Validation of chip grafting inoculation assay to assess the resistance of Solanum species against phytoplasma

Abstract

AbstractBig bud caused by several different phytoplasmas is an emerging threat to tomato production worldwide. The development of resistant varieties would be an effective approach to manage this problem, but it requires an appropriate screening technique. Recently, we have described a simple and efficient chip graft inoculation assay (CGIA) for the first time to screen tomato germplasm against Tomato leaf curl New Delhi virus. The present study was conducted to first validate the CGIA for phytoplasma transmission, then to assess the resistance of 74 genotypes belonging to different Solanum species against 16SrII-D phytoplasma. CGIA success rate and phytoplasma transmission was 100% since all the grafts survived and phytoplasma was detected in these plants using nested polymerase chain reaction. No genotype was found resistant as all the grafted plants showed typical disease symptoms. In addition to phytoplasma transmission, CGIA can be used for better understanding the plant–phytoplasma interactions and biology of phytoplasmas in tomato.