Induction of Antiphytopathogenic Metabolite and Squalene Production and Phytotoxin Elimination by Adjustment of the Mode of Fermentation in Cocultures of Phytopathogenic Nigrospora oryzae and Irpex lacteus

Abstract

The investigation of the metabolites from different cocultures of Nigrospora oryzae and Irpex lacteus in solid medium revealed two new squalenes (1 and 2); one new azaphilone (3); two new tremulane sesquiterpenes (4 and 5); and three known compounds, conocenol B (6), conocenol C (7), and 4-(4-dihydroxymethylphenoxy)benzaldehyde (8). The antagonistic relationship was examined by studying metabolite production. The production of compounds 6 and 8 by I. lacteus after the induction of coculture indicated significant selectivity for antifungal activity against phytopathogenic N. oryzae, with MICs of 16 μg/mL; compounds 6 and 8 also exhibited antifungal activities in vivo against Cerasus cerasoides infected by N. oryzae at concentrations of 100 μg/mL. New compounds 2 and 4 showed antifungal activities against Colletotrichum gloeosporioides, with MICs of 8 μg/mL, and compound 4 showed antifungal activity against Didymella glomerata with an MIC of 1 μg/mL. These results indicate that the mutually antagonistic relationship in the coculture of the phytopathogen and the endophyte can result in antibiotics that inhibit the phytopathogen and downregulate the production of phytotoxins by phytopathogenic N. oryzae. New compound 5 from I. lacteus showed weak activity against acetylcholinesterase (AChE), with an inhibition ratio of 16% at a concentration of 50 μM.

Sesquiterpenoids From the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11

“…Tremulane derivatives have been found from cultures of Phellinus tremulae (Ayer and Cruz, 1993), P. igniarius (Liu et al, 2007;Wu et al, 2020), Conocybe siliginea (Zhou et al, 2008;Wu et al, 2010;He et al, 2020), Huperzia serrata (Ying et al, 2013), Flavodon flavus (Isaka et al, 2016), Coriolopsis sp. (Chen et al, 2017), Colletotrichum capsici (Wang et al, 2017), I. lacteus (Chen et al, 2018(Chen et al, , 2020Ding et al, 2018Ding et al, , 2019Ding et al, , 2020aZhou et al, 2018;Duan et al, 2019;Wu et al, 2019;Shi et al, 2020;Wang et al, 2020), and Gymnopilus junonius (Lee et al, 2020). This is the first time to find tremulane derivatives from Pseudogymnoascus.…”

“…Tremulanes, a family of sesquiterpenoids with characteristic structures of 5/7 fused bicyclic system, were rarely discovered in nature until 2015 (Guo et al, 2016). However, from 2016 to 2020, about 60 tremulane derivatives were found (Guo et al, 2016;Isaka et al, 2016;Wu, 2016;Chen et al, 2017Chen et al, , 2018Cong et al, 2020;Wang et al, 2017Wang et al, , 2020Ding et al, 2018Ding et al, , 2019Ding et al, , 2020aZhou et al, 2018;Duan et al, 2019;Wu et al, 2019Wu et al, , 2020He et al, 2020;Lee et al, 2020;Shi et al, 2020;, and the number is twice as many as before. Most of them were isolated from the cultures of the basidiomycetes Irpex lacteus (Chen et al, 2018(Chen et al, , 2020Ding et al, 2018Ding et al, , 2019Ding et al, , 2020aZhou et al, 2018;Duan et al, 2019;Wu et al, 2019;Shi et al, 2020;Wang et al, 2020).…”

“…All the tremulanes isolated from 2016 to 2020 were derived from fungi, except one derivative, which was obtained from a traditional Chinese medicine tabasheer (Wu, 2016). Some of them were discovered to have different bioactivities, such as tremutin A with the inhibition of the lipopolysaccharide-induced proliferation of B lymphocyte cells (Wang et al, 2020), and 5-demethyl conocenol C showed antifungal activities (Wu et al, 2019).…”

Progress on Terpenoids With Biological Activities Produced by Plant Endophytic Fungi in China Between 2017 and 2019

“…38 An investigation of the metabolites from different cocultures of Nigrospora oryzae and Irpex lacteus from seeds of Dendrobium officinale (collected from Wenshan City in the Yunnan Province, China) in solid medium revealed 2 tremulane sesquiterpenes, 5-demethyl conocenol C and nigrosirpexin A (74-75). 39 Compound 75 showed antifungal activities against Colletotrichum gloeosporioides and Didymella glomerata, with MICs of 8 and 1 µg/mL, respectively. 39 Six 5,6-secotremulane sesquiterpenoids (76-81) were isolated from a culture broth from the fresh fruiting bodies of the medicinal fungus I. lacteus HFG1102.…”

Recent advances in the chemistry and biology of azaphilones

“…65 However, when Nigrospora oryzae co-cultured with Irpex lacteus, nigirpexins A-D (152-155) and isonigirpexin C (156), the stereoisomer of 142, were obtained. 66,67 Among them, 155 showed weak activities in antibacterial and antifungal assays. 66…”