Complete Genome Sequence Data of Rare Actinomycetes Strain Saccharothrix texasensis 6-C, a Biological Control Agent for Potato Late Blight.

A rare actinomycetes strain of Saccharothrix texasensis, strain 6-C, has been isolated from the potato rhizosphere and it was shown to act as a biological control agent to potato late blight. It is also the first report on Saccharothrix spp. inhibiting Phytophthora infestans. Here, we present the complete genome data of S. texasensis strain 6-C, assembled by sequencing reads obtained by both PacBio and Illumina technologies with annotation. The final assembled genome length is 9,045,220 bp, without gaps and plasmid, and its GC content is 72.39%. Nine nonribosomal peptides synthetase, five type I polyketide synthase, four terpene, and three lanthipeptide gene clusters were identified in the genome, which would be likely to encode lots of antimicrobial active substances to help host plants against disease. This genome sequence could contribute to investigations of the molecular basis underlying the biocontrol activity of this Saccharothrix strain.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Seco-Tetracenomycins from the Marine-Derived Actinomycete Saccharothrix sp. 10-10.

Six new tetracenomycin congeners, saccharothrixones E⁻I (1⁻5) and 13-de-O-methyltetracenomycin X (6), were isolated from the rare marine-derived actinomycete Saccharothrix sp. 10-10. Their structures were elucidated by spectroscopic analysis and time-dependent density functional theory (TDDFT)-electronic circular dichroism (ECD) calculations. Saccharothrixones G (3) and H (4) are the first examples of tetracenomycins featuring a novel ring-A-cleaved chromophore. Saccharothrixone I (5) was determined to be a seco-tetracenomycin derivative with ring-B cleavage. The new structural characteristics, highlighted by different oxidations at C-5 and cleavages in rings A and B, enrich the structural diversity of tetracenomycins and provide evidence for tetracenomycin biosynthesis. Analysis of the structure⁻activity relationship of these compounds confirmed the importance of the planarity of the naphthacenequinone chromophore and the methylation of the polar carboxy groups for tetracenomycin cytotoxicity.