Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Caixa Postal 15.053, 91501-970, Porto Alegre, RS, Brazil.
LABRESIS - Laboratório de Pesquisa em Resistência Bacteriana, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos 2350, Porto Alegre, RS, 90.035-903, Brazil.
Microbiol Res. 2021 Jul;248:126754. doi: 10.1016/j.micres.2021.126754. Epub 2021 Apr 2.
Endophytic bacteria show important abilities in promoting plant growth and suppressing phytopathogens, being largely explored in agriculture as biofertilizers or biocontrol agents. Bacteria from canola roots were isolated and screened for different plant growth promotion (PGP) traits and biocontrol of Sclerotinia sclerotiorum. Thirty isolates belonging to Bacillus, Paenibacillus, Lysinibacillus, and Microbacterium genera were obtained. Several isolates produced auxin, siderophores, hydrolytic enzymes, fixed nitrogen and solubilized phosphate. Five isolates presented antifungal activity against S. sclerotiorum by the dual culture assay and four of them also inhibited fungal growth by volatile organic compounds production. All antagonistic isolates belonged to the Bacillus genus, and had their genomes sequenced for the search of biosynthetic gene clusters (BGC) related to antimicrobial metabolites. These isolates were identified as Bacillus safensis (3), Bacillus pumilus (1), and Bacillus megaterium (1), using the genomic metrics ANI and dDDH. Most strains showed several common BGCs, including bacteriocin, polyketide synthase (PKS), and non-ribosomal peptide synthetase (NRPS), related to pumilacidin, bacillibactin, bacilysin, and other antimicrobial compounds. Pumilacidin-related mass peaks were detected in acid precipitation extracts through MALDI-TOF analysis. The genomic features demonstrated the potential of these isolates in the suppression of plant pathogens; however, some aspects of plant-bacterial interactions remain to be elucidated.
内生细菌在促进植物生长和抑制植物病原菌方面表现出重要的能力，因此在农业中作为生物肥料或生物防治剂得到了广泛的研究。从油菜根部分离并筛选了具有不同植物生长促进（PGP）特性和防治核盘菌的内生细菌。获得了属于芽孢杆菌属、类芽孢杆菌属、短小芽孢杆菌属和微杆菌属的 30 个分离株。一些分离株产生了生长素、铁载体、水解酶、固定氮和溶解磷酸盐。通过双培养试验，有 5 个分离株对核盘菌表现出抗真菌活性，其中 4 个分离株还通过挥发性有机化合物的产生抑制了真菌的生长。所有拮抗分离株均属于芽孢杆菌属，对其基因组进行测序以寻找与抗菌代谢物相关的生物合成基因簇（BGC）。这些分离株被鉴定为芽孢杆菌 safensis（3）、短小芽孢杆菌（1）和巨大芽孢杆菌（1），使用基因组度量ANI 和 dDDH。大多数菌株表现出几种常见的 BGC，包括细菌素、聚酮合酶（PKS）和非核糖体肽合酶（NRPS），与 pumilacidin、bacillibactin、bacilysin 和其他抗菌化合物有关。通过 MALDI-TOF 分析在酸沉淀提取物中检测到 pumilacidin 相关的质量峰。基因组特征表明这些分离株具有抑制植物病原菌的潜力；然而，植物-细菌相互作用的某些方面仍有待阐明。
