sp. is a plant growth-promoting rhizobacteria largely recognized for its potential to increase the yield of different important crops. In this work, we present a thorough genomic and phenotypic analysis of Az39 to provide new insights into the beneficial mechanisms of this microorganism. Phenotypic analyses revealed the following abilities: growth at 20–38 °C (optimum, 28 °C), pH 6.0–8.0 (optimum, pH 6.8), and in the presence of 1% (w/v) NaCl; production of variable amounts of PHB as intracellular granules; nitrogen fixation under microaerophilic conditions; IAA synthesis in the presence of L-tryptophan. Through biochemical (API 20NE) and carbon utilization profiling (Biolog) assays, we proved that Az39 is able to use 15 substrates and metabolize 19 different carbon substrates. Lipid composition indicated a predominance of medium and long-chain saturated fatty acids. A total of 6 replicons classified as one main chromosome, three chromids, and two plasmids, according to their tRNA and core essential genes contents, were identified. Az39 genome includes genes associated with multiple plant growth-promoting (PGP) traits such as nitrogen fixation and production of auxins, cytokinin, abscisic acid, ethylene, and polyamines. In addition, Az39 genome harbor genetic elements associated with physiological features that facilitate its survival in the soil and competence for rhizospheric colonization; this includes motility, secretion system, and quorum sensing genetic determinants. A metadata analysis of Az39 agronomic performance in the pampas region, Argentina, demonstrated significant grain yield increases in wheat and maize, proving its potential to provide better growth conditions for dryland cereals. In conclusion, our data provide a detailed insight into the metabolic profile of Az39, the strain most widely used to formulate non-legume inoculants in Argentina, and allow a better understanding of the mechanisms behind its field performance.

中文翻译：

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南美接种剂行业参考菌株阿根廷固氮螺菌 Az39T 的表观发育特征和农艺贡献

sp。是一种促进植物生长的根际细菌，因其提高不同重要作物产量的潜力而得到广泛认可。在这项工作中，我们对 Az39 进行了彻底的基因组和表型分析，以提供对该微生物有益机制的新见解。表型分析揭示了以下能力：在 20–38 °C（最佳，28 °C）、pH 6.0–8.0（最佳，pH 6.8）和 1%（w/v）NaCl 存在下生长；生产不同数量的 PHB 作为细胞内颗粒；微需氧条件下的固氮作用； L-色氨酸存在下 IAA 的合成。通过生化 (API 20NE) 和碳利用分析 (Biolog) 测定，我们证明 Az39 能够使用 15 种底物并代谢 19 种不同的碳底物。脂质成分表明中链和长链饱和脂肪酸占主导地位。共鉴定出6个复制子，根据其tRNA和核心必需基因含量分为1个主染色体、3个染色体和2个质粒。 Az39 基因组包括与多种植物促生长 (PGP) 性状相关的基因，例如固氮和生长素、细胞分裂素、脱落酸、乙烯和多胺的产生。此外，Az39基因组含有与生理特征相关的遗传元件，有助于其在土壤中的生存和根际定植的能力；这包括运动性、分泌系统和群体感应遗传决定因素。对阿根廷潘帕斯草原地区 Az39 农艺性能的元数据分析表明，小麦和玉米的粮食产量显着增加，证明了其为旱地谷物提供更好的生长条件的潜力。总之，我们的数据提供了对 Az39（阿根廷最广泛用于配制非豆科接种剂的菌株）代谢特征的详细了解，并可以更好地了解其现场表现背后的机制。