哈茨木霉EMF910对宁夏盐碱地区黄芪根腐病致病菌的防治作用

The control effect of Trichoderma harzianum EMF910 on the root rot pathogens of Astragalus membranaceus in Ningxia saline-alkali regions

摘要:

【背景】 根腐病分布广，危害重，是我国西北盐碱地区黄芪(Astragalus membranaceus)大规模人工种植过程中最常见的病害之一，常引起黄芪产量及药材品质下降，目前尚无有效的防治手段。哈茨木霉对根茎类作物根腐病的致病菌有显著的防治作用，但在盐碱条件下的作用少见报道。【目的】 明确引起我国西北盐碱地区黄芪根腐病的主要致病菌，探究哈茨木霉(Trichoderma harzianum) EMF910在盐碱条件下对这些主要致病菌的抑制效果。【方法】 通过组织分离、离体回接、形态学和分子生物学方法等确定引起西北盐碱地区规模化种植黄芪根腐病的致病菌；通过平板对峙试验研究哈茨木霉EMF910在盐碱条件下对该致病菌的抑制效果；通过盆栽试验探究了哈茨木霉EMF910在盐碱土壤中对种植黄芪根腐病的防治效果。【结果】 引起西北地区黄芪根腐病的致病菌为腐皮镰孢(Fusarium solani) X12和斜隔孢镰孢(Fusarium obliquiseptatum) P1。在正常条件(0% NaCl，pH自然)下培养7 d后，哈茨木霉EMF910对菌株X12和P1的平板抑制率分别达到77.93%和73.82%，在盐碱条件(1% NaCl，pH 8.5)下培养7 d后，哈茨木霉EMF910对菌株X12和P1的平板抑制率分别达到70.22%和67.95%；在正常条件(0% NaCl，pH自然)培养12 h后，哈茨木霉EMF910对菌株X12和P1的孢子萌发抑制率分别为87.21%和86.11%，在盐碱条件下培养12 h后，哈茨木霉EMF910对菌株X12和P1的孢子萌发抑制率分别为72.29%和64.47%。盆栽试验表明，在根腐病致病菌预侵染的成熟期黄芪中，哈茨木霉EMF910菌剂处理组的黄芪存活率为56.3%，而未经哈茨木霉EMF910菌剂处理的清水对照组黄芪存活率仅为12.5%；统计存活黄芪根腐病发病率，结果表明，哈茨木霉EMF910菌剂处理组黄芪根腐病发病率为33.3%，而不施加哈茨木霉EMF910的清水对照组黄芪根腐病发病率则为50.0%。【结论】 引起我国西北盐碱地区黄芪根腐病的病原菌主要为腐皮镰孢与斜隔孢镰孢；在盐碱条件(1% NaCl，pH=8.5)下，哈茨木霉EMF910对这些致病菌生长和孢子萌发有较好的抑制作用，但与正常条件(0% NaCl，pH自然)的抑制效果相比有所下降；哈茨木霉EMF910对盐碱土壤中种植黄芪根腐病具有较好的防治效果。该结果可为后续使用哈茨木霉EMF910菌剂对宁夏盐碱地区种植黄芪根腐病的生物防治提供数据支撑，同时也可为我国其他盐碱地区利用哈茨木霉EMF910防治根腐病提供借鉴。

关键词:黄芪;根腐病;哈茨木霉;盐碱条件

Abstract:

[Background] Root rot is widespread and harmful, being one of the most common diseases in the process of large-scale cultivation of Astragalus membranaceus in the northwest saline-alkali regions of China, which causes a decrease in yield and quality of A. membranaceus, and there is currently no effective control method. Trichoderma harzianum has a significant control effect on the pathogens causing root rot in rhizome crops, but its effect under saline-alkali conditions has been reported rarely. [Objective] To clarify the main pathogens causing root rot in A. membranaceus in the northwest saline-alkali areas of China, and to explore the inhibitory effect of T. harzianum EMF910 on these main pathogens under saline-alkali conditions. [Methods] The pathogens causing root rot of A. membranaceus in large-scale cultivation in the saline-alkali areas of northwest China were determined through tissue isolation, in vitro tie-back, morphological, and molecular biology methods. The inhibitory effect of T. harzianum EMF910 on these pathogens under saline-alkali conditions was studied through plate confrontation experiments. The control effect of T. harzianum EMF910 on root rot in A. astragalus in saline-alkali soil was investigated by pot experiment. [Results] The main pathogens causing root rot in A. astragalus in the northwest region were identified as Fusarium solani X12 and Fusarium obliquiseptatum P1. After culturing for 7 days under normal conditions (0% NaCl, pH natural), the plate inhibition rates of T. harzianum EMF910 on X12 and P1 reached 77.93% and 73.82%, respectively. After culturing for 7 days under saline-alkali conditions (1% NaCl, pH=8.5), the plate inhibition rates of T. harzianum EMF910 on X12 and P1 reached 70.22% and 67.95%, respectively. After culturing for 12 hours under normal conditions (0% NaCl, pH natural), the spore germination inhibition rates of T. harzianum EMF910 on X12 and P1 reached 87.21% and 86.11%, respectively. After culturing for 12 hours under saline-alkali conditions, the spore germination inhibition rates of T. harzianum EMF910 on X12 and P1 reached 72.29% and 64.47%, respectively. The pot experiments showed that in A. membranaceus pre-infected with root rot pathogens, the survival rate of A. membranaceus treated with T. harzianum EMF910 was 56.3%, while the survival rate of the control group treated with water without T. harzianum EMF910 was only 12.5%. The statistical survival rate of A. membranaceus with root rot showed that the incidence rate of root rot in T. harzianum EMF910 treatment group was 33.3%, while that in the water control group without T. harzianum EMF910 was 50.0%. [Conclusion] The main pathogens causing root rot in A. mezmbranaceus in the northwest saline-alkali areas of China are mainly F. solani and F. obliquiseptatum. T. harzianum EMF910 can effectively inhibit the growth and spore germination of these pathogens under saline-alkali conditions (1% NaCl, pH 8.5), but the inhibitory effect is lower compared to that under normal conditions (0% NaCl, pH natural). T. harzianum EMF910 has a good control effect on root rot in A. membranaceus in saline-alkali soil. These results provide data support for the biological control of root rot in A. membranaceus in saline-alkali areas of Ningxia using T. harzianum EMF910 and also provide a reference for the use of T. harzianum EMF910 to control the root rot in other saline-alkali areas of China.

Key words:Astragalus membranaceus;root rot;Trichoderma harzianum;saline-alkali condition