Acylsugars in tomato varieties confer resistance to the whitefly and reduce the spread of fumagine

Abstract

Whiteflies (Bemisia tabaci) are a serious threat to tomato (Solanum lycopersicum) yield and production since all varieties are highly susceptible to this insect. The wild tomato Solanum pennellii shows resistance towards whiteflies infestation due the high contents of acylsugars presents in its leaflets, which is not observed in S. lycopersicum. Thus, plants from the F2 BC2 population derived from the cross between the cultivar S. lycopersicum ‘Redenção’ and S. pennellii (accession LA-716) were selected for acylsugars levels and evaluated for resistance to whitefly and fumagine, a saprophyte fungus from genus Capnodium (sooty mold) that grows on leaves using whiteflies excretion. Biological behavior of B. tabaci was significantly influenced by the levels of acylsugars on the leaflets of the different genotypes. Solanum pennellii and the genotypes with higher acylsugars contents exhibited the lowest whitefly oviposition preference, number of nymphs, exuviae and adult survival. Also, the percentage of leaf coverage with fumagine was significantly reduced on leaves of the S. pennellii and the genotypes with higher acylsugars. Thus, it confirms that the use of S. pennellii LA-716 enabled the introgression of genes to increase the degrees of resistance in the F2 BC2 genotypes. Finally, the results presented suggest that the genotypes RVTA-2010-31-177pl#39, RVTA-2010-31-319pl#214 and RVTA-2010-83-347pl#257 can be used as potential sources of genes for resistance to B. tabaci in tomato breeding programs.