Colletotrichum gloeosporioides sensu lato (s.l.) is one of the most economically and scientifically important fungal pathogens, causing serious diseases in tropical and subtropical region. The ...detection of C. gloeosporioides s.l. is of importance for disease control. In this study, an ACT-based real-time PCR assay was developed for quantification of C. gloeosporioides s.l., which reliably detected as little as 100 fg genomic DNA, 100 copies of target DNA and 20 conidia. This method could recognize all four tested C. gloeosporioides s.l. isolates, while no amplification was observed in other Colletotrichum species and Botrytis cinerea, indicating the specificity of this assay. Detection and quantification of C. gloeosporioides s.l. was demonstrated in artificially and naturally infected host leaves. First, the real-time PCR analysis was performed using leaf samples collected at different time points post inoculation to monitor the growth of C. gloeosporioides s.l. over time. Secondly, the method was used to compare the resistance in two Stylosanthes cultivars and two Arabidopsis cultivars. Finally, naturally infected and symptomless leaves of Stylosanthes in the fields were tested by the real-time PCR method. Overall, the real-time PCR assay could allow the detection at early symptomless phase of infection; and the results was well correlated with microscopic observation and later disease symptoms. Therefore, our studies have provided a rapid and effective detection method for studying the plant-Colletotrichum interaction as well as disease prediction and control.
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•Established a detection method for C. gloeosporioides.•The specificity and sensitivity of the method.•Suitable for the detection in Stylosanthes and Arabidopsis.•Suitable for the natural infected host samples.
Anthracnose is a destructive disease that affects a wide range of crop plants especially in tropical and subtropical regions. Colletotrichum spp. are the major pathogens causing anthracnose. In this ...study, we collected and identified the pathogen from diseased samples of Stylosanthes, a major tropical forage crop. The ability of the pathogen to naturally infect Arabidopsis thaliana was examined. Sequence analysis of ITS, ACT, CHS, and GAPDH genes showed the pathogen to be Colletotrichum gloeosporioides sensu lato (s.l.), and this was supported further by morphological characterization of representative isolates. The disease symptoms and cellular infection process of aggressive isolates (DZ‐19 and HK‐04) and a weak isolate (CJ‐04) were compared. DZ‐19 and HK‐04 caused more severe disease symptoms on both young seedlings and adult plants of Col‐0 and Ws‐2 ecotypes compared to CJ‐04. Furthermore, the more aggressive isolates showed faster and earlier germination of conidia, formation of appressoria, and growth and development of hyphae during the infection. Genetic analysis of the defence response and expression profiling of defence marker genes demonstrated the involvement of MAP kinase, Ca2+‐dependent protein kinase, salicylic acid, ethylene, and jasmonic acid pathways in the resistance against anthracnose. These results suggest that the Arabidopsis–Colletotrichum gloeosporioides pathosystem should provide a valuable tool for exploring the resistance mechanisms against this pathogen.
A pathosystem between Arabidopsis and C. gloeosporioides sensu lato from Stylosanthes has been established, which could be an effective tool for studying the resistance mechanisms of anthracnose.
