Rapid and Accurate Detection of Marssonina coronariae in Apple Trees using Loop-Mediated Isothermal Amplification (LAMP).

Marssonina blotch of apple is a well-known plant disease caused by Marssonina coronariae, which can cause severe economic consequences. Due to the importance of early diagnosis for effective plant disease management, we aimed to develop a loop-mediated isothermal amplification (LAMP) assay that could rapidly detect M. coronariae in apple plants. The ribosomal DNA internal transcribed spacer (rDNA-ITS) sequence of M. coronariae was selected as the target for primer design. Our results showed optimal conditions for the LAMP reaction at 62℃ for 50 min, as indicated by color change and gel electrophoresis. The LAMP assay demonstrated specific discriminatory capability in differentiating M. coronariae from other pathogenic fungi in apple plants. In addition, the sensitivity tests revealed a detection limit of 100 fg μL-1 genomic DNA and 100 spores of M. coronariae for the LAMP assay. Finally, we successfully applied the LAMP assay to detect M. coronariae in apple leaf samples from the field. In general, our study provided a straightforward and efficient method for rapid diagnosis of apple blotch caused by M. coronariae, which could be applied in field condition and early occurrence of disease caused by M. coronariae could be detected.