A mutation in the tomato Rme1 locus decreases the Mi-1.2-mediated resistance against whitefly Bemisia tabaci

Abstract

Two experimental assays were carried out evaluating the influence of the Rme1 locus on the Mi-1-mediated resistance to the B-biotype of B. tabaci. In a free-choice assay under greenhouse conditions, 10 two-month-old rme1 mutant plants, together with the same number of Motelle and Moneymaker (near isogenic susceptible control: mi-1/mi-1) plants, were randomised in a complete block design and whitefly adults were freely released in the greenhouse. Five days later, whitefly adults on every plant were counted, and counting was repeated every other day during a 15-day time period. The mean number of adult whiteflies per plant was significantly greater on rme1 mutants than on Motelle plants and slightly lower but not significantly different from those on Moneymaker. For the no-choice assay, 11 eight-week old plants of each genotype were kept in a growing chamber. Five adult female whiteflies were placed into a plastic clip-cage attached to the under surface of one leaf (one cage per plant). After 6 days, the averaged number of eggs observed on the rme1 mutant plants was almost identical to Moneymaker and significantly greater than that observed on Motelle. These results suggest that Rme1 locus is also required for Mi-1-mediated resistance to the B-biotype of B. tabaci.