Napier grass stunt disease: Effector gene prediction

Napier grass stunt disease (NGSD) is associated with the presence of a ‘Candidatus Phytoplasma oryzae’-related strain belonging to the 16SrXI group and can also be found in other grasses such as rice, sugarcane and Bermudagrass. After the infection to plant hosts, phytoplasmas are restricted to the phloem for colonization. However, they secrete effector proteins that change plant morphology via Sec-dependent pathways that requires signal peptide (SP) sequences in the effector genes. In this experiment, twenty contigs of NGSD were analysed for the presence of effector proteins containing SP sequences by the PrediSi program and the result found fourteen candidate proteins. Primers were designed for amplification of these potential effector genes from NGSD and sugarcane white leaf (SCWL) infected samples and the result showed 7 and 2 PCR products from NGSD and SCWL, respectively. These PCR products are now being ligated into plant plasmid vectors and transformed into Arabidopsis thaliana plants for symptom observation.