The root-knot nematode resistance gene Mi-1.2 of tomato is responsible for resistance against the whitefly Bemisia tabaci

Abstract

The tomato gene Mi-1.2 confers resistance against root-knot nematodes and some isolates of potato aphid. Resistance to the whitefly Bemisia tabaci has been previously observed in Mi-bearing commercial tomato varieties, suggesting that Mi, or a closely linked gene, is responsible for the resistance. The response of two biotypes of B. tabaci to tomato carrying the cloned Mi was compared to that of the isogenic untransformed tomato line Moneymaker. Our results indicate that Mi-1.2 is responsible for the resistance in tomato plants to both B- and Q- biotypes. Mi-1.2 is unique among characterized resistance genes in its activity against three very different organisms (root-knot nematodes, aphids and whiteflies). These pests are among the most important on tomato crops worldwide, making Mi a valuable resource in Integrated Pest Management Programs.