Transcriptomic Changes Drive Physiological Responses to Progressive Drought Stress and Rehydration in Tomato

Abstract

Tomato is a major crop in the Mediterranean basin, where the cultivation in the open field is often vulnerable to drought. In order to adapt and survive to naturally occurring cycles of drought stress and recovery, plants employ a coordinated array of physiological, biochemical, and molecular responses. Transcriptomic studies on tomato responses to drought and subsequent recovery are few in number. As the search for novel traits to improve the genetic tolerance to drought increases, a better understanding of these responses is required. To address this need we designed a study in which we induced two cycles of prolonged drought stress and a single recovery by rewatering in tomato. In order to dissect the complexity of plant responses to drought, we analyzed the physiological responses (stomatal conductance, CO2 assimilation, and chlorophyll fluorescence), abscisic acid (ABA), and proline contents. In addition to the physiological and metabolite assays, we generated transcriptomes for multiple points during the stress and recovery cycles. Cluster analysis of differentially expressed genes (DEGs) between the conditions has revealed potential novel components in stress response. The observed reduction in leaf gas exchanges and efficiency of the photosystem PSII was concomitant with a general down-regulation of genes belonging to the photosynthesis, light harvesting, and photosystem I and II category induced by drought stress. Gene ontology (GO) categories such as cell proliferation and cell cycle were also significantly enriched in the down-regulated fraction of genes upon drought stress, which may contribute to explain the observed growth reduction. Several histone variants were also repressed during drought stress, indicating that chromatin associated processes are also affected by drought. As expected, ABA accumulated after prolonged water deficit, driving the observed enrichment of stress related GOs in the up-regulated gene fractions, which included transcripts putatively involved in stomatal movements. This transcriptomic study has yielded promising candidate genes that merit further functional studies to confirm their involvement in drought tolerance and recovery. Together, our results contribute to a better understanding of the coordinated responses taking place under drought stress and recovery in adult plants of tomato.

Transcriptional Responses in Root and Leaf of Prunus persica under Drought Stress Using RNA Sequencing

“…The transcript GF677_11309 encodes NCED3 and it was significantly induced in roots, confirming that a water deficit enhances the synthesis of ABA (Supplementary Table S3). In agreement with previous reports, protein phosphatases PP2C, which are major ABA regulators, were also upregulated (Tang et al, 2013; Yang et al, 2015; Iovieno et al, 2016; Magalhães et al, 2016). The accumulation of ABA leads to activation of ABA-dependent TFs, such as MYB factors, as was shown in this study.…”

The ratio of trichomes to stomata is associated with water use efficiency in Solanum lycopersicum (tomato)

“…The highly inbred tomato cultivar M82 has traditionally been used as a check variety in breeding programmes (Grandillo et al, 1999) and as a reference cultivar for scientific research, used in relation to the response to water stress as a drought-sensitive cultivar (Iovieno et al, 2016), in contrast with the drought-tolerant S. pennellii (Egea et al, 2018). The IL population has been used extensively for functional and physiological studies (Steinhauser et al, 2011;Chitwood et al, 2013;de Oliveira Silva et al, 2018), and the natural variation within the IL population provides an excellent platform to investigate the role of differences in epidermal features on performance under water stress.…”

Poaceae vs. Abiotic Stress: Focus on Drought and Salt Stress, Recent Insights and Perspectives

“…Various crops such as, wheat, soybean, tomato, showed higher levels of pectin remodeling enzymes in tolerant cultivars than susceptible genotypes (Leucci et al, 2008; An et al, 2014; Iovieno et al, 2016). …”