Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus Universitat Autònoma de Barcelona (UAB), Bellaterra (Cerdanyola del Vallés), Barcelona, Spain.
Arch Microbiol. 2021 Jan;203(1):241-249. doi: 10.1007/s00203-020-02030-7. Epub 2020 Sep 10.
The genus Colletotrichum comprises a large number of filamentous fungi responsible for anthracnose diseases in many tropical and subtropical fruits and vegetables. In particular, Colletotrichum higginsianum infects Brassicaceae species, including Arabidopsis. The C. higginsianum strain IMI349063A is naturally infected with a dsRNA virus, named Colletorichum higginsianum non-segmented virus (ChNRV1). Here, we investigated the biological effect of ChNRV1 in C. higginsianum by comparing strains with and without the virus. ChNRV1 does not have an effect on C. higginsianum growth under salt and cell-wall stress conditions. However, thermal stress reduced C. higginsianum growth rate, this effect being more evident in the wild-type C. higginsianum strain containing the virus. Although ChNRV1 had no effect in conidiation, conidia were narrower when the virus is present. More importantly, ChNRV1 causes a mild increase in C. higginsianum virulence (hypervirulence) when infecting Arabidopsis plants. These findings indicated that, whereas the ChNRV1 mycovirus does not impair growth and conidiation of C. higginsianum, it confers hypervirulence to the fungal host. These findings will help in future research on the effect of mycoviral infection on pathogenic fungi in plant species of agronomical relevance.
炭疽菌属包含大量丝状真菌，这些真菌可导致许多热带和亚热带水果和蔬菜发生炭疽病。特别是，炭疽菌可侵染十字花科植物，包括拟南芥。炭疽菌菌株 IMI349063A 天然感染一种 dsRNA 病毒，称为炭疽菌非分段病毒（ChNRV1）。在这里，我们通过比较有和没有病毒的菌株来研究 ChNRV1 在炭疽菌中的生物学效应。ChNRV1 对盐和细胞壁胁迫条件下的炭疽菌生长没有影响。然而，热应激降低了炭疽菌的生长速度，在含有病毒的野生型炭疽菌菌株中，这种效应更为明显。尽管 ChNRV1 对分生孢子形成没有影响，但当病毒存在时，分生孢子变窄。更重要的是，ChNRV1 导致炭疽菌在感染拟南芥植物时的毒力（超毒力）轻度增加。这些发现表明，虽然 ChNRV1 真菌病毒不会损害炭疽菌的生长和分生孢子形成，但它赋予真菌宿主超毒力。这些发现将有助于未来研究真菌病毒感染对农业相关植物种中病原真菌的影响。
