Control of Wheat Fusarium Head Blight by Heat-Stable Antifungal Factor (HSAF) from <i>Lysobacter enzymogenes</i>

Zhao, Yangyang; Cheng, Chao; Jiang, Tianping; Xu, Huiyong; Chen, Yun; Ma, Zhonghua; Qian, Guoliang; Liu, Fengquan

doi:10.1094/pdis-09-18-1517-re

Cited by 32 publications

(21 citation statements)

References 36 publications

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“…The EC 50 for mycelium growth in C. fructicola is 0.43 mg L −1 , which is equivalent to many chemical fungicides such as propiconazole, bitertanol, imazalil and hexaconazole as reported by de los Santos García de Paredes 36 . In this study, HSAF‐treated C. fructicola hyphae showed deformities, such as hyperbranching, curling, swelling and depolarized growth, similar to those reported previously in A. nidulans and F. graminearum 16,22 . Thus, HSAF may have a conservative mode of action that affects the growth of filamentous hyphae.…”

Section: Discussionsupporting

confidence: 88%

“…In previous studies, L. enzymogenes C3 (HSAF‐producing strain) has been shown to have field efficacy against Bipolaris sorokiniana , causing Bipolaris leaf spot in turf grasses 21 . Recently, HSAF was also found to have good biocontrol against wheat head blight caused by Fusarium graminearum in field experiments 22 . However, there has been no detailed study of the antifungal effect of HSAF against Colletotrichum spp.…”

Section: Introductionmentioning

confidence: 99%

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Biocontrol ability and action mechanism of dihydromaltophilin against Colletotrichum fructicola causing anthracnose of pear fruit

Tang

Cao

et al. 2020

Pest Management Science

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BACKGROUND Anthracnose caused by Colletotrichum fructicola is one of the most important diseases in pear fruit, resulting in huge economic losses. Public awareness of protecting the environment and food safety, together with pathogen resistance to many key fungicides have led to an urgent need to develop alternative strategies for controlling fruit diseases. Here, the antifungal activity of a natural product, dihydromaltophilin [heat‐stable antifungal factor (HSAF)], against C. fructicola in vitro and in vivo was investigated to determine its efficacy for anthracnose management. RESULTS HSAF exhibited pronounced antifungal activity against in vitro mycelial growth of C. fructicola, with a half‐inhibition concentration of 0.43 mg L−1. Hyphae treated with HSAF showed defects such as hyperbranching, swelling and depolarized growth. Conidia germination in the pathogen was inhibited by HSAF in a dose‐dependent manner. In the presence of 4 mg L−1 HSAF, conidia germination was significantly delayed, and germ tube growth was inhibited. HSAF at 8 mg L−1 completely blocked conidia germination in C. fructicola. In addition, HSAF disrupted coordination of cytokinesis with growth and nuclear division, induced reactive oxygen species production in conidia, and damaged the integrity of the conidia cell wall. Moreover, an in vivo test confirmed that 50 mg L−1 HSAF significantly reduced the development of anthracnose decay in pear fruit caused by C. fructicola. CONCLUSION HSAF was highly effective in reducing pear anthracnose caused by C. fructicola and has great potential to become a new type of fruit preservative.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Biocontrol ability and action mechanism of dihydromaltophilin against Colletotrichum fructicola causing anthracnose of pear fruit

Tang

Cao

et al. 2020

Pest Management Science

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“…Lysobacter enzymogenes is a nonpathogenic strain that was used to control crop fungal diseases known for the synthesis of an antifungal weapon (heat-stable antifungal factor, HSAF) that exhibits inhibitory activity against a wide range of fungal species [16][17][18][19][20][21][22][23] . Our previous work revealed that RpfG affects production of the antifungal weapon HSAF in L. enzymogenes 24 .…”

Section: Introductionmentioning

confidence: 99%

A predatory soil bacterium reprograms a quorum sensing signal system to regulate antifungal weapon production in a cyclic-di-GMP-independent manner

Wang

et al. 2021

Preprint

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Soil bacteria often provide multiple weapons for eukaryotes or prokaryotes to use against predators. Diffusible signal factors (DSFs) represent a unique group of quorum sensing (QS) chemicals that modulate interspecies competition in bacteria that do not produce antibiotic-like molecules. However, the molecular mechanism by which DSF-mediated QS systems regulate weapons production for interspecies competition remains largely unknown in soil biocontrol bacteria. In this study, we found that the necessary QS system component protein RpfG from Lysobacter, in addition to being a cyclic dimeric GMP (c-di-GMP) phosphodiesterase (PDE), regulates the biosynthesis of an antifungal weapon (heat-stable antifungal factor, HSAF), which does not appear to depend on the enzymatic activity. Interestingly, we showed for the first time that RpfG interacts with three hybrid two-component system (HyTCS) proteins, HtsH1, HtsH2, and HtsH3, to regulate HSAF production in Lysobacter. In vitro studies showed that each of these proteins interacted with RpfG, which reduced the PDE activity of RpfG. Finally, we showed that the cytoplasmic proportions of these proteins depended on their phosphorylation activity and binding to the promoter controlling the genes implicated in HSAF synthesis. These findings reveal a new mechanism of DSF signalling in antifungal weapon production in soil bacteria.

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“…Lysobacter enzymogenes (Le) strain OH11, originally isolated from the rhizosphere of green pepper, is a nonpathogenic strain that was used to control crop fungal diseases (1)(2)(3)(4).…”

Section: Introductionmentioning

confidence: 99%

“…Heat-stable antifungal factor (HSAF), a polycyclic tetramate macrolactam, is a newly identified broad-spectrum antifungal antibiotic isolated from the biocontrol species L. enzymogenes and is regarded as an attractive agent for the biological control of fungal diseases of agriculturally important plants (5)(6)(7)(8). HSAF exhibits inhibitory activity against a wide range of fungal species, and its chemical structure and mode of action are distinct from those of existing antifungal drugs or fungicides (1,7). Therefore, the identification of genes and growth conditions that regulate HSAF production is of significant interest.…”

Section: Introductionmentioning

confidence: 99%

Two Functional Fatty Acyl Coenzyme A Ligases Affect Free Fatty Acid Metabolism To Block Biosynthesis of an Antifungal Antibiotic in Lysobacter enzymogenes

Hou

et al. 2020

Appl Environ Microbiol

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In Lysobacter enzymogenes OH11, RpfB1 and RpfB2 were predicted to encode acyl coenzyme A (CoA) ligases. RpfB1 is located in the Rpf gene cluster. Interestingly, we found an RpfB1 homolog (RpfB2) outside this canonical gene cluster, and nothing is known about its functionality or mechanism. Here, we report that rpfB1 and rpfB2 can functionally replace EcFadD in the Escherichia coli fadD mutant JW1794. RpfB activates long-chain fatty acids (n-C16:0 and n-C18:0) for the corresponding fatty acyl-CoA ligase (FCL) activity in vitro, and Glu-361 plays critical roles in the catalytic mechanism of RpfB1 and RpfB2. Deletion of rpfB1 and rpfB2 resulted in significantly increased heat-stable antifungal factor (HSAF) production, and overexpression of rpfB1 or rpfB2 completely suppressed HSAF production. Deletion of rpfB1 and rpfB2 resulted in increased L. enzymogenes diffusible signaling factor 3 (LeDSF3) synthesis in L. enzymogenes. Overall, our results showed that changes in intracellular free fatty acid levels significantly altered HSAF production. Our report shows that intracellular free fatty acids are required for HSAF production and that RpfB affects HSAF production via FCL activity. The global transcriptional regulator Clp directly regulated the expression of rpfB1 and rpfB2. In conclusion, these findings reveal new roles of RpfB in antibiotic biosynthesis in L. enzymogenes. IMPORTANCE Understanding the biosynthetic and regulatory mechanisms of heat-stable antifungal factor (HSAF) could improve the yield in Lysobacter enzymogenes. Here, we report that RpfB1 and RpfB2 encode acyl coenzyme A (CoA) ligases. Our research shows that RpfB1 and RpfB2 affect free fatty acid metabolism via fatty acyl-CoA ligase (FCL) activity to reduce the substrate for HSAF synthesis and, thereby, block HSAF production in L. enzymogenes. Furthermore, these findings reveal new roles for the fatty acyl-CoA ligases RpfB1 and RpfB2 in antibiotic biosynthesis in L. enzymogenes. Importantly, the novelty of this work is the finding that RpfB2 lies outside the Rpf gene cluster and plays a key role in HSAF production, which has not been reported in other diffusible signaling factor (DSF)/Rpf-producing bacteria.

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Control of Wheat Fusarium Head Blight by Heat-Stable Antifungal Factor (HSAF) from Lysobacter enzymogenes

Cited by 32 publications

References 36 publications

Biocontrol ability and action mechanism of dihydromaltophilin against Colletotrichum fructicola causing anthracnose of pear fruit

Biocontrol ability and action mechanism of dihydromaltophilin against Colletotrichum fructicola causing anthracnose of pear fruit

A predatory soil bacterium reprograms a quorum sensing signal system to regulate antifungal weapon production in a cyclic-di-GMP-independent manner

Two Functional Fatty Acyl Coenzyme A Ligases Affect Free Fatty Acid Metabolism To Block Biosynthesis of an Antifungal Antibiotic in Lysobacter enzymogenes

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