Genome-wide data (ChIP-seq) enabled identification of cell wall-related and aquaporin genes as targets of tomato ASR1, a drought stress-responsive transcription factor

MARTINIANO M RICARDI; RODRIGO M GONZÁLEZ; SILIN ZHONG; PÍA G DOMÍNGUEZ; TOMAS DUFFY; PABLO G TURJANSKI; JUAN D SALGADO SALTER; KARINA ALLEVA; FERNANDO CARRARI; JAMES J GIOVANNONI; JOSÉ M ESTÉVEZ; NORBERTO D IUSEM

BMC PLANT BIOLOGY

BIOMED CENTRAL LTD

Lugar: Londres; Año: 2014 vol. 14 p. 1 - 14

1471-2229

Background: Identifying the target genes of transcription factors is important for unraveling regulatory networks inall types of organisms. Our interest was precisely to uncover the spectrum of loci regulated by a widespread planttranscription factor involved in physiological adaptation to drought, a type of stress that plants have encounteredsince the colonization of land habitats 400 MYA. The regulator under study, named ASR1, is exclusive to the plantkingdom (albeit absent in Arabidopsis) and known to alleviate the stress caused by restricted water availability. Asits target genes are still unknown despite the original cloning of Asr1 cDNA 20 years ago, we examined the tomatogenome for specific loci interacting in vivo with this conspicuous protein.Results: We performed ChIP followed by high throughput DNA sequencing (ChIP-seq) on leaves from stressedtomato plants, using a high-quality anti-ASR1 antibody. In this way, we unraveled a novel repertoire of target genes,some of which are clearly involved in the response to drought stress. Many of the ASR1-enriched genomic lociwe found encode enzymes involved in cell wall synthesis and remodeling as well as channels implicated in waterand solute flux, such as aquaporins. In addition, we were able to determine a robust consensus ASR1-bindingDNA motif.Conclusions: The finding of cell wall synthesis and aquaporin genes as targets of ASR1 is consistent with theirsuggested role in the physiological adaptation of plants to water loss. The results gain insight into theenvironmental stress-sensing pathways leading to plant tolerance of drought.