Efficacy of a mixed extract of Salvia miltiorrhiza and Paeonia lactiflora in inhibiting the aging of vascular wall through in vitro and in vivo experiments.

Vascular wall aging has been strongly associated with cardiovascular diseases. Thus, this study aimed to investigate the efficacy of USCP-GVH-014, a mixed extract of Salvia miltiorrhiza Bunge and Paeonia lactiflora Pall., in inhibiting vascular wall aging through in vitro and in vivo experiments. The results revealed that USCP-GVH-014 inhibited abnormal cell proliferation, collagen overproduction, and MMP-2 and MMP-9 overexpression caused by various stimuli and recovered the antioxidant enzyme superoxide dismutase on human aortic smooth muscle cells. In addition, it inhibited the increase in ICAM-1 and VCAM-1 expression induced by tumor necrosis factor alpha on human aortic endothelial cells and prevented the aging of the vascular wall by regulating related proteins such as epidermal growth factor and interleukin-1ß. Furthermore, it reduced vascular aging in in vivo studies. These results demonstrate that USCP-GVH-014 effectively reduces vascular aging, thereby rendering it a potential therapeutic candidate for cardiovascular diseases.

Antioxidant Activity Analysis of Native Actinidia arguta Cultivars.

Kiwiberry (Actinidia arguta) is a perennial fruit tree belonging to the family Actinidiaceae. Kiwiberries are known to have an extremely high concentration of sugars, phenolics, flavonoids, and vitamin C, and possess delicious taste and health-promoting properties. Numerous studies have focused on kiwiberry fruits, demonstrating that they possess a higher phytochemical content and greater antioxidant activities than other berry fruits. The purpose of this study was to compare the phytochemical content and antioxidant potential of leaf, stem, root, and fruit extracts from twelve kiwiberry cultivars grown in Wonju, Korea, characterized by a Dwa climate (Köppen climate classification). In most kiwiberry cultivars, the total phenolic (TPC) and total flavonoid (TFC) phytochemical content was significantly higher in leaf and stem tissues, while the roots exhibited higher antioxidant activity. In fruit tissues, the TPC and TFC were higher in unripe and ripe kiwiberry fruits, respectively, and antioxidant activity was generally higher in unripe than ripe fruit across most of the cultivars. Based on our results, among the 12 kiwiberry cultivars, cv. Daebo and cv. Saehan have a significantly higher phytochemical content and antioxidant activity in all of the tissue types, thus having potential as a functional food and natural antioxidant.

The Anti-Inflammatory Effects of Broccoli (Brassica oleracea L. var. italica) Sprout Extract in RAW 264.7 Macrophages and a Lipopolysaccharide-Induced Liver Injury Model.

Brassica oleracea var. italica (broccoli), a member of the cabbage family, is abundant with many nutrients, including vitamins, potassium, fiber, minerals, and phytochemicals. Consequently, it has been used as a functional food additive to reduce oxidative stress and inflammatory responses. In the current study, the effects of sulforaphane-rich broccoli sprout extract (BSE) on the inflammatory response were investigated in vitro and in vivo. Comparative high-performance liquid chromatography analysis of sulforaphane content from different extracts revealed that 70% ethanolic BSE contained more sulforaphane than the other extracts. qPCR and enzyme immunoassay analyses revealed that BSE markedly reduced the expression of proinflammatory cytokines and mediators, including cyclooxygenase 2, interleukin (IL)-1ß, IL-6, IL-1, inducible nitric oxide synthase (iNOS), and tumor necrosis factor-α (TNF-α), in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Pretreatment with BSE improved the survival rate and suppressed alanine aminotransferase and aspartate aminotransferase expression in LPS-induced endotoxemic mice, while proinflammatory cytokines such as IL-1ß, TNF-α, IL-6, cyclooxygenase-2, and iNOS decreased dramatically in the LPS-induced liver injury model via BSE treatment. Additionally, F4/80 immunostaining showed that BSE suppressed hepatic macrophage infiltration in the liver after lipopolysaccharide injection. In conclusion, BSE may be a potential nutraceutical for preventing and regulating excessive immune responses in inflammatory disease.

Overexpression of a C3HC4-type E3-ubiquitin ligase contributes to salinity tolerance by modulating Na+ homeostasis in rice.

Soil salinity has a negative effect on crop yield. Therefore, plants have evolved many strategies to overcome decreases in yield under saline conditions. Among these, E3-ubiquitin ligase regulates salt tolerance. We characterized Oryza sativa Really Interesting New Gene (RING) Finger C3HC4-type E3 ligase (OsRFPHC-4), which plays a positive role in improving salt tolerance. The expression of OsRFPHC-4 was downregulated by high NaCl concentrations and induced by abscisic acid (ABA) treatment. GFP-fused OsRFPHC-4 was localized to the plasma membrane of rice protoplasts. OsRFPHC-4 encodes a cellular protein with a C3HC4-RING domain with E3 ligase activity. However, its variant OsRFPHC-4C161A does not possess this activity. OsRFPHC-4-overexpressing plants showed enhanced salt tolerance due to low accumulation of Na+ in both roots and leaves, low Na+ transport in the xylem sap, high accumulation of proline and soluble sugars, high activity of reactive oxygen species (ROS) scavenging enzymes, and differential regulation of Na+ /K+ transporter expression compared to wild-type (WT) and osrfphc-4 plants. In addition, OsRFPHC-4-overexpressing plants showed higher ABA sensitivity under exogenous ABA treatment than WT and osrfphc-4 plants. Overall, these results suggest that OsRFPHC-4 contributes to the improvement of salt tolerance and Na+ /K+ homeostasis via the regulation of changes in Na+ /K+ transporters.

Plant tissue succulence engineering improves water-use efficiency, water-deficit stress attenuation and salinity tolerance in Arabidopsis.

Tissue succulence (ratio of tissue water/leaf area or dry mass) or the ability to store water within living tissues is among the most successful adaptations to drought in the plant kingdom. This taxonomically widespread adaptation helps plants avoid the damaging effects of drought, and is often associated with the occupancy of epiphytic, epilithic, semi-arid and arid environments. Tissue succulence was engineered in Arabidopsis thaliana by overexpression of a codon-optimized helix-loop-helix transcription factor (VvCEB1opt ) from wine grape involved in the cell expansion phase of berry development. VvCEB1opt -overexpressing lines displayed significant increases in cell size, succulence and decreased intercellular air space. VvCEB1opt -overexpressing lines showed increased instantaneous and integrated water-use efficiency (WUE) due to reduced stomatal conductance caused by reduced stomatal aperture and density resulting in increased attenuation of water-deficit stress. VvCEB1opt -overexpressing lines also showed increased salinity tolerance due to reduced salinity uptake and dilution of internal Na+ and Cl- as well as other ions. Alterations in transporter activities were further suggested by media and apoplastic acidification, hygromycin B tolerance and changes in relative transcript abundance patterns of various transporters with known functions in salinity tolerance. Engineered tissue succulence might provide an effective strategy for improving WUE, drought avoidance or attenuation, salinity tolerance, and for crassulacean acid metabolism biodesign.

Oryza sativa, C4HC3-type really interesting new gene (RING), OsRFPv6, is a positive regulator in response to salt stress by regulating Na+ absorption.

Salinity negatively affects plant growth, productivity, and metabolism. Therefore, plants have evolved diverse strategies to survive in saline environments. To identify such strategies involving the ubiquitin/26S proteasome system, we characterized molecular functions of a rice C4HC3 really interesting new gene (RING)-type E3-ubiquitin ligase gene. Oryza sativa RING finger protein v6 (OsRFPv6) was highly expressed under conditions of abiotic stress, induced by 100 mM NaCl and 20% PEG. The GFP-OsRFPv6 protein was localized in the plasma membrane and cytosol in rice protoplasts. In vitro ubiquitin assay revealed that OsRFPv6 possessed E3-ubiquitin ligase activity, but its variant OsRFPv6C100A did not. OsRFPv6-overexpressing plants were insensitive to salinity, but their growth was delayed under normal conditions. Under saline conditions, transgenic plants exhibited higher proline, soluble sugar, and chlorophyll content and lower H2 O2 accumulation than wild-type plants. Moreover, transgenic plants exhibited lower Na+ uptake, lower Na+ content, and higher K+ content in the xylem sap assay. Under saline conditions, the expression levels of nine Na+ /K+ transporter genes in roots and leaves were significantly different between transgenic and wild-type plants. Specifically, under both normal and saline conditions, the expression of OsHKT2;1, a Na+ transporter, in the roots of transgenic plants was lower than that in the roots of wild-type plants. These results suggest that OsRFPv6 E3-ubiquitin ligase serves as a positive regulator of salinity response via Na+ uptake.

Identification and analysis of a differentially expressed wheat RING-type E3 ligase in spike primordia development during post-vernalization.

KEY MESSAGE: We identified a RING-type E3 ligase (TaBAH1) protein in winter wheat that targets TaSAHH1 for degradation and might be involved in primordia development by regulating targeted protein degradation. Grain yield per spike in wheat (Triticum aestivum), is mainly determined prior to flowering during mature primordia development; however, the genes involved in primordia development have yet to be characterized. In this study, we demonstrated that, after vernalization for 50 days at 4 °C, there was a rapid acceleration in primordia development to the mature stages in the winter wheat cultivars Keumgang and Yeongkwang compared with the Chinese Spring cultivar. Although Yeongkwang flowers later than Keumgang under normal condition, it has the same heading time and reaches the WS9 stage of floral development after vernalization for 50 days. Using RNA sequencing, we identified candidate genes associated with primordia development in cvs. Keumgang and Yeongkwang, that are differentially expressed during wheat reproductive stages. Among these, the RING-type E3 ligase TaBAH1 (TraesCS5B01G373000) was transcriptionally upregulated between the double-ridge (WS2.5) stage and later stages of floret primordia development (WS10) after vernalization. Transient expression analysis indicated that TaBAH1 was localized to the plasma membrane and nucleus and was characterized by self-ubiquitination activity. Furthermore, we found that TaBAH1 interacts with TaSAHH1 to mediate its polyubiquitination and degradation through a 26S proteasomal pathway. Collectively, the findings of this study indicate that TaBAH1 might play a prominent role in post-vernalization floret primordia development.

Oryza sativa drought-, heat-, and salt-induced RING finger protein 1 (OsDHSRP1) negatively regulates abiotic stress-responsive gene expression.

Plants are sessile and unable to avoid environmental stresses, such as drought, high temperature, and high salinity, which often limit the overall plant growth. Plants have evolved many complex mechanisms to survive these abiotic stresses via post-translational modifications. Recent evidence suggests that ubiquitination plays a crucial role in regulating abiotic stress responses in plants by regulating their substrate proteins. Here, we reported the molecular function of a RING finger E3 ligase, Oryza sativa Drought, Heat and Salt-induced RING finger protein 1 (OsDHSRP1), involved in regulating plant abiotic stress tolerance via the Ub/26S proteasome system. The OsDHSRP1 gene transcripts were highly expressed under various abiotic stresses such as NaCl, drought, and heat and the phytohormone abscisic acid (ABA). In addition, in vitro ubiquitination assays demonstrated that the OsDHSRP1 protein possesses a RING-H2 type domain that confers ligase functionality. The results of yeast two-hybrid (Y2H), in vitro pull-down, and bimolecular fluorescence complementation assays support that OsDHSRP1 is able to regulate two substrates, O. sativa glyoxalase (OsGLYI-11.2) and O. sativa abiotic stress-induced cysteine proteinase 1 (OsACP1). We further confirmed that these two substrate proteins were ubiquitinated by OsDHSRP1 E3 ligase and caused protein degradation via the Ub/26S proteasome system. The Arabidopsis plants overexpressing OsDHSRP1 exhibited hypersensitivity to drought, heat, and NaCl stress and a decrease in their germination rates and root lengths compared to the control plants because the degradation of the OsGLYI-11.2 protein maintained lower glyoxalase levels, which increased the methylglyoxal amount in transgenic Arabidopsis plants. However, the OsDHSRP1-overexpressing plants showed no significant difference when treated with ABA. Our finding supports the hypothesis that the OsDHSRP1 E3 ligase acts as a negative regulator, and the degradation of its substrate proteins via ubiquitination plays important roles in regulating various abiotic stress responses via an ABA-independent pathway.

Molecular characterization of a RING E3 ligase SbHCI1 in sorghum under heat and abscisic acid stress.

MAIN CONCLUSION: Molecular function ofRING E3 ligase SbHCI1is involved in ABA-mediated basal heat stress tolerancein sorghum. Global warming generally reduces plant survival, owing to the negative effects of high temperatures on plant development. However, little is known about the role of Really Interesting New Gene (RING) E3 ligase in the heat stress responses of plants. As such, the aim of the present study was to characterize the molecular functions of the Sorghum bicolor ortholog of the Oryza sativa gene for Heat- and Cold-Induced RING finger protein 1 (SbHCI1). Subcellular localization revealed that SbHCI1 was mainly associated with the cytosol and that it moved to the Golgi apparatus under heat stress conditions. The fluorescent signals of SbHCI1 substrate proteins were observed to migrate to the cytoplasm under heat stress conditions. Bimolecular fluorescence complementation (BiFC) and yeast two-hybrid (Y2H) assays revealed that SbHCI1 physically interacted with OsHCI1 ortholog partner proteins in the cytoplasm. Moreover, an in vitro ubiquitination assay revealed that SbHCI1 polyubiquitinated each of the three interacting proteins. The ectopic overexpression of SbHCI1 in Arabidopsis revealed that the protein was capable of inducing abscisic acid (ABA)-hypersensitivity and basal heat stress tolerance. Therefore, SbHCI1 possesses E3 ligase activity and may function as a positive regulator of heat stress responses through the modulation of interacting proteins.

Oryza sativa heat-induced RING finger protein 1 (OsHIRP1) positively regulates plant response to heat stress.

KEY MESSAGE: OsHIRP1 is an E3 ligase that acts as a positive regulator in the plant response to heat stress, thus providing important information relating to adaptation and regulation under heat stress in plant. Extreme temperature adversely affects plant growth, development, and productivity. Here, we report the molecular functions of Oryza sativa heat-induced RING finger protein 1 (OsHIRP1), which might play an important role in the response to heat. Transcription of the OsHIRP1 was upregulated in response to heat and drought treatment. We found that the OsHIRP1-EYFP fusion protein was localized to the nucleus after heat treatment (45 °C). Two interacting partners, OsARK4 and OsHRK1, were identified via yeast-two-hybrid screening, which were mainly targeted to the nucleus (OsARK4) and cytosol (OsHRK1), and their interactions with OsHIRP1 were confirmed by biomolecular fluorescence complementation (BiFC). An in vitro ubiquitination assay showed that OsHIRP1 E3 ligase directly ubiquitinates its interacting proteins, OsAKR4 and OsHRK1, as substrates. Using an in vitro cell-free degradation assay, we observed a clear reduction in the levels of the two proteins under high temperature (45 °C), but not under low temperature conditions (4 °C and 30 °C). Seeds of OsHIRP1-overexpressing plants exhibited high germination rates compared with the control under heat stress. The OsHIRP1-overexpressing plants presented high survival rates of approximately 62-68%, whereas control plants displayed a low recovery rate of 34% under condition of acquired thermo-tolerance. Some heat stress-inducible genes (HsfA3, HSP17.3, HSP18.2 and HSP20) were up-regulated in OsHIRP1-overexpressing Arabidopsis than control plants under heat stress conditions. Collectively, these results suggest that OsHIRP1, an E3 ligase, positively regulates plant response to heat stress.

A rice really interesting new gene H2-type E3 ligase, OsSIRH2-14, enhances salinity tolerance via ubiquitin/26S proteasome-mediated degradation of salt-related proteins.

Salinity is a deleterious abiotic stress factor that affects growth, productivity, and physiology of crop plants. Strategies for improving salinity tolerance in plants are critical for crop breeding programmes. Here, we characterized the rice (Oryza sativa) really interesting new gene (RING) H2-type E3 ligase, OsSIRH2-14 (previously named OsRFPH2-14), which plays a positive role in salinity tolerance by regulating salt-related proteins including an HKT-type Na+ transporter (OsHKT2;1). OsSIRH2-14 expression was induced in root and shoot tissues treated with NaCl. The OsSIRH2-14-EYFP fusion protein was predominately expressed in the cytoplasm, Golgi, and plasma membrane of rice protoplasts. In vitro pull-down assays and bimolecular fluorescence complementation assays revealed that OsSIRH2-14 interacts with salt-related proteins, including OsHKT2;1. OsSIRH2-14 E3 ligase regulates OsHKT2;1 via the 26S proteasome system under high NaCl concentrations but not under normal conditions. Compared with wild type plants, OsSIRH2-14-overexpressing rice plants showed significantly enhanced salinity tolerance and reduced Na+ accumulation in the aerial shoot and root tissues. These results suggest that the OsSIRH2-14 RING E3 ligase positively regulates the salinity stress response by modulating the stability of salt-related proteins.

A Vitis vinifera basic helix-loop-helix transcription factor enhances plant cell size, vegetative biomass and reproductive yield.

Strategies for improving plant size are critical targets for plant biotechnology to increase vegetative biomass or reproductive yield. To improve biomass production, a codon-optimized helix-loop-helix transcription factor (VvCEB1opt ) from wine grape was overexpressed in Arabidopsis thaliana resulting in significantly increased leaf number, leaf and rosette area, fresh weight and dry weight. Cell size, but typically not cell number, was increased in all tissues resulting in increased vegetative biomass and reproductive organ size, number and seed yield. Ionomic analysis of leaves revealed the VvCEB1opt -overexpressing plants had significantly elevated, K, S and Mo contents relative to control lines. Increased K content likely drives increased osmotic potential within cells leading to greater cellular growth and expansion. To understand the mechanistic basis of VvCEB1opt action, one transgenic line was genotyped using RNA-Seq mRNA expression profiling and revealed a novel transcriptional reprogramming network with significant changes in mRNA abundance for genes with functions in delayed flowering, pathogen-defence responses, iron homeostasis, vesicle-mediated cell wall formation and auxin-mediated signalling and responses. Direct testing of VvCEB1opt -overexpressing plants showed that they had significantly elevated auxin content and a significantly increased number of lateral leaf primordia within meristems relative to controls, confirming that cell expansion and organ number proliferation were likely an auxin-mediated process. VvCEB1opt overexpression in Nicotiana sylvestris also showed larger cells, organ size and biomass demonstrating the potential applicability of this innovative strategy for improving plant biomass and reproductive yield in crops.

Molecular dissection of Oryza sativa salt-induced RING Finger Protein 1 (OsSIRP1): possible involvement in the sensitivity response to salinity stress.

Ubiquitination-mediated protein degradation via Really Interesting New Gene (RING) E3 ligase plays an important role in plant responses to abiotic stress conditions. Many plant studies have found that RING proteins regulate the perception of various abiotic stresses and signal transduction. In this study, Oryza sativa salt-induced RING Finger Protein 1 (OsSIRP1) gene was selected randomly from 44 Oryza sativa RING Finger Proteins (OsRFPs) genes highly expressed in rice roots exposed to salinity stress. Transcript levels of OsSIRP1 in rice leaves after various stress treatments, including salt, heat, drought and hormone abscisic acid (ABA), were observed. Poly-ubiquitinated products of OsSIRP1 were investigated via an in vitro ubiquitination assay.35S:OsSIRP1-EYFP was distributed in the cytosol of untreated and salt-treated rice protoplasts. Heterogeneous overexpression of OsSIRP1 in Arabidopsis reduced tolerance for salinity stress during seed germination and root growth. Our findings indicate that OsSIRP1 acts as a negative regulator of salinity stress tolerance mediated by the ubiquitin 26S proteasome system.

Molecular dissection of a rice microtubule-associated RING finger protein and its potential role in salt tolerance in Arabidopsis.

Although a number of RING E3 ligases in plants have been demonstrated to play key roles in a wide range of abiotic stresses, relatively few studies have detailed how RING E3 ligases exert their cellular actions. We describe Oryza sativa RING finger protein with microtubule-targeting domain 1 (OsRMT1), a functional RING E3 ligase that is likely involved in a salt tolerance mechanism. Functional characterization revealed that OsRMT1 undergoes homodimer formation and subsequently autoubiquitination-mediated protein degradation under normal conditions. By contrast, OsRMT1 is predominantly found in the nucleus and microtubules and its degradation is inhibited under salt stress. Domain dissection of OsRMT1 indicates that the N-terminal domain is required for microtubule targeting. Bimolecular fluorescence complementation analysis and degradation assay revealed that OsRMT1-interacted proteins localized in various organelles were degraded via the ubiquitin (Ub)/26S proteasome-dependent pathway. Interestingly, when OsRMT1 and its target proteins were co-expressed in N. benthamiana leaves, the protein-protein interactions appeared to take place mainly in the microtubules. Overexpression of OsRMT1 in Arabidopsis resulted in increased tolerance to salt stress. Our findings suggest that the abundance of microtubule-associated OsRMT1 is strictly regulated, and OsRMT1 may play a relevant role in salt stress response by modulating levels of its target proteins.

A roadmap for research on crassulacean acid metabolism (CAM) to enhance sustainable food and bioenergy production in a hotter, drier world.

Crassulacean acid metabolism (CAM) is a specialized mode of photosynthesis that features nocturnal CO2 uptake, facilitates increased water-use efficiency (WUE), and enables CAM plants to inhabit water-limited environments such as semi-arid deserts or seasonally dry forests. Human population growth and global climate change now present challenges for agricultural production systems to increase food, feed, forage, fiber, and fuel production. One approach to meet these challenges is to increase reliance on CAM crops, such as Agave and Opuntia, for biomass production on semi-arid, abandoned, marginal, or degraded agricultural lands. Major research efforts are now underway to assess the productivity of CAM crop species and to harness the WUE of CAM by engineering this pathway into existing food, feed, and bioenergy crops. An improved understanding of CAM has potential for high returns on research investment. To exploit the potential of CAM crops and CAM bioengineering, it will be necessary to elucidate the evolution, genomic features, and regulatory mechanisms of CAM. Field trials and predictive models will be required to assess the productivity of CAM crops, while new synthetic biology approaches need to be developed for CAM engineering. Infrastructure will be needed for CAM model systems, field trials, mutant collections, and data management.

Positive regulation of rice RING E3 ligase OsHIR1 in arsenic and cadmium uptakes.

The metalloid arsenic (As) and the heavy metal cadmium (Cd) are ubiquitously found at low concentrations in the earth. High concentrations of these elements in the soil and crops are severely dangerous to human health. We attempted to retrieve the RING E3 ubiquitin ligase gene for regulating As and Cd uptakes via the ubiquitin 26S proteasome system. Semi-quantitative reverse transcription polymerase chain reaction was conducted for a total of 47 Oryza sativa RING finger protein (OsRFP) genes to assess their expression patterns when exposed to As and Cd treatments. We identified one gene Oryza sativa heavy metal induced RING E3 ligase 1 (OsHIR1), which was significantly upregulated with both treatments. A yeast hybrid screen and a bimolecular fluorescence complementation assay showed that OsHIR1 clearly interacts with 5 substrate proteins, including tonoplast intrinsic protein 4;1 (OsTIP4;1) in the plasma membrane. In addition, OsHIR1 strongly degraded the protein level of OsTIP4;1 via the ubiquitin 26S proteasome system. Heterogeneous overexpression of OsHIR1 in Arabidopsis exhibited As- and Cd-insensitive phenotypes and resulted in decreased As and Cd accumulation in the shoots and roots, relative to the control. Herein, we report the novel finding that the OsHIR1 E3 ligase positively regulates OsTIP4;1 related to As and Cd uptakes.

The rice RING E3 ligase, OsCTR1, inhibits trafficking to the chloroplasts of OsCP12 and OsRP1, and its overexpression confers drought tolerance in Arabidopsis.

Plant growth under low water availability adversely affects many key processes with morphological, physiological, biochemical and molecular consequences. Here, we found that a rice gene, OsCTR1, encoding the RING Ub E3 ligase plays an important role in drought tolerance. OsCTR1 was highly expressed in response to dehydration treatment and defense-related phytohormones, and its encoded protein was localized in both the chloroplasts and the cytosol. Intriguingly, the OsCTR1 protein was found predominantly targeted to the cytosol when rice protoplasts transfected with OsCTR1 were treated with abscisic acid (ABA). Several interacting partners were identified, which were mainly targeted to the chloroplasts, and interactions with OsCTR1 were confirmed by using biomolecular fluorescence complementation (BiFC). Interestingly, two chloroplast-localized proteins (OsCP12 and OsRP1) interacted with OsCTR1 in the cytosol, and ubiquitination by OsCTR1 led to protein degradation via the Ub 26S proteasome. Heterogeneous overexpression of OsCTR1 in Arabidopsis exhibited hypersensitive phenotypes with respect to ABA-responsive seed germination, seedling growth and stomatal closure. The ABA-sensitive transgenic plants also showed improvement in their tolerance against severe water deficits. Taken together, our findings lend support to the hypothesis that the molecular functions of OsCTR1 are related to tolerance to water-deficit stress via ABA-dependent regulation and related systems.

The rice RING finger E3 ligase, OsHCI1, drives nuclear export of multiple substrate proteins and its heterogeneous overexpression enhances acquired thermotolerance.

Thermotolerance is very important for plant survival when plants are subjected to lethally high temperature. However, thus far little is known about the functions of RING E3 ligase in response to heat shock in plants. This study found that one rice gene encoding the RING finger protein was specifically induced by heat and cold stress treatments but not by salinity or dehydration and named it OsHCI1 (Oryza sativa heat and cold induced 1). Subcellular localization results showed that OsHCI1 was mainly associated with the Golgi apparatus and moved rapidly and extensively along the cytoskeleton. In contrast, OsHCI1 may have accumulated in the nucleus under high temperatures. OsHCI1 physically interacted with nuclear substrate proteins including a basic helix-loop-helix transcription factor. Transient co-overexpression of OsHCI1 and each of three nuclear proteins showed that their fluorescent signals moved into the cytoplasm as punctuate formations. Heterogeneous overexpression of OsHCI1 in Arabidopsis highly increased survival rate through acquired thermotolerance. It is proposed that OsHCI1 mediates nuclear-cytoplasmic trafficking of nuclear substrate proteins via monoubiquitination and drives an inactivation device for the nuclear proteins under heat shock.

Tissue succulence in plants: Carrying water for climate change.

Tissue succulence in plants involves the storage of water in one or more organs or tissues to assist in maintaining water potentials on daily or seasonal time scales. This drought-avoidance or drought-resistance strategy allows plants to occupy diverse environments including arid regions, regions with rocky soils, epiphytic habitats, and saline soils. Climate-resilient strategies are of increasing interest in the context of the global climate crisis, which is leading to hotter and drier conditions in many regions throughout the globe. Here, we describe a short history of succulent plants, the basic concepts of tissue succulence, the anatomical diversity of succulent morphologies and associated adaptive traits, the evolutionary, phylogenetic, and biogeographical diversity of succulent plants, extinction risks to succulents due to poaching from their natural environments, and the myriad uses and applications of economically important succulent species and the products derived from them. Lastly, we discuss current prospects for engineering tissue succulence to improve salinity and drought tolerance in crops.

A gene family encoding RING finger proteins in rice: their expansion, expression diversity, and co-expressed genes.

The proteins harboring RING finger motif(s) have been shown to mediate protein-protein interactions that are relevant to a variety of cellular processes. In an effort to elucidate the evolutionary dynamics of the rice RING finger protein family, we have attempted to determine their genomic locations, expression diversity, and co-expressed genes via in silico analysis and semi-quantitative RT-PCR. A total of 425 retrieved genes appear to be distributed over all 12 of the chromosomes of rice with different distributions, and are reflective of the evolutionary dynamics of the rice genome. A genome-wide dataset harboring 155 gene expression omnibus sample plates evidenced some degree of differential evolutionary fates between members of RING-H2 and RING-HC types. Additionally, responses to abiotic stresses, such as salinity and drought, demonstrated that some degree of expression diversity existed between members of the RING finger protein genes. Interestingly, we determined that one RING-H2 finger protein gene (Os04g51400) manifested striking differences in expression patterns in response to abiotic stresses between leaf and culm-node tissues, further revealing responses highly similar to the majority of randomly selected co-expressed genes. The gene network of genes co-expressed with Os04g51400 may suggest some role in the salt response of the gene. These findings may shed further light on the evolutionary dynamics and molecular functional diversity of these proteins in complex cellular regulations.