Nouioui Imen, Cortés-Albayay Carlos, Carro Lorena, Castro Jean Franco, Gtari Maher, Ghodhbane-Gtari Faten, Klenk Hans-Peter, Tisa Louis S, Sangal Vartul, Goodfellow Michael
School of Natural and Environmental Sciences, Faculty of Science, Agriculture and Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom.
Microbiology and Genetics Department, Universidad de Salamanca, Salamanca, Spain.
Front Microbiol. 2019 Jul 4;10:1457. doi: 10.3389/fmicb.2019.01457. eCollection 2019.
This study was designed to determine the plant growth promoting (PGP) potential of members of the genus . To this end, the genomes of 21 representative strains were examined for genes associated directly or indirectly with plant growth. All of the genomes contained genes that encoded for products associated with the biosynthesis of auxins [indole-3-glycerol phosphate synthases, anthranilate phosphoribosyltransferases (D), anthranilate synthases, and aminases (A and B)], cytokinins (11 well-conserved genes within the predicted biosynthetic gene cluster), siderophores, and nitrogenases ( operon except for atypical ) as well as genes that modulate the effects of biotic and abiotic environmental stress (e.g., alkyl hydroperoxide reductases, aquaporin Z, heat shock proteins). In contrast, other genes were associated with strains assigned to one or more of four host-specific clusters. The genes encoding for phosphate solubilization (e.g., low-affinity inorganic phosphate transporters) and lytic enzymes (e.g., cellulases) were found in cluster 1 genomes, while other genes were found only in cluster 3 genomes (e.g., alkaline phosphatases, extracellular endoglucanases, pectate lyases) or cluster 4 and subcluster 1c genomes (e.g., NAD(P) transhydrogenase genes). Genes encoding for chitinases were found only in the genomes of the type strains of , , , and . In short, these genome analyses provide an insight into the PGP abilities of strains of known taxonomic provenance. This is the first study designed to establish the underlying genetic basis of cytokinin production in strains. Also, the discovery of additional genes in the biosynthetic gene cluster involved in cytokinin production opens up the prospect that may have novel molecular mechanisms for cytokinin biosynthesis.
本研究旨在确定该属成员促进植物生长（PGP）的潜力。为此，对21株代表性菌株的基因组进行了检测，以查找与植物生长直接或间接相关的基因。所有这些基因组均包含编码与生长素生物合成相关产物的基因[吲哚-3-甘油磷酸合酶、邻氨基苯甲酸磷酸核糖转移酶（D）、邻氨基苯甲酸合酶和氨基酶（A和B）]、细胞分裂素（预测生物合成基因簇内11个保守性良好的基因）、铁载体和固氮酶（除非典型菌株外的操纵子），以及调节生物和非生物环境胁迫影响的基因（例如烷基过氧化氢还原酶、水通道蛋白Z、热休克蛋白）。相比之下，其他基因与分配到四个宿主特异性簇中一个或多个簇的菌株相关。编码磷溶解（例如低亲和力无机磷转运蛋白）和裂解酶（例如纤维素酶）的基因存在于簇1基因组中，而其他基因仅存在于簇3基因组（例如碱性磷酸酶、细胞外内切葡聚糖酶、果胶酸裂解酶）或簇4和亚簇1c基因组（例如NAD(P)转氢酶基因）中。编码几丁质酶的基因仅在某些特定菌株的基因组中发现。简而言之，这些基因组分析为了解已知分类来源的该属菌株的PGP能力提供了见解。这是第一项旨在确定该属菌株中细胞分裂素产生潜在遗传基础的研究。此外，在细胞分裂素生物合成相关的生物合成基因簇中发现额外基因，为该属可能具有细胞分裂素生物合成新分子机制开辟了前景。
