New Delhi, Aug 17 : The Tomato leaf curl New Delhi virus (ToLCNDV) causes severe losses in tomato yield worldwide. Lack of information on resistance genes against ToLCNDV has considerably retarded the pace of crop improvement against this rapidly spreading pathogen. Several attempts have been made to identify antiviral genes against ToLCNDV and other related viruses. Scientists from the National Institute of Plant Genomics Research (NIPGR) have now reported an effective defence strategy deployed by a resistant tomato cultivar against ToLCNDV. It employs Sw5a (resistance gene) that recognises AC4 protein (viral effector) of ToLCNDV to restrict virus spread. At the transcriptional level, the sly-miR159-SlMyb33 module has been identified as the governing gene expression of Sw5a. Thus, the investigators have provided a mechanistic insight into the defence response in tomato against ToLCNDV. These findings could be translated into development of resistance in susceptible cultivars of tomato through modern breeding or molecular approaches. /IANS