Abstract
Differential display was employed to isolate gene fragments that were regulated by pathogenic and nons-pathogenic Ralstonia solanacearum inoculations. Among cDNA fragments, we focused on cDNA, which showed similarity to a small heat shock protein (Nicotiana tabacum small heat shock protein 17; Ntshsp17 and its ortholog N. benthamiana small heat shock protein 17; Nbshsp17). Recombinant Ntshsp showed chaperon activity in vitro. Expression of Ntshsp was significantly induced by inoculation with non-pathogenic R. solanacearum, heat treatment and the treatment with intracellular signaling molecules such as methyl jasmonate and salicylic acid. The appearance of HR was not affected in the Nbshsp17-silencing N. benthamiana plants. Expression of defense related genes and disease resistance were compromised in the silencing plants. Moreover, the appearance of wilt symptoms was accelerated in silenced plants. Taken together small heat shock protein might have an important role in plant defenses.
