Bedside Diagnosis for Disseminated Deep Dermatophytosis: a Case Series Study

Mycopathologia - Deep cutaneous fungal infections including deep dermatophytosis are responsible for significant morbidity and mortality, especially in immunocompromised patients. Variable and...     

Development of molecular markers based on CRa gene sequencing of different clubroot disease-resistant cultivars of Chinese cabbage

Background

CRa is a key gene in Chinese cabbage (Brassica rapa ssp. pekinensis) that confers resistance to Plasmodiophora brassicae. In order to efficiently screen the clubroot resistance (CR) gene CRa in breeding, two functional codominant markers of the CRa gene were developed.

Methods and results

In this study, through comparing the CRa allele sequences in resistant and susceptible cultivars of Chinese cabbage, we found two insertion and deletion of sequence variations in the fourth exon between resistant and susceptible cultivars. Two functional codominant markers for CRa gene were obtained based on the variations, namely, CRaEX04-1 and CRaEX04-3. The lengths of the extended fragment of CRaEX04-1 marker were 321 bp and 186 bp in resistant and susceptible cultivars, respectively. In contrast, those of CRaEX04-3 were 704 bp and 413 bp, respectively. We verified the genetic stability between the developed markers and CRa gene using 57 Chinese cabbage cultivars with known resistance and two genetic populations. The results showed that the marker identification was completely consistent with the known phenotypes in 57 cultivars. The marker identification results followed the 3:1 of Mendel’s first law in the F₂ population, and the 1:1 of Mendel’s first law in the BC₁.

Conclusions

CRaEX04-1 and CRaEX04-3 can be used as a practical molecular marker for breeding and germplasm resource creation of clubroot disease-resistant Chinese cabbage.

     

BRD4 inhibition by JQ1 protects against LPS-induced cardiac dysfunction by inhibiting activation of NLRP3 inflammasomes

Molecular Biology Reports - JQ1, a BRD4 inhibitor, first identified its therapeutic role in cancer, has gradually demonstrated a protective effect on the heart in recent years; however, it is...     

microRNA-21-5p from M2 macrophage-derived extracellular vesicles promotes the differentiation and activity of pancreatic cancer stem cells by mediating KLF3

Cell Biology and Toxicology - Given the fact that tumor-associated macrophage-derived extracellular vesicles (EVs) are attributable to tumor aggressiveness, this research intends to decode the...     

Silencing TRPM2 enhanced erastin- and RSL3-induced ferroptosis in gastric cancer cells through destabilizing HIF-1α and Nrf2 proteins

Cytotechnology - Ferroptosis is a regulated form of cell death driven by small molecules or conditions that induce lipid-based reactive oxygen species (ROS) accumulation. Cation channel transient...     

Modulation of α7nAchR by Melatonin Alleviates Ischemia and Reperfusion-Compromised Integrity of Blood–Brain Barrier Through Inhibiting HMGB1-Mediated Microglia Activation and CRTC1-Mediated Neuronal Loss

Cellular and Molecular Neurobiology - The only food and drug administration (FDA)-approved drug currently available for the treatment of acute ischemic stroke is tissue plasminogen activator (tPA),...     

Auxin Resistant1 and PIN-FORMED2 Protect Lateral Root Formation in Arabidopsis under Iron Stress

A stunted root system is a significant symptom of iron (Fe) toxicity, yet little is known about the effects of excess Fe on lateral root (LR) development. In this work, we show that excess Fe has different effects on LR development in different portions of the Arabidopsis (Arabidopsis thaliana) root system and that inhibitory effects on the LR initiation are only seen in roots newly formed during excess Fe exposure. We show that root tip contact with Fe is both necessary and sufficient for LR inhibition and that the auxin, but not abscisic acid, pathway is engaged centrally in the initial stages of excess Fe exposure. Furthermore, Fe stress significantly reduced PIN-FORMED2 (PIN2)-green fluorescent protein (GFP) expression in root tips, and pin2-1 mutants exhibited significantly fewer LR initiation events under excess Fe than the wild type. Exogenous application of both Fe and glutathione together increased PIN2-GFP expression and the number of LR initiation events compared with Fe treatment alone. The ethylene inhibitor aminoethoxyvinyl-glycine intensified Fe-dependent inhibition of LR formation in the wild type, and this inhibition was significantly reduced in the ethylene overproduction mutant ethylene overproducer1-1. We show that Auxin Resistant1 (AUX1) is a critical component in the mediation of endogenous ethylene effects on LR formation under excess Fe stress. Our findings demonstrate the relationship between excess Fe-dependent PIN2 expression and LR formation and the potential role of AUX1 in ethylene-mediated LR tolerance and suggest that AUX1 and PIN2 protect LR formation in Arabidopsis during the early stages of Fe stress.Iron (Fe) is an essential trace element for plants (Pilon et al., 2009), and species differ greatly in how much Fe they require for optimal growth (Wheeler and Power, 1995; Batty and Younger, 2003). As Fe is frequently limiting, Fe deficiency is more commonly studied than toxicity arising from excess Fe exposure (Lei et al., 2014; Bashir et al., 2015; Briat et al., 2015). Fe is also a major focus for efforts in biofortification by targeting Fe transporters (Zhai et al., 2014; Pinto and Ferreira, 2015). However, the excessive presence of Fe in soils is equally common, in particular in soils characterized by low pH and hypoxic or anoxic conditions (Connolly and Guerinot, 2002). Toxicity arising from excess Fe exposure is recognized as one of the major plant diseases attributable to abiotic factors that impact the development and yield potential in the world’s leading cereal crops, rice (Oryza sativa) and wheat (Triticum aestivum; Becker and Asch, 2005; Khabaz-Saberi et al., 2012). Understanding the mechanisms underlying excess Fe toxicity is therefore essential.Plastic responses in the plant’s root system architecture are known to constitute a major mechanism by which plants cope with fluctuating environments. Lateral roots (LRs), which typically comprise the majority of the root system, contribute pivotally to nutrient acquisition from soil, and modulating LR development is a very important avoidance strategy for plants when confronted with unfavorable edaphic conditions, such as high salinity or heavy metals (Ivanov et al., 2003). In the case of excess exposure to Fe, stunting of the root system is among the chief symptoms of toxicity (Becker and Asch, 2005). However, while some information has been emerging on the primary root axis (Li et al., 2015), the specific role of the plant’s LR apparatus remains poorly studied. Yamauchi and Peng (1995) reported retardation of root growth and a reduction in LR length and number under excess Fe conditions. Recently, Reyt et al. (2015) showed that excess Fe had no significant effect on LR initiation in the LR branching zone and that ferritins play an important role in LR emergence under excess Fe in this portion of the root, although the authors had not investigated LR development in the root portions near the growing tip of the primary root. Because LR initiation is restricted to specific pericycle cell files adjacent to a xylem pole in the basal region of the meristem (De Smet et al., 2007; Fukaki and Tasaka, 2009), and LR formation in this new growing root portion may be more susceptible to stress stimuli, such as observed with exposure to high NH₄⁺ and salt (Duan et al., 2013; Li et al., 2013), it is reasonable to suggest that modulation of LR formation near the growing tip of the primary root is critical to the response to excess Fe stress.In Arabidopsis (Arabidopsis thaliana), the development of LRs proceeds through the following stages: lateral root primordia (LRP) initiation, establishment, emergence, activation into mature LRs, and final maintenance of LR elongation (Fukaki and Tasaka, 2009; Péret et al., 2009). The hormones abscisic acid (ABA) and auxin are important internal negative and positive regulators during LR development, respectively (Fukaki and Tasaka, 2009). ABA has been implicated in LRP emergence and meristem activation independent of auxin (De Smet et al., 2003). Auxin is an important internal positive regulator during LR development (Fukaki and Tasaka, 2009), and auxin transport is critical (Blilou et al., 2005). Mutants in auxin efflux carriers such as PIN-FORMED (PIN) and P-Glycoprotein show significant defects in LR formation (Fukaki and Tasaka, 2009; Péret et al., 2009). For example, LR initiation frequency was significantly reduced in pin2 and pin3 mutants (Dubrovsky et al., 2009), and PIN2 was also shown to be involved in exogenous and endogenous signal-mediated LR development (by brassinosteroid, jasmonate, and fungal challenge; Li et al., 2005; Felten et al., 2009; Sun et al., 2009). Similarly, Auxin Resistant1 (AUX1), an auxin influx carrier, also regulates LRP positioning and initiation (De Smet et al., 2007). While both AUX1 and PIN2 are required specifically for the basipetal transport of auxin through the outer root cell layers (Fukaki and Tasaka, 2009), PIN1 localized at the basal end of vascular cells is responsible for direct acropetal auxin flow in the root stele (Blilou et al., 2005). Recently, the roles of ethylene on LR development have also been highlighted, and the ethylene-mediated LR formation is dependent on the auxin pathway (Ivanchenko et al., 2008; Lewis et al., 2011). Ethylene treatment could mediate fluorescence of AUX1 and PIN2 fluorescent protein fusions at the root tip (Růzicka et al., 2007; Lewis et al., 2011). Although ABA, auxin, and ethylene signals have been implicated as important for LR development, it is not known whether and how the three hormones are involved in the response of LR formation to Fe stress.The previously described phenotypes and physiological processes related to Fe toxicity do not clarify the effect of excess Fe on LR formation. In this study, we employed the Arabidopsis wild type and ABA-, auxin-, and ethylene-related mutants to explore the LR formation response to Fe toxicity and to elucidate the roles of ABA, auxin, and ethylene. Potential mechanisms involved in the early stress response to Fe stress are discussed.     

Genome-Wide Association of Carbon and Nitrogen Metabolism in the Maize Nested Association Mapping Population

Carbon (C) and nitrogen (N) metabolism are critical to plant growth and development and are at the basis of crop yield and adaptation. We performed high-throughput metabolite analyses on over 12,000 samples from the nested association mapping population to identify genetic variation in C and N metabolism in maize (Zea mays ssp. mays). All samples were grown in the same field and used to identify natural variation controlling the levels of 12 key C and N metabolites, namely chlorophyll a, chlorophyll b, fructose, fumarate, glucose, glutamate, malate, nitrate, starch, sucrose, total amino acids, and total protein, along with the first two principal components derived from them. Our genome-wide association results frequently identified hits with single-gene resolution. In addition to expected genes such as invertases, natural variation was identified in key C₄ metabolism genes, including carbonic anhydrases and a malate transporter. Unlike several prior maize studies, extensive pleiotropy was found for C and N metabolites. This integration of field-derived metabolite data with powerful mapping and genomics resources allows for the dissection of key metabolic pathways, providing avenues for future genetic improvement.Carbon (C) and nitrogen (N) metabolism are the basis for life on Earth. The production, balance, and tradeoffs of C and N metabolism are critical to all plant growth, yield, and local adaptation (Coruzzi and Bush, 2001; Coruzzi et al., 2007). In plants, there is a critical balance between the tissues that are producing energy (sources) and those using it (sinks), as the identities and locations of these vary through time and developmental stage (Smith et al., 2004). While a great deal of research has focused on the key genes and proteins involved in these processes (Wang et al., 1993; Kim et al., 2000; Takahashi et al., 2009), relatively little is known about the natural variation within a species that fine-tunes these processes in individual plants.In addition, a key aspect of core C metabolism involves the nature of plant photosynthesis. While the majority of plants use standard C₃ photosynthetic pathways, some, including maize (Zea mays) and many other grasses, use C₄ photosynthesis to concentrate CO₂ in bundle sheath cells to avoid wasteful photorespiration (Sage, 2004). Under some conditions (such as drought or high temperatures), C₄ photosynthesis is much more efficient than C₃ photosynthesis. Since these conditions are expected to become more prevalent in the near future due to climate change, various research groups are working to convert C₃ crop species to C₄ metabolism in order to boost crop production and food security (Sage and Zhu, 2011). Beyond this, better understanding of both C₃ and C₄ metabolic pathways will aid efforts to breed crops for superior yield, N-use efficiency, and other traits important for global food production.In the last two decades, quantitative trait locus (QTL) mapping, first with linkage analysis and later with association mapping, has been used to dissect C and N metabolism in several species, including Arabidopsis (Arabidopsis thaliana; Mitchell-Olds and Pedersen, 1998; Keurentjes et al., 2008; Lisec et al., 2008; Sulpice et al., 2009), tomato (Solanum lycopersicum; Schauer et al., 2006), and maize (Hirel et al., 2001; Limami et al., 2002; Zhang et al., 2006, 2010a, 2010b). These studies identified key genetic regions underlying variation in core C and N metabolism, many of which include candidate genes known to be involved in these processes.Previous studies of genetic variation for C and N metabolism are limited by the fact that they identified trait loci only through linkage mapping in artificial families or through association mapping across populations of unrelated individuals. Linkage mapping benefits from high statistical power due to many individuals sharing the same genotype at any given location, but it suffers from low resolution due to the limited number of generations (and hence recombination events) since the initial founders. Association mapping, in turn, enjoys high resolution due to the long recombination histories of natural populations but suffers from low power, since most genotypes occur in only a few individuals. In addition, many of these studies focused on C and N in artificial settings (e.g. greenhouses or growth chambers) instead of field conditions, running the risk that important genetic loci could be missed if the conditions do not include important (and potentially unknown) natural environmental variables.To address these issues and improve our understanding of C and N metabolism in maize, we used a massive and diverse germplasm resource, the maize nested association mapping (NAM) population (Buckler et al., 2009; McMullen et al., 2009), to evaluate genetic variation underlying the accumulation of 12 targeted metabolites in maize leaf tissue under field conditions. This population was formed by mating 25 diverse maize lines to the reference line, B73, and creating a 200-member biparental family from each of these crosses. The entire 5,000-member NAM population thus combines the strengths of both linkage and association mapping (McMullen et al., 2009), and it has been used to identify QTLs for important traits such as flowering time (Buckler et al., 2009), disease resistance (Kump et al., 2011; Poland et al., 2011), and plant architecture (Tian et al., 2011; Peiffer et al., 2013). Most importantly, this combination of power and resolution frequently resolves associations down to the single-gene level, even when using field-based data.The metabolites we profiled are key indicators of photosynthesis, respiration, glycolysis, and protein and sugar metabolism in the plant (Sulpice et al., 2009). By taking advantage of a robotized metabolic phenotyping platform (Gibon et al., 2004), we performed more than 100,000 assays across 12,000 samples, with two independent samples per experimental plot. Raw data and the best linear unbiased predictors (BLUPs) of these data were included as part of a study of general functional variation in maize (Wallace et al., 2014), but, to our knowledge, this is the first in-depth analysis of these metabolic data. We find strong correlations among several of the metabolites, and we also find extensive pleiotropy among the different traits. Many of the top QTLs are also near or within candidate genes relating to C and N metabolism, thus identifying targets for future breeding and selection. These results provide a powerful resource for those working with core C and N metabolism in plants and for improving maize performance in particular.