Tomato (Solanum lycopersicum) is threatened by a number of major diseases
worldwide, and developing management practices against them has been
difficult. University of Florida researchers, led by Juliana Pereira, aimed
to improve tomato disease resistance by overexpressing genes encoding the
Arabidopsis thaliana Elongator subunits, AtELP3 and AtELP4.
Overexpression of AtELP3 and AtELP4 significantly enhanced resistance to
tomato bacterial speck caused by Pseudomonas syringae pv. tomato without
clear detrimental effects on plant growth and development. Interestingly,
the transgenic plants only exhibited resistance to Pst when inoculated
through foliar sprays but not through infiltration into the leaf apoplast.
Further analysis revealed that a group of defense-related genes were highly
induced after infection in the AtELP4 transgenic tomato plants compared to
control plants. This suggests that the enhanced resistance of the transgenic
plants may be attributed to elevated induction of defense responses.
Furthermore, the tomato genome contains single-copy genes encoding all six
Elongator subunits (SlELPs), which share high similarities with the AtELP
genes. The SlELP3 and SlELP4 also complemented the Arabidopsis Atelp3 and
Atelp4 knock-out mutants, respectively, suggesting that the AtELP and SlELP
genes have similar functions.
These results reveal potential candidate genes for engineering disease
resistance in tomato.