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The Root-Knot Nematode Resistance Gene Mi-1.2 of Tomato Is Responsible for Resistance Against the Whitefly Bemisia tabaci

July 2003 , Volume 16 , Number  7
Pages  645 - 649

Gloria Nombela , 1 Valerie M. Williamson , 2 and Mariano Muñiz 1

1Centro de Ciencias Medioambientales (CSIC). Serrano 115 Dpdo. 28006 Madrid, Spain; 2Department of Nematology, University of California, Davis 95616, U.S.A.


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Accepted 21 February 2003.

The tomato gene Mi-1.2 confers resistance against root-knot nematodes and some isolates of potato aphid. Resistance to the whitefly Bemisia tabaci previously has been observed in Mi-bearing commercial tomato cultivars, 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 with 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.


Additional keywords: Bemisia argentifolii, Macrosiphum euphorbiae, Meloidogyne spp., Mi gene, plant resistance, transgenic plants.

© 2003 The American Phytopathological Society