Diversity analysis of type I ketosynthase in rhizosphere soil of cucumber

Abstract

Fusarium wilt [Fusarium oxysporum (Sch1.) f.sp. cucumerinum Owen.] is a major soil-borne disease of cucumber worldwide, and can cause huge yield losses. Biological control of Fusarium wilt of cucumber has received considerable attention. Many bacteria, particularly actinomycetes, are known to produce secondary metabolites synthesized by Polyketide synthases (PKSs) with a diverse range of biological activities. Ketosynthase (KS) gene diversity was analyzed in samples which were collected from rhizosphere soil of both diseased cucumber and healthy cucumber in Dalian, China. The phylogenetic analysis amino acid (AA) sequences indicated that the KS genes in the rhizosphere soil samples were clustered into diverse seven clades, including Sorangium cellulosum, Anabaena variabilis, Nostoc punctiforme, Xanthobacter autotrophicus, Streptomyces, myxobacteria and uncultured bacteria. Among seven major clades in the phylogenetic tree, two clades were peculiar to rhizosphere soil of diseased cucumber and one was peculiar to healthy cucumber. Among the 182 cloned KS genes, 147 KS genes were clustered with the uncultured bacteria group. Most of the KS genes showed about 80% similarity at the AA level to sequences known in GenBank. These results revealed the great diversity and novelty of KS genes in rhizosphere soil of cucumber.

Elucidating the diversity and potential function of nonribosomal peptide and polyketide biosynthetic gene clusters in the root microbiome

“…Future studies will focus on expressing these cosmid library BGCs in suitable hosts, enabling us to characterize their encoded metabolites and test their in vitro and in planta activity against various phytopathogens. Our results coincide with studies conducted in other plants, showcasing the yet unexplored diversity of NRPSs and PKSs (43, 62).…”

Elucidating the Diversity and Potential Function of Nonribosomal Peptide and Polyketide Biosynthetic Gene Clusters in the Root Microbiome

“…Future studies will focus on expressing these cosmid library BGCs in suitable hosts, enabling us to characterize their encoded metabolites and test their in vitro and in planta activities against various phytopathogens. Our results coincide with studies conducted in other plants, showcasing the as-yet-unexplored diversity of NRPSs and PKSs (43,61).…”

The natural product biosynthesis potential of the microbiomes of Earth – Bioprospecting for novel anti-microbial agents in the meta-omics era

“…In terrestrial systems, the plant-associated microbiomes of the phyllo- and rhizospheres represent rich repositories for novel BGCs [54] , [55] . However, even within identical plant cultivars, the biosynthetic gene composition is significantly different between individuals, and is additionally affected by plant health, growth stage, and geographical distance [56] , [57] . This suggests that plants engage in host-microbe interactions with microorganisms producing distinct collections of diverse bioactive compounds.…”