Wu Shengxin, Wu Jia, Wang Yun, Qu Yifei, He Yao, Wang Jingyan, Cheng Jianhui, Zhang Liqin, Cheng Chihang
School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, Zhejiang, China.
Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, Huzhou University, Huzhou, Zhejiang, China.
Front Plant Sci. 2022 Dec 28;13:1061520. doi: 10.3389/fpls.2022.1061520. eCollection 2022.
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.
基于昆虫病原体的生物防治对于阻断媒介传播疾病至关重要；然而，对于森林生态系统中传播木本植物疾病的媒介昆虫，昆虫病原体的跨纬度调查报道较少。松墨天牛是一种重要的蛀干害虫，也是中国传播松材线虫病的主要媒介，有助于松材线虫的入侵。由于采样区域的地理范围有限，松墨天牛成虫上真菌共生体（尤其是昆虫病原真菌）的物种多样性及其潜在生态功能被显著低估。在本研究中，通过传统的真菌分离结合形态学和分子鉴定，从中国南方该害虫五个区域种群的81具被菌丝覆盖的甲虫尸体或有症状存活的甲虫尸体中分离出640株真菌菌株（隶属于15个属和39个种）。多变量分析显示，松墨天牛地理种群间的真菌群落组成存在显著差异，呈现区域化特征，而甲虫性别间或身体部位间的真菌组成未发现显著差异。四种具有区域代表性的真菌，即浙江被毛孢（浙江）、球孢白僵菌（四川）、绿僵菌（福建）和布氏白僵菌（广西），以及三种真菌球孢白僵菌、绿僵菌和布氏白僵菌，表现出比其他真菌更强的昆虫致病活性。此外，昆虫寄生性昆虫病原真菌（球孢白僵菌、绿僵菌、布氏白僵菌和莱氏野村菌）对寄主松树表现出较低或无明显的植物致病活性，而从松墨天牛体表分离出的层出镰刀菌、链格孢属和某些镰刀菌属物种表现出显著更高的植物致病性。我们的研究结果为媒介昆虫松墨天牛上的昆虫病原真菌群落提供了更广阔的视角，其中一些在中国松墨天牛上是首次报道。此外，作为松材线虫和植物病原真菌的潜在多病原体媒介，这种甲虫在松林中的风险可能比以前认为的更高。
