Development of Colloidal Gold‐Based Lateral Flow Immunoassay for Rapid Qualitative and SemiQuantitative Analysis of Ustiloxins A and B in Rice Samples

Abstract

Rice false smut is a worldwide devastating rice disease infected by the fungal pathogen Villosiclava virens. Ustiloxin A (UA) and ustiloxin B (UB), cyclopeptide mycotoxins, were the major ustiloxins isolated from the rice false smut balls (FSBs) that formed in the pathogen-infected rice spikelets. Based on the specific monoclonal antibodies (mAbs) 2D3G5 and 1B5A10, respectively, against UA and UB, the lateral flow immunoassays (LFIAs) were developed, and the indicator ranges for UA and UB both were 50–100 ng/mL. The cross-reactivities of UB for UA LFIA, and UA for UB LFIA were 5% and 20%, respectively, which were consistent with the icELISA results reported previously. Even at 50,000 ng/mL, none of other commonly existent metabolites in rice samples caused noticeable inhibition. The LFIAs were used for determination of UA and UB contents in rice FSBs and rice grains, and the results were agreeable with those by HPLC and icELISA. There was no change in the sensitivity of either dipstick stored at 4 °C after at least three months. The developed LFIA has specificity and sensitivity for detecting UA and UB as well as simplicity to use. It will be a potential point-of-care device for rapid evaluation of the rice samples contaminated by UA and UB.

A Novel Effector Gene SCRE2 Contributes to Full Virulence of Ustilaginoidea virens to Rice

“…Besides, U. virens produces different types of mycotoxins, such as ustiloxins and ustilaginoidins in chlamydospore balls (Zhou et al, 2012). Seven ustiloxin and 26 ustilaginoidin derivatives have been identified and detected in the smut balls and/or in the mycelia so far (Zhou et al, 2012; Fu et al, 2017; Wang et al, 2017). These secondary metabolites, which are toxic to human and animals, reduce grain quality severely (Koyama et al, 1988; Luduena et al, 1994; Nakamura et al, 1994; Li et al, 1995; Shan et al, 2012; Wang et al, 2016; Fu et al, 2017).…”

“…Seven ustiloxin and 26 ustilaginoidin derivatives have been identified and detected in the smut balls and/or in the mycelia so far (Zhou et al, 2012; Fu et al, 2017; Wang et al, 2017). These secondary metabolites, which are toxic to human and animals, reduce grain quality severely (Koyama et al, 1988; Luduena et al, 1994; Nakamura et al, 1994; Li et al, 1995; Shan et al, 2012; Wang et al, 2016; Fu et al, 2017). Recent studies illustrate infection processes of U. virens , including conidial germination on the surface of spikelet, mycelial growth, floral organ infection, and eventual false smut ball formation (Ashizawa et al, 2012; Tang et al, 2013; Hu et al, 2014; Fan et al, 2015; Yong et al, 2018).…”

Rice False Smut: An Increasing Threat to Grain Yield and Quality

“…Ustiloxins A and B are Rice False Smut: An Increasing Threat to Grain Yield and Quality DOI: http://dx.doi.org/10.5772/intechopen.84862 among the most abundant ustiloxins in RFS ball and are mainly contained in the middle layer of mycelia and immature chlamydospores at early maturity stage [18]. Recently, rapid qualitative or quantitative detection methods, such as monoclonal antibody-based enzyme-linked immunosorbent assay and colloidal gold-based lateral flow immunoassay, have been established for detecting ustiloxins A and B in rice and feed samples [19,20]. Ustilaginoidins are bis-naphtho-γ-pyrones and can be easily dissolved in organic solvent.…”

MAT1-1-3, a Mating Type Gene in the Villosiclava virens, Is Required for Fruiting Bodies and Sclerotia Formation, Asexual Development and Pathogenicity

“…V. virens infects rice florets to produce the RFS balls, which can generate sclerotia on their surface ( Ashizawa et al, 2012 ; Tang et al, 2013 ; Hu et al, 2014 ; Song et al, 2016 ; Yong et al, 2018 ). Additionally, V. virens directly affects the rice food safety by producing mycotoxins, which are harmful to humans and animals ( Li et al, 2008 ; Fu et al, 2017 ; Wang et al, 2017 ). In addition to the completion of genome sequencing and the available transcriptome data ( Zhang et al, 2014 ), the recently established clustered regularly interspaced short palindromic repeats (CRISPR) mediated gene knockout system provides an effective tool to study the gene function in V. virens ( Liang et al, 2018 ; Fang et al, 2019 ; Guo et al, 2019 ; Yu et al, 2019 ).…”