Water and salinity stress in grapevines: early and late changes in transcript and metabolite profiles

Abstract

Grapes are grown in semiarid environments, where drought and salinity are common problems. Microarray transcript profiling, quantitative reverse transcription-PCR, and metabolite profiling were used to define genes and metabolic pathways in Vitis vinifera cv. Cabernet Sauvignon with shared and divergent responses to a gradually applied and long-term (16 days) water-deficit stress and equivalent salinity stress. In this first-of-a-kind study, distinct differences between water deficit and salinity were revealed. Water deficit caused more rapid and greater inhibition of shoot growth than did salinity at equivalent stem water potentials. One of the earliest responses to water deficit was an increase in the transcript abundance of RuBisCo activase (day 4), but this increase occurred much later in salt-stressed plants (day 12). As water deficit progressed, a greater number of affected transcripts were involved in metabolism, transport, and the biogenesis of cellular components than did salinity. Salinity affected a higher percentage of transcripts involved in transcription, protein synthesis, and protein fate than did water deficit. Metabolite profiling revealed that there were higher concentrations of glucose, malate, and proline in water-deficit-treated plants as compared to salinized plants. The metabolite differences were linked to differences in transcript abundance of many genes involved in energy metabolism and nitrogen assimilation, particularly photosynthesis, gluconeogenesis, and photorespiration. Water-deficit-treated plants appear to have a higher demand than salinized plants to adjust osmotically, detoxify free radicals (reactive oxygen species), and cope with photoinhibition.

SWAPDT: A method for Short-time Withering Assessment of Probability for Drought Tolerance in Camellia sinensis validated by targeted metabolomics

“…The metabolite changes for amino acids, flavonoids and sugars, were similar in this five-hour withering in plucked tea shoots, as found in other plant species with whole plants growing in pots or in the field over longer periods of drought (Cramer et al, 2007). This method relies only on the %RWC of tea leaves after the five-hour withering method.…”

Purification and functional characterization of the vacuolar malate transporter tDT from Arabidopsis

“…Since drought induced malate accumulation and the accompanied citrate mobilization are absent in tdt1 mutants, while this phenomenon is markedly pronounced in both tdt overexpressor lines (Figure 2A,B), we conclude that the tDT protein is responsible for reciprocal malate/citrate changes in Arabidopsis leaves. Interestingly, drought induced malate accumulation is not limited to Arabidopsis but has also been observed on other species (28). Accordingly, the stimulatory effect of malate on tdt gene expression (14) is fully in line with the observed impact of altered tDT activity on malate accumulation (Figure 2A,B).…”

What Is Stress? Dose-Response Effects in Commonly Used in Vitro Stress Assays

“…However, these are specific for osmotic stress and are not induced by salt stress, although this stress also has an osmotic component. While some studies attempted to study molecular responses at different stress levels, this was usually done in progressive soil-drying experiments (Cramer et al, 2007;Harb et al, 2010;Bonhomme et al, 2012), where the time factor cannot be separated from the stress severity factor. To our knowledge, no dedicated controlled studies have been performed on the effects of stress severity on gene expression.…”