Bioactive Metabolites from the Endophytic Fungus Aspergillus sp. SPH2.

Viridiana Morales-Sánchez,Sonia A Olmeda,Carmen E Díaz,Felix Valcarcel,Elena Trujillo,Azucena González-Coloma,María Fe Andrés,Rubén Muñoz

doi:10.3390/jof7020109

Abstract

In the current study, an ethyl acetate extract from the endophytic fungus Aspergillus sp. SPH2 isolated from the stem parts of the endemic plant Bethencourtia palmensis was screened for its biocontrol properties against plant pathogens (Fusarium moniliforme, Alternaria alternata, and Botrytis cinerea), insect pests (Spodoptera littoralis, Myzus persicae, Rhopalosiphum padi), plant parasites (Meloidogyne javanica), and ticks (Hyalomma lusitanicum). SPH2 gave extracts with strong fungicidal and ixodicidal effects at different fermentation times. The bioguided isolation of these extracts gave compounds 1–3. Mellein (1) showed strong ixodicidal effects and was also fungicidal. This is the first report on the ixodicidal effects of 1. Neoaspergillic acid (2) showed potent antifungal effects. Compound 2 appeared during the exponential phase of the fungal growth while neohydroxyaspergillic acid (3) appeared during the stationary phase, suggesting that 2 is the biosynthetic precursor of 3. The mycotoxin ochratoxin A was not detected under the fermentation conditions used in this work. Therefore, SPH2 could be a potential biotechnological tool for the production of ixodicidal extracts rich in mellein.

Highlights

Received: 15 December 2020Endophytes are a interesting group of microorganisms that can be isolated from asymptomatic plant tissue
After long-term coexistence with their host, endophytes can synthesize biologically active substances similar to the secondary metabolites produced by host plants [2,5,6]
In this work the endophytic fungus SPH2 was isolated from a stem portion of the endemic plant Bethencourtia palmensis and identified as Aspergillus sp., isolate SPH2, similar to these in the group Circumdati (A. ochraceus y A. westerdijkiae)

Summary

Introduction

Received: 15 December 2020Endophytes are a interesting group of microorganisms that can be isolated from asymptomatic plant tissue. Most species belong to the ascomycota and deuteromycota phyla and might be the producers of several groups of new, unique secondary metabolites [1]. After long-term coexistence with their host, endophytes can synthesize biologically active substances similar to the secondary metabolites produced by host plants [2,5,6]. The potential of fungal endophytes for producing novel biologically active compounds with promising medicinal or agricultural applications has been demonstrated [7,8]. These molecules can play an important role in communication between organisms, in plant protection, and plant adaptation to habitat and environmental changes [8]

Methods

Results

Discussion

Conclusion