Dry artificial seeds through induction of desiccation tolerance of somatic embryos by abscisic acid and study of mechanism of the desiccation tolerance

人工种子技术可以在植物繁殖系统中提供潜在的益处。如果体细胞胚在含水量降低到真种子水平后仍能保持活力，则可作为种质保存的方法、植物发育生物学研究的模式系统和人工种子的利用。本研究旨在探讨外源ABA对芸苔属作物小孢子胚脱水耐性的诱导作用，并对脱水耐性胚的蛋白质和基因进行分析。ABA诱导胚的脱水耐性。这些现象受胚的大小和ABA浓度的影响，但不依赖于基因型。用10 ^-10 ^M ABA处理干子叶胚，转化率为41 - 53%。<-4><-5>相比之下， ...更多信息 所有的胚在干燥后，当它们没有用ABA处理时，都失去了它们的生活力。球形胚即使经过ABA处理也不能获得脱水耐性。高浓度拟南芥也能诱导胚的脱水耐性，但转化率（1.3 - 8.3%）低于ABA处理。干胚在室温条件下储存6个月后保持其植物转化能力。经ABA处理的胚在形态上与未处理胚无明显差异，蛋白质的SDS-PAGE和westernblot分析表明，ABA处理的胚积累了种子贮藏蛋白。对胚蛋白质的双向电泳分析表明，ABA处理过程中合成了几种新的多肽，它们可能与脱水耐性的获得有关。以莱亚基因（pLEA76）为探针，筛选了ABA处理的胚中存在的mRNA的cDNA文库。选择了6个cDNA克隆。现在我们正在鉴定这些cDNA克隆。少

Artificial seed technology may provide potential benefits in plant propagation systems. If somatic embryos could maintain their viability after their water content was decreased to the level of true seeds, they were used as a method of germplasm storage and a model system of study of developmental plant biology as well as a utilization of artificial seed. The objective of this study was to investigate induction of desiccation tolerance in microspore-derived embryos of Brassica crops by exogenous application of ABA and to analyze the proteins and genes of the desiccation tolerant embryos.After desiccation treatment, the relative water content of embryos had decreased to about 10%. Desiccation tolerance of the embryos was induced by ABA. These phenomena were influenced by the size of embryos and the concentration of ABA, but not dependent on genotypes. The frequency of plant conversion of dry cotyledonary embryos which were treated with 10^<-4>-10^<-5>M ABA was 41-53%. In contrast, almos … More t all embryos lost their viability after desiccation, when they were not treated with ABA. Globular embryos could not acquire desiccation tolerance, even if they were treated with ABA. Though desiccation tolerance of the embryos was also induced by high osmoticum, the frequency of plant conversion (1.3-8.3%) was lower than that treated with ABA. The dry embryos maintained their plant conversion ability after six months of storage under room temperature conditions. The plantlets recovered from dry embryos were not morphologically different from those from non-desiccated ones.SDS-PAGE and western blot analysis of proteins revealed that the embryos treated with ABA accumulated seed storage proteins. And two dimensional gel analysis of the embryo proteins indicated that several new polypeptides were synthesized during ABA treatment and they may be associated with the acquisition of desiccation tolerance. A cDNA library representing mRNA's present in embryos treated with ABA was screened using Lea gene (pLEA76) as a probe. Six cDNA clones were selected. Now we are characterizing these cDNA clones. Less