茶树根系耐铝促生内生细菌的分离鉴定及其特性研究

茶树喜酸耐铝,且低浓度的铝促进茶树生长,然而其调控机理并不清晰。从耐铝促生菌的角度,探究其可能的原因。以铝处理的茶树根系为材料,经分离鉴定,得到可培养的内生细菌38株,其中厚壁菌门27株,放线菌门11株。从利用1-氨基环丙烷-1-羧酸（ACC）能力、溶磷能力、产铁载体能力和分泌吲哚乙酸（Indole-3-acetic acid,IAA）能力对38株内生细菌进行了探究,结果表明,38株内生细菌都有一种以上的促生能力,其中厚壁菌FBA、FPC以及放线菌AMM、ACP032155等菌株的综合促生能力较好;38株内生细菌在1 mmol·L^-1 Al³⁺浓度下均能存活,其中放线菌AME2耐铝能力最强,在8 mmol·L^-1 Al³⁺浓度下仍能存活,说明铝能促进茶树耐铝促生菌的生长,从而间接促进茶树的生长,为选育具有显著耐铝促生能力的茶树内生细菌用于茶树的栽培育种奠定基础。

Isolation,Identification and Characterization of Aluminum-tolerant Growth-promoting Endophytic Bacteria in Tea Roots

Tea plants are aluminum-tolerant plants. Low concentration of aluminum promotes the growth of tea plants, but its regulation mechanism remains unclear. In this experiment, 38 strains of culturable endophytic bacteria were isolated and identified from the roots of tea plants treated with aluminum, including 27 strains of Firmicutes and 11 strains of Actinomycetes. Plant growth promoting abilities of the isolated endophytic bacteria were explored from ACC deaminase, phosphate solubilization, siderophore and IAA production. It was found that the comprehensive plant growth promoting abilities of Firmicutes FBA, FPC and Actinomycetes AMM, ACP032155 were better. The relative activities of the 38 strains at different aluminum ion concentrations were further investigated. The results show that the 38 strains of endophytic bacteria could survive under 1 mmol·L^-1 Al^{3 +} concentration, among which Actinomycetes AME2 could still survive under 8 mmol·L^-1Al³⁺, which showed the strongest aluminum tolerance. The results show that aluminum treatment could promote the growth of aluminum-tolerant bacteria in tea plants, thus indirectly promoting the growth of tea plants. This study laid a foundation for the cultivation and breeding of endophytic bacteria of tea plants with significant aluminum tolerance and growth promotion ability.