巴西橡胶树中碱性转化酶HbNINa基因的克隆和表达模式分析

检索橡胶树EST和基因组数据库,发现了1个在叶片中高丰度表达的中碱性转化酶基因.采用RT-PCR和RACE技术获得了该基因的cDNA和基因组序列,命名为Hb NINa.序列分析结果显示,HbNINa基因cDNA序列的编码区(CDS)序列长度为1 719 bp,对应的基因组序列为3 696 bp.序列分析表明,该基因编码571个氨基酸多肽,推测其分子量大小为65.7 ku,等电点为6.36.HbNINa蛋白包含植物中碱性转化酶的全部保守结构域.基因组结构分析显示Hb NINa基因包含4个外显子和3个内含子.QPCR分析结果表明,HbNINa基因在在胶乳中表达水平极低,而在其他组织如树皮、树叶和雌花中的表达丰度相对较高.在叶片发育过程中,Hb NINa在叶片发育的初期高丰度表达,推测HbNINa可能参与叶片蔗糖利用,进而在橡胶树叶片发育过程中起重要作用.     

Evaluation of performance of sorghum varieties grown in Tokyo for sugar accumulation and its correlation with vacuolar invertase genes SbInv1 and SbInv2

ABSTRACT

The sugar-accumulating potential of global and local sweet and grain sorghum varieties were tested under the local conditions. The basis for this study was the dependency of sugar accumulation on temperature and photoperiod. Thus, the efficacy of cultivars as a bioenergy source would need to be determined based on their performance under the local environmental conditions. A strong correlation of sucrose content with brix was observed, enabling large-scale screening of varieties for high sucrose content. The morphological characteristics inherent in sweet sorghum, such as tall stems, greater number of leaves and a longer vegetative period, were found to correlate with the total stem sugar content. Assessment of sugars along the stem revealed maximum sugar accumulation in the upper intermediate to upper internodes in most of the varieties tested. The maximum theoretical ethanol yield (MTEY), a function of brix and juice yield, was determined as a better indicator of testing the performance of a variety as a potential source of bioethanol, mainly due to a negative correlation of stem juiciness and sucrose content in the varieties tested. Further, the relative expression of vacuolar invertase genes, SbINV1 and SbINV2, was studied, and a strong negative correlation of SbINV2 to stem sucrose content was observed. This reveals a possibility of involvement of vacuolar invertase gene, SbINV2, in sugar accumulation in sweet sorghum stems, and as a key candidate for molecular breeding studies for higher stem sugar content.     

葡萄霜霉菌候选效应子RXLR5信号肽的鉴定

利用Getorf、SignalP 3.0、BLASTP等生物信息学软件和PERL语言从葡萄霜霉菌基因组中预测到一条编码RXLR-EER结构域的效应蛋白候选基因,将该基因编码的蛋白命名为RXLR5。将RXLR5信号肽SP5编码序列连接到pSUC2T7M13ORI载体并转化到酵母蔗糖酶缺陷菌株YTK12后,重组菌株能成功分泌蔗糖酶,促使棉籽糖分解成单糖,因此,能在YPRAA培养基上正常生长;同时生成的单糖能与TTC反应产生红色不溶于水的氯化三苯基四氮唑。由此推测,SP5具有信号肽活性,可能在RXLR5从葡萄霜霉菌细胞内泌到胞外的过程中起重要作用。     

Variation in sugar levels and invertase activity in mature fruit representing a broad spectrum of Cucumis melo genotypes

Sugar accumulation is a very important physiological process that determines dessert-melon fruit quality. Considerable variation in the sugar content and composition in the mature flesh of Cucumis melo L. fruits was observed among 56 genotypes which represent the wide range of morphological and horticultural types found in this species. Sucrose accumulation was observed not only among 'dessert melons' of the inodorus and cantalupensis types, but also in representatives of other subgroups of C. melo, including some of the accessions from agrestis and conomon groups. Among the genotypes that accumulate sucrose, the levels of this sugar, and not of the hexoses, were correlated with the total sugar concentration. Hexose levels were correlated with total sugar levels only among low-sugar genotypes that did not accumulate sucrose. Activities of the sucrose hydrolyzing enzymes acid invertase (EC 3.2.1.26) and alkaline invertase (EC 3.2.1.27) were measured in the mature fruit flesh and the results of this survey support the hypothesis that low acid invertase activity is a prerequisite for sucrose accumulation. The sucrose accumulating, high sugar genotypes had less-acidic flesh pH values (pH> 6) than the low-sugar genotypes. The latter were characterized by a broader range of pH values, including acidic (pH< 5.5) fruit flesh.     

Transformation of Sucrose to Starch and Protein in Rice Leaves and Grains under Two Establishment Methods

Six rice varieties, PR120, PR116, Feng Ai Zan, PR115, PAU201 and Punjab Mehak 1 were raised under aerobic and transplanting conditions to assess the effects of planting conditions on sucrose metabolising enzymes in relation to the transformation of free sugars to starch and protein in flag leaves and grains. Activities of sucrose synthase, sucrose phosphate synthase and acid invertase increased till flowering stage in leaves and mid-milky stage(14 d after flowering) in grains and thereafter declined in concomitant with the contents of reducing sugar. Under aerobic conditions, the activities of acid invertase and sucrose synthase(cleavage) significantly decreased in conjunction with the decrease in non-reducing sugars and starch content in all the varieties. Disruption of starch biosynthesis under the influence of aerobic conditions in both leaves and grains and the higher build up of sugars possibly resulted in their favoured utilization in nitrogen metabolism. Feng Ai Zan, PR115 and PR120 maintained higher levels of sucrose synthase enzymes in grains and leaves and contents of metabolites(amino acid, protein and non-reducing sugar) under aerobic conditions, while PR116, Punjab Mehak 1 and PAU201 performed better under transplanting conditions, thus showing their adaptation to environmental stress. Yield gap between aerobic and transplanting rice is attributed primarily to the difference in sink activity and strength. Overall, it appear that up-regulation of sucrose synthase(synthesis) and sucrose phosphate synthase under aerobic conditions might be responsible in enhancing growth and productivity of rice varieties.     

多菌灵与氟硅唑对土壤微生物及酶活性的影响

针对混配农药的使用,研究了多菌灵、氟硅唑单施及其混配施用后28 d内对土壤微生物和土壤酶的影响.实验结果表明,在施药28 d内,多菌灵(20 mg/kg)与氟硅唑(2 mg/kg)单施后对土壤微生物量、呼吸强度、土壤脲酶活性、蔗糖酶活性均有明显的抑制作用,对土壤过氧化氢酶活性呈激活作用,将多菌灵(20 mg/kg)与氟硅唑(2 mg/kg)按剂量混施后,一定程度上降低了单一处理情况对土壤微生物及其土壤酶的毒理效应.     

黄土高原不同苹果园土壤酶、有机质、微生物及树体产量品质的调查研究

测定了黄土高原苹果主栽区洛川县6个苹果园土壤脲酶、磷酸酶、蔗糖酶的活性、土壤有机质的含量和微生物数量,调查了6个果园土壤微生物的分布情况,并对土壤酶活性、土壤有机质含量、土壤微生物数量及与苹果品质的相关性进行了分析。结果表明:①6个果园三种土壤酶活性均随着土层剖面加深呈现下降趋势。在0~20 cm土层范围酶活性较高,20 cm土层以下开始迅速下降,之后趋势减缓。②6个果园土壤有机质含量较低,平均为0.945%。③不同树龄果园微生物总量的变化为:盛果期果园(15 a)>老龄期果园(20 a)>幼龄期果园(7 a),微生物类群数量的分布规律为:细菌>放线菌>真菌,其中细菌和真菌的数量相差100倍以上。不同树龄的果园随着土层的深入,土壤细菌、放线菌和真菌在数量上均呈现出减少的趋势。0~20 cm的表层土是菌群分布比较集中的区域。④有机质与脲酶、磷酸酶和蔗糖酶均呈正向相关,r值分别为0.400、0.565和0.788,且三种酶之间也有很强的相关性。⑤三种土壤酶、土壤有机质、土壤微生物与苹果品质的5个指标之间均呈正相关,说明这三类因素可以影响苹果品质。     

三氯生与镉单一及复合污染对土壤呼吸和酶活性的影响

为了解典型药品和个人护理品(PPCPs)——三氯生与镉复合污染的生态效应,采用室内培养实验和联合毒性预测模型,首次评价了三氯生与镉单一及复合污染对土壤呼吸及参与土壤碳氮循环的相关酶活性的生态毒性。结果表明:三氯生与镉单一及复合污染对土壤呼吸呈现激活—抑制—激活的生态效应;刺激了蛋白酶活性,激活率先降低后升高,56 d时达到最大。整个实验期间均抑制了蔗糖酶活性,镉(10.0 mg kg-1)单一污染培养14 d抑制率达到最大值(81%),三氯生单一胁迫呈现负的剂量效应关系,两者复合污染无显著的剂量效应关系。联合效应评价模型预测表明,相比三氯生或镉单一污染,两者的复合胁迫对土壤呼吸呈现随时间变化的拮抗—协同—加和效应,对土壤蛋白酶呈现协同—加和—协同的联合效应,而对土壤蔗糖酶活性则主要为协同效应。     

二氧化碳升高与干旱对植物生理、土壤碳及土壤酶活的影响

Global climate models have indicated high probability of drought occurrences in the coming future decades due to the impacts of climate change caused by a mass release of CO2.Thus,climate change regarding elevated ambient CO2 and drought may consequently affect the growth of crops.In this study,plant physiology,soil carbon,and soil enzyme activities were measured to investigate the impacts of elevated CO2 and drought stress on a Stagnic Anthrosol planted with soybean (Glycine max).Treatments of two CO2 levels,three soil moisture levels,and two soil cover types were established.The results indicated that elevated CO2 and drought stress significantly affected plant physiology.The inhibition of plant physiology by drought stress was mediated via prompted photosynthesis and water use efficiency under elevated CO2 conditions.Elevated CO2 resulted in a longer retention time of dissolved organic carbon (DOC) in soil,probably by improving the soil water effectiveness for organic decomposition and mineralization.Drought stress significantly decreased C:N ratio and microbial biomass carbon (MBC),but the interactive effects of drought stress and CO2 on them were not significant.Elevated CO2 induced an increase in invertase and catalase activities through stimulated plant root exudation.These results suggested that drought stress had significant negative impacts on plant physiology,soil carbon,and soil enzyme activities,whereas elevated CO2 and plant physiological feedbacks indirectly ameliorated these impacts.     

甜高粱SAI基因的表达与茎秆糖分积累的相关性分析

【目的】通过检测不同甜高粱品种在各个生育时期叶片和茎秆中SAI基因的差异表达量与含糖量,探讨二者之间的相关性,为研究甜高粱糖分积累机制提供理论依据。【方法】高效液相色谱（HPLC）测定甜高粱品种不同生育时期茎秆中的含糖量,qRT-PCR分析叶片和茎秆中SAI基因的表达水平。【结果】拔节期蔗糖含量很低,主要是还原性糖,抽穗和开花期蔗糖含量显著增加,灌浆和成熟期持续增加至最高值,成熟后又有所下降。高糖品种整个生育时期叶片中SAI基因的表达水平高于中糖、低糖和髓干型三类品种,茎秆中SAI基因的表达水平则相反。甜高粱成熟期糖分含量与叶片中SAI基因的表达量呈显著正相关关系,相关系数达0.7239,而与茎秆中的表达量呈负相关关系,相关系数为-0.5971。【结论】甜高粱茎秆蔗糖积累与SAI基因在叶片和茎秆中的表达水平具有相关性,叶片中SAI基因的表达与蔗糖积累正相关,茎秆中SAI基因表达与蔗糖积累负相关,叶片的相关系数高于茎秆。