采用异硫氰酸胍法从发芽3-4天的番茄幼苗中提取出总RNA，用Oligo（dT）纤维素亲和层析分离纯化mRNA。以mRNA为模板，Oligo（dT）为引物用逆转录法合成双链cDNA。将cDNA与EcoRI接头连接后克隆到表达载体λgt11的单一EcoRI位点，经体外包装后感染宿主菌Y1090，成功地构建了完整的番茄幼苗cDNA文库。用颜色筛选法筛选重组子，然后用植酸酶抗体做探针进行免疫筛选，得到两个阳性克隆。挑取阳性克隆噬菌斑扩增后纯化DNA，经琼脂糖凝胶电泳鉴定，显示确有外源DNA存在。该插入片断序列测定正在进行。

本文选择低磷耐性较强的羽扇豆和低磷耐性较弱的番茄两种作物，在不同磷水平下水培，对其根系分泌特性进行了比较研究。结果表明，在低磷条件下，羽扇豆酸性磷酸酶和有机酸分泌能力比番茄高2-3倍。番茄体内磷的生理临界浓度显著比羽扇豆为高，可能是其低磷耐性较低的重要原因。

黑芥子酶是一类催化水解芥子油苷的同工酶，Pyk10是在拟南芥根和下胚轴中特异表达的黑芥子酶基因，Pyk10基因的启动子具有根组织特异性。根据已发表的序列，用PCR方法从拟南芥基因组中扩增并克隆了Pyk10基因启动子片段。序列分表明：该片段全长1454bp，与已发表序列同源性达到98%。该启动子片段中含有多种在其他植物启动子中发现的通用启动子元件，并含有器官和组织特异性转录因子的结合位点有ACGT-、CANNTG-、GATA-以及I盒等顺式元件。Pyk10根特异性启动子的成功克隆，为培育抗根部病虫害和营养高效利用型转基因植物奠定了基础。

An intact insulin gene was synthesized by half-enzymic method and cloned into expression vector pPIN9K. After transferring the expression vector pPINS319 into Pichia pastoris GS115, two Pichia pastoris strains secreting high-level human insulin were obtained. The expressed human insulin proteins of recombinant 4 and 9 were 76 and 62 times higher than that of the negative control, respectively. Moreover 88%-90% of the insulin was secreted out of the cells. The actual insulin products of recombinant 4 and 9 calculated according to the sample volume reached 0.563g/l and 0.441g/l, respectively.

The cDNA encoding quail (coturnix) ovalbumin was cloned from quail oviduct by the method of RT-PCR, which was inserted into the P. pastoris genome downstream of the methanol inducible 5' alcohol oxidase (AOX) promoter to replace the AOX1 gene using the plasmid vector pPIC9, and a recombinant P. pastoris strain efficiently secreting quail ovalbumin was successfully constructed. ELISA analysis using a polyclonal antibody raised against quail ovalbumin showed that, induction by 0.75% methanol for 48h led to synthesis of secreted quail ovalbumin to give around 5.45 g l-1, respectively. The recombinant ovalbumin was purified into homogeneity later through ion exchange and gel filtration chromatography. SDS-PAGE analysis revealed that, compared to natural ovalbumin, the recombinant ovalbumin is glycosylated in the similar extent by P. pastoris.