Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil.
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.
Environ Microbiol. 2018 Jan;20(1):62-74. doi: 10.1111/1462-2920.13957. Epub 2017 Nov 10.
Fluorescent Pseudomonas spp. are widely studied for their beneficial activities to plants. To explore the genetic diversity of Pseudomonas spp. in tropical regions, we collected 76 isolates from a Brazilian soil. Genomes were sequenced and compared to known strains, mostly collected from temperate regions. Phylogenetic analyses classified the isolates in the P. fluorescens (57) and P. putida (19) groups. Among the isolates in the P. fluorescens group, most (37) were classified in the P. koreensis subgroup and two in the P. jessenii subgroup. The remaining 18 isolates fell into two phylogenetic subclades distinct from currently recognized P. fluorescens subgroups, and probably represent new subgroups. Consistent with their phylogenetic distance from described subgroups, the genome sequences of strains in these subclades are asyntenous to the genome sequences of members of their neighbour subgroups. The tropical isolates have several functional genes also present in known fluorescent Pseudomonas spp. strains. However, members of the new subclades share exclusive genes not detected in other subgroups, pointing to the potential for novel functions. Additionally, we identified 12 potential new species among the 76 isolates from the tropical soil. The unexplored diversity found in the tropical soil is possibly related to biogeographical patterns.
荧光假单胞菌因其对植物的有益作用而被广泛研究。为了探索热带地区假单胞菌的遗传多样性,我们从巴西土壤中收集了 76 个分离株。对基因组进行测序并与主要来自温带地区的已知菌株进行比较。系统发育分析将分离株分为荧光假单胞菌(57 株)和恶臭假单胞菌(19 株)群。在荧光假单胞菌群的分离株中,大多数(37 株)被分类为 P. koreensis 亚群,2 株为 P. jessenii 亚群。其余 18 株分离株分为两个与目前公认的荧光假单胞菌亚群不同的系统发育亚分支,可能代表新的亚群。与从描述的亚群中分离出的菌株的系统发育距离一致,这些亚分支中的菌株的基因组序列与它们的邻群亚群的成员的基因组序列不一致。这些热带分离株具有几种与已知荧光假单胞菌菌株中存在的功能基因。然而,新亚群的成员共享其他亚群中未检测到的特有基因,这表明可能具有新的功能。此外,我们从热带土壤的 76 个分离株中鉴定出了 12 个潜在的新物种。在热带土壤中发现的未被探索的多样性可能与生物地理模式有关。