Molecular Detection of QoI Resistance in Colletotrichum gloeosporioides Causing Strawberry Anthracnose Based on Loop-Mediated Isothermal Amplification Assay.

Anthracnose is one of the most common diseases in strawberry plants. Colletotrichum gloeosporioides is the major cause of anthracnose in China, including Zhejiang Province. Early, specific, reliable, and time-saving detection is urgently needed to prevent the further spread of C. gloeosporioides, guiding farmers to utilize chemicals to control anthracnose. In this study, we showed that the high resistance to pyraclostrobin, caused by a point mutation at codon 143 (GGT→GCT) in the cytochrome b gene of C. gloeosporioides was prevalent in the strawberry growing regions, and we developed a loop-mediated isothermal amplification (LAMP) assay as a detection method. Primer sets S0 and S4 could be used to specifically detect C. gloeosporioides isolates and the G143A mutations, respectively. A detection limit of 10-2 ng (10 pg), which is at least 10-fold more sensitive than conventional polymerase chain reaction, was achieved by the LAMP assay. Here, we utilized lateral-flow devices (LFDs), nitrocellulose membranes that can absorb nucleic acids, to acquire the total genomic DNA of strawberry plants within 2 min. The LFD membranes were used as DNA templates for the LAMP assays to accurately detect strawberry plants infected with C. gloeosporioides. This diagnostic method for strawberry anthracnose was accomplished within 1 h, including the sample preparation and LAMP assays. Collectively, we developed a sensitive and practical method for monitoring C. gloeosporioides and its quinone outside inhibitor-resistant mutants. The LAMP assay for detection of C. gloeosporioides in strawberry plants has great potential for rapid strawberry anthracnose surveillance and will provide farmers with advice on preventing C gloeosporioides at the early stages of strawberry development.