Induction of Tomato Jasmonate-Resistant 1-Like 1 Gene Expression Can Delay the Colonization of Ralstonia Solanacearum in Transgenic Tomato

The bacterial wilt in tomato caused by Ralstonia solanacearum infection is common and widespread, especially in hot and humid environments. Combating this disease is difficult due to unstable host resistance and the variation and diversity of the bacterial strains. Thus, the molecular mechanisms underlying tomato resistance against Ralstonia solanacearum remain unknown. Here, we isolated a homolog of tomato Solanum lycopersicum Jasmonate-Resistant 1 (SlJAR1), named SIJAR1-like 1 (SlJRL1), and generated transgenic tomato lines harboring an inducible promoter-driven SlJRL1 construct. SlJRL1 shares 99% amino acid identity with SlJAR1. Intriguingly, SlJRL1 showed preferential expression in aerial parts and SlJAR1 in roots. DNA gel blot analysis revealed multiple copies of SlJRL1 in the tomato genome. Transgenic tomato containing a single copy of the transgene SlJRL1 exhibited high levels of SlJRL1 expression two days after dexamethasone (DEX) induction. Moreover, DEX-induced SlJRL1 expression could delay the symptoms of tomato bacterial wilt, and efficiently reduce the amount of Ralstonia in stems. The phytohormone jasmonic acid may play a role in this resistance response. This study of inducible SlJRL1 expression in transgenic tomato contributes to the molecular understanding of tomato resistance against bacterial wilt.