Development of species specific SCAR based molecular marker for the detection of Pseudocercospora eumusae, the causal agent of eumusae leaf spot disease in banana

Abstract

Eumusae leaf spot disease caused by Pseudocercopra eumusae is one of the destructive leaf spot diseases in banana. A diagnostic method based on conventional and quantitative real-time PCR (qPCR) assay was developed in the present study for the specific detection of P. eumusae from pure cultures and leaf spot tissues. The sequence characterized amplified region (SCAR) based molecular marker and TaqMan probe was designed and validated using the genomic DNA of different Pseudocercopra spp. and 11 other leaf spot pathogens of banana. The primers and TaqMan probe proved to be highly specific to the target pathogen P. eumusae and no cross reactivity was encountered with any of the other leaf spot pathogens tested. Both conventional and qPCR assay developed detected the target pathogen P. eumusae directly from single leaf spot tissue and thus simplifies the identification by eliminating the need for culturing of pathogen. However, the sensitivity of qPCR (1 pg/μL) is higher compared to conventional PCR (100 pg/μL). To the best of our knowledge, this is the first report on the use of SCAR based molecular marker for the specific and early detection of P. eumusae in banana.