生防菌哈茨木霉Trichoderma harzianum T4对西瓜根围土壤细菌群落的影响

Effect of Trichoderma harzianum T4 on Bacterial Community in Watermelon(Citrullus lanatus) Rhizosphere Soil

采用平板培养、末端限制性片段长度多态性(terminal restriction fragment length polymorphism,T-RFLP)以及变性梯度凝胶电泳(denatured gradient gel electrophoresis,DGGE)的方法相结合探讨生防菌哈茨木霉Trichoderma harzianum T4对大棚西瓜根围土壤细菌群落及氨氧化细菌群落的影响,为其在田间应用的生态安全性的评估提供支撑。末端限制性片段长度多态性以及变性梯度凝胶电泳的结果均表明哈茨木霉T4施入田间约四周内对根围土壤细菌群落产生明显的影响,随后这种扰动现象逐渐减小。对DGGE中受影响条带的测序结果表明,生防菌T4促进了假单胞菌Pseudomonas,芽孢杆菌Bacillus,苍白杆菌Ochrobactrum以及中慢生根瘤菌Mesorhizobium等细菌类群的生长,对短杆菌Brevibacterium,克雷白氏肺炎杆菌Klebsiella pneumoniae,根瘤菌Rhizobium sp等表现出抑制作用。生防菌T4对根围土壤中氨氧化细菌群落并没有产生明显的影响。可见,生防菌木霉T4引入初期对根围土壤中细菌群落产生明显的扰动,但这种干扰是短暂的,并没有对根围土壤细菌群落形成持续的影响。

The effects ofbiocontrol strain Trichoderma harzianum T4 on bacterial and ammonia-oxidizing bacteria （AOB） communities in watermelon （Citrullus lanatus） rhizosphere soil were studied using plate colony calculation, T-RFLP and DGGE method, in order to provide a theoretical basis and technique for assessing the microbial ecology risk of biocontrol agents application. Both T-RFLP and DGGE method demonstrated that T. harzianum T4 had short-term influence on rhizosphere soil bacterial communities which lasted about four weeks. Biocontrol strain T, harzianum T4 increased population of some bacteria, such as Pseudomonas, Bacillus, Ochrobactrum and Mesorhizobium. Meanwhile population of other bacteria such as Brevibacterium and Klebsiella pneumoniae were suppressed. The T4 had no significant influence on the soil AOB community. In general, T. harzianum T4 had notable effect on bacterial communities in first four or five weeks after inoculation, but this was just a temperal phenomenon. The T4 would not impact the soil bacterial communities for a long time.