Journal Article

NAC transcription factor JUNGBRUNNEN1 enhances drought tolerance in tomato

Devkar, Vikas, Mueller‐Roeber, Bernd, Mehterov, Nikolay, Thirumalaikumar, Venkatesh P., Turkan, Ismail, Ali, Shawkat, Balazadeh, Salma, Ozgur, Rengin

2018

Overview

Summary Water deficit (drought stress) massively restricts plant growth and the yield of crops; reducing the deleterious effects of drought is therefore of high agricultural relevance. Drought triggers diverse cellular processes including the inhibition of photosynthesis, the accumulation of cell‐damaging reactive oxygen species and gene expression reprogramming, besides others. Transcription factors (TF) are central regulators of transcriptional reprogramming and expression of many TF genes is affected by drought, including members of the NAC family. Here, we identify the NAC factor JUNGBRUNNEN1 (JUB1) as a regulator of drought tolerance in tomato (Solanum lycopersicum). Expression of tomato JUB1 (SlJUB1) is enhanced by various abiotic stresses, including drought. Inhibiting SlJUB1 by virus‐induced gene silencing drastically lowers drought tolerance concomitant with an increase in ion leakage, an elevation of hydrogen peroxide (H2O2) levels and a decrease in the expression of various drought‐responsive genes. In contrast, overexpression of AtJUB1 from Arabidopsis thaliana increases drought tolerance in tomato, alongside with a higher relative leaf water content during drought and reduced H2O2 levels. AtJUB1 was previously shown to stimulate expression of DREB2A, a TF involved in drought responses, and of the DELLA genes GAI and RGL1. We show here that SlJUB1 similarly controls the expression of the tomato orthologs SlDREB1, SlDREB2 and SlDELLA. Furthermore, AtJUB1 directly binds to the promoters of SlDREB1, SlDREB2 and SlDELLA in tomato. Our study highlights JUB1 as a transcriptional regulator of drought tolerance and suggests considerable conservation of the abiotic stress‐related gene regulatory networks controlled by this NAC factor between Arabidopsis and tomato.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc
• Subject: Arabidopsis / Arabidopsis thaliana / Crop yield / Damage accumulation / DELLA / Drought / Drought resistance / drought tolerance / Droughts / Gene expression / Gene Expression Regulation, Plant - genetics / Gene Expression Regulation, Plant - physiology / gene regulatory networks / Gene silencing / Genes / Hydrogen peroxide / leaves / Lycopersicon esculentum - genetics / Lycopersicon esculentum - metabolism / Lycopersicon esculentum - physiology / Moisture content / Photosynthesis / Plant growth / Plant Proteins - genetics / Plant Proteins - metabolism / Plants, Genetically Modified - genetics / Plants, Genetically Modified - metabolism / Plants, Genetically Modified - physiology / Reactive oxygen species / Reactive Oxygen Species - metabolism / Regulators / Solanum lycopersicum / tomato / Tomatoes / transcription (genetics) / transcription factor / Transcription factors / Transcription Factors - genetics / Transcription Factors - metabolism / Viruses / Water content / Water deficit / water stress