Authors

N W Warnock²; L W Wilson²; J C Canet-Perez²; T F Fleming²; C F Fleming¹; A M Maule²; J D Dalzell²;  ¹ Agri-Food and Biosciences Institute;  ² Queen's University Belfast

Discussion

We present a simple and rapid method for RNAi-induced knockdown of genes in tomato seedlings, through treatment with an aqueous solution of double-stranded RNA (exoRNAi) to assess the involvement of tomato Sugar Transporter Protein genes, STP1 and STP2 on the root exudation of glucose, fructose and xylose. Our data show that infective juveniles of the promiscuous PPN, Meloidogyne incognita are attracted to glucose and fructose, but not xylose in vitro. Glucose and fructose also agonise serotonergic stylet thrusting in M. incognita infective juveniles; a key parasitic behaviour necessary for invasion and parasitism. In contrast, monosaccharides did not attract or stimulate stylet thrusting in infective juveniles of the selective Solanaceae PPN, Globodera pallida in vitro. Knockdown of both STP1 and STP2 in tomato seedlings by the exoRNAi method is robust and specific, and corresponding reductions of glucose and fructose, but not xylose in exudate, correlate directly with reduced infectivity and stylet thrusting of M. incognita. Knockdown of STP1 or STP2 have no impact on the infectivity or stylet thrusting of G. pallida. The exoRNAi platform can underpin future efforts to understand the early stages of plant-pathogen interactions in tomato, and potentially other crop plants.