Ustilaginoidea virens: Insights into an Emerging Rice Pathogen

Abstract

False smut of rice, caused by Ustilaginoidea virens, has become one of the most important diseases in rice-growing regions worldwide. The disease causes a significant yield loss and imposes health threats to humans and animals by producing mycotoxins. In this review, we update our understanding of the pathogen, including the disease cycle and infection strategies, the decoding of the U. virens genome, comparative/functional genomics, and effector biology. Whereas the decoding of the U. virens genome unveils specific adaptations of the pathogen in successfully occupying rice flowers, progresses in comparative/functional genomics and effector biology have begun to uncover the molecular mechanisms underlying U. virens virulence and pathogenicity. We highlight the identification and characterization of the produced mycotoxins and their biosynthetic pathways in U. virens. The management strategies for this disease are also discussed. The flower-specific infection strategy makes the pathogen a unique tool to unveil novel mechanisms for the interactions beteen nonobligate biotrophic pathogens and their hosts. Expected final online publication date for the Annual Review of Phytopathology, Volume 58 is August 25, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Mapping quantitative trait loci for disease resistance to false smut of rice

“…It is urgent to develop efficient management strategies to control rice false smut because of severe epidemics and economic importance of the disease (Sun et al 2020). Screening of false smut resistant cultivars and identification of genes/QTLs for false smut resistance facilitate controlling this devastating disease.…”

“…False smut of rice, which was previously considered a minor disease due to its sporadic occurrence (Cooke 1878), has become one of the most destructive diseases in major rice-growing countries (Fan et al 2015;Sun et al 2020). The disease has expanded rapidly worldwide, particularly in China and in South Asia, probably because of large-scale planting of high-yield rice varieties and overuse of nitrogenous fertilizers in the past decades (Deng 1989;Zhou et al 2008).…”

“…Because of economic importance, the disease has been extensively studied in different aspects including disease occurrence, pathogen detection, mycotoxin isolation and identification, infection process, resistance evaluation of germplasms, and disease control in recent years (Tang et al 2013;Wang et al 2019;Sun et al 2020). Rapid detection and quantification of U. virens from soils and seeds provide practicable techniques for predicting epidemic risks and assessing U. virens distribution in the fields (Chen et al 2014;Yang et al 2018).…”

“…Interestingly, the pathogen might hijack rice nutrient supply system to benefit the formation of false smut balls by simulating ovule fertilization (Fan et al 2015;Song et al 2016). Furthermore, U. virens genome and the predicted protein-protein interaction network greatly accelerate progress in identifying pathogenicity factors and understanding effector biology in this pathogen (Zhang et al 2017;Fan et al 2019;Fang et al 2019;Sun et al 2020;Zhang et al 2020).…”

UvWHI2 is Required for Stress Response and Pathogenicity in Ustilaginonidea Virens

“…Rice false smut disease is caused by the ascomycete filamentous fungus Ustilaginoidea virens, which has emerged to be one of the most devastating rice fungal diseases in the rice-cultivated areas (Fan et al, 2016, Liang et al, 2018, Guo et al, 2019, Sun et al, 2020. The occurrence of rice false smut seriously affects high and stable yield and quality of rice (Lu et al, 2015, Zheng et al, 2017, Lin et al, 2018.…”