影响辣椒离体再生芽伸长因素研究(英文)

以辣椒子叶为外植体,比较不同浓度BA和IAA激素组合对辣椒再生芽诱导的差异,利用筛选出的高效芽诱导培养基为基础,研究了赤霉素、芽诱导时间、培养基有机成分、不同激素组合和品种等因素对辣椒不定芽伸长的影响。结果表明:不同基因型辣椒子叶再生能力不同,BA3.0mg·L^-1+IAA0.5mg·L^-1的激素配比对不定芽诱导频率最高;不定芽的伸长百分率随着GA₃浓度的增加而增加,GA₃的适合浓度为1.0～2.0mg·L^-1;不定芽诱导时间对不定芽的伸长有一定的影响,诱导21d的不定芽,其伸长频率明显高于诱导14d的不定芽;B5有机成分在辣椒不定芽的伸长中效果优于MS有机成分;激素组合对不定芽伸长有一定的影响,Zeatin+GA₃激素组合对伸长效果最好,BA+IAA+GA₃伸长效果较好,BA+PAA(苯乙酸,phenylaceticacid)+GA₃伸长效果次之;不同品种辣椒不定芽的伸长能力有一定差异,楚风和苏椒五号再生芽伸长能力最佳。与IAA和NAA相比,IBA对再生芽生根效果较好。     

Regulation of Eukaryotic Initiation Factor 4E and Its Isoform： Implications for Antiviral Strategy in Plants

In recent years, biotechnology has permitted regulation of the expression of endogenous plant genes to improve agronomlcally important traits. Genetic modification of crops has benefited from emerging knowledge of new genes, especially genes that exhibit novel functions, one of which is eukaryotlc initiation factor 4E （eIF4E）. eIF4E Is one of the most important translation initiation factors Involved in eukaryotic initiation. Recent research has demonstrated that virus resistance mediated by eIF4E and Its isoform elf （Iso）4E occurs in several plant-virus interactions, thus indicating a potential new role for eIF4E/elF（Iso）4E In resistance strategies against plant viruses. In this review, we briefly describe eIF4E activity In plant translation, its potential role, and functions of the eIF4E subfamily In plant-virus interactions. Other initiation factors such as elF4G could also play a role In plant resistance against viruses. Finally, the potential for developing eIF4E-mediated resistance to plant viruses in the future Is discussed. Future research should focus on elucidation of the resistance mechanism and spectrum mediated by eIF4E. Knowledge of a particu- lar plant-virus interaction will help to deepen our understanding of eIF4E and other eukaryotic Initiation factors, and their involvement in virus disease control.     

Molecular cloning, expression and mapping analysis of a novel cytosolic ascorbate peroxidase gene from tomato.

Ascorbate peroxidase (APX, EC 1.11.1.11) plays a major role in H(2)O(2)-scavenging in plants and can help to avoid reactive oxygen species (ROS) damage. A new cytosolic APX gene was cloned from tomato (designated LecAPX2) by RACE-PCR. The full-length cDNA of LecAPX2 contained a complete open reading frame (ORF) of 753 bp, which encoding 250 amino acid residues. Homology analysis of LecAPX2 showed a 94% identity with potato cAPX gene and 92% identity with another tomato cAPX gene (APX20), the deduced amino acid showed 88% homology with APX20 protein and 75-92% identity with cAPX from other plants such as potato, tobacco, broccoli, spinach, pea, rice, etc. LecAPX2 revealed the existence of a haem peroxidase and plant APX family signatures. Northern blot analysis showed that LecAPX2 was constitutively expressed in root, stem, leaf, flower and fruit of tomato, whereas the expression levels were different. LecAPX2 was mapped to 6-A using 75 tomato introgression lines (ILs), each containing a single homozygous RFLP-defined chromosome segment from the green-fruited species Lycopersicon pennellii.     

Molecular Cloning and Characterization of a Gene Encoding Eukaryotic Initiation Factor iso4E in Tomato (Solanum lycopersicum)

The eukaryotic translation initiation factor 4E (eIF4E) and its isoform, eIF(iso)4E, play important roles in protein translation and recently reported to be involved in plant–virus interactions. A cDNA encoding the tomato eIF(iso)4E was cloned based on a tentative consensus (TC170275) in TIGR (), and was designated as SleIF(iso)4E, with an open reading frame of 603 nucleotides encoding a protein of 200 amino acids. The calculated molecular weight of the SleIF(iso)4E protein was 22.85 kD, and the theoretical isoelectric point was 5.76. The amino acid sequence of SleIF(iso)4E showed 66–91% identity with eIF(iso)4Es in pepper, tobacco, pea and maize, and 44–51% identity with eIF4Es from other plants. The phylogenetic relationship and tertiary structure comparisons indicate that SleIF(iso)4E share high homology and strict conserved regions with other members of the eIF4E family, a characteristic of all members of this family. Semi-quantitative RT-PCR showed varying expression levels of SleIF(iso)4E in different tissues. By comparing eIF(iso)4E coding sequences between resistant and susceptible tomato genotypes, correlation between sequence variations and virus resistance was identified. These findings provide good grounds for future research on the role of SleIF(iso)4E in translation initiation and plant–virus interactions. Sequence data of SleIF(iso)4E from this article have been deposited at GenBank under accession number EU119958.     

几种白菜类蔬菜卡那霉素抗性的研究

标记基因的利用是筛选和鉴定基因转化的细胞、组织和转基因植株的有效方法。针对目前遗传转化中常用的卡那霉素(Km)抗性基因,对几种白菜类蔬菜的卡那霉素抗性作了较系统的探索,发现5.0 mg/L Km可完全抑制大白菜、小白菜及菜心子叶的再生;幼苗Km抗性测验表明各品种均表现出随着Km浓度的提高,子叶黄化率升高、根茎变短、鲜重减轻的趋势。白菜类蔬菜的卡那霉素抗性检测为遗传转化和阳性后代筛选奠定了基础。     

两种细胞分裂素对大白菜子叶再生的影响

以华阳三号(HY)和鲁白六号(LB)大白菜具柄子叶为外植体,建立了高频率不定芽再生体系,并比较了所使用的2种细胞分裂素作用的异同。MS 0．25mg／L TDZ O．5mg／L NAA 5mg／L AgN03组合中,HY的再生频率达到98．8％,在MS 2mg／L BA 0．5mg／L NAA 5mg／L AgN03组合中,HY和LB的再生频率分别为92．8％和82．4％。TDZ具有比BA高的细胞分裂活性,含有TDZ的培养基中,子叶再生频率高、出芽迅速、芽点多。子叶再生过程中,硝酸银的作用必不可少。     

番茄GDP-D-甘露糖焦磷酸化酶cDNA的克隆、表达及定位

GDP-D-甘露糖焦磷酸化酶催化GDP-D-甘露糖的合成,是植物抗坏血酸生物合成途径中上游的关键酶。以马铃薯GDP-D-甘露糖焦磷酸化酶cDNA序列为信息探针,在GenBank dbEST数据库中找到65条高度同源的番茄EST序列,通过序列拼接及RACE-PCR得到了番茄该基因的全长cDNA序列,命名为LeGMP。LeGMP与马铃薯GDP-D-甘露糖焦磷酸化酶cDNA序列一致率为96％,推导的氨基酸序列与马铃薯、烟草、紫苜蓿、拟南芥的GDP-D-甘露糖焦磷酸化酶基因的一致率分别为99％、97％、91％、89％。经Northern杂交分析,LeGMP在番茄根、茎、叶、花、果实中都有表达,但表达水平有差异。利用75个番茄远缘杂交重组系（IL系）将LeGMP定位在番茄第3染色体上的D区段（3-D）。     

影响辣椒离体再生芽伸长因素研究

以辣椒子叶为外植体,比较不同浓度BA和IAA激素组合对辣椒再生芽诱导的差异,利用筛选出的高效芽诱导培养基为基础,研究了赤霉素、芽诱导时间、培养基有机成分、不同激素组合和品种等因素对辣椒不定芽伸长的影响。结果表明:不同基因型辣椒子叶再生能力不同,BA3.0mg.L-1 IAA0.5mg.L-1的激素配比对不定芽诱导频率最高;不定芽的伸长百分率随着GA3浓度的增加而增加,GA3的适合浓度为1.0～2.0mg.L-1;不定芽诱导时间对不定芽的伸长有一定的影响,诱导21d的不定芽,其伸长频率明显高于诱导14d的不定芽;B5有机成分在辣椒不定芽的伸长中效果优于MS有机成分;激素组合对不定芽伸长有一定的影响,Zeatin GA3激素组合对伸长效果最好,BA IAA GA3伸长效果较好,BA PAA(苯乙酸,phenylaceticacid) GA3伸长效果次之;不同品种辣椒不定芽的伸长能力有一定差异,楚风和苏椒五号再生芽伸长能力最佳。与IAA和NAA相比,IBA对再生芽生根效果较好。