Transcription Factor JUNGBRUNNEN1 Enhances Drought Tolerance in Tomato

Drought stress hinders plant growth and crop yield. Transcription factors (TF) are known regulators of transcription reprogramming, and expression of many TF genes including members of the NAC family, is affected by drought. Venkatesh P. Thirumalaikumar from the Max Planck Institute of Molecular Plant Physiology focused on the NAC factor JUNGBRUNNEN1 (JUB1) and its role on drought tolerance in tomato (Solanum lycopersicum).

Expression of tomato JUB1 (SlJUB1) was found to be enhanced by various abiotic stresses, including drought. On the other hand, inhibiting SlJUB1 expression greatly lowered drought tolerance, alongside increases in ion leakage and hydrogen peroxide levels, as well as a decrease in the expression of drought-responsive genes.

Meanwhile, overexpression of AtJUB1 from Arabidopsis thaliana increased drought tolerance in tomato, alongside a higher relative leaf water content during drought and reduced hydrogen peroxide levels. The AtJUB1 protein was previously shown to stimulate expression of DREB2A, a TF involved in drought responses, and of the DELLA genes GAI and RGL1, which promote stress tolerance.

These results show that SlJUB1 protein controls the expression of the tomato orthologs of the DREB2A TF and the DELLA genes. The study revealed JUB1 as a transcriptional regulator of drought tolerance.

For information on this study, read the article in Plant Biotechnology Journal.