Project description:Climate change has increased the frequency and intensity of floods that impact global agricultural productivity. To better understand the response mechanisms and evolutionary history of gene family member regulation across angiosperm phyla, we studied the rapid submergence response of rice, the legume Medicago truncatula, and two Solanum species, domesticated tomato (S. lycopersicum cv. M82) and its dryland-adapted wild relative S. pennellii. Response to hypoxic conditions was measured by analyzing transcriptional and post-translational regulation in root tips of each species. This was achieved by the use of Nuclei Tagged in specific Cell Types (INTACT) and Translating Ribosome Affinity Purification to obtain chromatin and sub-populations of gene transcripts. (1) Chromatin accessibility was evaluated by coupling INTACT with ATAC-seq (assay for Transposon-Accessible Chromatin). (2) INTACT was used to capture nuclear RNA (nRNA). (3) Polyadenylated mRNA (polyA RNA) was obtained by standard oligo(dT) selection. (4) Ribosome-associated polyA mRNA (polyA RNA) was obtained by use of Translating Ribosome Affinity Purification (TRAP). Ribosome footprinting (Ribo-seq) was accomplished by using TRAP to capture ribosome protected fragments after RNAseI digestion. Samples evaluated include the apical root tip (four species) and shoot region (Solanum species only) under control conditions and after 2 h of submergence
Project description:Transcriptomics study which main goal is to elucidate the programme of gene expression triggered by water stress in leaflets of the drought-tolerant wild-related tomato Solanum pennellii (acc. PE47) compared with domesticated tomato (S. lycopersicum, cv. P73). In this study we used S. lycopersicum (Sl) (cv. P73) and S. pennellii (Sp) (acc. PE47) species displaying remarkable divergences regarding drought tolerance, to investigate the physiological and molecular responses in leaves of plants grown without stress (control) and after four days of water withholding (water stress, WS), when plant water loss was significant but leaves did not show visual dehydration symptoms yet. Significant physiological differences between species were found, showing Sp leaves higher ability to avoid water loss. Leaf transcriptomic analysis showed important constitutive expression differences between Sp and Sl, including genes with unknown function. In relation to the genes specifically induced by drought in Sp, those linked to stomatal closure, cell wall and primary carbohydrate metabolism and, specially, nitrogen metabolism were identified. Thus, genes linked to NH4+ assimilation, GOGAT/GS cycle and the GDH- and GABA-shunt were specifically induced by water stress in leaves of Sp. Our results showed also the up-regulation in Sp of genes involved in JA biosynthesis pathway, which were induced in both conditions, whereas genes involved in ET biosynthesis were specifically induced under WS. Regarding ET signaling, ERF genes were up-regulated by WS in Sp, hinting at the importance of these transcriptional regulators in the drought response of Sp.
