芸薹属CesA基因家族在AC基因组中的进化及其多态性分析

植物细胞壁在保持细胞完整和维持功能等方面发挥了极其重要的作用,纤维素合成酶(CesA)基因家族编码了参与细胞壁多糖生物合成的许多酶。为了系统地了解CesA基因家族在芸薹属AC基因组的基本情况及CesA多态性与抗菌核病之间的关系,本研究利用拟南芥CesA1基因AT4G32410的蛋白种子序列对白菜、甘蓝和甘蓝型油菜全基因组数据进行全基因组水平CesA鉴定(E-value=0),基因结构域特征、生化特征、进化关系等的分析。从连续3年用牙签茎秆接种菌核病的甘蓝型油菜田间抗病性鉴定试验中,筛选出高抗病和高感病材料8份,克隆其C07染色体上的CesA基因片段,记为C07-BnaCesA,并进行序列多态性与抗病关联性分析。结果显示,在芸薹属AC基因组中共鉴定到78个CesA基因,其中白菜23个,甘蓝16个,甘蓝型油菜39个(A亚基因组20个,C亚基因组19个)。基于UPGMA法CesA蛋白系统进化树在遗传距离0.24处明显分成2大类。2000 bp启动子区预测到被转录因子(TFs)结合位点最多的TFs为BBR-BPC、ERF,14个CesA没有预测到TFs结合位点,在白菜和甘蓝杂交形成油菜的进化过程中,可能发生了基因沉默。在8份材料中C07-BnaCesA基因片段共鉴定到58个SNPs。芸薹属AC基因组CesA基因在进化过程中有的比较保守,C07-BnaCesA基因片段多态性与菌核病抗性没有强的关联性。     

基于转录组的巨龙竹CesA基因家族的生物信息学分析

纤维素是植物细胞壁的重要组成成分,主要由多个纤维素合成酶(CesA)基因家族参与编码.本研究基于巨龙竹单分子实时测序(SMRT)转录组数据库,利用高质量转录本非冗余序列结合转录本功能注释,共筛选出45个CesA基因候选序列.巨龙竹CesA基因家族编码蛋白的氨基酸数目为351～1 652个,其分子量为40.45～186....     

刺槐纤维素合酶基因(RpCesA2)克隆、表达及SNP分析

利用同源克隆及RACE结合方法,首次从刺槐(Robinia pseudoacacia)茎部cDNA中获得纤维素合酶基因RpCesA2并获取基因组DNA序列。通过生物信息学分析,发现该基因内部含有3 291 bp完整编码区,编码1 097个氨基酸残基的蛋白;包含纤维素合成酶蛋白典型结构域:如1个锌指结构(zinc finger)及8个跨膜区(Transmembrane domain),与拟南芥纤维素合成酶基因CesA1至CesA10蛋白序列相似性达56.27%(At CesA8)~79.67%(AtCesA2)。通过构建系统进化树,发现RpCesA2基因与CesA5、CesA6、CesA9基因亲缘关系较近。组织特异性Realtime-PCR结果表明,RpCesA2基因在刺槐根、茎、叶片、叶柄4个组织部位具有不同的表达模式:第一时期、第三时期均在叶片中表达量最高,第二个时期茎中表达量最高。在此基础上,对10个刺槐无性系单株RpCesA2序列进行测序比对分析,检测到50个单核苷酸多态性(SNP)位点,其出现频率为1/130。CDS区域共有22个SNPs,其中15个是同义突变,7个为错义突变,非同义突变与同义突变比率为0.47。该研究结果为RpCesA2基因进一步连锁不平衡作图与关联研究提供理论依据,并最终有助于刺槐纤维素合成途径研究、标记辅助分子育种。     

慈竹BeCesA1和BeCesA7基因的克隆及组织表达分析

植物的纤维素合成酶(CesA)是纤维素合成途径的关键酶,不仅与纤维素含量相关,也与植物生长发育相关。但有关慈竹CesA基因的克隆与分析,以及GA3对慈竹CesA基因表达的影响未见报道。本研究通过慈竹转录组数据库、在线NCBI基因组数据库及毛竹基因组数据库,同源克隆得到两个CesA基因,BeCesA1(GenBank注册号:KY435488)和BeCesA7 (GenBank注册号:KY435489),分别编码1 078和1 053个氨基酸残基。保守结构域分析及多重序列比对分析表明,慈竹BeCesA1和BeCesA7蛋白均在N端存在一个RING finger结构和两个高度可变区域。组织表达结果表明,BeCesA1和BeCesA7两个基因在竹不同组织中表达模式各不相同,但均在100 cm笋等组织中高表达,然而BeCesA7的表达量明显高于BeCesA1。在竹的发育过程中,BeCesA1基因随着笋的发育表达量逐渐降低,而BeCesA7则随着笋的发育逐渐增高。外源施加GA3后,以BeCesA1的CK未展开叶为参照,BeCesA1在茎秆中的表达量降低,而BeCesA7则在茎秆中的表达量增加。     

西瓜防御素(ClPDF)基因挖掘及序列分析

为明确西瓜防御素基因(ClPDF)的结构和功能,采用生物信息学方法对西瓜防御素基因进行了详细的全基因组挖掘和序列分析.结果表明,从西瓜基因组中共获得7个防御素基因,ClPDFs基因编码的氨基酸序列都含有高度保守的8个半胱氨酸、1个甘氨酸、1个丝氨酸和1个芳香族氨基酸残基.分析发现,ClPDFs基因在理化性质上有一定的差异.系统进化分析说明,ClPDFs与拟南芥PDF2基因家族聚为一类.二级结构预测结果说明,所有ClPDFs序列均以不规则卷曲为主要组成元件,在延伸链和α-螺旋组成上存在差异.信号肽和跨膜结构预测结果相似,仅有1条序列无信号肽,1条序列有跨膜区,而其他序列都含有信号肽、无跨膜区.证明了西瓜防御素基因为多基因家族,都含有高度保守的结构域,但在结构上西瓜防御素基因差异较大,为进一步探讨西瓜防御素ClPDFs的生物功能奠定了基础.     

新城疫病毒La Sota株HN基因的克隆与序列分析

旨在从分子生物学角度进一步研究新城疫病毒La Sota株HN基因,探究NDV La Sota HN基因的遗传变异情况。研究以试验室冻存的p NDV-HN为模版,根据Gen Bank中登录的NDV La Sota株序列设计引物扩增HN基因,将其克隆到pMD18-T载体后进行鉴定,对鉴定正确的重组质粒p MD-NDV-HN进行测序分析。应用生物信息学软件对新城疫病毒Lasota株HN基因进行系统进化树分析、氨基酸序列同源性分析、糖基化位点、蛋白结构跨膜区分析及磷酸化位点预测分析。核苷酸序列测定结果表明:HN基因的序列长度为1743bp,该基因的开放阅读框(Open Reading Frame,ORF)总长为1716 bp,编码571个氨基酸。生物信息学表明:试验获得的HN基因具有6个潜在糖基化位点及12个半胱氨酸残基,第5个潜在糖基化位点(508-510 aa)发生缺失及第123位半胱氨酸残基被色氨酸残基取代。La Sota株HN基因编码的蛋白质中有29个丝氨酸、10个酪氨酸和16个苏氨酸可能成为蛋白激酶磷酸化位点。将试验获得的La Sota株HN基因序列和推导的氨基酸序列与新城疫毒株的HN基因相应序列比较后发现,它们的核苷酸序列同源性和氨基酸序列同源性最高均可达到99%,表明HN基因在种属间具有较高的保守性。研究为新城疫病毒的分子病毒学研究奠定了基础。     

南荻纤维素合成酶CesA基因的生物信息学分析

于PacBio SMRT单分子实时测序技术进行3代转录组测序,辅以2代测序,构建出一个完整的,准确的南荻Unigene库。通过与近源物种比对后,拼接出南荻(Miscanthus lutarioriparius)纤维素合成酶基因(cellulose synthase gene) CesA4、CesA7和CesA9的序列,并将其命名为MlCesA4、MlCesA7、MlCesA9。使用生物信息学分析软件构建出蛋白质系统进化树,对氨基酸翻译后修饰的磷酸化位点进行预测和分析,对蛋白质的保守结构域进行预测和分析。结果显示,MlCesA4、MlCesA7和MlCesA9基因序列长度分别为2 980、3 310、3 208 bp与高粱和玉米的亲缘关系最近;南荻纤维素合成酶(MlCesA) MlCesA4和MlCesA9有43个磷酸化位点,MlCesA7有48个磷酸化位点;Ml CesA4是不稳定蛋白,具有6个跨膜结构域,其中4个在膜外,3个在膜内,MlCesA7和MlCesA9是稳定蛋白质,具有8个跨膜结构域,其中5个在膜外,4个在膜内。三者都是亲水性蛋白,二级结构均以α-螺旋和无规则卷曲为主。     

D-氨基酸抑制植物生长的现象

丙氨酸、丝氨酸、缬氨酸和蛋氨酸4种氨基酸的L-和D-异构体对小麦胚试管植株生长影响的试验结果表明,丙氨酸和丝氨酸的D-异构体在3 mmol/L以上浓度强烈抑制试管植株生长,L-异构体不抑制或轻的多,这是少见的D-氨基酸抑制植物生长的现象。把在丙氨酸、丝氨酸处理中生长4 d的已经受到抑制的植株再转入无氨基酸培养基后,植株可恢复生长,这显示D-丙氨酸和D-丝氨酸的抑制作用可能有反馈机制存在。D-氨基酸的这些作用在筛选植物生长延缓剂、离体植物遗传标记等方面有重要价值。     

小麦耐盐相关基因TaSTK的克隆

利用RACE方法,从小麦耐盐突变体RH8706-49中扩增获得小麦丝氨酸/苏氨酸蛋白激酶（Triticum aestivum serine-threonine protein kinase）基因TaSTK的全长cDNA序列,含1 958 bp,其中开放阅读框1 431 bp,编码476个氨基酸。其编码区基因组DNA全长为4 095 bp,含5个外显子。该基因的全长cDNA序列及基因组序列均已提交GenBank数据库（登录号：DQ103756和DQ341377）。经过NCBI比对发现该基因的氨基酸序列与丝氨酸/苏氨酸蛋白激酶、酪氨酸蛋白激酶、蛋白激酶都具有较高的同源性。Northern杂交检测表明,TaSTK在小麦中属于盐诱导增强型基因,并且在耐盐材料RH8706-49中诱导增强程度高于敏盐材料H8706-34。TaSTK的杂交信号非常弱,表明TaSTK在小麦幼苗的叶片组织中属于低表达的基因类型。     

黄毛草莓丝氨酸/苏氨酸基因FnSTPK1和启动子克隆及表达分析

为探究丝氨酸/苏氨酸基因STPK1在黄毛草莓(Fragaria nilgerrensis Schltdl.)抗炭疽病中的作用,采用RT-PCR技术从黄毛草莓中克隆了FnS TPK1基因的cDNA (GenBank登录号:MN709781)及其启动子序列(GenBank登录号:MN709783),序列分析结果表明:FnSTPK1基因开放阅读框长为1581 bp,编码526个氨基酸,包含1个STKc结构域,该基因起始密码子上游启动子pFnSTPK1序列为752bp,预测包含TATA-box、CAAT-box、激素响应元件、光响应元件、环境胁迫顺式作用元件等.同源性分析结果显示:FnSTPK1基因编码的氨基酸序列与森林草莓(Fragaria vesca)编码的氨基酸序列相似性为97.92％.RT-qPCR结果表明,黄毛草莓叶片接种胶孢炭疽菌(Colletotrichum gloeosprioides)后,FnS PK1基因在接种后不同时间点的相对表达量均显著增加,且在接种48 h时达到最高值,为0 h的10.3倍;黄毛草莓叶片在外源喷施水杨酸(SA) 12 h时,FnSTPK1基因的相对表达量达到峰值,为0 h的2.9倍.因此,FnSTPK1可能在草莓抗炭疽病和SA诱导等过程中发挥重要的作用.本研究为进一步探究STPK1基因在野生黄毛草莓抗炭疽病中的功能提供了参考.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.