Genetic architecture of flag leaf length and width in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) revealed by association mapping

Rice flag leaf is the main photosynthetic organ and plays a key role in grain yield. In this study, 106 loci associated with flag leaf length and width were identified using association mapping in a rice mini core collection. Analyzing the phenotypic effects of each allele represented 156 positive and 167 negative alleles, with a few alleles showing inconsistent effect in different environments. Among the 106 loci, 69 were environment-specific loci, 16 were environmentally stable and 21 were environmentally sensitive. Fifteen associated markers were shared by two traits and were designated as pleiotropic markers. According to the frequency distribution of alleles in different variety types, 343 alleles were categorized into three types based on geographic source and usage in breeding. Among these, 156 were used alleles, 138 were unused and 49 were foreign alleles. The results further our understanding of the genetic mechanisms of flag leaf length and width.     

Bone marrow mesenchymal stem cell transplantation improves radiation-induced heart injury through DNA damage repair in rat model

Radiotherapy is an effective form of therapy for most thoracic malignant tumors. However, myocardial injury resulting from the high doses of radiation is a severe complication. Here we aimed to study the possibility of reducing radiation-induced myocardial injury with mesenchymal stem cell (MSC) transplantation. We used MSCs extracted from bone marrow (BMSCs) to transplant via the tail vein into a radiation-induced heart injury (RIHI) rat model. The rats were divided into six groups: a Sham group, an IRR (irradiation) group, and four IRR + BMSCs transplantation groups obtained at different time points. After irradiation, BMSC transplantation significantly enhanced the cardiac function in rats. By analyzing the expression of PPAR-α, PPAR-γ, TGF-β, IL-6, and IL-8, we found that BMSC transplantation alleviated radiation-induced myocardial fibrosis and decreased the inflammatory reaction. Furthermore, we found that expression of γ-H2AX, XRCC4, DNA ligase4, and TP53BP1, which are associated with DNA repair, was up-regulated, along with increased secretion of growth factors SDF-1, CXCR4, VEGF, and IGF in rat myocardium in the IRR + BMSCs transplantation groups compared with the IRR group. Thus, BMSC transplantation has the potential to improve RIHI via DNA repair and be a new therapeutic approach for patients with myocardial injury.     

Isolation and molecular characterization of herpesvirus from cultured European eels Anguilla anguilla in Taiwan

A herpesvirus has been isolated for the first time from a population of European eels Anguilla anguilla cultured in a recirculated system in Taiwan. Syncytia formation was detected in EP-1 (eel epidermis) cell cultures inoculated with cell-free homogenates prepared from both integument and visceral organs of moribund fish. Inoculation of homogenates onto EK (eel kidney) cell cultures induced giant cell formation. Subsequent passages produced a consistent and progressive cytopathic effect (CPE) in cell cultures. In this study, EP-1 cell cultures infected with EEHV (European eel herpesvirus) were examined using an electron microscope. Numerous nucleocapsids of about 100 nm in diameter were found within the nucleus of infected cells, whereas enveloped particles were observed within the cytoplasm. The mature viral particle, about 235 nm in diameter, had an electron-dense core with a hexagonal nucleocapsid surrounded by a coarse capsule. Histopathological examination of moribund fish showed epithelial hyperplasia with intracytoplasmic metabolic inclusions in the skin. Macrophage aggregates were found in liver, spleen, and kidney. A pair of primers designed from channel catfish virus and salmonid herpesvirus 1 was used in a polymerase chain reaction. A 402 bp fragment was amplified and cloned from genomic DNA of EEHV. The nucleotide homology was 99% (298 of 300) with DNA polymerase of eel herpesvirus (anguillid herpesvirus). EEHV nucleic acids were detected within melanomacrophages in the skin, liver, spleen and kidney by in situ hybridization (ISH).     

A dynamic reversible RNA N6-methyladenosine modification: current status and perspectives

N⁶-methyladenosine (m⁶A), as the most abundant RNA epigenetic modifications, has been shown to play critical roles in various biological functions. Research about enzymes that can catalyze and remove m⁶A have revealed its comprehensive roles in messenger RNA (mRNA) metabolism and other physiological processes. The “readers” including YTH domain-containing proteins, hnRNPC, hnRNPG, hnRNPA2B1, IGF2BP1, IGF2BP2, and IGF2BP3, which can affect the fates of mRNA in an m⁶A-dependent manner. In this review, we focus on recent advances in the research of the m⁶A modifications, especially about the latest functions of its writers, erasers, readers in RNA metabolism, cancer, and lipid metabolism. In the end, we provide insights into the underlying molecular mechanisms of m⁶A modifications.     

基于ITS和ndhF-rpl32序列的荞麦种间亲缘关系分析

荞麦起源于我国, 演化形成了丰富的物种和遗传多样性。为了有效研究和利用荞麦及其野生种资源, 以从四川、甘肃、贵州等地采集的荞麦属(Fagopyrum)10个种(含变种、亚种和复合体种)共71份材料为对象, 通过ITS和叶绿体ndhF-rpl32序列分析, 利用MEGA5.0构建系统进化树, 探讨了荞麦种内及种间亲缘关系。结果表明, 在ITS序列矩阵中, 序列长度为725 bp, 信息位点为150个, 占序列总长度的20.7%; 在ndhF-rpl32序列矩阵中, 序列长度为940 bp, 信息位点为158个, 占序列总长度的16.8%。由ITS序列和ndhF-rpl32序列构建的两个进化树都可以将71份材料分为大粒荞麦种组和小粒荞麦种组; 其中, 大粒荞麦种组包括栽培苦荞和米苦荞(F. tataricum)、金荞复合体(F. cymosum complex)、栽培甜荞(F. esculentum)和野生甜荞(F. esculentum ssp. ancestralis); 小粒荞麦种组包括齿翅野荞(F. gracilipes var. odontopterum)、疏穗小野荞(F. leptopodum var. grossii)、小野荞(F. leptopodum)、密毛野荞(F. densovillosum)、细柄野荞(F. gracilipes)和硬枝万年荞(F. urophyllum)。而ndhF-rpl32序列构建的系统发育树还能区分栽培甜荞和野生甜荞, 具有更好的聚类效果。另外, 与栽培甜荞相比, 金荞复合体与栽培苦荞的亲缘关系更近。该研究为荞麦属种的分类和条形码研究提供了一定的科学依据。     

Differential Expression of microRNAs and their Regulatory Networks in Skin Tissue of Liaoning Cashmere Goat during Hair Follicle Cycles

MicroRNAs (miRNAs) are endogenous small noncoding RNA molecules that negatively regulate gene expression. Herein, we investigated a selective number of miRNAs for their expression in skin tissue of Liaoning Cashmere goat during hair follicle cycles, and their intracellular regulatory networks were constructed based on bioinformatics analysis. The relative expression of six miRNAs (mir-103-3p, -15b-5p, 17-5p, -200b, -25-3p, and -30c-5p) at anagen phase is significantly higher than that at catagen and/or telogen phases. In comparison to anagen, the relative expression of seven miRNAs (mir-148a-3p, -199a-3p, -199a-5p, -24-3p, -30a-5p, -30e-5p, and -29a-3p) was revealed to be significantly up-regulated at catagen and/or telogen stages. The network analyses of miRNAs indicated those miRNAs investigated might be directly or indirectly involved in several signaling pathways through their target genes. These results provided a foundation for further insight into the roles of these miRNAs in skin tissue of Liaoning Cashmere goat during hair follicle cycles.     

Genomic and physiological analysis reveals versatile metabolic capacity of deep-sea <Emphasis Type="Italic">Photobacterium phosphoreum</Emphasis> ANT-2200

Bacteria of the genus Photobacterium thrive worldwide in oceans and show substantial eco-physiological diversity including free-living, symbiotic and piezophilic life styles. Genomic characteristics underlying this variability across species are poorly understood. Here we carried out genomic and physiological analysis of Photobacterium phosphoreum strain ANT-2200, the first deep-sea luminous bacterium of which the genome has been sequenced. Using optical mapping we updated the genomic data and reassembled it into two chromosomes and a large plasmid. Genomic analysis revealed a versatile energy metabolic potential and physiological analysis confirmed its growth capacity by deriving energy from fermentation of glucose or maltose, by respiration with formate as electron donor and trimethlyamine N-oxide (TMAO), nitrate or fumarate as electron acceptors, or by chemo-organo-heterotrophic growth in rich media. Despite that it was isolated at a site with saturated dissolved oxygen, the ANT-2200 strain possesses four gene clusters coding for typical anaerobic enzymes, the TMAO reductases. Elevated hydrostatic pressure enhances the TMAO reductase activity, mainly due to the increase of isoenzyme TorA1. The high copy number of the TMAO reductase isoenzymes and pressure-enhanced activity might imply a strategy developed by bacteria to adapt to deep-sea habitats where the instant TMAO availability may increase with depth.     

ER-localized adenine nucleotide transporter ER-ANT1: an integrator of energy and stress signaling in rice

Most environmental perturbations have a direct or indirect deleterious impact on photosynthesis, and, in consequence, the overall energy status of the cell. Despite our increased understanding of convergent energy and stress signals, the connections between photosynthesis, energy and stress signals through putative common nodes are still unclear. Here we identified an endoplasmic reticulum (ER)-localized adenine nucleotide transporter1 (ER-ANT1), whose deficiency causes seedling lethality in air but viable under high CO₂, exhibiting the typical photorespiratory phenotype. Metabolic analysis suggested that depletion of ER-ANT1 resulted in circadian rhythm disorders in sucrose synthesis and induced sucrose signaling pathways, indicating that the ER is involved in the regulation of vital energy metabolism in plants. In addition, the defect of ER-ANT1 triggers ER stress and activates the unfolded protein response in plant cells, suggesting ER stress and photorespiration are closely linked. These findings provide an important evidence for a key role of ER-localized ER-ANT1 in convergent energy and stress signals in rice. Our findings support the idea that ATP is a central signal involved in the plant response to a variety of stresses.