Characterization and localization of prodiginines from Streptomyces lividans suppressing Verticillium dahliae in the absence or presence of Arabidopsis thaliana

Abstract

The ascomycete Verticillium dahliae causes worldwide vascular wilt of many field and horticultural plants. The melanized resting structures of this fungus, so-called microsclerotia, survive for many years in soils and continuously re-infect plants. Due to the absence of known fungicides, Verticillium wilt causes immense crop losses. We discovered that the Gram-positive, spore-forming soil bacterium Streptomyces lividans expresses members of the prodiginine family during co-cultivation with V. dahliae. Using HPLC and LC-MS analysis of cultures containing S. lividans alone or grown together with V. dahliae, we found that undecylprodigiosin [394.4 M+H](+) is highly abundant, and streptorubin B [392.4 M+H](+) is present in smaller amounts. Within co-cultures, the quantity of undecylprodigiosin increased considerably and pigment concentrated at and within fungal hyphae. The addition of purified undecylprodigiosin to growing V. dahliae hyphae strongly reduced microsclerotia formation. Undecylprodigiosin was also produced when S. lividans grew on the roots of developing Arabidopsis thaliana plants. Furthermore, the presence of the undecylprodigiosin producer led to an efficient reduction of V. dahliae hyphae and microsclerotia on plant-roots. Based on these novel findings and previous knowledge, we deduce that the prodiginine investigated leads to multiple cellular effects, which ultimately impair specific pathways for signal transduction and apoptosis of the fungal plant pathogen.

Sympatric inhibition and niche differentiation suggest alternative coevolutionary trajectories among Streptomycetes

“…Streptomycetes are Gram positive, filamentous bacteria that are excellent saprophytes, prolific producers of extracellular enzymes and ubiquitous in soil and marine sediments (Gontang et al, 2007;Chater et al, 2010). Streptomycetes are the source of many clinically significant antibiotics and have been investigated in agricultural settings for their capacities to suppress plant pathogens (Bressan and Figueiredo, 2007;Hiltunen et al, 2009;Karimi et al, 2012;Kinkel et al, 2012;Meschke et al, 2012;Otto-Hanson et al, 2013). Because of their capabilities at producing bioactive compounds and in response to the tremendous therapeutic value of many of these compounds, antibiotic production in Streptomycetes has been studied extensively in vitro.…”

Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent

“…Comparable amount of incorporated prodigiosin was found in inactivated autoclaved cells (46.7 ± 0.8 mg L -1 versus 41.0 ± 1.0 mg L -1 in viable cells), indicating that incorporation of prodigiosin was not coupled to an active metabolic process. Due to its physicochemical properties prodigiosin most likely accumulated into the lipid bilayer [3,34], although prodigiosin presence in the cytoplasm has been observed as well [35]. …”

Plant growth-promoting actinobacteria: a new strategy for enhancing sustainable production and protection of grain legumes

“…These kinds of actinobacteria have a competitive edge over other microbial communities as it increases their chances of survival. This characteristic has been exploited more than five decades ago and studied by several researchers for the biological control of plant pathogens and disease suppression (Weindling et al 1950;Chamberlain and Crawford 1999;Meschke et al 2012). Several commercial formulations with the antibiotic or microbes as an active ingredient are marketed as biocontrol products.…”