Transcriptional repression of GTL1 by water-deficit stress promotes anthocyanin and polyamine biosynthesis to enhance drought tolerance

GT2-LIKE 1 (GTL1) is a negative regulator of stomatal development and its repressed expression under water deficit can result in enhanced drought tolerance. As a transcription factor, GTL1 has been implicated in diverse developmental roles. We hypothesized that GTL1 represses multiple drought tolerance pathways, leading to the drought tolerance phenotype of the gtl1-4 knockout mutant. RNA-Seq data indicates that GTL1 regulates genes involved in ribosome biogenesis in emerging leaves and secondary metabolite synthesis in expanding leaves. Overall design: RNA was collected from emerging and expanding leaves of Col-0 wildtype Arabidopsis thaliana and the knockout mutant gtl1-4 that had been maintained under well-watered or a 30% media water content water-deficit stress. There were three biological replicates per genotype/treatment/leaf age combination, with 10 plants were pooled into a replicate. Emerging leaves were sampled one-day post-emergence and expanding leaves sampled at 14/15 days post-emergence.