耐盐植物促生菌W-1鉴定及其对红豆草耐盐性的影响

Identification of Salt-tolerant Plant Growth-promoting Bacterium W-1 and Its Effect on the Salt-tolerance of Sainfoin(Onobrychis viciaefolia)

【目的】为获得耐盐植物促生菌,从甘肃景泰一处盐碱地中的植物根系中分离出多株耐盐菌,其中部分耐盐菌具有明显的植物促生特性。【方法】在前期研究基础上,选取1株耐盐菌W-1和盐敏感植物红豆草(Onobrychis viciaefolia)为试验材料,对菌株W-1的物种分类、耐盐、耐酸碱能力和植物促生特性进行检测,并探究其对不同浓度NaCl处理下红豆草生长和生理特性的影响。【结果】耐盐菌W-1为革兰氏阳性菌、产芽孢、无荚膜、有鞭毛,16S rDNA测序及比对结果显示,菌株W-1为暹罗芽孢杆菌(Bacillus siamensis)。菌株W-1对NaCl最高耐受度为13%,pH耐受范围为4.5-8.5。菌株W-1具有溶磷、解钾、固氮、产铁载体、产吲哚-3-乙酸(indole-3-acetic acid,IAA)和1-氨基环丙烷-1-羧酸(1-aminocyclopropane-1-carboxylic acid,ACC)脱氨酶活性等多种植物促生功能。接种菌株W-1可显著提高红豆草的干重、鲜重,促进其根系生长。在100和150 mmol/L NaCl胁迫下,接种W-1可显著增加红豆草可溶性糖、可溶性蛋白、脯氨酸和叶绿素含量以及过氧化氢酶活力,降低过氧化氢含量以及叶片黄化率和死亡率,减缓盐胁迫对红豆草生长的不利影响。【结论】W-1是一株具有耐盐、耐酸碱的优良植物促生菌,可增强豆科牧草的耐盐性。

【Objective】To obtain salt-tolerant plant growth-promoting bacteria,several strains of salt-tolerant bacteria were isolated from plant roots in a saline-alkali soil in Jingtai,Gansu province,and some of them had obvious plant growth-promoting characteristics.【Method】Based on the previous work,a strain of salt-tolerant bacterium W-1 and a salt-sensitive plant sainfoin(Onobrychis viciaefolia)were selected as experimental materials,and the species classification,salt tolerance,acid and alkali tolerance and plant growth-promoting characteristics of strain W-1 were tested.The effects of strain W-1 on the physiological status of sainfoin treated with different concentrations of NaCl were investigated.【Result】The salt-tolerant bacterium W-1 was Gram-positive,spore-producing,without capsule and flagellated.The 16S rDNA sequencing and comparison results showed that the bacterium W-1 was Bacillus siamensis.The maximum NaCl tolerance of strain W-1 was 13%,and the pH tolerance range was 4.5-8.5.W-1 has various plant growth-promoting functions,such as phosphate and potassium solubilization,nitrogen fixation,siderophores production,indole-3-acetic acid(IAA)production and 1-aminocyclopropane-1-carboxylic acid(ACC)deaminase activity.Strain W-1 significantly increased dry weight and fresh weight and promoted root growth of sainfoin seedlings.Under 100 and 150 mmol/L NaCl stresses,strain W-1 significantly increased the contents of soluble sugar,soluble protein,proline,chlorophyll,and catalase activity,decreased the content of hydrogen peroxide,leaf yellowing rate and mortality,and alleviated the adverse effects of salt stress on the growth of sainfoin seedlings.【Conclusion】The W-1 strain was an excellent plant growth-promoting bacterium with salt tolerance,acid and alkali tolerance,and enhanced the salt tolerance of legume forage.