四川攀枝花地区印度块菌菌根根际土壤内可培养放线菌功能多样性

Functional diversity of culturable actinomycetes isolated from Tuber inducum mycorrhizal soils in Panzhihua, Sichuan

以四川攀枝花地区印度块菌菌根根际土壤为对象,利用4种放线菌分离培养基筛选其中的放线菌,采用基于16S rRNA基因的PCR-RFLP方法结合传统的形态学观察进行鉴定。通过测定各分离菌株摇瓶培养发酵液中酶活性或代谢产物获取各菌株降解碳水化合物以及产促生剂的能力,采用平板对峙法测定各菌株抗病原真菌活性。结果共分离得到125株放线菌,经形态学观察去重复得到57株(W1-W57),经多样性分析将其归于3个属的23个种,其中以链霉菌属最多(91.3%),功能分析表明:有23株、17株、15株和18株放线菌能分别降解1,3-β-葡聚糖、几丁质、纤维素和果胶,其中有47.8%、26.1%和26.1%的菌株能同时降解4、3和2类碳水化合物;有19株、3株和2株放线菌分别能产含铁载体、IAA和ACC脱氨酶,其中有21.7%、56.6%和21.7%的菌株能分别产生3、2和1种根际促生剂;有10株放线菌表现出对不止一种病源真菌的拮抗能力,其中菌株W2和W19对4种病源真菌同时具有拮抗活性,且这2株菌对4种病源真菌抑菌能力比其他菌强;同时获得了包括W2、W3、W17、W19、W20、W34、W36和W54等在内的多功能高活性菌株,该研究表明四川攀枝花地区印度块菌菌根土壤内含丰富的多功能放线菌。所获结果可为我国印度块菌人工种植新技术的开发提供新思路。

In this study,we isolated actinomyces from Tuber inducum mycorrhizal soils in Panzhihua,Sichuan by four types of medium,and all isolates were identified by PCR-RFLP based on 16S rRNA gene in combination with morphological observation.The abilities of each strain to degrade carbohydrates and produce growth promoters were obtained by measuring the enzyme activity or metabolites in shaking flask fermentation broth of each isolate.Then,dual-culture inhibition was adopted for screening strains antifungal activity.A total of 125 actinomyces were isolated,of which 57 strains(W1-W57)were selected after morphological character observation and assigned to 3 genera.Actinomyces could be divided into 23 species,and among all isolates the Streptomyces were the most(91.3%).Result of functional analysis was as follows:23,17,15,and 18 strains of all isolates degraded 1,3-β-glucan,chitin and cellulose and pectin,respectively,of which 47.8%,26.1%and 26.1%were able to degrade simultaneously 4,3 and 2 carbohydrates,respectively.19 isolates produced the siderophore,3 isolates secreted indoleacetic acid,and 2 strains produced ACC deaminase,of which 21.7%,56.6%and 21.7%respectively had simultaneously the above bioactivities of 3,2 and 1,respectively.10 isolates had more than one ability to resist pathogenic fungi;W2 and W19 showed better inhibitory ability to four pathogenic fungi than other isolates.At the same time,the multifunctional functions and high bioactive strains including W2,W3,W17,W19,W20,W34,W36 and W54 were obtained.This study shows that there are lots of multifunctional actinomycetes in T.inducum mycorrhizal of Panzhihua,Sichuan,and the results can also provide new ideas for the development of new planting techniques in artificial cultivation of T.inducums.