Endophyte-induced Verticillium protection in tomato is range-restricted

Endophytes, bacterial, fungal or viral, colonize plants often without causing visible symptoms. More important, they may benefit host plants in many ways, most notably by preventing diseases caused by normally virulent pathogens. Previous studies have shown that an isolate of V. dahliae from eggplant, Dvd-E6, can colonize tomato endophytically, producing taller and more robust tomato plants while providing protection against a virulent V. dahliae, race 1 (Vd1) isolate. Expression analyses suggest this requires interplay between Dvd-E6 and the plant that involves resistance and defense genes. To examine the possibility of a broader effect, dual interactions have been further examined with a more distantly related pathogen, Verticillium albo-atrum (Vaa). The results indicate Dvd-E6 colonization selectively modifies the expression of specific tomato genes to be detrimental to Vd1 but not Vaa, providing evidence that Verticillium-induced protection is range-restricted.