哈茨木霉T9131鉴定及其拮抗病原菌和诱导黄芪抗病的作用分析

Identification of Trichoderma harzianum T9131 and analysis of its antagonistic action on pathogen and inducing disease resistance of Astragalus membranaceus

关键词:  黄芪根腐病, 哈茨木霉, 腐皮镰刀菌, 拮抗作用, 生理指标测定

Key words:  Astragalus membranaceus root rot, Trichoderma harzianum, Fusarium solani, antagonistic action, physiological indexes determination

摘要:

木霉是土壤和植物根系中常见的真菌,在农业生物防治中起到重要作用。为探究木霉在黄芪抗根腐病中的作用,该研究从黄芪根腐病病根中分离鉴定木霉并研究其对病原菌的拮抗作用和对黄芪抗病生理指标的影响。通过形态学观察、ITS序列和tef1序列分析确定木霉类型; 利用平板对峙试验分析分离木霉对腐皮镰刀菌HYFS-1的拮抗作用; 测定黄芪生理指标过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和脯氨酸(Pro)来明确分离木霉在诱导黄芪抗病中的作用。结果表明:(1)从黄芪病根中分离鉴定的木霉为哈茨木霉,命名为T9131。(2)哈茨木霉T9131与腐皮镰刀菌HYFS-1平板对峙6 d时T9131对HYFS-1的抑制率为72%±1% 。(3)与只接种腐皮镰刀菌HYFS-1相比,当HYFS-1侵染0 h时,T9131显著提高SOD活性; 当HYFS-1侵染24 h时,T9131显著提高SOD和POD的活性及Pro含量; 当HYFS-1侵染48 h时,T9131显著提高POD和PAL的活性及Pro含量。综上认为,哈茨木霉T9131可以通过直接抑制病原菌HYFS-1的生长和诱导黄芪抗病生理指标SOD、POD和PAL的活性及Pro含量来防治黄芪根腐病,为进一步探究哈茨木霉的生防作用和在黄芪抗根腐病中的作用机理奠定基础。

Abstract:

The fungus Trichoderma spp. is ubiquitously detectable in soil and plant roots, and it plays a crucial role in the biological control of agriculture. To explore the influence of Trichoderma spp. on the resistance of Astragalus membranaceus to root rot, the aim of this study is to isolate and identify type of Trichoderma spp. from Astragalus membranaceus root rot, and subsequently investigate its antagonistic action on pathogen and analyze its effect on physiological indexes of disease resistance of Astragalus membranaceus. The type of Trichoderma spp. was determined through morphological characteristics, ITS and tef1 sequence analysis. The antagonistic action of Trichoderma spp. isolate against Fusarium solani HYFS-1 was analyzed by plate confrontation assay. To determine the role of Trichoderma spp. isolate in inducing the disease resistance of Astragalus membranaceus, the physiological indexes such as catalase(CAT), superoxide dismutase(SOD), phenylalanine ammonlyase(PAL), peroxidase(POD)and proline(Pro)were determined. The results were as follows:(1)The Trichoderma spp. type from Astragalus membranaceus root rot was identified as Trichoderma harzianum and named T9131.(2)The inhibition rate of Trichoderma harzianum T9131 against Fusarium solani HYFS-1 reached 72%±1% after 6 days of two confrontation.(3)Compared to HYFS-1 alone, T9131 significantly enhanced SOD activity at 0 h after HYFS-1 infection; at the 24 h HYFS-1 infection, T9131 markedly increased SOD activity, POD activity, and Pro content; by the 48 h HYFS-1 infection, T9131 significantly elevated POD activity, PAL activity, and Pro content. To sum up, Trichoderma harzianum T9131 can control Astragalus membranaceus root rot by directly inhibiting the growth of HYFS-1 and inducing acitivities of SOD, POD, PAL and Pro content of Astragalus membranaceus under Fusarium solani HYFS-1 stress. This research will lay the foundation for exploring the biocontrol effect of Trichoderma harzianum and its machanism of resistance of Astragalus membranaceus root rot.