Regulation of gene expression during conifer embryogenesis

针叶树胚胎发生过程中基因表达的调控

• 批准号: 42346-2006
• 负责人: Misra, Santosh
• 金额: $ 1.18万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=390472
• 关键词: Regulation; gene; expression; during; conifer

Clonal propagation by somatic embryogenesis (SE) has the potential for the delivery of superior material to the commercial forest in a much shorter time and used in combination with the sexual process for seed production will help maintain the correct genetic balance from seed orchards. Presently constraints to the successful introduction of commercial embryogenesis in conifers are perceived to be: a) improvement of embryo quality; b) efficiency and the number of responding genotypes; c) induction of SE from mature tissues. To develop SE for white spruce and Douglas fir, two economically important species in Canada, we have been examining the molecular events during development of SE and ZE. The analysis of cDNA and genomic sequences expressed during maturation have provided important information on molecular biology of conifer embryo maturation and form the basis of continuing proposed studies that will focus on very early stages of embryogeny. The molecular basis of early embryogeny, role of MG, suspensor, and other factors in self- and cross-pollinated seeds will be studied using the homologous embryo regulatory probes (transcription factor PmLEC1, and PmCOP1, two critical genes expressed during early Douglas fir ZE and SE, (isolated in my lab), and DD-PCR. The functional analysis of these genes will be performed by reverse genetics. In addition, differences between E and NE cultures during the induction phase will be examined to understand what roles the gene products play in initiation of SE. Formation of conifer E culture is genotype dependent and induction frequencies can vary widely among families. Approaches include PCR based SSH cDNA libraries coupled with microarray and/or quantitative RT-PCR based profile analyses. Microarray based methodology will allow the simultaneous quantification of a large number of transcripts to identify coordinated gene groups during SE initiation and response (s) to PGRs including Brassinolide treatment implicated in increased SE frequency from a wide range of genotypes of conifers, including Douglas fir. The research is of fundamental and practical interest and will also be important in training of HQP.

体细胞胚发生（SE）的无性系繁殖有可能在更短的时间内向商业林输送优质材料，并与有性繁殖过程相结合用于种子生产，将有助于维持种子园正确的遗传平衡。目前，在针叶树中成功引入商业胚胎发生的限制因素被认为是：a)胚胎质量的提高；B)应答基因型的效率和数量；c)从成熟组织中诱导SE。为了开发加拿大两种重要的经济树种白云杉和花旗松的SE，我们研究了SE和ZE发育过程中的分子事件。成熟过程中表达的cDNA和基因组序列的分析为针叶树胚胎成熟的分子生物学提供了重要信息，并为将重点放在胚胎发生的早期阶段的持续研究奠定了基础。我们将利用同源胚胎调控探针（转录因子PmLEC1和PmCOP1）和DD-PCR研究早期胚胎发生的分子基础，以及MG、悬柄和其他因子在自花授粉和异花授粉种子中的作用，这两个关键基因在花旗松ZE和SE早期表达（我的实验室分离）。这些基因的功能分析将通过反向遗传学进行。此外，在诱导阶段，E和NE培养物之间的差异将被检查，以了解基因产物在SE起始中起什么作用。针叶树E培养物的形成依赖于基因型，不同家族之间的诱导频率差异很大。方法包括基于PCR的SSH cDNA文库，结合微阵列和/或基于定量RT-PCR的谱分析。基于微阵列的方法将允许同时定量大量转录本，以确定在SE起始和对pgr (s)的反应期间的协调基因群，包括油菜素内酯处理，涉及从包括花旗松在内的广泛基因型针叶树中增加SE频率。该研究具有基础性和实践性的意义，对HQP的培训也具有重要意义。