Transcriptional and biochemical analyses of Planomicrobium strain AX6 from Qinghai-Tibetan Plateau, China, reveal hydrogen peroxide scavenging potential.

BACKGROUND: The bacterial mechanisms responsible for hydrogen peroxide (H2O2) scavenging have been well-reported, yet little is known about how bacteria isolated from cold-environments respond to H2O2 stress. Therefore, we investigated the transcriptional profiling of the Planomicrobium strain AX6 strain isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China, in response to H2O2 stress aiming to uncover the molecular mechanisms associated with H2O2 scavenging potential. METHODS: We investigated the H2O2-scavenging potential of the bacterial Planomicrobium strain AX6 isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China. Furthermore, we used high-throughput RNA-sequencing to unravel the molecular aspects associated with the H2O2 scavenging potential of the Planomicrobium strain AX6 isolate. RESULTS: In total, 3,427 differentially expressed genes (DEGs) were identified in Planomicrobium strain AX6 isolate in response to 4 h of H2O2 (1.5 mM) exposure. Besides, Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analyses revealed the down- and/or up-regulated pathways following H2O2 treatment. Our study not only identified the H2O2 scavenging capability of the strain nevertheless also a range of mechanisms to cope with the toxic effect of H2O2 through genes involved in oxidative stress response. Compared to control, several genes coding for antioxidant proteins, including glutathione peroxidase (GSH-Px), Coproporphyrinogen III oxidase, and superoxide dismutase (SOD), were relatively up-regulated in Planomicrobium strain AX6, when exposed to H2O2. CONCLUSIONS: Overall, the results suggest that the up-regulated genes responsible for antioxidant defense pathways serve as essential regulatory mechanisms for removing H2O2 in Planomicrobium strain AX6. The DEGs identified here could provide a competitive advantage for the existence of Planomicrobium strain AX6 in H2O2-polluted environments.

Novel insights into host receptors and receptor-mediated signaling that regulate arbuscular mycorrhizal symbiosis.

More than 80% of land plant species benefit from symbiotic partnerships with arbuscular mycorrhizal (AM) fungi, which assist in nutrient acquisition and enhance the ability of host plants to adapt to environmental constraints. Host-generated plasma membrane-residing receptor-like kinases and the intracellular α/ß-hydrolase DWARF14-LIKE, a putative karrikin receptor, detect the presence of AM fungi before physical contact between the host and fungus. Detection induces appropriate symbiotic responses, which subsequently enables a favorable environment for AM symbiosis to occur. To prevent hyper-colonization and maintain a mutually beneficial association, the host plant precisely monitors and controls AM colonization by receptor-like kinases, such as SUPER NUMERIC NODULES. Previous studies have elucidated how host plant receptors and receptor-mediated signaling regulate AM symbiosis, but the underlying molecular mechanisms remain poorly understood. The identification of a rice CHITIN ELICITOR RECEPTOR KINASE 1 interaction partner, MYC FACTOR RECEPTOR 1, and new insights into DWARF14-LIKE receptor- and SUPER NUMERIC NODULES receptor-mediated signaling have expanded our understanding of how host plant receptors and their corresponding signals regulate AM symbiosis. This review summarizes these and other recent relevant findings. The identified receptors and/or their signaling components could be manipulated to engineer crops with improved agronomic traits by conferring the ability to precisely control AM colonization.

Bacterial diversity patterns of desert dunes in the northeastern Qinghai-Tibet Plateau, China.

Limited knowledge about the variation patterns of bacterial community composition in the sand and vegetative ecosystems confines our understanding regarding the contribution of the sand dune to desert areas. In this study, 454 pyrosequencing platforms were adopted to determine the community structure of bacteria and diversity of sand dunes in northeastern Qinghai-Tibet Plateau, China: 50 cm deep, rhizosphere, physical crusts, and biological crusts representing sand and vegetative ecosystems, respectively. The findings revealed significant variation in bacterial diversities and the structure of communities in the sand and vegetative ecosystems. The dominant bacterial phyla of sand and vegetative ecosystems were Firmicutes (47%), Actinobacteria (21%), Proteobacteria (16%), and Bacteroidetes (13%), while Lactococcus (50%) was found to be the dominant genus. Furthermore, samples with high alpha-diversity indices (Chao 1 and Shannon) for the vegetative ecosystem have the lowest modularity index and the largest number of biomarkers, with some exceptions. Redundancy analysis exhibited that environmental factors could explain 72% (phyla) and 67% (genera) of the bacterial communities, with EC, TC, and TOC being the major driving factors. This study expands our understanding of bacterial community composition in the desert ecosystem. The findings suggest that variations in the sand and vegetative ecosystems, such as those predicted by environmental factors, may reduce the abundance and diversity of bacteria, a response that likely affects the provision of key ecosystem processes by desert regions.

Impacts of replanting American ginseng on fungal assembly and abundance in response to disease outbreaks.

Soil physicochemical properties and fungal communities are pivotal factors for continuous cropping of American ginseng (Panax quinquefolium L.). However, the response of soil physicochemical properties and fungal communities to replant disease of American ginseng has not yet been studied. High-throughput sequencing and soil physicochemical analyses were undertaken to investigate the difference of soil fungal communities and environmental driver factors in new and old ginseng fields; the extent of replant disease in old ginseng fields closely related to changes in soil properties and fungal communities was also determined. Results indicated that fungal communities in an old ginseng field were more sensitive to the soil environment than those in a new ginseng field, and fungal communities were mainly driven by soil organic matter (SOM), soil available phosphorus (AP), and available potassium (AK). Notably, healthy ginseng plants in new and old ginseng fields may influence fungal communities by actively recruiting potential disease suppressive fungal agents such as Amphinema, Cladophialophora, Cadophora, Mortierella, and Wilcoxina. When these key groups and members were depleted, suppressive agents in the soil possibly declined, increasing the abundance of pathogens. Soil used to grow American ginseng in the old ginseng field contained a variety of fungal pathogens, including Alternaria, Armillaria, Aphanoascus, Aspergillus, Setophoma, and Rhexocercosporidium. Additionally, micro-ecological factors affecting disease outbreaks in the old ginseng field included a strengthening in competition relationships, a weakening in cooperation relationships, and a change of trophic strategies among fungal communities.

Current understanding of pattern-triggered immunity and hormone-mediated defense in rice (Oryza sativa) in response to Magnaporthe oryzae infection.

Plant pathogens represent a huge threat to world food security, affecting both crop production and quality. Although significant progress has been made in improving plant immunity by expressing key, defense-related genes and proteins from different species in transgenic crops, a challenge remains for molecular breeders and biotechnologists to successfully engineer elite, transgenic crop varieties with improved resistance against critical plant pathogens. Upon pathogen attack, including infection of rice (Oryza sativa) by Magnaporthe oryzae, host plants initiate a complex defense response at molecular, biochemical and physiological levels. Plants perceive the presence of pathogens by detecting microbe-associated molecular patterns via pattern recognition receptors, and initiate a first line of innate immunity, the so-called pattern-triggered immunity (PTI). This results in a series of downstream defense responses, including the production of hormones, which collectively function to fend off pathogen attacks. A variety of studies have demonstrated that many genes are involved in the defense response of rice to M. oryzae. In this review, the current understanding of mechanisms that improve rice defense response to M. oryzae will be discussed, with special focus on PTI and the phytohormones ethylene, jasmonic acid, salicylic acid, and abscisic acid; as well as on the mediation of defense signaling mechanisms by PTI and these hormones. Potential target genes that may serve as promising candidates for improving rice immunity against M. oryzae will also be discussed.

Optimal Duration of Aspirin Plus Clopidogrel After Ischemic Stroke or Transient Ischemic Attack.

Background and Purpose- The role of aspirin plus clopidogrel (A+C) therapy compared with aspirin monotherapy in patients presenting with acute ischemic stroke (IS) or transient ischemic attack remains uncertain. We conducted this study to determine the optimal period of efficacy and safety of A+C compared with aspirin monotherapy. Methods- Ten randomized controlled trials (15 434 patients) were selected using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) (inception June 2018) comparing A+C with aspirin monotherapy in patients with transient ischemic attack or IS. The primary efficacy outcome was recurrent IS, and the primary safety outcome was major bleeding. The secondary outcomes were major adverse cardiovascular events (composite of stroke, myocardial infarction, and cardiovascular mortality) and all-cause mortality. We stratified analysis based on the short- (≤1 month), intermediate- (≤3 month), and long-term (>3 month) A+C therapy. Effects were estimated as relative risk (RR) with 95% CI. Results- A+C significantly reduced the risk of recurrent IS at short-term (RR, 0.53; 95% CI, 0.37-0.78) and intermediate-term (RR, 0.72; 95% CI, 0.58-0.90) durations. Similarly, major adverse cardiovascular event was significantly reduced by short-term (RR, 0.68; 95% CI, 0.60-0.78) and intermediate-term (RR, 0.76; 95% CI, 0.61-0.94) A+C therapy. However, long-term A+C did not yield beneficial effect in terms of recurrent IS (RR, 0.81; 95% CI, 0.63-1.04) and major adverse cardiovascular events (RR, 0.87; 95% CI, 0.71-1.07). Intermediate-term (RR, 2.58; 95% CI, 1.19-5.60) and long-term (RR, 1.87; 95% CI, 1.36-2.56) A+C regimens significantly increased the risk of major bleeding as opposed to short-term A+C (RR, 1.82; 95% CI, 0.91-3.62). Excessive all-cause mortality was limited to long-term A+C (RR, 1.45; 95% CI, 1.10-1.93). Conclusions- Short-term A+C is more effective and equally safe in comparison to aspirin alone in patients with acute IS or transient ischemic attack.

Comparative analysis of the rhizomicrobiome of the wild versus cultivated crop: insights from rice and soybean.

Plant domestication was a pivotal accomplishment in human history, which led to a reduction in genetic diversity of crop species; however, there was less research focus on how this reduced genetic diversity of crops in affecting rhizosphere microbial communities during crop domestication process. Here, we used high-throughput sequencing to explore the different effects of crops domestication on rhizosphere microbial community structure of rice (Oryza sativa L. and Oryza rufipogon Griff.) and soybean (Glycine max L. and Glycine soja Sieb. et Zucc.). Results indicated that rhizosphere fungal communities are more strongly influenced by crop domestication than bacterial communities. There was a stronger relationship for fungi and bacteria in the cultivated crops than in the wild relatives. Results also showed that the wild varieties had a higher abundance of beneficial symbionts and a lower abundance of pathogens comparing with the cultivated varieties. There was a similar tendency for both rice and soybean in rhizosphere microbial communities by comparing wild crops and their cultivated varieties. In conclusion, crop domestication had a stronger effect on the fungal communities than on the bacterial communities and had improved the microbial relationship in rhizosphere of cultivated crops.

The rhizomicrobiomes of wild and cultivated crops react differently to fungicides.

The fungicides used to control diseases in cereal production can have adverse effects on non-target microbial communities, with possible consequences for plant health and productivity. Although we know that fungicides affect microbial community structure and soil activities, it is unclear how crop cultivars have altered the impact of fungicides on rhizomicrobiomes. In this study, the rhizosphere bacterial and fungal communities and structures of cultivated crops and their wild relatives were studied by Illumina MiSeq sequencing analysis. The results indicated that the rhizomicrobiome communities of wild crops reacted more strongly to fungicides than that of their cultivated relatives. Furthermore, fungal community composition was more affected by fungicides than bacterial community composition. Remarkably, the same trend was observed in both soybean and rice with regard to the influence of crop cultivar on the response of the rhizomicrobiome to fungicide application, although the level of the response was not similar. We report for the first time that the rhizomicrobiomes of wild crops reacted more strongly to fungicides than the rhizomicrobiomes of cultivated crops.

Differential responses of molecular mechanisms and physiochemical characters in wild and cultivated soybeans against invasion by the pathogenic Fusarium oxysporum Schltdl.

Cultivated soybean (Glycine max) was derived from the wild soybean (Glycine soja), which has genetic resources that can be critically important for improving plant stress resistance. However, little information is available pertaining to the molecular and physiochemical comparison between the cultivated and wild soybeans in response to the pathogenic Fusarium oxysporum Schltdl. In this study, we first used comparative phenotypic and paraffin section analyses to indicate that wild soybean is indeed more resistant to F. oxysporum than cultivated soybean. Genome-wide RNA-sequencing approach was then used to elucidate the genetic mechanisms underlying the differential physiological and biochemical responses of the cultivated soybean, and its relative, to F. oxysporum. A greater number of genes related to cell wall synthesis and hormone metabolism were significantly altered in wild soybean than in cultivated soybean under F. oxysporum infection. Accordingly, a higher accumulation of lignins was observed in wild soybean than cultivated soybean under F. oxysporum infection. Collectively, these results indicated that secondary metabolites and plant hormones may play a vital role in differentiating the response between cultivated and wild soybeans against the pathogen. These important findings may provide future direction to breeding programs to improve resistance to F. oxysporum in the elite soybean cultivars by taking advantage of the genetic resources within wild soybean germplasm.

Mechanistic Insights into Arbuscular Mycorrhizal Fungi-Mediated Drought Stress Tolerance in Plants.

Arbuscular mycorrhizal fungi (AMF) establish symbiotic interaction with 80% of known land plants. It has a pronounced impact on plant growth, water absorption, mineral nutrition, and protection from abiotic stresses. Plants are very dynamic systems having great adaptability under continuously changing drying conditions. In this regard, the function of AMF as a biological tool for improving plant drought stress tolerance and phenotypic plasticity, in terms of establishing mutualistic associations, seems an innovative approach towards sustainable agriculture. However, a better understanding of these complex interconnected signaling pathways and AMF-mediated mechanisms that regulate the drought tolerance in plants will enhance its potential application as an innovative approach in environmentally friendly agriculture. This paper reviews the underlying mechanisms that are confidently linked with plant-AMF interaction in alleviating drought stress, constructing emphasis on phytohormones and signaling molecules and their interaction with biochemical, and physiological processes to maintain the homeostasis of nutrient and water cycling and plant growth performance. Likewise, the paper will analyze how the AMF symbiosis helps the plant to overcome the deleterious effects of stress is also evaluated. Finally, we review how interactions between various signaling mechanisms governed by AMF symbiosis modulate different physiological responses to improve drought tolerance. Understanding the AMF-mediated mechanisms that are important for regulating the establishment of the mycorrhizal association and the plant protective responses towards unfavorable conditions will open new approaches to exploit AMF as a bioprotective tool against drought.

Root-associated bacterial diversities of Oryza rufipogon and Oryza sativa and their influencing environmental factors.

Oryza rufipogon is the ancestor of human-cultivated Oryza sativa. However, little is known about the difference between the root-associated microorganisms of O. rufipogon and O. sativa. In this study, the root-associated bacteria of O. rufipogon, Leersia hexandra, and O. sativa from different latitudes in China were studied by DGGE analysis. Their bacterial community structures were compared by principal component analysis. The relationship between root-associated bacteria and soil properties was explored by canonical correspondence analysis. The relationships of glomalin-related soil protein (GRSP) content, soluble sugar content, proline content of the plant, and bacterial diversity indices of their root-associated microorganisms were also investigated. We found both broad-spectrum and host-specific bacteria, and the similarity, diversity and abundance indices of O. rufipogon and L. hexandra were higher than O. sativa root-associated bacteria. However, even living in the same habitat, O. rufipogon and L. hexandra selected different root-associated bacteria. Microbial composition was primarily correlated with available N, P, and K and the annual precipitation. We also found a positive correlation between the soluble sugar content of the plant and GRSP content of the root soil. The above results indicated that the community structure of root-associated bacteria differs between wild rice and cultivated rice. Human activity and the natural selection of the host plants shaped the differences, consistent with our hypothesis.

Short- and intermediate-term outcomes of transcatheter aortic valve replacement in low-risk patients: A meta-analysis and systematic review.

Background: Transcatheter aortic valve replacement (TAVR) being currently employed in low surgical risk patients with severe symptomatic aortic stenosis (AS). The durability and extended outcomes of TAVR as compared to surgical aortic valve replacement (SAVR) in low-risk patients remains uncertain. Methods: We selected randomized controlled trials (RCT) comparing outcomes of TAVR vs. SAVR in low surgical risk patients having severe AS using online databases. The primary outcome was all-cause death. The secondary outcomes were composite of all-cause death & disabling stroke, cardiovascular (CV) death, stroke, myocardial infarction (MI), permanent pacemaker (PPM) placement, new onset atrial fibrillation (AF), valve re-intervention and valve thrombosis. The outcomes were stratified at short- (1-year) and intermediate-term (≤5 years) follow-up. We used a random effect model to report outcomes as relative risk (RR) with a 95 % confidence interval (CI). Results: The analysis consisted of six RCTs comprising 5,122 subjects with a mean age of 75.4 years. At short-term follow up, there was a significant reduction in all-cause death (RR: 0.62, 0.46-0.82, p = 0.001) and composite of all-cause death and disabling stroke (RR: 0.62, 0.45-0.83, p = 0.002) in patients undergoing TAVR. At intermediate-term follow-up, there was no significant difference in survival (RR:0.95, 0.73-1.24, p = 0.71) and composite outcome (RR: 0.95, 0.74-1.22, p = 0.71). TAVR patients had lower incidence of new onset AF, however, higher PPM placement. Conclusion: In patients with severe AS having low-surgical risk, patients undergoing TAVR had improved short-term survival as compared to SAVR. This survival advantage was absent at intermediate-term follow-up. The long-term outcomes remain uncertain.

Competitive interactions in two different plant species: Do grassland mycorrhizal communities and nitrogen addition play the same game?

In the Tibetan Plateau grassland ecosystems, nitrogen (N) availability is rising dramatically; however, the influence of higher N on the arbuscular mycorrhizal fungi (AMF) might impact on plant competitive interactions. Therefore, understanding the part played by AMF in the competition between Vicia faba and Brassica napus and its dependence on the N-addition status is necessary. To address this, a glasshouse experiment was conducted to examine whether the grassland AMF community's inocula (AMF and NAMF) and N-addition levels (N-0 and N-15) alter plant competition between V. faba and B. napus. Two harvests took day 45 (1st harvest) and day 90 (2nd harvest), respectively. The findings showed that compared to B. napus, AMF inoculation significantly improved the competitive potential of the V. faba. In the occurrence of AMF, V. faba was the strongest competitor being facilitated by B. napus in both harvests. While under N-15, AMF significantly enhanced tissue N:P ratio in B. napus mixed-culture at 1st harvest, the opposite trend was observed in 2nd harvest. The mycorrhizal growth dependency slightly negatively affected mixed-culture compared to monoculture under both N-addition treatments. The aggressivity index of AMF plants was higher than NAMF plants with both N-addition and harvests. Our observation highlights that mycorrhizal associations might facilitate host plant species in mixed-culture with non-host plant species. Additionally, interacting with N-addition, AMF could impact the competitive ability of the host plant not only directly but also indirectly, thereby changing the growth and nutrient uptake of competing plant species.

Addition of cellulose degrading bacterial agents promoting keystone fungal-mediated cellulose degradation during aerobic composting: Construction the complex co-degradation system.

To excavate a complex co-degradation system for decomposing cellulose more efficiently, cellulose-degrading bacteria, including Bacillus subtilis WF-8, Bacillus licheniformis WF-11, Bacillus Cereus WS-1 and Streptomyces Nogalater WF-10 were added during maize straw and cattle manure aerobic composting. Bacillus and Streptomyces successfully colonized, which improve cellulose degrading ability. Continuous colonization of cellulose-degrading bacteria can promote the fungi to produce more precursors for humus and promote the negative correlation with Ascomycota. In the current study, the addition of cellulose-degrading bacteria has resulted in the rapid development of Mycothermus and Remersonia in the phylum Ascomycota as keystone fungal genera which constitute the foundation of the co-degradation system. Network analysis reveals the complex co-degradation system of efficient cellulose bacteria and mature fungi to treat cellulose in the process of straw aerobic composting mainly related to the influence of total carbon (TC) /total nitrogen (TN) and humic acid (HA)/fulvic acid (FA). This research offers a complex co-degradation system more efficiently to decompose cellulose aiming to maintain the long-term sustainability of agriculture.

The Structure of Rhizosphere Fungal Communities of Wild and Domesticated Rice: Changes in Diversity and Co-occurrence Patterns.

The rhizosphere fungal community affects the ability of crops to acquire nutrients and their susceptibility to pathogen invasion. However, the effects of rice domestication on the diversity and interactions of rhizosphere fungal community still remain largely unknown. Here, internal transcribed spacer amplicon sequencing was used to systematically analyze the structure of rhizosphere fungal communities of wild and domesticated rice. The results showed that domestication increased the alpha diversity indices of the rice rhizosphere fungal community. The changes of alpha diversity index may be associated with the enrichment of Acremonium, Lecythophora, and other specific rare taxa in the rhizosphere of domesticated rice. The co-occurrence network showed that the complexity of wild rice rhizosphere fungal community was higher than that of the domesticated rice rhizosphere fungal community. Arbuscular mycorrhizal fungi (AMF) and soilborne fungi were positively and negatively correlated with more fungi in the wild rice rhizosphere, respectively. For restructuring the rhizomicrobial community of domesticated crops, we hypothesize that microbes that hold positive connections with AMF and negative connections with soilborne fungi can be used as potential sources for bio-inoculation. Our findings provide a scientific basis for reshaping the structure of rhizomicrobial community and furthermore create potential for novel intelligent and sustainable agricultural solutions.

Outbreaks of Root Rot Disease in Different Aged American Ginseng Plants Are Associated With Field Microbial Dynamics.

American ginseng (Panax quinquefolium L.) is a perennial plant that is cultivated for medicinal purposes. Unfortunately, outbreaks of root rot disease in American ginseng (AG) reduce yields and result in serious economic losses. Information on the dynamics of soil microbial communities associated with healthy and diseased AG of different ages is limited. The present study explored the differences in field soil microbial community structure, composition, interaction, and their predictive functions associated with healthy and diseased AG at different growth ages. Changes in soil physicochemical properties were also examined to determine the possible reasons for disease outbreaks. Results revealed that in different growth years, the genera of soil-borne pathogens, such as Alternaria, Botrytis, Cladosporium, Sarocladium, and Fusarium, were increased in diseased AG soil samples in comparison with those in the healthy AG soil samples. In contrast, the abundance of some key and potentially beneficial microbes, such as Bacillus, Chaetomium, Dyella, Kaistobacter, Paenibacillus, Penicillium, and Trichoderma, was decreased. Additionally, as AG plants age, the relative abundance of symbiotic fungi tended to decrease, while the relative abundance of potential plant pathogenic fungi gradually increased. Various soil properties, such as available phosphorus, the ratio of total nitrogen to total phosphorus (N/P), and pH, were significantly (P < 0.05) associated with microbial community composition. Our findings provide a scientific basis for understanding the relationship among the root rot disease outbreaks in American ginseng as well as their corresponding soil microbial communities and soil physicochemical properties.

Bacterial Diversity and Community Composition Distribution in Cold-Desert Habitats of Qinghai-Tibet Plateau, China.

Bacterial communities in cold-desert habitats play an important ecological role. However, the variation in bacterial diversity and community composition of the cold-desert ecosystem in Qinghai-Tibet Plateau remains unknown. To fill this scientific gape, Illumina MiSeq sequencing was performed on 15 soil samples collected from different cold-desert habitats, including human-disturbed, vegetation coverage, desert land, and sand dune. The abundance-based coverage estimator, Shannon, and Chao indices showed that the bacterial diversity and abundance of the cold-desert were high. A significant variation reported in the bacterial diversity and community composition across the study area. Proteobacteria accounted for the largest proportion (12.4-55.7%) of all sequences, followed by Actinobacteria (9.2-39.7%), Bacteroidetes (1.8-21.5%), and Chloroflexi (2.7-12.6%). Furthermore, unclassified genera dominated in human-disturbed habitats. The community profiles of GeErMu, HongLiangHe, and CuoNaHu sites were different and metagenomic biomarkers were higher (22) in CuoNaHu sites. Among the soil physicochemical variables, the total nitrogen and electric conductivity significantly influenced the bacterial community structure. In conclusion, this study provides information regarding variation in diversity and composition of bacterial communities and elucidates the association between bacterial community structures and soil physicochemical variables in cold-desert habitats of Qinghai-Tibet Plateau.

Does Karrikin Signaling Shape the Rhizomicrobiome via the Strigolactone Biosynthetic Pathway?

A recent study by Choi et al. provides evidence of the interaction between the karrikin (KAR) signaling and strigolactone (SL) biosynthetic pathways. Since SLs shape rhizomicrobiome composition, it is of interest to determine whether KAR signaling could affect rhizomicrobiome composition by improving the synthesis of root-derived SLs to support climate-smart agriculture.

Meta-analysis of safety and efficacy of oral anticoagulants in patients requiring catheter ablation for atrial fibrillation.

BACKGROUND: The ideal oral anticoagulant agent during catheter ablation (CA) for atrial fibrillation (AF) remained unclear. HYPOTHESIS: Novel oral anticoagulants (NOACs) are safer and effective compared to uninterrupted vitamin K antagonists (U-VKA) among patients requiring CA for AF. METHODS: Four randomized controlled trials (RCTs) and 9 observational studies (OS) were selected using PubMed/Medline, EMBASE and the CENTRAL data bases (Inception-December-2017). Estimates were reported as random effects risk ratio (RR) with 95% confidence interval (CI). The primary safety outcome was major bleeding and main efficacy endpoint was thromboembolism. RESULTS: In RCTs restricted analysis, NOACs significantly reduced the relative risk of major bleeding by 72% compared to U-VKA (RR, 0.28, 95% CI, 0.14-0.58, P < 0.001). This significant effect was not achieved in OS based analysis (RR, 0.86, 95% CI, 0.42-1.78, P = 0.68). In terms of thromboembolism, both anticoagulation strategies were equally effective in analysis of RCTs (RR, 0.28, 95% CI, 0.05-1.70, P = 0.17) or OS (RR, 1.43, 95% CI, 0.46-4.39, P = 0.54). In sensitivity analysis, there was no difference among uninterrupted NOACs (U-NOACs) and U-VKA in terms of major bleeding [(RCTs: RR, 0.33, 95% CI, 0.10-1.06, P = 0.06); (OS: RR, 0.70, 95% CI, 0.28-1.78, P = 0.46)] or thromboembolism [(RCTs: RR, 0.25, 95% CI, 0.03-2.29, P = 0.22); (OS: RR, 0.68, 95% CI, 0.08-5.53, P = 0.72)]. CONCLUSION: NOACs, either interrupted or un-interrupted, are safer and equally effective drugs compared to U-VKA in AF patients requiring CA.

Strigolactones positively regulate defense against Magnaporthe oryzae in rice (Oryza sativa).

This study presents evidence that strigolactones (SLs) promote defense against devastating rice blast fungal pathogen Magnaporthe oryzae. Impairment in either SL-biosynthetic dwarf17 (d17) or -signaling (d14) led to increased susceptibility towards M. oryzae. Comparative transcriptome profiling of the SL-signaling d14 mutant and WT plants revealed that a large number of defense-associated genes including hydrogen peroxide (H2O2)-, ethylene- and cell wall-synthesis-related genes were remarkably suppressed in d14 with respect to that of WT plants, during M. oryzae infection. In addition, various KEGG metabolic pathways related to sugar metabolism were significantly suppressed in the d14 plants compared to WT, during M. oryzae infection. Accordingly, WT plants accumulated increased levels of H2O2 and soluble sugar content compared to that of d17 and d14 in response to M. oryzae infection. Altogether, these results propose that SLs positively regulated rice defense against M. oryzae through involvement in the induction of various defense associated genes/pathways.