UvVelC is important for conidiation and pathogenicity in the rice false smut pathogen Ustilaginoidea virens

ABSTRACT

Rice false smut disease is one of the most significant rice diseases worldwide. Ustilaginoidea virens is the causative agent of this disease. Although several developmental and pathogenic genes have been identified and functionally analyzed, the pathogenic molecular mechanisms of U. virens remain elusive. The velvet family regulatory proteins are involved in fungal development, conidiation, and pathogenicity. In this study, we demonstrated the function of the VelC homolog UvVELC in U. virens. We identified the velvet family protein UvVELC and characterized its functions using a target gene deletion-strategy. Deletion of UvVELC resulted in conidiation failure and pathogenicity. The UvVELC expression levels during infection suggested that this gene might be involved in the early infection process. UvVELC is also important in resistance to abiotic stresses, the utilization efficiency of glucose, stachyose, raffinose, and other sugars, and the expression of transport-related genes. Moreover, UvVELC could physically interact with UvVEA in yeast, and UvVELC/UvVEA double-knockout mutants also failed in conidiation and pathogenicity. These results indicate that UvVELC play a critical role in the conidiation and pathogenicity in U. virens. Functional analysis indicated that UvVELC-mediated conidiation and nutrient acquisition from rice regulates the pathogenicity of U. virens. Understanding the function of the UvVELC homolog could provide a potential molecular target for controlling rice false smut disease.

KEYWORDS:

• Ustilaginoidea virens
• velvet family
• conidiation
• pathogenicity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

YFL and WDL designed the study. MNY, TQS, JJY, HJC, XYP, ZQQ, and YD performed methodology, validation, investigation, and data curation. MNY was a major contributor to writing the manuscript. YFL performed the reviewed and edited the manuscript. All authors have read and approved the final manuscript.

Availability of data and material

The datasets supporting the conclusions of this study are included within the article and its additional files.

List of abbreviations

CFW, calcofluor white; CR, Congo red; dpi, days post-inoculation; HYG, hygromycin resistance cassette; NLS: Nuclear localization signals; PS, potato sucrose media; qRT-PCR, real-time quantitative PCR; RFS, rice false smut; SDS, sodium dodecyl sulphate

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/21505594.2023.2301243

Additional information

Funding

This research was funded by the National Science Foundation of China [Grant number:32272512] and Jiangsu Agricultural Science and Technology Innovation Fund [Grant number: CX(22)2009].