Fusaricidins in Paenibacillus polymyxa A21 and their antagonistic activity against Botrytis cinerea on tomato

Abstract

Four kinds of antifungal compounds from an extract of Paenibacillus polymyxa A21 with molecular masses of 883.56, 897.59, 947.55, and 961.58 Da were characterized as the members of fusaricidin-type of antibiotics according to LC-MS analysis. Fusaricidins isolated from culture filtrate displayed high antagonistic activity against several plant fungal pathogens, especially Botrytis cinerea, the causal agent of gray mold. The fusaricidins biosynthetic gene cluster (BGC) from A21 was cloned by PCR and comparative cluster analysis revealed that gene fusTE, the 3′ boundary of the fusaricidin BGC in strain PKB1, was not present in fusaricidin BGC of A21, indicating that fusTE is not necessary for fusaricidin synthesis. Fusaricidin extract from A21 significantly reduced gray mold disease incidence and severity on tomato. The mRNA levels for three pathogenesis-related proteins (PRs) revealed that treatment of tomato leaves with fusaricidin extract induced the expression of PR genes to different levels, suggesting that one reason for the reduction of gray mold infection by fusaricidin is induction of PR proteins, which lead to increased resistance to pathogens. This is the first report of the application of fusaricidins to control tomato gray mold and the comparative cluster analysis provides important molecular basis for research on fusaricidin biosynthesis.

Comparative and Functional Analyses of Two Sequenced Paenibacillus polymyxa Genomes Provides Insights Into Their Potential Genes Related to Plant Growth-Promoting Features and Biocontrol Mechanisms

“…Fusaricidin is a peptide antibiotic consisting of a group of cyclic depsipeptides with an unusual 15-guanidino-3-hydroxypentadecanoic acid moiety bound to a free amino group (Kajimura and Kaneda, 1996) that has been identified as the most important antifungal compound produced by P. polymyxa (Kajimura and Kaneda, 1997). Many members of the fusaricidin family have been isolated from P. polymyxa, including fusaricidins A-D and LI-F03 to LI-F08 (Han et al, 2012;Liu et al, 2018). The fusaricidin biosynthetic gene cluster (BGC) contains 7 ORFs (fusB, fusC, fusD, fusE, fusF, fusG, and fusTE) totaling 32.4 kb and one large ORF (fusA) of approximately 23.7 kb, encoding a six-module non-ribosomal peptide synthetase involved in fusaricidin production (Li and Jensen, 2008).…”

“…P. polymyxa is a prominent biofertilizer and biocontrol agent that has been reported to suppress a wide variety of fungal and bacterial plant diseases, such as those caused by the fungi Rhizoctonia solani, Fusarium oxysporum, Botrytis cinereal, Phytophthora parasitica var. nicotianae, and Penicillium digitatum Lai et al, 2012;Ren et al, 2012;Weselowski et al, 2016;Liu et al, 2018) and the bacteria Pseudomonas syringae pv. tomato, P. syringae pv.…”

“…Plant growth-promoting rhizobacteria stably colonize the plant rhizosphere and enhance plant growth due to their capacities for phytohormone production, phosphate solubilization, nitrogen fixation, and antibiotic biosynthesis (Xie et al, 2016). P. polymyxa has been reported to produce various potent antimicrobial and volatile compounds that reduce plant disease severity (Eastman et al, 2014), such as antifungal and antibacterial metabolites (Zhao et al, 2011;Mageshwaran et al, 2012;Raza et al, 2015;Liu et al, 2018), thereby promoting growth (Anand et al, 2013;Padda et al, 2016) and inducing plant defenses (Mei et al, 2014;Shi et al, 2017;Luo et al, 2018). The types and amounts of antimicrobial substances generated by a beneficial bacterium affect its antimicrobial spectra and biocontrol efficacy.…”

“…The types and amounts of antimicrobial substances generated by a beneficial bacterium affect its antimicrobial spectra and biocontrol efficacy. P. polymyxa can produce several kinds of antibiotic compounds, that can suppress the growth of pathogens under both laboratory and field conditions, including polymyxins and antifungal compounds such as fusaricidin (Choi et al, 2009;Padda et al, 2017;Liu et al, 2018). Moreover, it has been reported that P. polymyxa secretes other types of antibiotics, such as 1-octen-3-ol, benzothiazole, citronellol (Zhao et al, 2011), paenibacillin (Huang and Yousef, 2015), di-n-butyl phthalate (Deng et al, 2011), lipopeptide (Mageshwaran et al, 2012), and phenazine-1-carboxylic acid (Tupinamba et al, 2008), and systemic resistance inducers, including 2,3-butanediol, methanethiol and isoprene (Gao et al, 2010;Lee et al, 2012).…”

Isolation, Identification and Characterization of Rhizobacteria Strains for Biological Control of Bacterial Wilt (Ralstonia solanacearum) of Eggplant in China

“…In Bacillus spp., prominent among these are surfactins, iturins, polymyxins, fengycins, kurstakins and bacitracins [11], while in P. polymyxa, antibiotics are known to include two types. One type, consisting of polymyxin, polypeptin, gavaserin, saltavalin, and jolipeptin, is only active against bacteria, and a second type, made up of gatavalin and fusaricidin, against fungi, Gram-positive bacteria and actinomycetes [12]. However, due to the complex soil environment, biocontrol disease efficacy usually depends on local edaphic adaptation of the biocontrol agents, while poor competition ability and poor edaphic adaptation of the introduced strains lead to limited success only.…”