Antagonism between Byssochlamys spectabilis (anamorph Paecilomyces variotii) and plant pathogens: Involvement of the bioactive compounds produced by the endophyte

Abstract

Fungal endophytes can be part of the defensive system of plants against multiple pathogens by competing for resources, hyperparasitism or producing bioactive compounds with antimicrobial properties. There is an ever‐increasing interest for obtaining new and environmentally friendly products to use in the fight against pathogens. With this purpose, Byssochlamys spectabilis (anamorph Paecilomyces variotii), which is a fungal species that commonly occurs, was evaluated as an antagonistic organism towards three phytopathogens (Biscogniauxia mediterranea, Fusarium moniliforme and Phytophthora cinnamomi). First, an in vitro experiment was designed to test the effect that the endophyte filtrate had on the three pathogens. The endophyte filtrate decreased the radius growth rate of F. moniliforme by nearly 10%. Consequently, the antagonism between B. spectabilis and F. moniliforme was evaluated in Lolium rigidum plants under greenhouse conditions by means of co‐inoculations. The endophyte produced a decrease of 50–75% in the disease severity caused by the pathogen in the earliest infection stages. Crude extracts of B. spectabilis were obtained to determine the secondary metabolites responsible for such an effect. The bioactivity‐guided chromatography and HPLC‐MS (high performance liquid chromatography coupled with mass spectrometry) of the active fraction suggested that the antibiotic activity was caused by viriditoxin. In conclusion, the fungal endophyte B. spectabilis and/or its bioactive compounds showed antagonism towards several phytopathogens and deserves further study to investigate its actual potential for use as a biocontrol agent.

Endophytic Fungi of Olive Tree

“…Already employed in the formulation of biopesticides, the latter species has been reported for antagonism against V. dahliae on eggplant, along with plant growth promoting effects [ 77 ]. Again, found in association with V. dahliae in southern Italy [ 41 ], Paecilomyces variotii is known for its antagonistic behavior against plant pathogenic fungi in vitro and in vivo [ 78 ], as well as nematodes [ 79 ]. Species of Cosmospora have been reported as mycoparasites [ 80 ], and pathogens of armored scales (Hemiptera, Diaspididae) [ 81 ].…”

Paecilomyces and Its Importance in the Biological Control of Agricultural Pests and Diseases

“…There are also descriptions of metabolites with antitumour activity [ 54 , 55 ] or enzyme inhibitors, such as Paecilomide, which acts as an acetylcholinesterase inhibitor and can be used to control human diseases such as Alzheimer’s [ 56 ]. In addition, they have a role in aromatic compound degradation [ 57 , 58 ], ethanol production from agro-industrial wastes [ 59 ], or removal of ammonium from synthetic media or ammonia emission reduction in poultry manure [ 60 , 61 ]. Nevertheless, we cannot ignore the fact that Paecilomyces has been associated with several human infectious diseases in immunosuppressed patients [ 62 , 63 ] and has also been described as a phytopathogen.…”

Paecilomyces variotii as A Plant-Growth Promoter in Horticulture

“…Among them, Byssochlamys spectabilis (Udagawa and Shoji Suzuki) Houbraken and Samson, formerly known as Paecilomyces variotii Bainier, is an ascomycete characterized by its ability to produce secondary metabolites, which belong to different chemical groups with wide biological activity [2][3][4][5]. This species has been described as a biological control agent (BCA) against nematodes [6,7], trematode eggs [8] and phytopathogenic fungi, such as Biscogniauxia mediterranea, Fusarium moniliforme and Phytophthora cinnamomi [9], Pyricularia oryzae [10], Fusarium graminearum [11] and Magnaphorte oryzae [12], among others, that function through their raw extracts, secondary bioactive metabolites or their mycelia. P. variotii produces metabolites with herbicidal [13] and insecticidal [14] activity and has been reported to control infections caused by pathogenic bacteria in fish [15] and humans [9].…”

“…This species has been described as a biological control agent (BCA) against nematodes [6,7], trematode eggs [8] and phytopathogenic fungi, such as Biscogniauxia mediterranea, Fusarium moniliforme and Phytophthora cinnamomi [9], Pyricularia oryzae [10], Fusarium graminearum [11] and Magnaphorte oryzae [12], among others, that function through their raw extracts, secondary bioactive metabolites or their mycelia. P. variotii produces metabolites with herbicidal [13] and insecticidal [14] activity and has been reported to control infections caused by pathogenic bacteria in fish [15] and humans [9]. In turn, this fungal species has even been shown to degrade aromatic compounds [16,17], in addition to removing ammonium from synthetic media and reducing ammonia emissions from chicken manure.…”