Department of Genetics, Universidade Federal Do Paraná, Av. Coronel Francisco Heráclito Dos Santos, 210. CEP, Curitiba, PR, 81531-970, Brazil.
Department of Biomedicine, Centro Universitário Católica de Santa Catarina, R. Visconde de Taunay, 427. CEP, Joinville, SC, 89203-005, Brazil.
Braz J Microbiol. 2021 Dec;52(4):1807-1823. doi: 10.1007/s42770-021-00596-y. Epub 2021 Aug 30.
Plant growth-limiting factors, such as low nutrient availability and weak pathogen resistance, may hinder the production of several crops. Plant growth-promoting bacteria (PGPB) used in agriculture, which stimulate plant growth and development, can serve as a potential tool to mitigate or even circumvent these limitations. The present study evaluated the feasibility of using bacteria isolated from the maize rhizosphere as PGPB for the cultivation of this crop. A total of 282 isolates were collected and clustered into 57 groups based on their genetic similarity using BOX-PCR. A representative isolate from each group was selected and identified at the genus level with 16S rRNA sequencing. The identified genera included Bacillus (61.5% of the isolates), Lysinibacillus (30.52%), Pseudomonas (3.15%), Stenotrophomonas (2.91%), Paenibacillus (1.22%), Enterobacter (0.25%), Rhizobium (0.25%), and Atlantibacter (0.25%). Eleven isolates with the highest performance were selected for analyzing the possible pathways underlying plant growth promotion using biochemical and molecular techniques. Of the selected isolates, 90.9% were positive for indolepyruvate/phenylpyruvate decarboxylase, 54.4% for pyrroloquinoline quinine synthase, 36.4% for nitrogenase reductase, and 27.3% for nitrite reductase. Based on biochemical characterization, 9.1% isolates could fix nitrogen, 36.6% could solubilize phosphate, 54.5% could produce siderophores, and 90.9% could produce indole acetic acid. Enzymatic profiling revealed that the isolates could degrade starch (90.1%), cellulose (72.7%), pectin (81.8%), protein (90.9%), chitin (18.2%), urea (54.5%), and esters (45.4%). Based on the data obtained, we identified three Bacillus spp. (LGMB12, LGMB273, and LGMB426), one Stenotrophomonas sp. (LGMB417), and one Pseudomonas sp. (LGMB456) with the potential to serve as PGPB for maize. Further research is warranted to evaluate the biotechnological potential of these isolates as biofertilizers under field conditions.
植物生长限制因素，如低养分可用性和弱病原体抗性，可能会阻碍几种作物的生产。在农业中使用的植物促生细菌（PGPB）可以刺激植物的生长和发育，可作为减轻甚至规避这些限制的潜在工具。本研究评估了从玉米根际分离的细菌作为 PGPB 用于该作物栽培的可行性。使用 BOX-PCR 根据遗传相似性将 282 个分离株聚类为 57 个组。从每组中选择一个代表分离株，并通过 16S rRNA 测序鉴定属水平。鉴定的属包括芽孢杆菌（61.5%的分离株）、解淀粉芽孢杆菌（30.52%）、假单胞菌（3.15%）、寡养单胞菌（2.91%）、类芽孢杆菌（1.22%）、肠杆菌（0.25%）、根瘤菌（0.25%）和 Atlantibacter（0.25%）。选择了 11 个表现最好的分离株，使用生化和分子技术分析植物生长促进的可能途径。在所选择的分离株中，90.9%为吲哚丙酮酸/苯丙酮酸脱羧酶阳性，54.4%为吡咯喹啉醌合酶阳性，36.4%为氮还原酶阳性，27.3%为亚硝酸盐还原酶阳性。基于生化特性，9.1%的分离株可以固氮，36.6%的分离株可以溶解磷酸盐，54.5%的分离株可以产生铁载体，90.9%的分离株可以产生吲哚乙酸。酶谱分析显示，这些分离株可以降解淀粉（90.1%）、纤维素（72.7%）、果胶（81.8%）、蛋白质（90.9%）、几丁质（18.2%）、尿素（54.5%）和酯类（45.4%）。根据获得的数据，我们鉴定了三个芽孢杆菌属（LGMB12、LGMB273 和 LGMB426）、一个寡养单胞菌属（LGMB417）和一个假单胞菌属（LGMB456），它们具有作为玉米 PGPB 的潜力。需要进一步研究以评估这些分离株作为生物肥料在田间条件下的生物技术潜力。
