不同浓度氮处理毛竹水通道蛋白基因表达模式及其调控网络

氮和水分平衡对植物生长发育具有重要作用,在长期进化过程中植物体内形成了氮运输和水分平衡的复杂调控网络。为揭示竹子速生的内在调控机制,研究了不同浓度氮处理下毛竹根中水通道蛋白(AQP)基因的表达模式,并预测了其表达调控网络。结果表明,在不同浓度氮处理下,在毛竹根的转录本中共鉴定到30个差异表达的PeAQPs,包括14个PePIPs、8个PeTIPs、7个PeNIPs和PeSIP2-1;随着氮浓度的提高,PeAQPs的表达模式主要分为2类：一类呈上调表达,另一类呈下调表达。在这些差异表达AQP基因的启动子中鉴定到了许多转录因子(TF)的结合元件,同时通过筛选差异表达TFs,构建了差异表达TFs和PeAQPs的共表达网络。代表性差异表达TFs和PeAQPs表达的相关性分析和共表达结果表明,这些TF可能参与调控毛竹中水分和氮的协调运输。研究结果可为深入解析毛竹快速生长的分子机制提供参考。     

茶树2个MYB转录因子基因的克隆及表达分析

MYB类转录因子是一类包含一段保守的DNA结合结构域的基因家族,广泛地参与植物发育和植物次生代谢的调节。根据前期芯片杂交和文库筛选得到的2个MYB转录因子的部分序列,采用RT-PCR和RACE技术分离得到它们的全长基因:CsMYB1和CsMYB2,在GenBank的登录号分别为HQ660373和HQ660374。序列分析表明:CsMYB1基因全长1132bp,开放阅读框长879bp,编码292个氨基酸,推测的蛋白分子量约为32.9ku,理论等电点为8.13;CsMYB2基因全长1020bp,其中开放阅读框长675bp,编码224个氨基酸,推测的蛋白分子量约为25.4ku,理论等电点为9.05。2个基因编码的蛋白均具有明显的R2R3MYB结构域,且在R3结构域的下游都含有1个相对保守的C1(LIXXGIDPXTHR)基序。同源性分析表明:茶树CsMYB1和CsMYB2编码的氨基酸序列与其他植物的MYB类转录因子具有较高的相似性,其中CsMYB1编码的氨基酸序列与陆地棉MYB1的相似性为57%,CsMYB2编码的氨基酸序列与葡萄MYBC2的相似性为75%。利用荧光定量PCR技术检测2个转录因子基因在遮荫处理条件下的表达规律,及其在茶树不同组织中的表达特性,结果表明:CsMYB1和CsMYB2在不同组织中均有表达,但表达量具有明显区别,其中CsMYB2在叶片中的相对表达量是根中的100多倍;而遮荫处理能明显降低叶片中的花青素含量,并提高CsMYB1的表达,但对转录因子CsMYB2的影响不大。     

Cloning and sequence analysis of nine novel MYB genes in Taxodiaceae plants

Myeloblastosis(MYB) is one of the largest transcribed factor families in plants. To gain an overall picture of the evolution of MYB genes in relict plants, we cloned nine novel MYB genes in Taxodiaceae plants(Taxodium distichum, Taxodium ascendens, Cryptomeria japonica var. Sinensis, Cryptomeria japonica cv. Araucarioides, Cryptomer Japonica, Metasequoia glyptostroboides, Cunninghamia lanceolata, Taiwania cryptomerioides and Glyptostrobus pensilis). The deduced amino acid sequences for MYBs showed that the nine MYB proteins contained two DNA binding domains. The first domain is from amino acid position 29 to 78, wherein three tryptophanes at 33, 53 and 73 were separated by 19 amino acids, respectively. The second domain is from amino acid position 82 to 127, wherein three tryptophanes at 86, 105 and 124 were separated by 18 amino acids, respectively, whereas the first tryptophane at amino acid position 86 is replaced by a phenylalanine. The characterization of these conserved domains at nine MYBs indicated that they all belong to the R2R3-MYB group. The secondary structure analysis showed that α-helix and β-turn are the major motifs of the predicted secondary structure of MYBs. The three dimensional model of each MYB protein showed that the structure is like clip, making it more flexible and mobile. The similarities between the nine MYB proteins in Taxodiaceae were calculated. The highest identical value of 99% is between CjsMYB, CjMYB and CjaMYB, whereas the lowest value of 82% is between TaMYB and ClMYB. According to the phylogenetic tree, the distances between different genera were relatively large whereas those within genera were relatively small. As expected, accessions of the same genus formed a subgroup before being grouped with other genera.     

植物花色素合成的转录调控研究进展

花色素是由植物类黄酮代谢途径产生的次生代谢产物,决定了花、果实和种子的颜色。随着类黄酮代谢途径的研究不断地深入,多种植物编码合成花色素的结构基因也已得到克隆,并研究证明花色素合成结构基因与转录因子(MYB、 bHLH和WD40)有着极其复杂的相互作用模式。本文主要对花青素合成相关的MYB、bHLH和WD40转录因子及其在调节结构基因表达和花青素合成中的作用进行了综述。     

杨树R2R3 MYB基因PeMYBLI的克隆及表达

An R2R3 MYB gene,PeMYBL1,was isolated from male inflorescence of Populus×euramericana by homologous cloning combined with in silico cloning techniques.The full length of PeMYBL1 cDNA was 1 094 bp encoding 276 amino acids.The deduced amino acid sequence contained two conserved MYB domains near the N-terminus,a conserved E1 motif and an acidic Ser/Thr rich region toward its C terminus.Phylogenetic analysis revealed that PeMYBL1 was clustered with AtMYB85 from Arabidopsis thaliana,ZmMYBL1 from Zea mays,OsMYB15...     

小兰屿蝴蝶兰R2R3-MYB转录因子分析

[目的]本研究为了探讨在植物发育和抗逆过程扮演着重要角色的MYB转录因子的潜在功能。[方法]利用拟南芥MYB转录因子家族蛋白序列(At MYBs)和已报道的蝴蝶兰R2R3-MYB转录因子家族蛋白序列(Pe MYBs),采用本地化软件BLASTP对小兰屿蝴蝶兰全基因组数据库进行搜索,并利用Pfam数据库验证MYB结构域,获得小兰屿蝴蝶兰MYB转录因子家族编码序列(Pe MYBs)125条,包含1R-MYB结构域的Pe MYBs蛋白序列27条,R2R3-MYB结构域96条,R1R2R3-MYB结构域2条。重点对96条R2R3-MYB结构Pe MYBs蛋白序列特点进行生物信息学分析。[结果]依据拟南芥的分类标准将小兰屿蝴蝶兰R2R3-MYB类转录因子划分为20个亚群,预测获得同源性较高的直系和旁系同源基因;各基因在四种器官(花、叶、根、茎)中的表达情况各异,39个Pe MYBs基因在4种器官中均表达,48个基因在不同器官中有特异性不表达现象,一些基因呈现器官特异性表达特点,推测其可能参与相应组织特定发育时期的调控。[结论]预测获得125条Pe MYBs蛋白序列,并对部分Pe MYB转录因子可能的调控功能进行了预测,将为细致研究蝴蝶兰MYB转录因子调控植物生长发育和逆境胁迫响应的分子机理提供一定的数据基础。     

Verification of the resistance of a LEA gene from Tamarix expression in Saccharomyces cerevisiae to abiotic stresses

The role of late embryogenesis abundant （LEA） proteins in stress tolerance was examined by using a yeast expression system. LEA protein tolerance to the abotic stresses in plants involved in salt, drought and freezing stresses and additional tolerance to heat, NaHCO3 （salt-alkali） and ultraviolet radiation was also investigated. The transgenic yeast harboring the Tamarix LEA gene （DQ663481） was generated under the control of inducible GAL promoter （pYES2 vector）, yeast cells transformed with pYES2 empty vector were also generated as a control. Stress tolerance tests showed that LEA yeast transformants exhibited a higher survival rates than the control transformants under high temperature, NaHCO3, ultraviolet radiation, salt （NaCl）, drought and freezing, indicating that the LEA gene is tolerant to these abiotic stresses. These results suggest that the LEA gene is resistant to a wider repertoire of stresses and may play a common role in plant acclimation to the examined stress conditions.     

ptc-miR213的人工microRNA植物表达载体的 构建及遗传转化

ptc-miR213是在构建盐胁迫条件下青杨microRNA文库中发现的,预测其靶基因为MYB4、PP2C、蛋白激酶等,其中MYB家族与植物的耐盐性密切相关。为了探索ptc-miR213在植物盐碱胁迫应答方面的作用,实验构建了植物表达载体pCAM2300-ami213,经根癌农杆菌EHA105介导转化拟南芥,成功获得转基因植株。RT-PCR分析表明amiR213在转基因拟南芥中能够超量表达。本研究为分析ptc-miR213及其靶基因参与植物盐碱胁迫应答奠定了基础。     

毛竹TIP基因成员鉴定及其响应胁迫的表达分析

液泡膜内在水通道蛋白（TIPs）在调节植物细胞膨压适应逆境胁迫环境过程中发挥着重要作用。研究毛竹TIP基因成员的分子特征及其在不同逆境胁迫条件下的表达模式，对揭示其在毛竹应答胁迫中的功能具有重要意义。利用生物信息学方法在毛竹基因组中共鉴定19个编码完整TIP蛋白的基因（PeTIP1-1~PeTIP1-3、PeTIP2-1~PeTIP2-4、PeTIP3-1~PeTIP3-2、PeTIP4-1~PeTIP4-7和PeTIP5-1~PeTIP5-3）；PeTIPs编码氨基酸的长度为238~434 aa，相对分子量为25.06~44.03 kDa；亚细胞位置预测显示，所有PeTIPs均定位于液泡膜上。PeTIPs包含7个保守基序，其中有4个为共有基序，不同成员的Ar/R选择性过滤器具有一定的差异，而Froger's残基均较为保守。系统进化分析显示，来自毛竹、水稻等6个物种的71条TIP氨基酸序列可分为5个分支，各分支中PeTIPs成员依次为3、4、2、7和3个。共线性分析结果表明，PeTIPs成员间共存在10对片段重复，在12个PeTIPs与水稻8个TIP基因间发现18对片段重复，这些重复基因多半发生在PeTIP4s和PeTIP5s中，且基因对的非同义对同义取代比（Ka/Ks）均小于1.0，表明PeTIPs经复制后的功能差异不大。在PeTIPs启动子区域中，发现多种与胁迫、激素响应相关的调控元件。基于叶片RNA-seq数据分析表明，不同PeTIPs响应低温、干旱和强光胁迫的表达模式均存在一定差异，既有显著性变化的成员（如PeTIP1-1和PeTIP1-2），也有几乎无变化的成员（如PeTIP5的成员）。qPCR结果显示，在不同胁迫条件下毛竹叶片和根中的PeTIPs的表达模式不同，多数呈现不同程度的显著上调，亦有在某一处理下基因表达变化不明显（如强光下叶片中的PeTIP1-1、PeTIP1-3和PeTIP4-2；干旱下根中的PeTIP1-1和PeTIP1-2），个别基因呈现下调（如低温下叶片中的PeTIP1-1）。毛竹叶片和根中PeTIPs的表达变化模式差异，说明它们在响应不同环境胁迫中可能发挥着不同的作用。     

Overexpression of AtNHX5 improves tolerance to both salt and drought stress in Broussonetia papyrifera (L.) Vent

Paper mulberry (Broussonetia papyrifera L. Vent) is well known for its bark fibers, which are used for making paper, cloth, rope, etc. It was found that, in addition to its well-documented role in the enhancement of plant salt tolerance, overexpression of the Na+/H+ antiporter (AtNHX5) gene in paper mulberry plants showed high drought tolerance. After exposure to water deficiency and salt stress, the wild-type (WT) plants all died, while the AtNHX5-overexpressing plants remained alive under high salt stress, and had a higher survival rate (>66%) under drought stress. Measurements of ion levels indicated that Na+ and K+ contents were all higher in AtNHX5-overexpressing leaves than in WT leaves in high saline conditions. The AtNHX5 plants had higher leaf water content and leaf chlorophyll contents, accumulated more proline and soluble sugars, and had less membrane damage than the WT plants under water deficiency and high saline conditions. Taken together, the results indicate that the AtNHX5 gene could enhance the tolerance of paper mulberry plants to multiple environmental stresses by promoting the accumulation of more effective osmolytes (ions, soluble sugars, proline) to counter the osmotic stress caused by abiotic factors.     

Utilization of lightflecks by seedlings of five dominant tree species of different subtropical forest successional stages under low-light growth conditions

We selected five typical tree species, including one early-successional species (ES) Pinus massoniana Lamb., two mid-successional species (MS) Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils. and two late-successional species (LS) Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry., which represent the plants at three successional periods in Dinghushan subtropical forest succession of southern China. Potted seedlings of the five species were grown under 12% of full sunlight for 36 months. The ES and MS showed the slowest and fastest responses to lightflecks, respectively, which correlated with the rate of stomatal opening. In contrast to P. massoniana and C. concinna, the other three species exhibited a high induction loss. Early-successional species showed the lowest specific leaf area and chlorophyll content, the highest photosynthetic capacity (A(max)) and respiratory carbon losses (R(d)). Compared with ES and MS, LS showed lower A(max) and R(d). The five tree species showed a similar chlorophyll a/b ratio after long-term low-light adaptations. On the other hand, LS had a relatively higher de-epoxidation state to protect themselves from excess light during lightflecks. Our results indicated that (i) slower responses to lightflecks could partially explain why ES species could not achieve seedling regeneration in low-light conditions; (ii) fast responses to lightflecks could partially explain why MS species could achieve seedling regeneration in low-light conditions; and (iii) smaller respiratory carbon losses might confer on the LS species a competitive advantage in low-light conditions.     

马尾松优树子代家系生产力评价的研究

对６片１３年生马尾松优树子代家系测定林的研究结果表明，５～１３年生时其高、径和材积生长性状具有丰富的遗传变异，受中度以上遗传控制。年度间相关分析表明，对８年生以上马尾松优树子代测定林进行选择是可行的。利用材积指标作为丰产性测度对马尾松优树子代家系的生产力水平进行评价，从参试的２２９个家系中评选出１０３个材积大于群体平均值的家系，可作为一代种子园疏伐时留优去劣的依据；６０个材积大于群体平均值１５．０％的优良家系，利用其亲本无性系开展杂交育种工作；３４个材积大于群体平均值２５．０％的优良家系，可以直接在一代种子园中进行单系采种、造林，提高马尾松的经营效益。     

植物苹果酸酶在抵御逆境中的作用

植物在成长过程中会遇到许多逆境,都会给其带来伤害,因此抗逆育种工作就显得尤为重要。苹果酸酶广泛地存在于各种植物中,并且能够响应不同的环境胁迫。通过总结与苹果酸酶抗逆性相关的研究,综述了在多种胁迫条件下苹果酸酶基因的表达情况和苹果酸酶的活性变化情况,分析了它在植物防御反应中的功能和作用机理,为将来利用苹果酸酶基因进行分子抗逆育种提供了一定的理论基础。     

不同种源马尾松优树家系在城步的生长表现

以来自湖南省城步、绥宁、通道、会同、安化、浏阳、南岳、慈利、资兴、临武、江永、衡南、茶陵、郴州等14个种源区的82个优树家系种子和城步试验区附近优良林分混合种子(对照)为试验材料,以容器苗造林于城步,对来自不同种源区的家系在城步的生长表现进行研究。结果表明:幼龄期城步本地马尾松优良林分子代表现较好,仅次于江永种源,而浏阳、通道种源幼龄期和中龄期平均胸径均显著小于城步马尾松优良林分子代的,但随着林龄的增长,资兴、会同、江永、临武种源的树高、胸径、材积的表现均逐渐超过了本地优良林分子代的表现。以11年生材积排名,表现最好的是来自于资兴的家系,排前5名的有4个(含前3名);来自于江永的家系表现较好,仅次于资兴的,排前5名的有1个。以11年生材积生长量为优良家系选择标准,按家系总数15%的入选率,江永家系的入选率最高,达50.0%;资兴的次之,为41.2%;临武的较小,为23.1%。马尾松家系的生长表现在幼龄期和中龄期有一定有差异,早晚表现一致的家系仅占50%。     

Improvement of paper mulberry tolerance to abiotic stresses by ectopic expression of tall fescue FaDREB1

Dehydration-responsive element binding/C-repeat-binding factors (DREB/CBF) control the activity of multiple stress response genes and therefore represent attractive targets for genetic improvement of abiotic stress tolerance. Paper mulberry (Broussonetia papyrifera L. Vent) is well known for its bark fibers and high levels of chalcone and flavonoid derivatives. Transgenic paper mulberry plants expressing a tall fescue (Festuca arundinacea Schreb.) FaDREB1 gene under the control of CaMV 35S were produced to examine the potential utility of FaDREB1 to increase the tolerance of paper mulberry plants to abiotic stress. The overexpressing FaDREB1 plants showed higher salt and drought tolerance than the wild-type plants (WT). After 13 days of withholding water, or 15 days in the presence of 250 mM NaCl, all the WT plants died, while the over-expressing FaDREB1 plants survived. The FaDREB1 plants had higher leaf water and leaf chlorophyll contents, accumulated more proline and soluble sugars, and had less ion leakage (which reflects membrane damage) than the WT plants had under high salt- and water-deficient conditions. The 35S promoter-driven expression of FaDREB1 did not cause growth retardation under normal growth conditions. Therefore, improved tolerance to multiple environmental stresses in paper mulberry might be achieved via genetic engineering through the ectopic expression of an FaDREB1 gene.     

山西太宽河自然保护区有毒植物多样性研究

有毒植物在人类的生产和生活中发挥着重要的作用。太宽河自然保护区有野生有毒植物127种,隶属于52科101属,约占太宽河自然保护区维管植物的14%。针对有毒植物资源进行了分析和评价,并提出了相应的保护和开发对策。