Overexpression of a sugarcane ScCaM gene negatively regulates salinity and drought stress responses in transgenic Arabidopsis thaliana

Calmodulin(CaM)proteins play a key role in signal transduction under various stresses.In the present study,the effects of a sugarcane ScCaM gene(NCBI accession number:GQ246454)on drought and salt stress tolerance in transgenic Arabidopsis thaliana and Escherichia coli cells were evaluated.The results demonstrated a significant negative role of ScCaM in the drought and salt stress tolerance of transgenic lines of A.thaliana,as indicated by the phenotypes.In addition,the expression of AtP5CS and AtRD29A,two genes tightly related to stress resistance,was significantly lower in the overexpression lines than in the wild type.The growth of E.coli BL21 cells expressing ScCaM showed weaker tolerance under mannitol and NaCl stress.Taken together,this study revealed that the ScCaM gene plays a negative regulatory role in both mannitol and NaCl stresses,and it possibly exerts protective mechanisms common in both prokaryotes and eukaryotes under stress conditions.

Characterization and Pathogenicity of Pseudopestalotiopsis vietnamensis Causing Gray Blight of Wuyi Rock Tea(Camellia sinensis)in China and Specific Mechanisms of Disease Infection

Gray blight disease(GBD)causes significant losses in tea production in China.Although genes and biological processes involved in resistance to fungal disease in tea plants have been identified,specific mechanisms of the GBD infection process remain unknown.In this study,morphological and multi-gene(TEF-TUB-ITS)phylogenetic characteristics were used to identify isolate CLBB1 of Pseudopestalotiopsis vietnamensis.Pathogenicity tests confirmed that isolate CLBB1 from tea leaves caused GBD in the susceptible tea cultivar Wuyi Rock(Camellia sinensis var.sinensis cv.Shuixian).Spores began to germinate 24 h after infection(hai),and after 48 h,elongated fungal hyphae formed from a single conidium.Transcriptome analysis revealed that 482,517,and 369 genes were differentially expressed at 24,48,and 72 hai,respectively,in Wuyi Rock tea leaves.Isolate CLBB1 infection elicited phenotype-related responses and activated defense-related pathways,including plant–pathogen interaction,MAPK signaling,and plant hormone signal transduction,suggesting a possible mechanism underlying phenotype-based susceptibility to CLBB1.Thus,a new Ps.vietnamensis strain causing GBD in the tea cultivar‘Shuixian’was discovered in this study.Transcriptome analysis indicated that pathogen invasion activated chitin-related MAPK pathways and that tea plants required a hormone to restrict CLBB1.

Microsatellite marker development and population genetic analysis revealed high connectivity between populations of a periwinkle Littoraria sinensis(Philippi,1847)

Periwinkle Littoraria sinensis is a widely distributed gastropod in rocky intertidal zone of the northwestern Pacifi c.To examine genetic diversity and genetic connectivity among coastal populations of L.sinensis in China,1636 pairs of primers were successfully designed using whole-genome shotgun sequencing,de novo assembly,and a bioinformatics pipeline QDD.Twelve highly variable polymorphic markers were selected to genotype 351 individuals from 15 populations.Data of nine microsatellite loci were retained for population genetic analysis,and weak genetic differentiation among populations were detected,suggesting high gene flow among populations.The long planktonic larval duration of L.sinensis might have played an important role in the high gene flow among populations.A tendency of genetic differentiation between north and south populations of L.sinensis was detected,which might be resulted from isolation due to lowered sea level in the last glacial maximum.Furthermore,the newly founded populations along the coast of Jiangsu Province were closely related to populations to the south of the Changjiang(Yangtze)River estuary,suggesting that the main source of the newly founded populations is from natural rocky populations south of the estuary.

不同退化阶段亚高山草甸土壤原生生物群落多样性特征及驱动因素

原生生物在草地生态系统养分循环、微生物群落稳定和土壤肥力维持方面发挥着重要作用。为了揭示亚高山草甸退化过程中土壤原生生物群落组成和多样性变化格局及环境驱动机制,本文利用18Sr DNA高通量测序技术研究了五台山不同退化阶段(未退化(nondegraded,ND)、轻度(lightly degraded,LD)、中度(moderately degraded,MD)和重度退化(heavily degraded,HD))亚高山草甸土壤原生生物群落组成和多样性的变化特征。结果表明:丝足门、褐藻门、纤毛门、叶足亚门、锥足亚门、绿藻门和顶复门是亚高山草甸土壤原生生物的优势门(相对丰度>1%)。纤毛门、叶足亚门、绿藻门、Choanoflagellida和Perkinsea的相对丰度在4种不同退化程度草甸中存在显著差异(P<0.05)。LEfSe分析显示未退化草甸中主要富集了Perkinsea类群,轻度退化草甸中富集了盾纤目类群,中度退化草甸中富集了变形虫纲和卵菌纲类群,中度退化草甸中主要富集了绿藻纲和硅藻纲类群等光合自养原生生物。随着亚高山草甸退化加剧,土壤原生生物群落α多样性呈下降的趋势(P<0.05)。总氮、植物Shannon-Wiener指数、地上生物量、土壤含水量和铵态氮是土壤原生生物群落结构变化的主要预测因子。方差分解分析(variancepartitioninganalysis,VPA)结果表明土壤理化因子和植被参数共同解释了原生生物群落结构变异的38.44%,且土壤理化因子(20.69%)解释度大于植被参数(7.85%)。五台山亚高山草甸退化过程中土壤原生生物群落α多样性和结构均发生了明显的变化,土壤环境因子是影响原生生物群落结构变化的重要因素。本研究结果加强了原生生物群落作为指示草地退化指标的潜力,可为科学全面地评价亚高山草甸土壤生态系统健康状况提供数据支撑与参考。

Fe(III)-Catalyzed Aerobic Oxidation of 1,4-Diols

Comprehensive Summary Aerobic oxidation has been catching more and more attention because of its atom economy and environmental friendliness.Oxidation of diols is a challenge due to various oxidative products.Thus,highly selective aerobic oxidation affording specific products is of current interest.In this work,a combination of Fe(NO_(3))_(3)·9H_(2)O/TEMPO/KCl catalysis has been identified as an efficient recipe for the aerobic oxidation of 1,4-diols affordingγ-butyrolactones under mild conditions.The reaction exhibits decent chemo-and regioselectivity of symmetrical and unsymmetrical 1,4-diols.The optically activeγ-lactones may also be prepared from optically active 1,4-diols without erosion of the ee via this method.Furthermore,this approach was successfully applied to synthesize NBP,a commercial drug.

华北落叶松树皮表面细菌群落多样性及其分布格局

附生在树皮表面的微生物,对于宿主植物的健康和环境适应性发挥重要作用,树皮微生境中微生物群落结构和多样性及其维持机制有待关注。【目的】本文对庞泉沟自然保护区不同海拔梯度的华北落叶松树干的背阴面与向阳面的树皮表面细菌群落的分布特征和适应机制进行了研究。【方法】通过PCR-DGGE和高通量测序技术研究细菌群落特征,对树皮表面细菌群落的空间分布特征进行了非度量多维尺度(NMDS)排序分析,通过冗余分析(RDA)研究细菌群落与树皮表面理化性质的关系,单因素方差分析(One-way ANOVA)比较树皮背阴面与向阳面细菌群落组成,基于零偏差分析研究背阴面与向阳面细菌群落构建的驱动因素。【结果】不同海拔梯度间的细菌群落结构有显著性差异(ANOSIM;P<0.05),树皮表面的微环境因子p H和总碳(TC)与群落结构显著相关(P<0.05);向阳面树皮表面的光合自养型细菌(隶属于蓝细菌门的未命名的目)的相对丰度显著高于背阴面,而根瘤菌目的相对丰度呈相反的趋势,光照可能是引起细菌群落结构发生变化的驱动因子;零偏差分析结果表明,华北落叶松树皮背阴面、向阳面细菌群落的多样性格局主要受环境过滤的影响。【结论】环境因子主导的确定性过程是驱动该地区华北落叶松树皮表面细菌群落结构和多样性的主导因素。

复合污染尾矿废水中真菌群落多样性及其驱动机制

金属尾矿废水中含有重金属以及多种有机和无机污染物,然而在该极端生境中仍然有大量微生物存在。为了揭示碱性尾矿废水中真菌群落的组成模式和多样性格局及其维持机制,本文利用ITS1区rDNA基因扩增子测序和qPCR技术对山西中条山十八河尾矿库废水中5个不同采样点真菌群落的组成、丰度和分布格局进行了研究。通过主坐标分析(PCoA)比较不同采样点间群落结构的差异性;通过冗余分析(RDA)探讨了水体理化因子对真菌群落结构的影响;通过零模型分析了影响群落结构的主要因素;通过网络图分析了真菌类群之间的种间相互作用。结果表明,布勒掷孢酵母属(Bullera)、Schizangiella、支顶孢属(Acremonium)和亚罗酵母属(Yarrowia)是主要的优势属,真菌群落在不同采样地点从门到属水平的相对丰度均有明显变化。真菌群落丰度沿水流方向逐渐增加且与有机碳(TOC)浓度呈显著正相关。真菌群落的α-多样性与pH、重金属(As和Cu)、无机碳(IC)和铵态氮(NH4+)浓度显著相关。真菌群落的空间结构在不同采样点具有明显差异,这种差异性与理化因子没有显著关系;不同采样点真菌群落的零偏差值均大于零,且不同物种之间存在复杂的种间相互作用。以上结果说明,在尾矿废水中环境因子只对真菌群落的α-多样性有显著影响,而群落的β-多样性主要受种间相互作用关系的影响,表明在碱性铜尾矿废水中存在比较复杂的真菌群落动态模式。