Evaluating LAMP assays for detection of phytoplasmas classified in different ribosomal groups

A new set of loop-mediated isothermal amplification assays was developed for detection of phytoplasmas associated with plant diseases and optimised for rapid laboratory detection. This set of assays was designed based on the leucyl tRNA synthetase gene expressed in most of the phytoplasmas and showing a good level of sequence divergence among strains from different 16Sr groups. This makes it a good target for developing discrete assays that can detect specific phytoplasma 16Sr groups. In this study, unique sets of LAMP assays were designed and validated for seven phytoplasma ribosomal groups (16SrI, 16SrII, 16SrIII, 16SrV, 16SrVI, 16SrX, and 16SrXII). These assays are specific, rapid and as sensitive as the nested PCR assays and the results could be obtained in less than 30 minutes in real-time LAMP assays.