Isolation, screening and application of peanut rhizobia

Abstract

[Objective] To isolate and screen peanut rhizobia of efficient nodulation and nitrogen fixation effects, and to provide theoretical basis and candidate strains for promotion and application of peanut rhizobia in field.

[Method] Rhizobia were isolated and purified from soil samples collected in field by plant capture method, and their 16S rDNA sequences were amplified for molecular identification. Excellent rhizobia strains and optimal symbiotic combination were screened by reinoculation and matching tests, and effects of inoculation with the excellent strains were investigated through soil pot field tests.

[Result] Fifteen strains of peanut rhizobia were isolated and purified, all belonging to Bradyrhizobium of α-proteobacteria. Two strains of peanut rhizobia, GDHS-5 and GDHS-14, with excellent symbiotic nitrogen fixation traits were screened through the reinoculation test. The matching test showed that these 2 strains had broad-spectrum nodulation, and matching Yueyou 901 with GDHS-5 produced the best effects, followed by matching it with GDHS-14. Under soil pot culture conditions, inoculation with GDHS-5 significantly increased above-ground part height, root nodule number and root nodule fresh weight of Yueyou 901 ( P<0.05, the same below), but no significant difference was found between strains inoculated with GDHS-14 and non-inoculated control (CK) ( P>0.05, the same below). Pod number per plant, yield and sucrose content in peanut were significantly increased by 35.82%, 9.92% and 165.88% respectively after inoculation with GDHS-5 under field conditions, and no significant difference was found between strains inoculated with GDHS-14 and CK.

[Conclusion] Peanut rhizobia GDHS-5 and GDHS-14 boast excellent symbiotic nitrogen fixation. GDHS-5 can efficiently fix nitrogen and has broad-spectrum nodulation and can significantly increase pod number per plant and yield of peanuts under field conditions, so it has great potential for application in field.

Abstract

摘要：【目的】 分离筛选高效结瘤固氮的花生根瘤菌, 为花生根瘤菌的田间推广应用提供理论依据和候选菌种。 【方法】采用植物捕获法从田间采集的土样中分离纯化根瘤菌, 扩增其16S rDNA序列进行分子鉴定。经回接试验和 匹配试验筛选优良菌株及最佳共生组合, 并通过土壤盆栽田间试验探究优良菌株的接种效果。 【结果】共分离纯化出 15株花生根瘤菌, 均属于α-变形菌纲的慢生根瘤菌属 ( Bradyrhizobium)。回接试验筛选出2株共生固氮性状优良的花 生根瘤菌GDHS-5和GDHS-14。匹配试验表明这2个菌株具有广谱结瘤性, GDHS-5与粤油901的匹配效果最好, GDHS-14次之。土壤盆栽条件下接种GDHS-5显著提高了粤油901的地上部分高度、根瘤数量和根瘤鲜重 ( P<0.05, 下同), 而接种GDHS-14与不接种对照 (CK) 无显著差异 ( P>0.05, 下同) 。田间条件下接种GDHS-5分别使单株荚果 数、产量和花生蔗糖含量显著增加35.82%、9.92%、165.88%, 接种GDHS-14与CK无显著差异。 【结论】花生根瘤菌 GDHS-5和GDHS-14共生固氮表现优异, 其中GDHS-5能高效共生固氮, 具有广谱结瘤性, 在田间条件下可显著提高 花生单株荚果数和产量, 具有较大的田间应用潜力。