30 research outputs found
Sulfate-induced stomata closure requires the canonical ABA signal transduction machinery
No full textPhytohormone abscisic acid (ABA) is the canonical trigger for stomatal closure upon abiotic stresses like drought. Soil-drying is known to facilitate root-to-shoot transport of sulfate. Remarkably, sulfate and sulfide—a downstream product of sulfate assimilation—have been independently shown to promote stomatal closure. For induction of stomatal closure, sulfate must be incorporated into cysteine, which triggers ABA biosynthesis by transcriptional activation of NCED3. Here, we apply reverse genetics to unravel if the canonical ABA signal transduction machinery is required for sulfate-induced stomata closure, and if cysteine biosynthesis is also mandatory for the induction of stomatal closure by the gasotransmitter sulfide. We provide genetic evidence for the importance of reactive oxygen species (ROS) production by the plasma membrane-localized NADPH oxidases, RBOHD, and RBOHF, during the sulfate-induced stomatal closure. In agreement with the established role of ROS as the second messenger of ABA-signaling, the SnRK2-type kinase OST1 and the protein phosphatase ABI1 are essential for sulfate-induced stomata closure. Finally, we show that sulfide fails to close stomata in a cysteine-biosynthesis depleted mutant. Our data support the hypothesis that the two mobile signals, sulfate and sulfide, induce stomatal closure by stimulating cysteine synthesis to trigger ABA production
The role of sulfite reductase in assimilatory sulfate reduction in Arabidopsis thaliana
No full textReductive assimilation of inorganic sulfate to sulfide is an essential metabolic process in higher plants for the synthesis of cysteine and all downstream compounds containing reduced sulfur in the cell. Sulfite reductase (SiR) palys a central role in the assimilatory sulfate reduction pathway by catalyzing the reduction of sulfite to sulfide. An Arabidopsis T-DNA insertion line (sir1-1) with an insertion in the promoter region of SiR was isolated in order to address the exact role of SiR in vivo. Detailed characterization of sir1-1 revealed that homozygous sir1-1 plants are viable, but severely affected in growth. Homozygous sir1-1 plants flower and set viable seeds, albeit later than wild-type plants grown under the same conditions. Evaluation of SiR transcript levels in the leaves of sir1-1 plants revealed that the mRNA was down-regulated to about 50% of wild-type level. Consequently, the amount of SiR protein and the SiR activity were reduced in the same manner. The significant differences between the leaves of sir1-1 and Col-0 plants for most of the sulfur-containing and other related compounds such as cysteine, O-acetylserine (OAS), sulfate, nitrate, total glucosinolates, total carbon (C), nitrogen (N), and sulfur (S) suggests strong perturbations in the entire metabolism of sir1-1 plants. A reduction of approximately 25.6-fold and 32.7-fold in the incorporation of 35S label into cysteine and GSH fractions, respectively, of sir1-1 leaves compared to wild-type plants was observed, suggesting the fact that the activity of SiR generates a severe bottleneck in the sulfur assimilation pathway. Investigations of the transcript levels through microarray analysis revealed that the expression of many genes related to sulfur metabolism was altered in response to reduced sulfide synthesis. Out of 920 selected genes related to sulfur metabolism, the expression of 67 genes in the leaves and 180 genes in the roots of sir1-1, were significantly up- or down-regulated compared to wild-type. The high affinity sulfate transporters, sulfate transporter 1;1 (SULTR 1;1) and sulfate transporter 1;2 (SULTR 1;2) showed a significant up-regulation in the roots of sir1-1 compared to Col-0. The up-regulation of the high affinity sulfate transporters in the roots of sir1-1 suggests that instead of steady-state sulfate levels, the amount of reduced sulfur present in the cell, likely forms the signal for their their induction. The preliminary results for a second T-DNA insertion line (sir1-2) strongly indicate that an insertion more closer to the gene, in the promoter region of SiR causes early seedling lethality. All results point towards the exclusiveness of SiR for sufite reduction and that its optimal activity is essential for the normal growth of Arabidopsis plants. Treatment of different Arabidopsis lines with selenate, which is quite similar to sulfate, caused an increase in the total sulfur and selenium contents of the plants. This might happen due to the up-regulation of sulfate transporters which might eventually lead to an increase in total sulfur and selenium due to elevated sulfate/selenate contents
Utilization of genes encoding osmoprotectants in transgenic plants for enhanced abiotic stress tolerance
No full textAbstractGlobal agriculture in the context of growing and expanding populations is under huge pressure to provide increased food, feed, and fiber. The recent phenomenon of climate change has further added fuel to the fire. It has been practically established now that the global temperature has been on the increase with associated fluctuations in annual rainfall regimes, and the resultant drought and flood events and increasing soil and water salinization. These challenges would be met with the introduction and utilization of new technologies coupled with conventional approaches. In recent years, transgenic technology has been proved very effective in terms of production of improved varieties of crop plants, resistant to biotic stresses. The abiotic stresses such as salt and drought are more complex traits, controlled by many genes. Transgenic plant development for these stresses has utilized many single genes. However, much emphasis has been placed on genes catalyzing the biosynthetic pathways of osmoprotectants. This review focuses on the current status of research on osmoprotectant genes and their role in abiotic stress tolerance in transgenic plants
Utilization of genes encoding osmoprotectants in transgenic plants for enhanced abiotic stress tolerance
No full textGlobal agriculture in the context of growing and expanding populations
is under huge pressure to provide increased food, feed, and fiber. The
recent phenomenon of climate change has further added fuel to the fire.
It has been practically established now that the global temperature has
been on the increase with associated fluctuations in annual rainfall
regimes, and the resultant drought and flood events and increasing soil
and water salinization. These challenges would be met with the
introduction and utilization of new technologies coupled with
conventional approaches. In recent years, transgenic technology has
been proved very effective in terms of production of improved varieties
of crop plants, resistant to biotic stresses. The abiotic stresses such
as salt and drought are more complex traits, controlled by many genes.
Transgenic plant development for these stresses has utilized many
single genes. However, much emphasis has been placed on genes
catalyzing the biosynthetic pathways of osmoprotectants. This review
focuses on the current status of research on osmoprotectant genes and
their role in abiotic stress tolerance in transgenic plants
Super twisting sliding mode control algorithm for developing artificial pancreas in type 1 diabetes patients
No full textInbreeding depression for reproductive and yield related traits in S1 lines of maize (Zea mays L.)
No full textThis research was conducted to determine inbreeding depression in S1 maize lines for reproductive and yield related traits, at NWFP Agricultural University, Peshawar, Pakistan, in two successive seasons during 2002. Maize variety"Pahari" was selfed for one generation and 63 S1 lines were evaluated using "lattice square design" with two replications along with the parental population. Days to mid silking and mid pollen shed (anthesis), plant height and ear height (cm), and 200 grain weight (g) showed inbreeding depression with varying degrees. Severe inbreeding depression was observed for yield with the average of 709 kg ha-1. Inbreeding depression for 200 grains weight averaged 19 g, while for plant height and ear height it was calculated as 33 and 16 cm. Inbreeding depression for days to mid silking and pollen shed was lower as compared to morphological and yield components. Silking and pollen shed were delayed by 1.8 and 1.5 days on the average, respectively, as compared to the parental variety. Yield was significantly correlated with all maturity and morphological characters. Maturity characters were positively and significantly correlated with each other, showing good synchronization in maturity characters, while they were negatively and significantly correlated with yield components
Moisture Sorption by Low-Cost Pyridinium-Based Protic Ionic Liquids: Kinetics and Physico-Electrochemical Properties
No full textWe report the synthesis of two pyridinium-based room temperature protic ionic liquids (PILs), pyridinium bisulfate, [HPyr][HSO4] and pyridinium sulphate, [HPyr]2[SO4] and investigation of the kinetics of their water sorption behaviour and its influence on their density, ionic conductivity, and potential windows. The PILs were synthesized by the reaction of pyridine base with an acid, H2SO4, under solventless conditions, and confirmed by FTIR spectroscopy and 1H NMR spectra. The appearance vibration bands in the 3095–3252 cm−1 range for −NH+ stretching in the FTIR spectra and a peak at a chemical shift of 8.439 ppm in the 1H-NMR of the liquids confirm their synthesis as no such bands/peaks can be seen in that of the pure pyridine spectra. The PILs’ hygroscopic nature was examined by exposing them (5 mL each sample with exposed surface area 3.143 cm2) to air for varied time intervals at a relative humidity, RH=58±5 % and T=20±5 °C. Coulometric Karl-Fischer (KF) titration was used to determine how much moisture each PIL sample absorbed at each time interval. The findings reveal that when the PIL was exposed to air for longer periods of time, more moisture was absorbed, and the results correspond well with the pseudo first-order kinetic model. The densities and conductivities of several samples of the two PILs were examined, and it was discovered that as the percentage water content of the PILs grew, density decreased but conductivities increased. Furthermore, it was discovered that when temperature rose, the conductivity of each of the PILs increased, and the results fit well to the Arrhenius linear equation since the regression coefficient, R2, for each of the samples approached the perfect fit value of one. The electrochemical window (EW) data, the mechanism of moisture oxidation within the EWs of each PIL at Pt and Au electrodes, and the electrocatalytic role played by the Pt and Au surface oxides during ethanol oxidation are evaluated and discussed in light of their future sustainable energy applications.Godkänd;2025;Nivå 0;2025-03-21 (u4);Fulltext license: CC BY</p
Evaluation of Drinking and Irrigation Water Quality for Selected Physiochemical Parameters of Darra Pezu and its Neighbouring Areas of the District Lakki Marwat Pakistan
No full textFor the protection of human health, clean and safe drinking water supply is important. In connection with this, the drinking and irrigation water of village Darra Pezu and its neighboring areas of district Lakki Marwat, Pakistan was evaluated for different physical and chemical constraints including pH, electrical conductivity (EC), alkalinity, turbidity, hardness, total dissolved solids (TDS) and total suspended solids (TSS). The standard analytical procedures were adopted for the study of each of these parameter. The obtained results of each parameter were compared to the standard permissible limits given by the National Drinking Water Quality Standard (NDWQS) as well as World Health Organization (WHO) standards for drinking water and were found to be according to the safe limits prescribed by NDWQS and WHO except well water. The two well water samples of Wanda Sharbat and Wanda Gulmir have high pH, turbidity, EC, hardness, alkalinity, TDS, TSS values than that given by WHO and NDWQS. It is because the well water is open to atmosphere so due to which there is contamination by chemicals pollutants and high growth of algae. Overall, water from all the sources is reported irrigation while well water of the area is not fit for drinking and needs the government attention
