Search

The oil derived from Psidium guajava seeds (TKSO) exhibits an abundance of diverse unsaturated fatty acids, notably oleic, linoleic, and α-linolenic acids, conferring substantial health advantages in addressing metabolic irregularities and human diseases. This research endeavor focused on elucidating the impacts of TKSO on colonic inflammatory responses and intestinal microbiota alterations in a murine model of colitis induced by dextran sulfate sodium (DSS), demonstrated that substantial supplementation with TKSO reduces the severity of colitis induced by DSS. Furthermore, TKSO effectively attenuated the abundance and expression of proinflammatory mediators while augmenting the expression of tight junction proteins in DSS-challenged mice. Beyond this, TKSO intervention modulated the intestinal microbial composition in DSS-induced colitis mice, specifically by enhancing the relative presence of Lactobacillus, Norank_f_Muribaculaceae, and Lachnospiraceae_NK4A136_group, while concurrently diminishing the abundance of Turicibacter. Additionally, an analysis of short-chain fatty acids (SCFAs) revealed noteworthy elevations in acetic, propionic, isobutyric, and butyric acids, and total SCFAs levels in TKSO-treated mice. In summary, these findings underscore the potential of TKSO to reduce the severity of colitis induced by DSS in mice through intricate modulation of the intestinal microbiota, metabolite profiles, and intestinal barrier repair, thereby presenting a promising avenue for the development of therapeutic strategies against intestinal inflammatory conditions. [ABSTRACT FROM AUTHOR]

Obesity has become one of the most serious chronic diseases threatening human health. Its onset and progression are closely related to the intestinal microbiota, as disruption of the intestinal flora promotes the production of endotoxins and induces an inflammatory response. This study aimed to investigate the variations in the physicochemical properties of various refined tea seed oils and their impact on intestinal microbiota disorders induced by a high-fat diet (HFD) through dietary intervention. In the present study, C57BL/6J mice on a HFD were randomly divided into three groups: HFD, T-TSO, and N-TSO. T-TSO and N-TSO mice were given traditionally refined and optimized tea seed oil for 12 weeks. The data revealed that tea seed oil obtained through degumming at 70 °C, deacidification at 50 °C, decolorization at 90 °C, and deodorization at 180 °C (at 0.06 MPa for 1 h) effectively removed impurities while minimizing the loss of active ingredients. Additionally, the optimized tea seed oil mitigated fat accumulation and inflammatory responses resulting from HFD, and reduced liver tissue damage in comparison to traditional refining methods. More importantly, N-TSO can serve as a dietary supplement to enhance the diversity and abundance of intestinal microbiota, increasing the presence of beneficial bacteria (norank_f__Muribaculaceae, Lactobacillus, and Bacteroides) while reducing pathogenic bacteria (Alistipes and Mucispirillum). Therefore, in HFD-induced obese C57BL/6J mice, N-TSO can better ameliorate obesity compared with a T-TSO diet, which is promising in alleviating HFD-induced intestinal microbiota disorders. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cyclophosphamide (Cy) is a frequently used chemotherapeutic drug, but long‐term Cy treatment can cause immunosuppression and intestinal mucosal damage. The intestinal mucosal barrier and gut flora play important roles in regulating host metabolism, maintaining physiological functions and protecting immune homeostasis. Dysbiosis of the intestinal flora affects the development of the intestinal microenvironment, as well as the development of various external systemic diseases and metabolic syndrome. RESULTS: The present study investigated the influence of sciadonic acid (SA) on Cy‐induced immunosuppression in mice. The results showed that SA gavage significantly alleviated Cy‐induced immune damage by improving the immune system organ index, immune response and oxidative stress. Moreover, SA restored intestinal morphology, improved villus integrity and activated the nuclear factor κB signaling pathway, stimulated cytokine production, and reduced serum lipopolysaccharide (LPS) levels. Furthermore, gut microbiota analysis indicated that SA increased t beneficial bacteria (Alistipes, Lachnospiraceae_NK4A136_group, Rikenella and Odoribacter) and decreased pathogenic bacteria (norank‐f‐Oscillospiraceae, Ruminococcus and Desulfovibrio) to maintain intestinal homeostasis. CONCLUSION: The present study provided new insights into the SA regulation of intestinal flora to enhance immune responses. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Over the years, the changes in the agriculture industry have been inevitable, considering the need to feed the growing population. As the world population continues to grow, food security has become challenged. Resources such as arable land and freshwater have become scarce due to quick urbanization in developing countries and anthropologic activities; expanding agricultural production areas is not an option. Environmental and climatic factors such as drought, heat, and salt stresses pose serious threats to food production worldwide. Therefore, the need to utilize the remaining arable land and water effectively and efficiently and to maximize the yield to support the increasing food demand has become crucial. It is essential to develop climate-resilient crops that will outperform traditional crops under any abiotic stress conditions such as heat, drought, and salt, as well as these stresses in any combinations. This review provides a glimpse of how plant breeding in agriculture has evolved to overcome the harsh environmental conditions and what the future would be like. [ABSTRACT FROM AUTHOR]

Objective: To investigate the potential beneficial effects of sciadonic acid (SA) on improving obesity induced by a high-fat diet in mice. Methods: Forty-eight male C57BL/6 mice were adaptively fed for one week and then randomly divided into the following groups: Control group (C), positive control group (S), model group (M), low-dose sciadonic acid group (LSA), medium-dose sciadonic acid group (MSA), and high-dose sciadonic acid group (HSA). The modeling process lasted for 16 weeks, and the low and high-dose groups were orally administered different doses of SA solution at a fixed time each day. After the modeling period, potential mechanisms of SA in regulating lipid metabolism in obese mice were explored, including aspects such as blood lipid metabolism, hepatic fat metabolism, hepatic oxidative stress, hepatic lipid synthesis, and expression of metabolism-related genes. Results: The high-dose SA intervention in obese mice significantly decreased the levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) in serum, while increasing high-density lipoprotein cholesterol (HDL-C) (P<0.05). It inhibited weight gain, reduced epididymal fat accumulation, and improved liver tissue damage. Additionally, SA significantly increased the activities of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in mice (P<0.05), and significantly reduced the production of oxidative end products MDA (P<0.05), alleviated oxidative stress in vivo, and inhibited lipid synthesis by regulating the expression of genes related to lipid metabolism to improve lipid metabolism. Conclusion: SA could improve lipid metabolism disorders in obese mice by suppressing fat accumulation, alleviate oxidative stress, regulate lipid synthesis and metabolism. [ABSTRACT FROM AUTHOR]

Soil salinization is a severe abiotic stress that negatively affects plant growth and development, leading to physiological abnormalities and ultimately threatening global food security. The condition arises from excessive salt accumulation in the soil, primarily due to anthropogenic activities such as irrigation, improper land uses, and overfertilization. The presence of Na⁺, Cl−, and other related ions in the soil above normal levels can disrupt plant cellular functions and lead to alterations in essential metabolic processes such as seed germination and photosynthesis, causing severe damage to plant tissues and even plant death in the worst circumstances. To counteract the effects of salt stress, plants have developed various mechanisms, including modulating ion homeostasis, ion compartmentalization and export, and the biosynthesis of osmoprotectants. Recent advances in genomic and proteomic technologies have enabled the identification of genes and proteins involved in plant salt-tolerance mechanisms. This review provides a short overview of the impact of salinity stress on plants and the underlying mechanisms of salt-stress tolerance, particularly the functions of salt-stress-responsive genes associated with these mechanisms. This review aims at summarizing recent advances in our understanding of salt-stress tolerance mechanisms, providing the key background knowledge for improving crops' salt tolerance, which could contribute to the yield and quality enhancement in major crops grown under saline conditions or in arid and semiarid regions of the world. [ABSTRACT FROM AUTHOR]

BACKGROUND: Type 2 diabetes (T2D) mellitus is a major metabolic disease, and its incidence and lethality have increased significantly in recent years, making it a serious threat to human health. Among numerous previous studies, polysaccharides have been shown to alleviate the adverse effects of T2D, but there are still problems such as insufficient analysis and poor understanding of the mechanisms by which polysaccharides, especially those of marine origin, regulate T2D. METHODS: In this study, we used multiple allosteric approaches to further investigate the regulatory effects of mussel polysaccharides (MPs) on T2D and gut microbiota disorders in mice by identifying changes in genes, proteins, metabolites and target organs associated with glucolipid metabolism using an animal model of T2D fed with high‐fat diets, and to explore the underlying molecular mechanisms. RESULTS: After MP intervention, serum levels of superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px) and high‐density lipoprotein cholesterol (HDL‐C) were up‐regulated, and blood glucose and lipid levels were effectively reduced in T2D mice. Activation of signaling molecules related to the upstream and downstream of the insulin PI3K/Akt signaling pathway reduced hepatic insulin resistance. The relative abundance of short‐chain fatty acid (SCFA)‐producing bacteria (including Akkermansia, Siraeum Eubacterium and Allobaculum) increased and harmful desulfurizing Vibrio decreased. In addition, the levels of SCFAs were increased. CONCLUSION: These results suggest that MP can increase SCFA levels by altering the abundance of intestinal flora, thereby activating the PI3K/Akt signaling pathway and exerting hypoglycemic effects. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Olive (Olea europaea L.) is a world-famous woody oil tree and popular for redundant unsaturated fatty acids. Fatty acid desaturase (FAD) genes are responsible for fatty acid desaturation and stress regulation but have not yet been identified in olive at the whole genome level. This study identified 40 and 27 FAD genes in the cultivated olive O. europaea cv. Farga and the wild olive O. europaea var. Sylvestris, respectively. Phylogenetic analysis showed that all the FAD genes could be classified into the soluble FAB2/SAD clade and membrane-bound clade, including ADS/FAD5, DES, FAD4, SLD, ω-6 and ω-3, with the high consistency of subcellular localization, motif composition and exon-intron organization in each group. FAD genes in olive showed the diverse functional differentiation in morphology of different tissues, fruit development and stress responses. Among them, OeFAB2.8 and OeFAD2.3 were up-regulated and OeADS.1, OeFAD4.1 and OeFAD8.2 were down-regulated under the wound, Verticillium dahliae and cold stresses. This study presents a comprehensive analysis of the FAD genes at the whole-genome level in olives and will provide guidance for the improvement of oil quality or stress tolerance of olive trees. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the protective effect of mussel polysaccharide (MP) on cyclophosphamide (Cy)-induced intestinal mucosal immunosuppression and microbial dysbiosis in mice. MP was shown to stimulate secretion of cytokines (SIgA, IL-2, IF-γ, IL-4, IL-10) and production of transcription factors (occludin, claudin-1, ZO-1, mucin-2, IL-2, IF-γ, IL-4, IL-10). Key proteins (p-IκB-α, p-p65) of the NF-κB pathway were upregulated after MP administration. SCFAs levels, which were decreased after the Cy treatment, were improved after treatment with MP. Furthermore, 16 S rRNA sequencing data of fecal samples revealed, through α-diversity and β-diversity analysis, that MP improved microbial community diversity and modulate the overall composition of gut microbiota. Taxonomic composition analysis showed that MP increased the abundance of probiotics species (Lactobacillus) and decreased the proportion of pathogenic species (Desulfovibrio). These findings suggested that MP has a potential immunomodulatory activity on the immunosuppressive mice. [ABSTRACT FROM AUTHOR]

Salt stress affects the plant growth and productivity worldwide and NHX is one of those genes that are well known to improve salt tolerance in transgenic plants. It is well characterized in several plants, such as Arabidopsis thaliana and cotton; however, not much is known about NHXs in tea plant. In the present study, NHX genes of tea were obtained through a genome-wide search using A. thaliana as reference genome. Out of the 9 NHX genes in tea, 7 genes were localized in vacuole while the remaining 2 genes were localized in the endoplasmic reticulum (ER; CsNHX8) and plasma membrane (PM; CsNHX9), respectively. Furthermore, phylogenetic relationships along with structural analysis which includes gene structure, location, and protein-conserved motifs and domains were systematically examined and further, predictions were validated by the expression analysis. The dN/dS values show that the majority of tea NHX genes is subjected to strong purifying selection under the course of evolution. Also, functional interaction was carried out in Camellia sinensis based on the orthologous genes in A. thaliana. The expression profiles linked to various stress treatments revealed wide involvement of NHX genes from tea in response to various abiotic factors. This study provides the targets for further comprehensive identification, functional study, and also contributed for a better understanding of the NHX regulatory network in C. sinensis. [ABSTRACT FROM AUTHOR]

Mitogen activated protein kinase kinase kinase (MAPKKK) form the upstream component of MAPK cascade. It is well characterized in several plants such as Arabidopsis and rice however the knowledge about MAPKKKs in tea plant is largely unknown. In the present study, MAPKKK genes of tea were obtained through a genome wide search using Arabidopsis thaliana as the reference genome. Among 59 candidate MAPKKK genes in tea, 17 genes were MEKK-like, 31 genes were Raf-like and 11 genes were ZIK- like. Additionally, phylogenetic relationships were established along with structural analysis, which includes gene structure, its location as well as conserved motifs, cis-acting regulatory elements and functional domain signatures that were systematically examined. Also, on the basis of one orthologous gene found between tea and Arabidopsis, functional interaction was carried out in C. sinensis based on an Arabidopsis association model. The expressional profiles indicated major involvement of MAPKKK genes from tea in response to various abiotic stress factors. Taken together, this study provides the targets for additional inclusive identification, functional study, and provides comprehensive knowledge for a better understanding of the MAPKKK cascade regulatory network in C. sinensis. [ABSTRACT FROM AUTHOR]

In this study, the detection method of caloric value in sludge was established using oxygen bomb automatic calorimeter based on the optimized experimental factors which included drying temperature, drying time, sample weighing amount and combustion supporting material adding amount of sludge sample. Moreover,the difficulty of low caloric value in sludge samp! was also solved. The study shows that accurate and stabe resutts are acquired when the ground sludge sample was fully burned in an oxygen bomb filed with 3.0 MPa oxygen after the drying process of wet sludge. Furthermore, for the detecion of the calorfc value in sludge sampels lower than 7.0 MJ/kg,the accurate results could be obtained wth the add-on of 0. 2 g benzoic acid reference material for the assist of combusion. [ABSTRACT FROM AUTHOR]

Summary: Abiotic stresses such as extreme temperatures, water‐deficit and salinity negatively affect plant growth and development, and cause significant yield losses. It was previously shown that co‐overexpression of the Arabidopsis vacuolar pyrophosphatase gene AVP1 and the rice SUMO E3 ligase gene OsSIZ1 in Arabidopsis significantly increased tolerance to multiple abiotic stresses and led to increased seed yield for plants grown under single or multiple abiotic stress conditions. It was hypothesized that there might be synergistic effects between AVP1 overexpression and OsSIZ1 overexpression, which could lead to substantially increased yields if these two genes are co‐overexpressed in real crops. To test this hypothesis, AVP1 and OsSIZ1 were co‐overexpressed in cotton, and the impact of OsSIZ1/AVP1 co‐overexpression on cotton's performance under normal growth and multiple stress conditions were analysed. It was found that OsSIZ1/AVP1 co‐overexpressing plants performed significantly better than AVP1‐overexpressing, OsSIZ1‐overexpressing and wild‐type cotton plants under single, as well as under multiple stress conditions in laboratory and field conditions. Two field studies showed that OsSIZ1/AVP1 co‐overexpressing plants produced 133% and 81% more fibre than wild‐type cotton in the dryland conditions of West Texas. This research illustrates that co‐overexpression of AVP1 and OsSIZ1 is a viable strategy for engineering abiotic stress‐tolerant crops and could substantially improve crop yields in low input or marginal environments, providing a solution for food security for countries in arid and semiarid regions of the world. [ABSTRACT FROM AUTHOR]

Summary: Arabidopsis thaliana AKR2A plays an important role in plant responses to cold stress. However, its exact function in plant resistance to cold stress remains unclear. In the present study, we found that the contents of very long‐chain fatty acids (VLCFAs) in akr2a mutants were decreased, and the expression level of KCS1 was also reduced. Overexpression of KCS1 in the akr2a mutants could enhance VLCFAs contents and chilling tolerance. Yeast‐2‐hybrid and bimolecular fluorescence complementation (BIFC) results showed that the transmembrane motif of KCS1 interacts with the PEST motif of AKR2A both in vitro and in vivo. Overexpression of KCS1 in akr2a mutants rescued akr2a mutant phenotypes, including chilling sensitivity and a decrease of VLCFAs contents. Moreover, the transgenic plants co‐overexpressing AKR2A and KCS1 exhibited a greater chilling tolerance than the plants overexpressing AKR2A or KCS1 alone, as well as the wild‐type. AKR2A knockdown and kcs1 knockout mutants showed the worst performance under chilling conditions. These results indicate that AKR2A is involved in chilling tolerance via an interaction with KCS1 to affect VLCFA biosynthesis in Arabidopsis. Significance Statement: AKR2A is positively involved in chilling tolerance by interacting with KCS1 to regulate VLCFA biosynthesis in Arabidopsis. [ABSTRACT FROM AUTHOR]

Summary: The biosynthesis of very‐long‐chain fatty acids (VLCFAs) and their transport are required for fibre development. However, whether other regulatory factors are involved in this process is unknown. We report here that overexpression of an Arabidopsis gene ankyrin repeat‐containing protein 2A (AKR2A) in cotton promotes fibre elongation. RNA‐Seq analysis was employed to elucidate the mechanisms of AKR2A in regulating cotton fibre development. The VLCFA content and the ratio of VLCFAs to short‐chain fatty acids increased in AKR2A transgenic lines. In addition, AKR2A promotes fibre elongation by regulating ethylene and synergizing with the accumulation of auxin and hydrogen peroxide. Analysis of RNA‐Seq data indicates that AKR2A up‐regulates transcript levels of genes involved in VLCFAs' biosynthesis, ethylene biosynthesis, auxin and hydrogen peroxide signalling, cell wall and cytoskeletal organization. Furthermore, AKR2A interacted with KCS1 in Arabidopsis both in vitro and in vivo. Moreover, the VLCFA content and the ratio of VLCFAs to short‐chain fatty acids increased significantly in seeds of AKR2A‐overexpressing lines and AKR2A/KCS1 co‐overexpressing lines, while AKR2A mutants are the opposite trend. Our results uncover a novel cotton fibre growth mechanism by which the critical regulator AKR2A promotes fibre development via activating hormone signalling cascade by mediating VLCFA biosynthesis. This study provides a potential candidate gene for improving fibre yield and quality through genetic engineering. [ABSTRACT FROM AUTHOR]

Sumoylation is one of the post translational modifications, which affects cellular processes in plants through conjugation of small ubiquitin like modifier (SUMO) to target substrate proteins. Response to various abiotic environmental stresses is one of the major cellular functions regulated by SUMO conjugation. SIZ1 is a SUMO E3 ligase, facilitating a vital step in the sumoylation pathway. In this report, it is demonstrated that over-expression of the rice gene OsSIZ1 in Arabidopsis leads to increased tolerance to multiple abiotic stresses. For example, OsSIZ1-overexpressing plants exhibited enhanced tolerance to salt, drought, and heat stresses, and generated greater seed yields under a variety of stress conditions. Furthermore, OsSIZ1-overexpressing plants were able to exclude sodium ions more efficiently when grown in saline soils and accumulate higher potassium ions as compared to wild-type plants. Further analysis revealed that OsSIZ1-overexpressing plants expressed higher transcript levels of P5CS, a gene involved in the biosynthesis of proline, under both salt and drought stress conditions. Therefore, proline here is acting as an osmoprotectant to alleviate damages caused by drought and salt stresses. These results demonstrate that the rice gene OsSIZ1 has a great potential to be used for improving crop’s tolerance to several abiotic stresses. [ABSTRACT FROM AUTHOR]

Phytoene synthase (PSY) is the crucial plastidial enzyme in the carotenoid biosynthetic pathway. However, its post-translational regulation remains elusive. Likewise, Clp protease constitutes a central part of the plastid protease network, but its substrates for degradation are not well known. In this study, we report that PSY is a substrate of the Clp protease. PSY was uncovered to physically interact with various Clp protease subunits (i.e., ClpS1, ClpC1, and ClpD). High levels of PSY and several other carotenogenic enzyme proteins overaccumulate in the clpc1 , clpp4 , and clpr1-2 mutants. The overaccumulated PSY was found to be partially enzymatically active. Impairment of Clp activity in clpc1 results in a reduced rate of PSY protein turnover, further supporting the role of Clp protease in degrading PSY protein. On the other hand, the ORANGE (OR) protein, a major post-translational regulator of PSY with holdase chaperone activity, enhances PSY protein stability and increases the enzymatically active proportion of PSY in clpc1 , counterbalancing Clp-mediated proteolysis in maintaining PSY protein homeostasis. Collectively, these findings provide novel insights into the quality control of plastid-localized proteins and establish a hitherto unidentified post-translational regulatory mechanism of carotenogenic enzymes in modulating carotenoid biosynthesis in plants. [ABSTRACT FROM AUTHOR]

Protein phosphatase 2A (PP2A) is an enzyme consisting of three subunits: a scaffolding A subunit, a regulatory B subunit and a catalytic C subunit. PP2As were shown to play diverse roles in eukaryotes. In this study, the function of the Arabidopsis PP2A-C5 gene that encodes the catalytic subunit 5 of PP2A was studied using both loss-of-function and gain-of-function analyses. Loss-of-function mutant pp2a-c5-1 displayed more impaired growth during root and shoot development, whereas overexpression of PP2A-C5 conferred better root and shoot growth under different salt treatments, indicating that PP2A-C5 plays an important role in plant growth under salt conditions. Double knockout mutants of pp2a-c5-1 and salt overly sensitive ( sos) mutants sos1-1, sos2-2 or sos3-1 showed additive sensitivity to NaCl, indicating that PP2A-C5 functions in a pathway different from the SOS signalling pathway. Using yeast two-hybrid analysis, four vacuolar membrane chloride channel (CLC) proteins, AtCLCa, AtCLCb, AtCLCc and AtCLCg, were found to interact with PP2A-C5. Moreover, overexpression of AtCLCc leads to increased salt tolerance and Cl− accumulation in transgenic Arabidopsis plants. These data indicate that PP2A-C5-mediated better growth under salt conditions might involve up-regulation of CLC activities on vacuolar membranes and that PP2A-C5 could be used for improving salt tolerance in crops. [ABSTRACT FROM AUTHOR]

Salinity and drought are two major environmental stresses that limit the growth and productivity of cotton. To improve cotton's drought and salt tolerance, transgenic cotton plants expressing the Arabidopsis vacuolar Na/H antiporter gene AtNHX1 and H-pyrophosphatase gene AVP1 were produced by cross-pollination of two single-gene-overexpressing plants. The salt tolerance and drought tolerance were further enhanced by simultaneously overexpressing AVP1 and AtNHX1 in comparison to AVP1 or AtNHX1 single-gene-overexpressing plants and to wild-type plants. Plant height, boll number, and fiber yield of AVP1/ AtNHX1-co-overexpressing plants were higher than those of AVP1-overexpressing, AtNHX1-overexpressing, segregated non-transgenic line, and wild-type plants under saline and drought conditions. The photosynthetic rate of AVP1/ AtNHX1-co-overexpressing plants was significantly higher than that of single-gene-overexpressing and wild-type plants under 200 mM NaCl treatment. In addition, the root systems of AVP1/ AtNHX1-co-overexpressing plants were larger than those of single-gene-overexpressing and wild-type plants, which was likely due to increased auxin polar transport in the root systems of the AVP1/ AtNHX1-co-overexpressing plants. Moreover, these AVP1/ AtNHX1-co-overexpressing cotton plants produced 24 % higher fiber yield under low-irrigation conditions and 35 % higher fiber yield under dryland conditions as compared to wild-type cotton in the field. [ABSTRACT FROM AUTHOR]

The Arabidopsis gene AVP1 encodes an H-pyrophosphatase that functions as a proton pump at the vacuolar membranes, generating a proton gradient across vacuolar membranes, which serves as the driving force for many secondary transporters on vacuolar membranes such as Na/H-antiporters. Overexpression of AVP1 could improve drought tolerance and salt tolerance in transgenic plants, suggesting a possible way in improving drought and salt tolerance in crops. The AVP1 was therefore introduced into peanut by Agrobacterium-mediated transformation. Analysis of AVP1-expressing peanut indicated that AVP1-overexpression in peanut could improve both drought and salt tolerance in greenhouse and growth chamber conditions, as AVP1-overexpressing peanuts produced more biomass and maintained higher photosynthetic rates under both drought and salt conditions. In the field, AVP1-overexpressing peanuts also outperformed wild-type plants by having higher photosynthetic rates and producing higher yields under low irrigation conditions. [ABSTRACT FROM AUTHOR]

Water-deficit stress is a major environmental factor that limits agricultural productivity worldwide. Recent episodes of extreme drought have severely affected cotton production in the Southwestern USA. There is a pressing need to develop cotton varieties with improved tolerance to water-deficit stress for sustainable production in water-limited regions. One approach to engineer drought tolerance is by delaying drought-induced senescence via up-regulation of cytokinin biosynthesis. The isopentenyltransferase gene (IPT) that encodes a rate limiting enzyme in cytokinin biosynthesis, under the control of a water-deficit responsive and maturation specific promoter PSARK was introduced into cotton and the performance of the PSARK::IPT transgenic cotton plants was analyzed in the greenhouse and growth chamber conditions. The data indicate that PSARK::IPT-transgenic cotton plants displayed delayed senescence under water deficit conditions in the greenhouse. These plants produced more root and shoot biomass, dropped fewer flowers, maintained higher chlorophyll content, and higher photosynthetic rates under reduced irrigation conditions in comparison to wild-type and segregated non-transgenic lines. Furthermore, PSARK::IPT-transgenic cotton plants grown in growth chamber condition also displayed greater drought tolerance. These results indicate that water-deficit induced expression of an isopentenyltransferase gene in cotton could significantly improve drought tolerance. [ABSTRACT FROM AUTHOR]

Salinity is a major environmental stress that affects agricultural productivity worldwide. One approach to improving salt tolerance in crops is through high expression of the Arabidopsis gene AtNHX1, which encodes a vacuolar sodium/proton antiporter that sequesters excess sodium ion into the large intracellular vacuole. Sequestering cytosolic sodium into the vacuoles of plant cells leads to a low level of sodium in cytosol, which minimizes the sodium toxicity and injury to important enzymes in cytosol. In the meantime, the accumulation of sodium in vacuoles restores the correct osmolarity to the intracellular milieu, which favors water uptake by plant root cells and improves water retention in tissues under soils that are high in salt. To improve the yield and quality of peanut under high salt conditions, AtNHX1 was introduced into peanut plants through Agrobacterium-mediated transformation. The AtNHX1-expressing peanut plants displayed increased tolerance of salt at levels up to 150 mM NaCl. When compared to wild-type plants, AtNHX1-expressing peanut plants suffered less damage, produced more biomass, contained more chlorophyll, and maintained higher photosynthetic rates under salt conditions. These data indicate that AtNHX1 can be used to enhance salt tolerance in peanut. [ABSTRACT FROM AUTHOR]

The Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump on the vacuolar membrane. Overexpression of AVP1 in Arabidopsis, tomato and rice enhances plant performance under salt and drought stress conditions, because up-regulation of the type I H-PPase from Arabidopsis may result in a higher proton electrochemical gradient, which facilitates enhanced sequestering of ions and sugars into the vacuole, reducing water potential and resulting in increased drought- and salt tolerance when compared to wild-type plants. Furthermore, overexpression of AVP1 stimulates auxin transport in the root system and leads to larger root systems, which helps transgenic plants absorb water more efficiently under drought conditions. Using the same approach, AVP1-expressing cotton plants were created and tested for their performance under high-salt and reduced irrigation conditions. The AVP1-expressing cotton plants showed more vigorous growth than wild-type plants in the presence of 200 m NaCl under hydroponic growth conditions. The soil-grown AVP1-expressing cotton plants also displayed significantly improved tolerance to both drought and salt stresses in greenhouse conditions. Furthermore, the fibre yield of AVP1-expressing cotton plants is at least 20% higher than that of wild-type plants under dry-land conditions in the field. This research indicates that AVP1 has the potential to be used for improving crop's drought- and salt tolerance in areas where water and salinity are limiting factors for agricultural productivity. [ABSTRACT FROM AUTHOR]

Arabidopsis thaliana ANKYRIN REPEAT-CONTAINING PROTEIN 2A (AKR2A) interacts with peroxisomal membrane-bound ASCORBATE PEROXIDASE3 (APX3). This interaction involves the C-terminal sequence of APX3 (i.e. a transmembrane domain plus a few basic amino acid residues). The specificity of the AKR2A–APX3 interaction suggests that AKR2A may function as a molecular chaperone for APX3 because binding of AKR2A to the transmembrane domain can prevent APX3 from forming aggregates after translation. Analysis of three akr2a mutants indicates that these mutant plants have reduced steady state levels of APX3. Reduced expression of AKR2A using RNA interference also leads to reduced steady state levels of APX3 and reduced targeting of APX3 to peroxisomes in plant cells. Since AKR2A also binds specifically to the chloroplast OUTER ENVELOPE PROTEIN7 (OEP7) and is required for the biogenesis of OEP7, AKR2A may serve as a molecular chaperone for OEP7 as well. The pleiotropic phenotype of akr2a mutants indicates that AKR2A plays many important roles in plant cellular metabolism and is essential for plant growth and development. [ABSTRACT FROM AUTHOR]

Chilling is common in nature and can damage most plant species, particularly young leaves and buds. Mulberry (Morus spp.) is an economically important food source for the domesticated silkworm (Bombyx mori). However, weather and climatic extremes, such as “late spring coldness”, seriously damage mulberry buds and young leaves. The molecular mechanism involved in the differing mulberry chilling tolerance is unclear. In the present study, we found that mSOD1, mFADII, and mKCS1 interacted with mAKR2A and that the expression of mAKR2A, mSOD, mFAD, and mKCS1 in the chilling-tolerant mulberry variety was higher than that in the chilling-sensitive variety. Unsaturated fatty acids content and superoxide dismutase (SOD) activity in the chilling-tolerant variety was higher than that in the chilling-sensitive variety. After chilling treatment, mSOD1, mKCS1 and mAKR2A expression in the chilling-tolerant variety was reduced to lower than that in the chilling-sensitive variety, whereas mFADII expression increased in the chilling-tolerant variety compared with that in the chilling-sensitive variety, suggesting that the increased expression of the molecular chaperon mAKR2A helped to maintain or prompted the chilling-related proteins in the chilling-tolerant variety. [ABSTRACT FROM AUTHOR]