The Salt Tolerance-Related Protein (STRP) Is a Positive Regulator of the Response to Salt Stress in Arabidopsis thaliana

: Salt stress is a major abiotic stress limiting plant survival and crop productivity. Plant adaptation to salt stress involves complex responses, including changes in gene expression, regulation of hormone signaling, and production of stress-responsive proteins. The Salt Tolerance-Related Protein (STRP) has been recently characterized as a Late Embryogenesis Abundant (LEA)-like, intrinsically disordered protein involved in plant responses to cold stress. In addition, STRP has been proposed as a mediator of salt stress response in Arabidopsis thaliana, but its role has still to be fully clarified. Here, we investigated the role of STRP in salt stress responses in A. thaliana. The protein rapidly accumulates under salt stress due to a reduction of proteasome-mediated degradation. Physiological and biochemical responses of the strp mutant and STRP-overexpressing (STRP OE) plants demonstrate that salt stress impairs seed germination and seedling development more markedly in the strp mutant than in A. thaliana wild type (wt). At the same time, the inhibitory effect is significantly reduced in STRP OE plants. Moreover, the strp mutant has a lower ability to counteract oxidative stress, cannot accumulate the osmocompatible solute proline, and does not increase abscisic acid (ABA) levels in response to salinity stress. Accordingly, the opposite effect was observed in STRP OE plants. Overall, obtained results suggest that STRP performs its protective functions by reducing the oxidative burst induced by salt stress, and plays a role in the osmotic adjustment mechanisms required to preserve cellular homeostasis. These findings propose STRP as a critical component of the response mechanisms to saline stress in A. thaliana

14-3-3 proteins and the plasma membrane H+-ATPase are involved in maize (Zea mays) magnetic induction

The geomagnetic field (GMF) is a natural component of the biosphere, and, during evolution, all organisms experienced its presence while some evolved the ability to perceive magnetic fields (MF). We studied the response of 14-3-3 proteins and the plasma membrane (PM) proton pump H+-ATPase to reduced GMF values by lowering the GMF intensity to a near-null magnetic field (NNMF). Seedling morphology, H+-ATPase activity and content, 14-3-3 protein content, binding to PM and phosphorylation, gene expression, and ROS quantification were assessed in maize (Zea mays) dark-grown seedlings. Phytohormone and melatonin quantification were also assessed by LG-MS/MS. Our results suggest that the GMF regulates the PM H+-ATPase, and that NNMF conditions alter the proton pump activity by reducing the binding of 14-3-3 proteins. This effect was associated with both a reduction in H2O2 and downregulation of genes coding for enzymes involved in ROS production and scavenging, as well as calcium homeostasis. These early events were followed by the downregulation of IAA synthesis and gene expression and the increase in both cytokinin and ABA, which were associated with a reduction in root growth. The expression of the homolog of the MagR gene, ZmISCA2, paralleled that of CRY1, suggesting a possible role of ISCA in maize magnetic induction. Interestingly, melatonin, a widespread molecule present in many kingdoms, was increased by the GMF reduction, suggesting a still unknown role of this molecule in magnetoreception

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Cold stress affects H+-ATPase and phospholipase D activity in Arabidopsis

Low temperature is an environmental stress that greatly influences plant performance and distribution. Plants exposed to cold stress exhibit modifications of plasma membrane physical properties that can affect their functionality. Here it is reported the effect of low temperature exposure of Arabidopsis plants on the activity of phospholipase D and H+-ATPase, the master enzyme located at the plasma membrane. The H+-ATPase activity was differently affected, depending on the length of cold stress imposed. In particular, an exposure to 4 °C for 6 h determined the strong inhibition of the H+-ATPase activity, that correlates with a reduced association with the regulatory 14-3-3 proteins. A longer exposure first caused the full recovery of the enzymatic activity followed by a significant activation, in accordance with both the increased association with 14-3-3 proteins and induction of H+-ATPase gene transcription. Different time lengths of cold stress treatment were also shown to strongly stimulate the phospholipase D activity and affect the phosphatidic acid levels of the plasma membranes. Our results suggest a functional correlation between the activity of phospholipase D and H+-ATPase mediated by phosphatidic acid release during the cold stress response

14-3-3 Proteins in Plant Hormone Signaling: Doing Several Things at Once

In this review we highlight the advances achieved in the investigation of the role of 14-3-3 proteins in hormone signaling, biosynthesis, and transport. 14-3-3 proteins are a family of conserved molecules that target a number of protein clients through their ability to recognize well-defined phosphorylated motifs. As a result, they regulate several cellular processes, ranging from metabolism to transport, growth, development, and stress response. High-throughput proteomic data and two-hybrid screen demonstrate that 14-3-3 proteins physically interact with many protein clients involved in the biosynthesis or signaling pathways of the main plant hormones, while increasing functional evidence indicates that 14-3-3-target interactions play pivotal regulatory roles. These advances provide a framework of our understanding of plant hormone action, suggesting that 14-3-3 proteins act as hubs of a cellular web encompassing different signaling pathways, transducing and integrating diverse hormone signals in the regulation of physiological processes

Fungal phytotoxin fusicoccin for the treatmant and diagnosis of coagulation-correlated pathologies.

Fusicoccin is a fungal phytotoxin known to induce a strong and permanent activation of the plant plasma membrane H+-ATPase. Fusicoccin promotes the association of 14-3-3 proteins to a mode III binding motif located at the C-terminal end of the enzyme. Here we show that fusicoccin can stimulate binding of 14-3-3 proteins to the platelet protein Glycoprotein Ib, which also contains a mode III 14-3-3 binding sequence. Glycoprotein Ib is the platelet receptor for von Willebrand Factor and it is essential in the first step of the coagulation process. Fusicoccin binding promotes activation of Glycoprotein Ib and consequent adhesion of platelets to von Willebrand Factor, therefore triggering the aggregation process. Our data propose fusicoccin as a novel compound able to induce platelet aggregation. Therapeutic implications of this finding are also discussed

Spodoptera littoralis oral secretions inhibit the activity of Phaseolus lunatus plasma membrane H+-ATPase.

Biotic stresses induced by herbivores result in diverse physiological changes in plants. In the interaction between the Lima bean (Phaseolus lunatus) and the herbivore Spodoptera littoralis, the earliest event induced by feeding on leaves is the depolarization of the plasma membrane potential (Vm), which is the results of both mechanical damage and insect oral secretions (OS). Although this herbivore-induced Vm depolarization depends on a calcium-dependent opening of potassium channels, the attacked leaf remains depolarized for an extended period, which cannot be explained by the sole action of potassium channels. Here we show that the plasma membrane H+-ATPase of P. lunatus leaves is strongly inhibited by S. littoralis OS. Inhibition of the H+-ATPase was also found in plasma membranes purified from leaf sections located distally from the application zone of OS, thus suggesting a long-distance transport of a signaling molecule(s). S. littoralis' OS did not influence the amount of the plasma membrane H+-ATPase, whereas the levels of membrane-bound 14-3-3 proteins were significantly decreased in membranes purified from treated leaves. Furthermore, OS strongly reduced the in vitro interaction between P. lunatus H+-ATPase and 14-3-3 proteins. The results of this work demonstrate that inhibition of the plasma membrane H+-ATPase is a key component of the S. littoralis OS mechanism leading to an enduring Vm depolarization in P. lunatus wounded leaves