Complete Genome Sequence of RON18713 from Brazil Nut Tree Phyllosphere Reveals Genes Involved in Plant Growth Promotion.

The Amazonian rainforest is a hyper-diverse ecosystem in the number of species and the myriad of intertaxon relationships that are mostly understudied. In order to characterize a dominant and economically important Amazonian species, the Brazil nut tree ( Bonpl.), at the genome level, wegenerated high-coverage long-read sequencing data from the leaves of a single individual. The genome assembly revealed an unexpected discovery: two circular contigs that could be assigned to the chromosome and a plasmid of a strain. Comparative genomics revealed that this strain belongs to the subspecies and displays high synteny with other strains isolated from diseased leaves of the neotropical palm Kunth. Investigation of pathogenicity-related genes revealed the absence of the entire type III secretion system gene cluster in the plasmid, which was otherwise highly similar to a plasmid from an isolate known to cause disease in Mast. In contrast, several genes associated with plant-growth promoting traits were detected, including genes involved in indole-3-acetic acid (IAA) production, phosphate solubilization, and biosynthesis of siderophores. In summary, we report the genome of an uncultivated subsp. strain associated with the Brazil nut tree and potentially a plant growth-promoting bacteria.