Exploring the effects of red light night break on the defence mechanisms of tomato against fungal pathogen Botrytis cinerea.

Plant infections caused by fungi lead to significant crop losses worldwide every year. This study aims to better understand the plant defence mechanisms regulated by red light, in particular, the effects of red light at night when most phytopathogens are highly infectious. Our results showed that superoxide production significantly increased immediately after red light exposure and, together with hydrogen peroxide levels, was highest at dawn after 30 min of nocturnal red-light treatment.

Glutathione Transferases Are Involved in the Genotype-Specific Salt-Stress Response of Tomato Plants.

Glutathione transferases (GSTs) are one of the most versatile multigenic enzyme superfamilies. In our experiments, the involvement of the genotype-specific induction of genes and glutathione- or redox-related genes in pathways regulating salt-stress tolerance was examined in tomato cultivars ( Moneymaker, Mobil, and Elán F1). The growth of the Mobil plants was adversely affected during salt stress (100 mM of NaCl), which might be the result of lowered glutathione and ascorbate levels, a more positive glutathione redox potential (), and reduced glutathione reductase (GR) and GST activities.

Crosstalk between the redox signalling and the detoxification: GSTs under redox control?

Reactive oxygen species (ROS), antioxidants and their reduction-oxidation (redox) states all contribute to the redox homeostasis, but glutathione is considered to be the master regulator of it. We aimed to understand the relationship between the redox potential and the diverse glutathione transferase (GST) enzyme family by comparing the stress responses of two tomato cultivars (Solanum lycopersicum 'Moneymaker' and 'Ailsa Craig'). Four-week-old plants were treated by two concentrations of mannitol, NaCl and salicylic acid.

Pest and disease management by red light.

Light is essential for plant life. It provides a source of energy through photosynthesis and regulates plant growth and development and other cellular processes, such as by controlling the endogenous circadian clock. Light intensity, quality, duration and timing are all important determinants of plant responses, especially to biotic stress.

Compensation of Mutation in () Genes under Control or Salt Stress Conditions.

Glutathione transferases (GSTs) play a crucial role in detoxification processes due to the fact of their glutathione (GSH) conjugating activity, and through glutathione peroxidase or dehydroascorbate reductase (DHAR) activities, they influence the redox state of GSH and ascorbate (AsA). The plant-specific tau (GSTU) group is the largest class of GSTs, and their members are involved in responses to different abiotic stresses. We investigated the effect of salt stress on two-week-old wild-type (Col-0), and mutant plants after applying 150 mM NaCl for two days.

Genome-wide identification of the glutathione transferase superfamily in the model organism Brachypodium distachyon.

The detoxification of harmful metabolites can determine the effectiveness of plant stress responses. Scavenging some of these toxic stress by-products through the reduced form of glutathione is catalysed by members of the glutathione transferase (GST) enzyme superfamily. The involvement of these enzymes was studied in the model organism Brachypodium distachyon (L.

The Arabidopsis glutathione transferases, AtGSTF8 and AtGSTU19 are involved in the maintenance of root redox homeostasis affecting meristem size and salt stress sensitivity.

The tau (U) and phi (F) classes of glutathione transferase (GST) enzymes reduce the glutathione (GSH) pool using GSH as a co-substrate, thus influence numerous redox-dependent processes including hormonal and stress responses. We performed detailed analysis of the redox potential and reactive oxygen species levels in longitudinal zones of 7-day-old roots of Arabidopsis thaliana L. Col-0 wild type and Atsgtf8 and Atgstu19 insertional mutants.

Plant Glutathione Transferases and Light.

The activity and expression of glutathione transferases (GSTs) depend on several less-known endogenous and well-described exogenous factors, such as the developmental stage, presence, and intensity of different stressors, as well as on the absence or presence and quality of light, which to date have received less attention. In this review, we focus on discussing the role of circadian rhythm, light quality, and intensity in the regulation of plant GSTs. Recent studies demonstrate that diurnal regulation can be recognized in GST activity and gene expression in several plant species.

Diurnal changes in tomato glutathione transferase activity and expression.

Although the participation of glutathione transferases (GSTs) in light-dependent pathways and the circadian changes in the whole detoxification system have been studied, there are fewer results regarding the exact daily fluctuation of GSTs. In the present study, it was demonstrated that light up-regulated, while dark period decreased the plant GST activity and the expression of the selected tau group GST genes in tomato. These findings provide additional information on our current knowledge on the circadian rhythm of GSTs in plants and could help in further defining detoxification processes.

Physiological and molecular responses to heavy metal stresses suggest different detoxification mechanism of Populus deltoides and P. x canadensis.

Plants have divergent defense mechanisms against the harmful effects of heavy metals present in excess in soils and groundwaters. Poplars (Populus spp.) are widely cultivated because of their rapid growth and high biomass production, and members of the genus are increasingly used as experimental model organisms of trees and for phytoremediation purposes.

The role of Arabidopsis glutathione transferase F9 gene under oxidative stress in seedlings.

Arabidopsis thaliana contains 54 soluble glutathione transferases (GSTs, EC 2.5.1.

Hardening with salicylic acid induces concentration-dependent changes in abscisic acid biosynthesis of tomato under salt stress.

The role of salicylic acid (SA) in the control of abscisic acid (ABA) biosynthesis is controversial although both plant growth regulators may accumulate in tissues under abiotic and biotic stress conditions. Hardening of tomato plants to salinity stress with 10(-4)M SA ("high SA") resulted in an up-regulation of ABA biosynthesis genes, zeaxanthin epoxidase (SlZEP1), 9-cis-epoxycarotenoid dioxygenase (SlNCED1) and aldehyde oxidases (SlAO1 and SlAO2) in the roots and led to ABA accumulation both in root and leaf tissues. In plants pre-treated with lower concentration of SA (10(-7)M, "low SA"), the up-regulation of SlNCED1 in the roots promoted ABA accumulation in the root tissues but the hormone concentration remained at control level in the leaves.

Plant glutathione peroxidases: emerging role of the antioxidant enzymes in plant development and stress responses.

The plant glutathione peroxidase (GPX) family consists of multiple isoenzymes with distinct subcellular locations which exhibit different tissue-specific expression patterns and environmental stress responses. Contrary to most of their counterparts in animal cells, plant GPXs contain cysteine instead of selenocysteine in their active site and while some of them have both glutathione peroxidase and thioredoxin peroxidase functions, the thioredoxin regenerating system is much more efficient in vitro than the glutathione system. At present, the function of these enzymes in plants is not completely understood.

Glutathione transferase supergene family in tomato: Salt stress-regulated expression of representative genes from distinct GST classes in plants primed with salicylic acid.

A family tree of the multifunctional proteins, glutathione transferases (GSTs, EC 2.5.1.

Isohydric and anisohydric strategies of wheat genotypes under osmotic stress: biosynthesis and function of ABA in stress responses.

Changes in water potential (ψw), stomatal conductance, abscisic acid (ABA) accumulation, expression of the major genes involved in ABA biosynthesis, activities of abscisic aldehyde oxidase (AO, EC 1.2.3.

Different peroxidase activities and expression of abiotic stress-related peroxidases in apical root segments of wheat genotypes with different drought stress tolerance under osmotic stress.

One-week-old seedlings of Triticum aestivum L. cv. Plainsman V, a drought tolerant; and Cappelle Desprez, a drought sensitive wheat cultivar were subjected gradually to osmotic stress using polyethylene glycol (PEG 6000) reaching 400 mOsm on the 11th day.

Glutathione transferase activity and expression patterns during grain filling in flag leaves of wheat genotypes differing in drought tolerance: Response to water deficit.

Total glutathione S-transferase (GST, EC 2.5.1.