New Lactones Produced by Streptomyces sp. SN5431 and Their Antifungal Activity against Bipolaris maydis

Abstract

Bipolaris maydis causes southern corn leaf blight and inflicts huge losses on maize production. In order to search for new natural products from insect gut bacteria to control plant fungal disease, 86 actinomycetes were isolated from more than 50 insect guts, in which crude extract of strain SN5431 showed significant inhibition of the mycelial growth of B. maydis. The strain was identified and named as Streptomyces sp. SN5431. Six compounds were obtained from the crude extract of strain SN5431, which includes five new γ-butyrolactones named as tiuslactone A–E (1–5), and one new long chain ester named as tiusester (6). Their structures were determined using NMR and HRESIMS data and then combined with the spectroscopic data of known similar compounds. Tiuslactone B (2) showed powerful antifungal activity against B. maydis. These results indicated metabolites of insect gut bacteria have the potential to be the leading compounds for the control of corn leaf blight.

Antifungal Activity of Streptomyces spp. Extracts In Vitro and on Post-Harvest Tomato Fruits against Plant Pathogenic Fungi

“…Exploring the nature of these "cysts" and their relationship with antifungal activity could also lead to a better understanding of the microbial defense mechanisms involved in the interaction between these filamentous bacteria and fungi when coexisting in a particular habitat. Although the production of bioactive secondary metabolites by the genus Streptomyces is well known [24,25], no similar data have been reported for the encapsulation of fungi by Streptomyces mycelium or the compounds related to the color change or staining of fungal mycelium when grown in co-cultures, making these data highly novel. Related results are the induction of the formation of mounds of M. xanthus by several Streptomyces species [26].…”

DFT investigation for the mechanisms of γ-butyrolactones from styrene and acrylic acid, catalyzed by NMA*BF4 and PhSSPh

“…They are also prevalent heterocycles in organic synthesis 1 and play a crucial role in various fields such as the chemical industry, petroleum, fragrance, medicine and other fields [2][3][4][5][6] . In the field of medicinal chemistry, γ-butyrolactones have demonstrated broad bioactivity including antibacterial, antiviral and anti-inflammatory properties, leading to their widespread use in the treatment of various diseases [7][8][9][10][11][12][13] . For instance, hispitolides [Figure 1(a)] exhibit activity against hepatitis C virus (HCV) 14 ; Paraconic acids [Figure 1(b)] are a significant five-membered cyclolide that exhibits anti-tumor and antibiotic bioactivity [15][16] ; The synthetic equinolactone analogues GR-24 [Figure 1(c)] have been identified to inhibit the growth of different breast cancer cell lines.…”

Serratiomycins D1–D3, Antibacterial Cyclic Peptides from a Serratia sp. and Structure Revision of Serratiomycin

“…SN5431, which is a bacterial strain derived from the intestines of Larva holotrichiae . Among these, tiuslactone B displayed potent antifungal activity against Bipolaris maydis , a pathogen responsible for corn leaf blight . Recently, 20 metabolites, including three previously unreported obscurolide-type metabolites, were isolated from Streptomyces neopeptinius , which was obtained from the surface of the termite Odontotermes formasanus .…”

“…Among these, tiuslactone B displayed potent antifungal activity against Bipolaris maydis, a pathogen responsible for corn leaf blight. 12 Recently, 20 metabolites, including three previously unreported obscurolide-type metabolites, were isolated from Streptomyces neopeptinius, which was obtained from the surface of the termite Odontotermes formasanus. Among these 20 metabolites, indole-3-carboxylic acid exhibited antifungal activity against C. neoformans.…”