马铃薯细菌多样性解析及促生高产IAA菌株的筛选

Analysis of potato bacterial diversity and screening of high-yielding IAA strains

采用3种不同的培养基从马铃薯根际土壤和叶片中共分离出78株细菌,优势菌属是Pantoea,占菌株总数的55.13%。马铃薯根际土采用R2A培养基(27株优势菌,13个菌属)分离的细菌多样性相对较好,阿须贝培养基(31株优势菌,9个菌属)次之,土壤浸提液培养基(1株优势菌,1个菌属)最少;马铃薯叶片内生菌用阿须贝培养基(19株优势菌,3个菌属)分离的细菌多样性较差。采用Salkowski比色液显色法定量测定菌株产IAA能力,结果表明有58株细菌具有分泌IAA的能力,占测定菌株总数的74.36%,从马铃薯根际土(42株优势菌,13个菌属)筛选的产IAA菌数量及细菌多样性均高于马铃薯叶片内生菌(16株优势菌,2个菌属)。根据菌株产IAA能力强弱和分离部位及分离培养基的差异,选择7株产IAA菌进行促生特性和马铃薯盆栽幼苗促生能力等研究,结果显示:有6株产IAA菌具有ACC脱氨酶能力,1株产IAA菌具有溶解无机磷能力,2株产IAA菌具有溶解有机磷能力;两轮温室促生实验结果显示,菌株Pantoea sp.MLS-34-25对马铃薯幼苗具有明显的促生作用,是生产微生物肥料的潜在菌种。

A total of 78 strains of bacteria were isolated from potato rhizosphere soil and leaves by three different cultures. The dominant genus was Pantoea,accounting for 55.13% of the total number of strains.The diversity of bacteria isolated from potato rhizosphere soil using R2 A medium(27 dominant bacterias,13 genera)was relatively good,followed by Ashby medium(31 dominant bacterias,9 genera),and soil extract medium(1 dominant bacteria,1 genera)was the least.The bacterial diversity of endophytic bacteria isolated from potato leaves by Ashby medium(19 dominant strains,3 genera)was poor.The ability of IAA production was quantitatively determined by Salkowski colorimetric method.The results showed that 58 strains had the ability to secrete IAA,accounting for 74.36% of the total strains tested.The number and diversity of IAA-producing bacteria screened from potato rhizosphere soil(42 dominant bacteria,13 genera)were higher than those from potato leaves(16 dominant bacteria,2 genera).Seven IAA-producing strains were selected to study their growth-promoting characteristics and potato seedling growth-promoting ability according to the difference of IAA-producing ability,isolation site and isolation medium.The results showed that six IAA-producing bacteria had the ability of ACC deaminase,one IAA-producing bacteria had the ability of dissolving inorganic phosphorus,and two IAA-producing bacteria had the ability of dissolving organic phosphorus.Twice greenhouse growth-promoting experiments showed that strain Pantoea sp.MLS-34-25 had obvious growth-promoting effect on potato seedlings and was a potential strain for microbial fertilizer production.