and p-Hydroxybenzoic Acid on Its Disease Prevention

旨在明确西瓜枯萎病生防真菌M3菌株的分类地位及环境pH与对羟基苯甲酸(p-hydroxybenzoic acid,PHBA)共同作用对其防病效果的影响。采用形态学和分子生物学方法分类鉴定,确定M3菌株为哈茨木霉(Trichoderma harzianum)。平板试验结果表明,PHBA对M3菌株和病原菌尖镰孢菌西瓜专化型的菌落生长均具有“低浓度促进、高浓度抑制”的作用,强酸和强碱环境均不利于2种菌的生长;M3菌株和病原菌的最适生长环境pH和最适PHBA质量浓度不同,前者为6和400 mg·L^(-1),后者为8和200 mg·L^(-1)。pH和PHBA共同作用下,M3菌株的抑菌率无显著变化。在pH 6和PHBA质量浓度400 mg·L^(-1)的土壤环境中,M3菌株的防病效果达到最高水平(85.72%)。总之,M3菌株的防病效果主要受土壤pH影响,其能够在PHBA积累环境中有效发挥防病作用,具有较好的生防应用潜力。

In order to clarify the taxonomic status of the biocontrol fungus M3 of watermelon Fusarium wilt,the effects of environmental pH and p-hydroxybenzoic acid(PHBA)on its disease control were studied.M3 strain was identified as Trichoderma harzianum based on morphological and molecular biology methods.The results showed that PHBA could promote and inhibit the colony growth of M3 and the pathogenic fungus Fusarium oxysporum f.sp.niveum at low concentration and high concentration conditions,respectively.Meanwhile,the strong acid and alkali were not conducive to the growth of the two fungi.The optimal growth environment pH and optimal PHBA mass concentration of M3 and pathogenic fungus were different,the former was 6 and 400 mg·L^(-1),the latter was 8 and 200 mg·L^(-1).Under the combination of pH and PHBA,the antibacterial rate of M3 did not change significantly.In soil environment with pH 6 and PHBA mass concentration of 400 mg·L^(-1),the disease control efficiency of M3 reached to 85.72%.In conclusion,the disease control efficiency of the M3 is mainly affected by soil pH,which can effectively play a role in disease control efficiency in PHBA accumulation environment and has a good potential for biocontrol applications.This study lays the foundation for the development and application of related fungus agents.