Instituto de Investigaciones para la Industria Química (INIQUI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Salta, Av. Bolivia 5150, 4400 Salta, Argentina, Argentina.
Instituto Nacional de Tecnología Agropecuaria (INTA)-Estación Experimental Salta, Ruta Nacional 68 Km 172, 4403, Cerrillos, Salta, Argentina.
Microbiol Res. 2018 Jun;211:21-30. doi: 10.1016/j.micres.2018.04.003. Epub 2018 Apr 7.
Bacillus sp. B19, Bacillus sp. P12 and B. amyloliquefaciens B14 were isolated from soils of Salta province, and PGPR properties on the common bean (Phaseolus vulgaris L.) cv. Alubia and antagonistic activity against Sclerotinia sclerotiorum were studied. It was determined that B19 and P12 increased crop germination potential (GP) from the common bean by 14.5% compared to control seeds; these strains also increased root length (10.4 and 15%, respectively) and stem length (20.2 and 30%, respectively) compared to the control; however, as for the B14 strain, no increases in growth parameters were detected. In addition, all the treatments that combined two bacilli: B14 + B19, B14 + P12 and B19 + P12, generated beneficial effects on GP and seedling growth compared to control seeds, but not compared to a single inoculant. B19 and P12 strains synthesized auxins at concentrations of 5.71 and 4.90 mg/mL, respectively, and it was qualitatively determined that they synthesize siderophores. In addition, previous studies have determined that B14 produces auxins in a concentration of 10.10 mg/mL, and qualitatively synthesizes siderophores. The phytosanitary state of the white bean cv. Alubia control seeds revealed bacterial contamination in 87% of all the evaluated seeds and different fungi such as Cladosporium sp., Fusarium sp., and Rhizopus sp. Bean seeds treated with B14, B19 or P12 showed no growth of contaminating bacteria or of pathogenic fungi; in fact, bacilli inoculum development was observed in all seeds. Additionally, B19, P12 and B14 strains inhibited in vitro the development of 9 native S. sclerotiorum strains isolated from the Salta region, with FI ranging between 60 and 100%. The three Bacillus strains synthesized different isoforms of the lipopeptides: surfactin, iturin, and fengycin in the presence of S. sclerotiorum, as determined by MALDI-TOF. In the in vivo trials, when common bean seeds were grown in soils contaminated with S. sclerotiorum, an incidence of 100% was determined when the seeds were not treated with any Bacillus. Seeds treated with the chemical fungicide and sown in S. sclerotiorum-infested soil did not produce seed emergence, while the inoculation of the seeds with B14 + P12, B14 + B19 or B19 + P12 reduced the effect of the pathogen by 46, 43 and 25%, respectively. Disease progression in B14 + P12 and B14 + B19 treatments was significantly lower than in the remaining treatments, with an AUDPC of 873.75 and 1071, respectively.
从萨尔塔省的土壤中分离到芽孢杆菌 B19、芽孢杆菌 P12 和解淀粉芽孢杆菌 B14，并研究了它们对普通菜豆（Phaseolus vulgaris L.）cv. Alubia 的植物促生特性和对核盘菌（Sclerotinia sclerotiorum）的拮抗活性。结果表明，与对照种子相比，B19 和 P12 使普通菜豆的种子发芽势（GP）提高了 14.5%；这两种菌株还分别使根长（10.4%和 15%）和茎长（20.2%和 30%）增加；然而，对于 B14 菌株，未检测到生长参数的增加。此外，所有组合两种芽孢杆菌的处理：B14+B19、B14+P12 和 B19+P12，与对照种子相比，对 GP 和幼苗生长均产生有益影响，但与单一接种物相比没有差异。B19 和 P12 菌株分别合成浓度为 5.71 和 4.90mg/mL 的生长素，并且定性地确定它们合成铁载体。此外，先前的研究已经确定 B14 以 10.10mg/mL 的浓度产生生长素，并定性地合成铁载体。白豆 cv. Alubia 对照种子的植物检疫状况显示，在所评估的所有种子中，87%的种子存在细菌污染，并且存在不同的真菌，如枝孢菌（Cladosporium sp.）、镰刀菌（Fusarium sp.）和根霉（Rhizopus sp.）。用 B14、B19 或 P12 处理的菜豆种子没有发现污染细菌或致病真菌的生长；事实上，在所有种子中都观察到了杆菌接种物的发育。此外，B19、P12 和 B14 菌株在体外抑制了从萨尔塔地区分离的 9 株本地核盘菌的发育，FI 范围为 60%至 100%。在存在核盘菌的情况下，三种芽孢杆菌合成了不同同型的脂肽：表面活性剂、伊枯草菌素和丰原素，这是通过 MALDI-TOF 确定的。在体内试验中，当普通菜豆种子在受核盘菌污染的土壤中生长时，未用任何芽孢杆菌处理的种子的发病率为 100%。用化学杀菌剂处理并播种在受核盘菌污染的土壤中的种子没有产生种子萌发，而用 B14+P12、B14+B19 或 B19+P12 接种种子可分别降低 46%、43%和 25%的病原菌效应。B14+P12 和 B14+B19 处理的病情进展明显低于其他处理，AUDPC 分别为 873.75 和 1071。
