Reactive Oxygen Species Signaling Cascades Research Articles

The MdmiR156n Regulates Drought Tolerance and Flavonoid Synthesis in Apple Calli and Arabidopsis.

Drought is the major abiotic stress that limits apple productivity and quality. To date, many important and divergent regulatory functions of miR156/SBP genes in plant growth and development have been well understood. However, little is known about the role of apple miR156 in response to abiotic stress. To better understand the functions of MdmiR156 in abiotic stress tolerance, we constructed the overexpression (OE) and short tandem target mimic (STTM) vector of MdmiR156n and performed its functional analysis through the characterization of transgenic apple calli and Arabidopsis thaliana plants. In this study, MdmiR156n overexpression significantly increased the length of primary roots and the number of lateral roots in transgenic Arabidopsis plants under drought stress. In addition, MdmiR156n transgenic Arabidopsis and apple calli had a lower electrolyte leakage rate and less cell membrane damage than WT and STTM156 after drought stress. Further studies showed that MdmiR156n overexpression promoted the accumulation of flavonoids and scavenging of reactive oxygen species (ROS) under drought conditions in transgenic apple calli and A. thaliana plants. Taken together, overexpression MdmiR156n enhances drought tolerance by regulating flavonoid synthesis and ROS signaling cascades in apple calli and A. thaliana.

CROStalk for Life: Uncovering ROS Signaling in Plants and Animal Systems, from Gametogenesis to Early Embryonic Development.

This review explores the role of reactive oxygen species (ROS)/Ca2+ in communication within reproductive structures in plants and animals. Many concepts have been described during the last years regarding how biosynthesis, generation products, antioxidant systems, and signal transduction involve ROS signaling, as well as its possible link with developmental processes and response to biotic and abiotic stresses. In this review, we first addressed classic key concepts in ROS and Ca2+ signaling in plants, both at the subcellular, cellular, and organ level. In the plant science field, during the last decades, new techniques have facilitated the in vivo monitoring of ROS signaling cascades. We will describe these powerful techniques in plants and compare them to those existing in animals. Development of new analytical techniques will facilitate the understanding of ROS signaling and their signal transduction pathways in plants and mammals. Many among those signaling pathways already have been studied in animals; therefore, a specific effort should be made to integrate this knowledge into plant biology. We here discuss examples of how changes in the ROS and Ca2+ signaling pathways can affect differentiation processes in plants, focusing specifically on reproductive processes where the ROS and Ca2+ signaling pathways influence the gametophyte functioning, sexual reproduction, and embryo formation in plants and animals. The study field regarding the role of ROS and Ca2+ in signal transduction is evolving continuously, which is why we reviewed the recent literature and propose here the potential targets affecting ROS in reproductive processes. We discuss the opportunities to integrate comparative developmental studies and experimental approaches into studies on the role of ROS/ Ca2+ in both plant and animal developmental biology studies, to further elucidate these crucial signaling pathways.

ROS signaling cascades: dual regulations for osteoclast and osteoblast.

Accumulating evidence indicates that intracellular reactive oxygen species (ROS) production is highly involved in bone homeostasis by intervening osteoclast or osteoblast differentiation. Interestingly, ROS that are known as oxidizing agents exert dose-dependent biphasic properties in bone remodeling, including preventing osteoblast activity but accelerating osteoclast resorption. ROS mainly composed of superoxide anion radical, hydroxyl radical, nitric oxide, and two-electron reduction product hydrogen peroxide, which are important components to regulate bone cell metabolism and function in mammal skeleton. These free radicals can be partly produced in bone and boosted in an inflammation state. Although numerous researches have emphasized the impacts of ROS on bone cell biology and verified the mechanism of ROS signaling cascades, the recapitulatory commentary is necessary. In this review article, we particularly focus on the regulation of the intracellular ROS and its potential mechanism impacting on cell-signaling transduction in osteoclast and osteoblast differentiation for preferable understanding the pathogenesis and searching for novel therapeutic protocols for human bone diseases.

Transcription Factor CaSBP12 Negatively Regulates Salt Stress Tolerance in Pepper (Capsicum annuum L.).

SBP-box (Squamosa-promoter binding protein) genes are a type of plant-specific transcription factor and play important roles in plant growth, signal transduction, and stress response. However, little is known about the role of pepper SBP-box transcription factor genes in response to abiotic stress. Here, one of the pepper SBP-box gene, CaSBP12, was selected and isolated from pepper genome database in our previous study. The CaSBP12 gene was induced under salt stress. Silencing the CaSBP12 gene enhanced pepper plant tolerance to salt stress. The accumulation of reactive oxygen species (ROS) of the detached leaves of CaSBP12-silenced plants was significantly lower than that of control plants. Besides, the Na+, malondialdehyde content, and conductivity were significantly increased in control plants than that in the CaSBP12-silenced plants. In addition, the CaSBP12 over-expressed Nicotiana benthamiana plants were more susceptible to salt stress with higher damage severity index percentage and accumulation of ROS as compared to the wild-type. These results indicated that CaSBP12 negatively regulates salt stress tolerance in pepper may relate to ROS signaling cascades.

Critical responses to nutrient deprivation: A comprehensive review on the role of ROS and RNS

Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) are central regulators of plant performance and adaptation to a changing environment. In this sense, increasing evidence points to a prominent role of ROS and RNS in coping with changes in nutrient availability (either deficiency or excess). However, decoding of ROS and RNS signatures into specific nutrient responses still remains a mystery. Thus far, it is known that nutrient deficiencies result in high levels of ROS and exert profound effects on the antioxidant cell machinery. ROS signal propagation relies, in part, on the activation of an array of transmembrane transport systems at the plasma membrane. The intracellular ROS signal leads to the upregulation of adaptation mechanisms (involving activation or de novo synthesis of proteins). Unlike ROS, RNS production under nutrient stress is a much less understood process. Nevertheless, RNS, and NO in particular, intensify the antioxidant responses through the stimulation of their respective scavengers which is helpful for minimizing oxidative damage that can occur during nutrient stress. In the present review, we summarize the current state in the field of ROS and RNS signaling in plant nutrition and identify the main gaps in our knowledge, which should be filled in the forthcoming years. Further understanding of the ROS and RNS signaling cascades is pivotal for improving crop function within a context of limited nutrient resources and harsher climatological conditions.

Overexpression of a SBP-Box Gene (VpSBP16) from Chinese Wild Vitis Species in Arabidopsis Improves Salinity and Drought Stress Tolerance.

Salinity and drought are two major abiotic stresses that limit grape productivity. Responses to stress in grape are known to be regulated by several families of transcription factors. However, little is known about the role of grape Squamosa promoter binding protein (SBP)-box transcription factor genes in response to abiotic stress. To better understand the functions of the grape SBP-box genes in abiotic stress tolerance, a full-length complementary DNA (cDNA) sequence of the putative SBP-box transcription factor gene, VpSBP16 was amplified from Chinese wild grapevine Vitis pseudoreticulata clone “Baihe-35-1”. We observed that the VpSBP16 protein fused to the green fluorescent protein (GFP) reporter accumulated in the nucleus when transiently expressed in onion epidermal cells. Moreover, VpSBP16 was shown to have transcriptional activation activity using a yeast trans-activation assay. We performed a VpSBP16 functional analysis through the characterization of transgenic Arabidopsis thaliana plants constitutively over-expressing VpSBP16. The transgenic lines had longer roots and the seeds had a higher germination rate than the wild type (WT) under osmotic stress. In addition, the accumulation of reactive oxygen species (ROS) of transgenic seedlings was significantly lower than WT in the transgenic lines, as was electrolyte leakage. VpSBP16 overexpression also elevated expression levels of stress-response genes involved in the salt overly sensitive (SOS) pathway. These results indicate that overexpression VpSBP16 in A. thaliana enhances tolerance of salt and drought stress during seed germination, as well in seedlings and mature plants, by regulating SOS and ROS signaling cascades.

Microglial peroxiredoxin V acts as an inducible anti‐inflammatory antioxidant through cooperation with redox signaling cascades

Reactive oxygen species (ROS) actively participate in microglia-mediated pathogenesis as pro-inflammatory molecules. However, little is known about the involvement of specific antioxidants in maintaining the microglial oxidative balance. We demonstrate that microglial peroxiredoxin (Prx) 5 expression is up-regulated by lipopolysaccharide (LPS) through activation of the ROS-sensitive signaling pathway and is involved in attenuation of both microglial activation and nitric oxide (NO) generation. Unlike in stimulation of oxidative insults with paraquat and hydrogen peroxide, Prx V expression is highly sensitive to LPS-stimulation in microglia. Reduction of ROS level by treatment with either NADPH oxidase inhibitor or antioxidant ablates LPS-mediated Prx V up-regulation in BV-2 microglial cells and is closely associated with the activation of the c-jun N-terminal kinase (JNK) signaling pathway. This suggests the involvement of ROS/JNK signaling in LPS-mediated Prx V induction. Furthermore, NO induces Prx V up-regulation that is ablated by the addition of inducible nitric oxide synthase inhibitor or deleted mutation of inducible nitric oxide synthase in LPS-stimulated microglia. Therefore, these results suggest that Prx V is induced by cooperative action among the ROS, RNS, and JNK signaling cascades. Interestingly, knockdown of Prx V expression causes the acceleration of microglia activation, including augmented ROS generation and JNK-dependent NO production. In summary, we demonstrate that Prx V plays a key role in the microglial activation process through modulation of the balance between ROS/NO generation and the corresponding JNK cascade activation.

Reactive oxygen species involved in prenylflavonoids, icariin and icaritin, initiating cardiac differentiation of mouse embryonic stem cells

The significant promoting effects of some prenylflavonoids on cardiac differentiation of mouse embryonic stem (ES) cells via reactive oxygen species (ROS) signaling pathway were investigated. The most effective differentiation was facilitated by icariin (ICA), followed by icaritin (ICT), while desmethylicaritin (DICT) displayed the weakest but still significant inducible effect. Contrarily, DICT demonstrated the strongest anti-oxidative activity while ICA displayed only little in vitro, which was well matched with the hydroxyl (OH) numbers and the positions in the molecular structures. Therefore, ROS signaling cascades were assumed to be involved in prenylflavonoids induced cardiomyogenesis. Treatment with ICA, intracellular ROS in embryoid bodies was rapidly elevated, which was abolished by the NADPH-oxidase inhibitor apocynin; elimination of intracellular ROS by vitamin E or pyrrolidine dithiocarbamate (PDTC) inhibited ICA induced cardiomyogenesis; ROS-sensitive extracellular-regulated kinase 1, 2 (ERK1, 2) and p38 activation were further observed, the cardiomyogenesis was significantly inhibited in the presence of ERK1, 2 or p38 inhibitor U0126 or SB203580, indicating the roles of NADPH-ROS-MAPKs signaling cascades in prenylflavonoids induced cardiac differentiation. There was no difference in Nox4 NADPH oxidase expression between ICA and ICT treatments, however, ROS concentration in EBs after ICT administration was lower than that after ICA treatment, followed by less activation of ERK1, 2, and p38. These results revealed that the significant promoting effects of prenylflavonoids on cardiac differentiation was at least partly via ROS signaling cascades, and the facilitating abilities preferentially based on the nature of prenylflavonoids themselves, but anti-oxidative activity determined by the OH numbers and the positions in the structures do influence the cardiomyogenesis in vitro.