Identification ofCollimonasgene loci involved in the biosynthesis of a diffusible secondary metabolite with broad‐spectrum antifungal activity and plant‐protective properties

Abstract

In greenhouse and field trials, a bacterial mixture of Collimonas arenae Cal35 and Bacillus velezensis FZB42, but not Cal35 alone or FZB42 alone, was able to protect tomato plants from challenge with the soilborne fungal pathogen Fusarium oxysporum f.sp. lycopersici (Fol). To identify genes and mechanisms underlying this property in Cal35, we screened a random transposon insertion library for loss of function and identified two mutants that were impaired completely or partially in their ability to halt the growth of a wide range of fungal species. In mutant 46A06, the transposon insertion was located in a biosynthetic gene cluster that was predicted to code for a hybrid polyketide synthase-non-ribosomal peptide synthetase, while mutant 60C09 was impacted in a gene cluster for the synthesis and secretion of sugar repeat units. Our data are consistent with a model in which both gene clusters are necessary for the production of an antifungal compound we refer to as carenaemins. We also show that the ability to produce carenaemin contributed significantly to the observed synergy between Cal35 and FZB42 in protecting tomato plants from Fol. We discuss the potential for supplementing Bacillus-based biocontrol products with Collimonas bacteria to boost efficacy of such products.

Discovery of a Natural Hybrid Polyketide Produced by Endophytic Cladosporium sphaerospermum for Biocontrol of Phytopathogenic Fungus Botrytis cinerea

“…Also, CLD is a natural hybrid polyketide compound that has been found to exhibit good antibacterial activity against P. aeruginosa and cytotoxicity against multiple cancer cell lines, such as HL-60, HCT-116, MCF-7, and HeLa. , Hybrid polyketide compounds can be synthesized by various endophytic fungi and exhibit a wide range of antifungal activities. , These compounds can also be used as lead compounds to optimize their antifungal ability and safety through chemical modification . Therefore, CLD, as a natural hybrid polyketide, displays the potential to develop a new biocontrol agent against B.…”

“…17,39 Hybrid polyketide compounds can be synthesized by various endophytic fungi and exhibit a wide range of antifungal activities. 40,41 These compounds can also be used as lead compounds to optimize their antifungal ability and safety through chemical modification. 42 Therefore, CLD, as a natural hybrid polyketide, displays the potential to develop a new biocontrol agent against B. cinerea, enrich the diversity of hybrid polyketide compounds with antifungal activity, and provide more raw materials for chemical modification as a lead compound.…”

Activity of Fengycin and Iturin A Isolated From Bacillus subtilis Z-14 on Gaeumannomyces graminis Var. tritici and Soil Microbial Diversity

“…The control effect of living microbial agents is often affected by the environment, which can fluctuate substantially in different years or different regions (Akum et al, 2020). Using lipopeptides directly to control plant diseases is not economical at present.…”

Collimonas rhizosphaerae sp. nov., a novel species isolated from the beech rhizosphere

“…The ability to inhibit fungal growth was shown to depend on various molecules (e.g. collimonin and carenaemin) [18,19]. Noticeably, some Collimonas have been shown to promote plant growth [20].…”

“…Members of the genus Collimonas are Gram-stain negative, aerobic rods and usually motile, although with some exceptions [9][10][11][12][13][14]. Regarding the functional potential of Collimonas, independent screenings of different collections have revealed a conserved ability to hydrolyse chitin and to utilize fungal hyphae as carbon source, to inhibit fungal growth, to weather minerals, and to produce quorum-sensing signal molecules [8, [15][16][17][18][19][20][21]. The ability to inhibit fungal growth was shown to depend on various molecules (e.g.…”