Secondary Metabolites with Agricultural Antagonistic Potentials from Beauveria felina, a Marine-Derived Entomopathogenic Fungus

Abstract

Soil-borne pathogens and weeds could synergistically affect vegetable growth and result in serious losses. The investigation of antagonistic metabolites from a marine-derived entomopathogenic fungus, Beauveria felina, obtained polyhydroxy steroid (1), tricyclic diterpenoid (2), isaridin (3), and destruxin cyclodepsipeptides (4–6). The structures and absolute configurations of new 1–3 were elucidated by extensive spectroscopic and X-ray crystallographic analyses, as well as electronic circular dichroism (ECD) calculations. Compounds 1 and 2 showed antifungal activities against carbendazim-resistant strains of Botrytis cinerea, with the minimum inhibitory concentration (MIC) values ranging from 16 to 32 μg/mL, which were significantly better than those of carbendazim (MIC = 256 μg/mL). Compound 5 exhibited significant antagonistic activity against the radicle growth of Amaranthus retroflexus seedlings, which was almost identical to that of the positive control (2,4-dichlorophenoxyacetic acid). The structure–activity differences of 4–6 suggested that the Cl atom in HMPA1 and β-Me in Pro2 should be the key factors to their herbicidal activities. Besides, compounds 3–6 showed moderate nematicidal activities against Meloidogyne incognita. These antagonistic effects of 1–6 were first reported and further revealed the synergistically antagonistic potential of B. felina to be developed into the biopesticide.

Phytotoxic Secondary Metabolites from Fungi

“…Two destruxin E derivatives, namely destruxin E chlorohydrin (398) and [β-Me-Pro]destruxin E chlorohydrin (399) from Beauveria feline were screened to have phytotoxic activity against the radicle growth of Amaranthus retroflexus seedlings. The structure-activity study showed that chlorine atom played an important role for their phytotoxic activity [28].…”

“…In recent years, more and more phytotoxic metabolites have been discovered from other fungi such as plant and animal endophytic fungi, soil-derived fungi, and marinederived fungi [21][22][23][24]27,28]. Most of these phytotoxic metabolites are non-host specific.…”

“…Some others were reported on the phytotoxins produced by fungi during interactions with one plant species or only one plant group [18]. Furthermore, with the expansion of research scope, more and more fungal phytotoxins with herbicidal potential have been recently revealed from non-phytopathogenic fungi such as plant endophytic fungi [19][20][21], animal endophytic fungi [22][23][24], soil-derived fungi [25,26], and marine-derived fungi [27,28].…”

Experimental and Computational Analysis of the Solution and Solid‐State Conformations of Hexadepsipeptides from Beauveria felina

“…As a continuation of our chemical investigation on various bioactive hexadepsipeptides from marine entomopathogenic fungus Beauveria felina , [ 11‐12 ] two new destruxins ( 1 and 2 , Figure 1), containing an L ‐Ala 5 residue instead of the usual N ‐Me‐L‐Ala 5 , were isolated and identified. Interestingly, the presence of this L ‐Ala 5 residue in 1 and 2 resulted in two sets of equilibrating solution conformers as evidenced by two groups of NMR signals of 1 and 2 .…”

Screening of Marine Bioactive Antimicrobial Compounds for Plant Pathogens

“…The currently commonly used method is Sephadex chromatography, a chromatographic method that uses Sephadex as the chromatographic matrix, which can be used to separate proteins and other compounds with smaller molecular weights [82]. This method has been successfully used to separate polyhydroxy steroid and tricyclic diterpenoid, which can inhibit gray mold, from the marine fungus [83]. Another compound, benzopyranone that inhibits the growth of Alternaria brassicicola, was also identified from the marine bacterium Alternaria sp.…”