茶树腐皮镰刀菌拮抗菌株的筛选鉴定及促生防病特性分析

Screening and Identification of Strains against Fusarium solani Isolated from Camellia sinensis and Analysis of its Biocontrol and Growth Promotion Characteristics

腐皮镰刀菌(Fusariumsolani)是可以引起茶树茎腐和枯萎的致病真菌。为获得对茶树腐皮镰刀菌有拮抗效果的生防菌株,从河南省信阳市新县茶园收集的茶树(Camelliasinensis)健康叶片中采用梯度稀释法分离纯化得到内生细菌56株,通过平板对峙法筛选对腐皮镰刀菌抑制效果较好的菌株,并根据形态特征、生理生化特征和分子生物学技术对其进行鉴定,测定其防病促生指标并进行抑菌谱试验,通过发酵液试验和平板对扣法评估挥发性物质对腐皮镰刀菌菌丝生长的影响。结果显示,筛选得到的菌株YB-1476对腐皮镰刀菌菌丝生长抑制率达到63.31%,拮抗效果最佳,鉴定其为贝莱斯芽孢杆菌(Bacillus velezensis)。该菌株有产铁载体和吲哚乙酸、分泌β-1,3-葡聚糖酶和纤维素酶及溶磷的能力。抑菌谱试验表明,菌株YB-1476对平脐蠕孢菌(Bipolarissorokinana)、禾谷镰刀菌(FusariumgraminearumPH-1)、念珠状镰刀菌(Fusarium moniliforme)、尖孢镰刀菌(Fusariumoxysporumf.sp.niveum)和茄链格孢菌(Alternariasolani)5种病原真菌的菌丝生长抑制率分别达到65.03%、42.32%、51.67%、52.33%和63.22%。发酵液原液、稀释10倍和稀释100倍发酵液对腐皮镰刀菌的菌丝生长抑制率分别为66.67%、51.85%和18.52%。菌株YB-1476产生的挥发性物质对腐皮镰刀菌的菌丝生长抑制率达到53.37%。以上结果表明,菌株YB-1476在防控茶树茎腐和枯萎病方面具有巨大应用潜力。

Fusarium solani is a pathogen that could cause collar canker and dieback of Camellia sinensis. To obtain strains with strong antagonistic activity against F. solani, a total of 56 endophytic strains were isolated and purified from healthy leaves of tea trees collected from a tea garden in Xinxian, Xinyang, Henan province by dilution plate method and were screened in dual cultures with F. solani. The strain was identified based on morphological characteristics, physiological, biochemical and molecular tests. Biocontrol and growth-promoting traits and antibacterial spectrum test were also detected. The effects on the mycelial growth of F. solani were evaluated by ferment product and volatile test by buckle culture. The results show that strain YB-1476 exhibited the strongest antagonistic activity against F. solani with growth inhibition rate of 63.31% and was identified as Bacillus velezensis. Strain YB-1476 could produce siderophore, indoleacetic acid, and be able to secrete β-1,3-glucanase,cellulase and solubilize phosphorus. Furthermore, strain YB-1476 displayed strong antagonistic activity against Bipolaris sorokinana, Fusarium graminearum PH-1, Fusarium moniliforme, Fusarium oxysporum f. sp. niveum and Alternaria solani and growth inhibition rates were 65.03%, 42.32%, 51.67%, 52.33% and 63.22%, respectively. In addition, ferment products show that the growth inhibition rates of the original fermentation broth, 10-fold, and 100-fold dilutions were 66.67%, 51.85%, 18.52%, respectively and the volatile test shows that growth inhibition rate against F. solani was 53.37%. The above results demonstrate that B. velezensis YB-1476 is a strain with great application potential to control collar canker and dieback of tea trees.