isolation-behavioral-identification-pathogenicity-assessment

Isolation, Behavioral Identification, and Pathogenicity Assessment of Entomopathogenic Fungi from a Forest Wood Borer

Forest wood borers (FWB) cause severe tree damage and economic losses worldwide. The release of entomopathogenic fungi (EPF) during the FWB emergence ...

Zhejiang A&F University

Huzhou University

Entomopathogen-based biocontrol is crucial for blocking the transmission of vector-borne diseases; however, few cross-latitudinal investigations of entomopathogens have been reported for vectors transmitting woody plant diseases in forest ecosystems. The pine sawyer beetle  is an important wood borer and a major vector transmitting pine wilt disease, facilitating invasion of the pinewood nematode  (PWN) in China. Due to the limited geographical breadth of sampling regions, species diversity of fungal associates (especially entomopathogenic fungi) on .  adults and their potential ecological functions have been markedly underestimated. In this study, through traditional fungal isolation with morphological and molecular identification, 640 fungal strains (affiliated with 15 genera and 39 species) were isolated from 81 beetle cadavers covered by mycelia or those symptomatically alive across five regional populations of this pest in southern China. Multivariate analyses revealed significant differences in the fungal community composition among geographical populations of . , presenting regionalized characteristics, whereas no significant differences were found in fungal composition between beetle genders or among body positions. Four region-representative fungi, namely,  (Zhejiang),  (Sichuan),  (Fujian), and .  (Guangxi), as well as the three fungal species , , and , showed significantly stronger entomopathogenic activities than other fungi. Additionally, insect-parasitic entomopathogenic fungi (. , . , . , and . ) exhibited less to no obvious phytopathogenic activities on the host pine , whereas . , , and certain species of  spp.-isolated from .  body surfaces-exhibited remarkably higher phytopathogenicity. Our results provide a broader view of the entomopathogenic fungal community on the vector beetle . , some of which are reported for the first time on  spp. in China. Moreover, this beetle might be more highly-risk in pine forests than previously considered, as a potential multi-pathogen vector of both PWN and phytopathogenic fungi.

Discovery of entomopathogenic fungi across geographical regions in southern China on pine sawyer beetle  and implication for multi-pathogen vectoring potential of this beetle.

Shengxin Wu

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