激光显微切割技术推进全面解析植物雄配子发生的分子机制

Laser Microdissection Facilitates a Comprehensive Understanding of Molecular Mechanisms of Plant Male Gametes Production

雄配子(又称小孢子,即花粉)的产生是显花植物生殖发育的重要阶段之一。花粉发育是在花药中与花药发育同步进行的,而花药内壁的绒毡层细胞直接为花粉发育提供营养。花药发育中各细胞(如花粉、绒毡层等)特异性的全基因组表达谱可为全面解析植物雄配子发育的分子调控机制提供丰富的信息。但以往的表达谱研究多基于整个花药甚至整个花序的取材,无法提供细胞特异性的表达信息。最近,激光显微切割技术被运用在水稻花粉发育研究这一领域,分别获得了处于减数分裂后各时期的小孢子以及绒毡层的专一细胞类型的全基因组表达谱。在此基础上,不仅发掘了更多新的花粉及绒毡层细胞特异性表达基因,鉴定了花粉及绒毡层细胞中富集的生化、代谢的细胞通路;而且还鉴定出了更多调控花粉及绒毡层细胞特异性基因表达的顺式元件,并通过系统分析得出了多种植物激素在花粉发育中细胞水平上的时空分布。总之,激光显微切割技术和基因组芯片联用的结果提供了很多可供检验的科学假说,大大推动了对植物雄配子发生发育分子机制的全面了解。

The production of male gametophyte （i.e. microspore, pollen） is important to sexual reproduction of flowering plants. The male gamete develops inside of the anther, and is synchronized with anther development. Tapetal cells in the anther directly provide nutrients to pollen. Genome-wide expression profiling of different types of cells （such as pollen, tapetum, etc） in anther can provide rich information for comprehensive understanding of molecular mechanisms in plant male gametophyte production. However, previous profiling used whole anthers or even whole inflorescence therefore can not provide cell-type specific expression information. Recently, laser microdissection technology has been used in the field of rice pollen development, and revealed the transcriptome of microspore and tapetum at various stages. This work not only provided, more pollen or tapetum-specific genes, but also identified pollen or tapetum-enriched biochemical and metabolizable pathways, and cis-regulatory elements of genes specifically expressed in pollen and tapetum. Meanwhile, spatiotemporal expressions of various phytohormones in pollen development have been systematically analyzed. In conclusion, results from laser microdissection combined with genome-scale microarray provided leads for many novel scientific hypothesis for testing, facilitated our studying towards a comprehensive understanding of molecular mechanisms of plant male gametes production.