GmCHS8和GmIFS2基因共同决定大豆中异黄酮的积累

大豆异黄酮受多基因控制,采用传统育种方法提高大豆异黄酮含量比较困难。我们之前的研究表明,CHS8基因在异黄酮生物合成过程中发挥着重要作用,但CHS8基因过量表达并不能显著提高异黄酮含量。本研究利用Microarray技术,检测了高异黄酮品种RCATAngra(RCAT)和低异黄酮品种Harovinton(HVNT)的18362基因在种子发育过程中表达水平的变化以及大豆种子中异黄酮累积的趋势,利用RT-PCR证实CHS8和IFS2分别是CHSs和IFSs基因家族中的主要基因;证实CHS8是类苯基丙醇主路径中的主基因,并发现异黄酮支路中的IFS2基因在RCAT和HVNT品种中表达差异亦达到显著水平。进一步利用发根农杆菌转化系统,在大豆上分别过量表达CHS8、IFS2和CHS8+IFS2,前两者异黄酮含量较对照分别提高65.9%和34.4%,但增幅未达显著水平;而后者则提高了82.3%,增幅达极显著水平(P<0.0001),因而证实大豆中异黄酮的积累由CHS8和IFS2基因共同决定。

Concentration difference of auxin involved in stem development in soybean

Auxin regulates cell division and elongation of the primordial cells through its concentration and then shaped the plant architecture. Cell division and elongation form the internode of soybean and result in different plant heights and lodging resistance. Yet the mechanisms behind are unclear in soybean. To elucidate the mechanism of the concentration difference of auxin related to stem development in soybean, samples of apical shoot, elongation zone, and mature zone from the developing stems of soybean seedlings, Charleston, were harvested and measured for auxin concentration distributions and metabolites to identify the common underlying mechanisms responsible for concentration difference of auxin. Distribution of indole-3-acetic acid(IAA), indole-3-butyric acid(IBA), and methylindole-3-acetic acid(Me-IAA) were determined and auxin concentration distributions were found to have a complex regulation mechanism. The concentrations of IAA and Me-IAA in apical shoot were significantly different between elongation zone and mature zone resulting in an IAA gradient. Tryptophan dependent pathway from tryptamine directly to IAA or through indole-3-acetonitrile to IAA and from indole-3-propionic acid(IPA) to IAA were three primary IAA synthesis pathways. Moreover, some plant metabolites from flavonoid and phenylpropanoid synthesis pathways showed similar or reverse gradient and should involve in auxin homeostasis and concentration difference. All the data give the first insight in the concentration difference and homeostasis of auxin in soybean seedlings and facilitate a deeper understanding of the molecular mechanism of stem development and growth. The gathered information also helps to elucidate how plant height is formed in soybean and what strategy should be adopted to regulate the lodging resistance in soybean.

A Review Article: Electrokinetic Bioremediation Current Knowledge and New Prospects

This study discusses factors affecting various processes involved in bioremediation coupled with electrokinetics. The study presents innovative solutions, and proposes new directions. Environmental conditions that have an influence on the characteristics, behavior, and metabolism of indigenous microorganisms are presented. The discussion focuses on overcoming the unfavorable conditions created by electrolysis reactions, prolongation the survival of the microbes at contaminated sites, increase of microbial enzyme secretion, improvement of the indigenous bacteria metabolic pathways, and exploration of metagenomics resources from soil biota. The challenge facing the implementation of conventional bioremediation techniques in precisely and effectively delivering nutrients to indigenous bacteria, particularly in soils with tortuous paths and low hydraulic conductivity is discussed. Current knowledge in application of enhanced biostimulation using electrokinetics is reviewed. The implementation of bioaugmentation in bioremediation coupled with electrokinetics to enhance the outcome of bioremediation is presented. Effects of phenomena associated with electrokinetics in the hybrid remediation approach are discussed.

Recent Progress of Transgenic Technology Development for Alfalfa

Alfalfa (Medicago sativa L.) is an important leguminous crop worldwide and it has important roles in different aspects of the agriculture system, including livestock feed, crop soil conservation, and improvement of soil nitrogen supply. As a perennial crop, alfalfa breeding for trait improvement takes longer periods of time compared to many other crops, therefore, genetic engineering is a faster route for alfalfa trait modification and improvement. Alfalfa was a first crop in which somatic embryogenesis was developed. Alfalfa was also a pioneering crop in which transgenic technology was developed and applied for trait improvement. Transgenic technology in alfalfa has since advanced steadily in various areas. In this review, we update the recent research progress in alfalfa genetic engineering, focusing on genetic transformation and use of transgenic technology for trait improvement and new trait development.

Evaluation of Drought Stress-Inducible W<i>si</i>18 Promoter in <i>Brachypodium distachyon</i>

The rice Wsi18 promoter confers drought-inducible gene expression. This property makes it a useful candidate to drive relevant genes for developing drought resistant traits for different monocot crops. In this study, we showed that the Bradi2G47700 gene, the closest homologue to rice Wsi18, was upregulated in Brachypodium distachyon plants exposed to ABA and mannitol. Wsi18: uidA transgenic B. distachyon plants were produced and then subjected to ABA or mannitol treatment. The expression of uidA in three transgenic lines (line 10, 18 and 37) was significantly upregulated in plants exposed to ABA (fold increases of 5.61 ± 0.98, 2.88 ± 0.75 and 9.13 ± 1.96, respectively) compared to the same transgenic plant lines without treatment. The expression of uidA in two transgenic lines (lines 18 and 37) also showed upregulation when treated with mannitol (fold increases of 4.43 ± 1.07 and 8.47 ± 2.90, respectively) compared to the same transgenic plant lines without mannitol treatment. Moreover, GUS histochemical assay showed increased Wsi18 promoter activity in the leaves and stems of transgenic lines upon treatment with ABA or mannitol. This is the first report of the drought inducible rice Wsi18 promoter being active in B. distachyon which is a model plant for molecular biology research of various monocot plants. Taken together, the results indicate that the Wsi18 promoter and its homologue may be explored as a useful tool for drought stress-inducible gene expression in different monocot crops.

Degradation of ^(14)C-glyphosate and aminomethylphosphonic acid (AMPA) in three agricultural soils

Glyphosate （N-phosphonomethyl glycine） is the most used herbicide worldwide. The degradation of ^14C-labeled glyphosate was studied under controlled laboratory conditions in three different agricultural soils： a silt clay loam, a clay loam and a sandy loam soil. The kinetic and intensity of glyphosate degradation varied considerably over time within the same soil and among different types of soil. Our results demonstrated that the mineralization rate of glyphosate was high at the beginning of incubation and then decreased with time until the end of the experiment. The same kinetic was observed for the water extractable residues. The degradation of glyphosate was rapid in the soil with low adsorption capacity （clay loam soil） with a short half-life of 4 days. However, the persistence of glyphosate in high adsorption capacity soils increased, with half-live of 19 days for silt clay loam soil and 14.5 days for sandy loam soil. HPLC analyses showed that the main metabolite of glyphosate, arninomethylphosphonic acid （AMPA） was detected after three days of incubation in the extracts of all three soils. Our results suggested that the possibility of contamination of groundwater by glyphosate was high on a long-term period in soils with high adsorption capacity and low degrading activities and/or acid similar to sandy loam soil. This risk might be faster but less sustainable in soil with low adsorption capacity and high degrading activity like the clay loam soil. However, the release of non-extractable residues may increase the risk of contamination of groundwater regardless of the type of soil.

Autophagy mediates a direct synergistic interaction during cotransmission of two distinct arboviruses by insect vectors

Multiple viral infections in insect vectors with synergistic effects are common in nature,but the underlying mechanism remains elusive.Here,we find that rice gall dwarf reovirus(RGDV)facilitates the transmission of rice stripe mosaic rhabdovirus(RSMV)by co-infected leafhopper vectors.RSMV nucleoprotein(N)alone activates complete anti-viral autophagy,while RGDV nonstructural protein Pns11 alone induces pro-viral incomplete autophagy.In co-infected vectors,RSMVexploits Pns11-induced autophagosomes to assemble enveloped virions via N-Pns11-ATG5 interaction.Furthermore,RSMV could effectively propagate in Sf9 cells.Expression of Pns11 in Sf9 cells or leafhopper vectors causes the recruitment of N from the ER to Pns11-induced autophagosomes and inhibits N-induced complete autophagic flux,finally facilitating RSMV propagation.In summary,these results demonstrate a previously unappreciated role of autophagy in the regulation of the direct synergistic interaction during co-transmission of two distinct arboviruses by insect vectors and reveal the functional importance of virus-induced autophagosomes in rhabdovirus assembly.

SUMOylation-modified Pelota-Hbs1 RNA surveillance complex restricts the infection of potyvirids in plants

RNA quality control nonsense-mediated decay is involved in viral restriction in both plants and animals.However,it is not known whether two other RNA quality control pathways,nonstop decay and no-go decay,are capable of restricting viruses in plants.Here,we show that the evolutionarily conserved Pelota–Hbs1 complex negatively regulates infection of plant viruses in the family Potyviridae(termed potyvirids),the largest group of plant RNA viruses that accounts for more than half of the viral crop damage worldwide.Pelota enables the recognition of the functional G1-2A6-7 motif in the P3 cistron,which is conserved in almost all potyvirids.This allows Pelota to target the virus and act as a viral restriction factor.Furthermore,Pelota interacts with the SUMO E2-conjugating enzyme SCE1 and is SUMOylated in planta.Blocking Pelota SUMOylation disrupts the ability to recruit Hbs1 and inhibits viral RNA degradation.These findings reveal the functional importance of Pelota SUMOylation during the infection of potyvirids in plants.

Plant and animal positive-sense single-stranded RNA viruses encode small proteins important for viral infection in their negative-sense strand

Positive-sense single-stranded RNA(+ssRNA)viruses,the most abundant viruses of eukaryotes in nature,require the synthesis of negative-sense RNA(-RNA)using their genomic(positive-sense)RNA(+RNA)as a template for replication.Based on current evidence,viral proteins are translated via viral+RNAs,whereas-RNA is considered to be a viral replication intermediate without coding capacity.Here,we report that plant and animal+ssRNA viruses contain small open reading frames(ORFs)in their-RNA(reverse ORFs[rORFs]).Using turnip mosaic virus(TuMV)as a model for plant+ssRNA viruses,we demonstrate that small proteins encoded by rORFs display specific subcellularlocalizations,and confirm the presence of rORF2 in infected cells through mass spectrometry analysis.The protein encoded by TuMV rORF2 forms punctuate granules that are localized in the perinuclear region and co-localized with viral replication complexes.The rORF2 protein can directly interact with the viral RNA-dependent RNA polymerase,and mutation of rORF2 completely abolishes virus infection,whereas ectopic expression of rORF2 rescues the mutant virus.Furthermore,we show that several rORFs in the-RNA of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)have the ability to suppress type l interferon production and facilitate the infection of ve-sicular stomatitis virus.In addition,we provide evidence that TuMV might utilize internal ribosome entry sites to translate these small rORFs.Taken together,these findings indicate that the-RNA of+ssRNA vi-ruses can also have the coding capacity and that small proteins encoded therein play critical roles in viral infection,revealing a viral proteome larger than previously thought.

Chromatin-associated SUMOylation controls the transcriptional switch between plant development and heat stress responses

The post-translational protein modification known as SUMOylation has conserved roles in the heat stress responses of various species.The functional connection between the global regulation of gene expression and chromatin-associatedSUMOylation in plant cells isunknown.Here,weuncovereda genome-wide relationship between chromatin-associated SUMOylation and transcriptional switches in Arabidopsis thaliana grown at room temperature,exposed to heat stress,and exposed to heat stress followed by recovery.The small ubiquitin-like modifier(SUMO)-associated chromatin sites,characterized by whole-genome ChIP-seq,were generally associated with active chromatin markers.In response to heat stress,chromatin-associated SUMO signals increased at promoter-transcriptional start site regions and decreased in gene bodies.RNAseq analysis supported the role of chromatin-associatedSUMOylation in transcriptional activation during rapid responses to high temperature.Changes inSUMOsignals on chromatinwere associated with the upregulation of heat-responsivegenesandthedownregulation ofgrowth-relatedgenes.Disruption of theSUMOligasegene SIZ1 abolished SUMOsignals on chromatin and attenuated rapid transcriptional responses to heat stress.The SUMO signal peaks were enriched in DNA elements recognized by distinct groups of transcription factors under different temperature conditions.These observations provide evidence that chromatin-associated SUMOylation regulates the transcriptional switch between development and heat stress response in plant cells.

抗生素耐药性环境中产生和转移的人类健康风险评估(HHRA)

[背景]直到最近,人们才明确环境能影响抗生素耐药性风险对临床结果的影响,但迄今为止,很少有文献记录正式评估这些风险的方法。[目标]我们研究可能的方法,并试图确定人类健康风险评估(HHRA)的研究需求,这项评估注重环境在抗生素耐药性病原体所致的抗生素治疗失败中所起的作用。[方法]作者参加了2012年3月4—8日在加拿大魁北克省举行的研讨会,定义抗生素耐药性风险与人类健康环境评估的范围和目标。我们专注于环境中耐药性产生"热点区域"的关键要素,(与食品无关的)暴露评估以及剂量反应,以描述风险特征,从而改善抗生素耐药性管理的方案。[讨论]识别传统风险评估中有助于评估环境中抗生素耐药性的各个新方面。包括:a)解释附加的选择压力对环境耐药基因组的作用,即随着时间的推移,促使抗生素耐药性细菌(ARB)产生;b)在相关的环境组成部分的"热点区域"中识别和描述水平基因转移(HGT)率;c)针对不同健康结局和途径的ARB剂量修改传统的剂量反应方法。[结论]我们建议将抗生素耐药性产生造成的环境影响纳入所有涉及ARB的HHRA过程之中。由于可用的数据有限,一种多标准决策分析方法将有助于进行环境中抗生素耐药性的HHRA,并使风险管理者了解环境抗生素耐药性。

减少向环境中释放抗生素和抗生素耐药基因的管理措施

[背景]全球越来越关注污染土壤、水环境对抗生素耐药性产生和蔓延的作用。[目的]本研究的目的是确定那些可以减少抗生素和抗生素耐药性经环境途径传播影响因素的管理措施,以最终达到延长抗生素使用寿命的目标。此外还研究了实施这些措施的激励和阻碍因素。[方法]着重研究有关农业源头限制,生活、医院和工业废水处理,以及水产养殖三方面的管理措施。[讨论]我们确定了若干措施,如养份管理、径流控制和基础设施升级。凡适当处,可提供世界不同地区的典型实例。研究还强调了监测和验证管理策略有效性的重要性。最后,介绍了一则瑞典的案例研究,展示了通过沟通来发动利益相关方参与和促进行动的重要作用。[结论]在许多情况下,可以花费很少或根本不花费成本来减少抗生素和抗生素耐药性细菌的环境释放。一些管理措施与现有的政策和目标协同作用。预期的效益是延长现有和未来的抗生素使用寿命。虽然往往难以量化所降低的风险,但是全球抗生素耐药性相关发病率和死亡率加速增长,这一情况的严重程度强烈表明采取行动的必要性。