西藏沙棘根瘤内生假单胞菌的分离鉴定及促生性研究

Identification and Growth-promoting Effects of Endophytic Pseudomonas sp.from Hippophae thibetana Root Nodules

【目的】获取西藏沙棘根瘤内生菌中具有多重生物学活性的假单胞菌属菌株,探究筛选所得菌株的促生作用,为研发高效生物菌肥提供基础材料。【方法】利用纯培养方法,从西藏沙棘根瘤中分离假单胞菌,通过形态、生理生化及16S rDNA序列比对鉴定菌株,测定菌株溶磷、产IAA、产铁载体及产降解纤维素酶的能力,接种宿主植物验证其促生效果。【结果】4株根瘤内生菌与参考假单胞菌属同源性为99%以上,鉴定为假单胞菌属。溶磷和产IAA的定性及定量结果表明,4株菌均具有溶解无机磷和产IAA的能力,其中溶解无机磷能力较强的菌株是QY-X10和QY-X22,均达到400 mg·L^(-1);菌株QY-X4产IAA能力较其他菌株强,达1.9 mg·L^(-1);4株菌株具有产铁载体的能力,除QY-X10以外,均具产降解纤维素酶的能力;促生试验结果表明,QY-X6可有效促进种子的萌发;QY-X6、QY-X10处理组叶片数显著高于对照;QY-X6、QY-X10处理组苗长显著高于对照;QY-X10、QY-X22处理组最大叶片长显著高于对照。【结论】分离筛选出4株假单胞菌,均可溶解无机磷和产IAA,兼具产铁载体;3株兼具产降解纤维素的能力;接种试验发现,4株菌株处理组可有效促进植株的生长发育,分离菌株可为研发生物菌肥提供基础材料。

【Objective】Endogenous Pseudomonas sp.in the root nodules of Hippophae thibetana that displayed a biological activity were isolated for toxicological identification and growth-promoting effect determination for the development of a biological agent for crop fertilization.【Methods】Strains of Pseudomonas sp.were isolated from the root nodules of H.thibetana by pure culture method.They were identified by morphology,physiological biochemistry,and 16S rDNA sequence,as well as examined for the growth-promoting effect on the host plant by artificial inoculation for evidence of phosphorusdissolving and IAA-,iron-and cellulase-producing capacities.【Results】Out of the isolated endophytic strains,4 showed greater than 99%16S rDNA alignment with the reference Pseudomonas.Among them,QY-X10 and QY-X22 produced 400 mg·L^(-1) of solubilized phosphorus;QY-X4 yielded the highest IAA at 1.9 mg·L^(-1);all 4 strains contained iron-generating carriers;except QY-X10,all could degrade cellulose;QY-X6 promoted seed germination;and QY-X6 and QY-X10 helped the host plant to grow significantly more leaves and longer seedlings,while QY-X10 and QY-X22 did significantly to make the maximum-length leaves longer than did control.【Conclusion】There were 4 Pseudomonas sp.identified in this study that exhibited significant abilities to dissolve inorganic phosphorus and produce IAA and iron.Three of them could also degrade cellulose.By inoculating these strains on the host plants,the seed germination and seedling growth were effectively promoted.It appeared that they could be applied for crop fertilization.