三七根际耐皂苷木霉菌的分离鉴定及其拮抗促生活性评价

Isolation and identification of ginsenosides-tolerant Trichoderma strains from rhizosphere of Panax notoginseng and evaluation of their effect on antagonistic and growth promotion activity

为筛选出三七根际具有拮抗促生活性的耐皂苷木霉菌,通过收集一年生健康三七根际土壤进行木霉菌株的分离,并测定三七根系分泌物对木霉菌孢子萌发的影响以及皂苷对木霉菌菌丝生长的抑制效果,筛选获得耐皂苷的菌株,进一步对其分类鉴定后进行拮抗根腐病病原菌活性测定以及盆栽促生效果、根际定殖能力及其对连作障碍缓解效果的评价。结果表明:试验共分离到6株木霉菌株,其中2株对三七根系分泌物敏感性较低,经过形态学特征和ITS序列比对鉴定为绿色木霉(Trichoderma viride)T3和渐绿木霉(T.viridescens)T20。T3和T20菌株对三七主要根腐病病原菌恶疫霉菌(Phytophthora cactorum)、毁灭柱孢菌(Cylindrocarpon destructans)、茄腐镰刀菌(Fusarium solani)、尖孢镰刀菌(F.oxysporum)和雪腐镰刀菌(Monographella cucumerina)均具有较强的拮抗效果,对恶疫霉菌抑制率分别可达到61.76%和70.59%;T3和T20菌株能促进三七植株的生长,将其接种于三七连作土中,在接种20 d后能够在根际较好的定殖,增加三七植株的存苗率,降低根腐病发病率。该研究结果为缓解三七连作障碍提供了重要的生防菌资源。

To identify ginsenosides-tolerant Trichoderma strains with antagonistic and growth promotion activity from the rhizosphere soil of healthy Panax notoginseng,rhizosphere soil of one-year-old healthy P.notoginseng was collected.Ginsenosides-tolerant Trichoderma strains were then screened by measuring the effect of P.notoginseng root exudates and ginsenosides on the spore germination and mycelium growth of Trichoderma.After the taxonomic identification test,the ginsenosides-tolerant Trichoderma strains were further assayed for their antagonistic activity against root rot pathogens as well as their growth promotion effect,rhizosphere colonization capacity and the alleviation effect of continuous cropping obstacles.The results showed that:A total of 6 Trichoderma strains were isolated,among which,two strains showed low sensitivity to the root exudates.Based on the morphological characteristics and ITS sequence comparison,the two strains were identified as T.viride strain T3 and T.viridescens strain T20.Both T3 and T20 strains had strong antagonistic effects against the major root rot pathogens of P.notoginseng,including Phytophthora cactorum,Cylindrocarpon destructans,Fusarium solani,Fusarium oxysporum and Monographella cucumerina,and their inhibition rates against Phytophthora cactorum reached 61.76%and 70.59%,respectively.Both T3 and T20 strains promoted the growth of P.notoginseng.And the two strains inoculating in P.notoginseng continuous crop soil had high colonization ability in the rhizosphere after inoculation of 20 days and also increased the survival rate of P.notoginseng plants and reduced the root rot incidence.This study provided important biocontrol resources for alleviating the continuous cropping obstacles of P.notoginseng.