甘蔗天冬氨酰半醛脱氢酶基因的电子克隆与分析

应用电子克隆技术，以水稻EF576477序列为探针，获得了甘蔗天冬氨酰半醛脱氢酶基因（aspartate．semialdehydedehy—drogenase，ASADH）的一条cDNA全长序列，命名为ScASADH。采用生物信息学方法，对该基因编码蛋白从氨基酸组成、理化性质、亚细胞定位、跨膜结构域、疏水性／亲水性、高级结构及功能域等方面进行预测和分析。结果表明：该基因全长1711bp，包含一个1128bp的开放阅读框，编码375个氨基酸，该基因编码蛋白定位于细胞核，为可溶性蛋白，存在信号肽，二级结构原件多为无规卷曲，含有多个保守功能域，主要功能为翻译。电子表达分析结果显示，该基因在甘蔗根尖、幼苗、花序、叶片和茎中组成型表达，其中在茎中的表达量比其他组织类型中表达量高。该基因的表达受葡萄糖杆菌和赤腐病菌的调控。

Electronic cloning and characterization of sugarcane ScASADH gene using bioinformatics tools

The full-length cDNA sequence of one sugarcane aspartate-semialdehyde dehydrogenase gene（ScASADH gene）was abtained by in silico cloning using EF576477 sequence from Oryza sativa, as the probe sequence. Some characters of the ScASADH gene encoding amino acid, including the composition of amino acid sequence, physical and chemical properties, subcellular localization, transmembrane domain, hydrophobicity/hydrophilicity, seconda- ry and tertiary structure of protein plus functional domains, were analyzed by bioinformatics tools. The results showed that the full-length ScASADH gene from sugarcane was 1 711 bp, including one 1 128bp open reading frame（ ORF）which encodes a polypeptide of 375 amino acids. The encoded protein of ScASADH gene, with the presence of signal peptide and several conserved domain sequences, was soluble and located in nucleus, and the corresponding secondary structure of this protein was mainly composed of random coil. The function of the ScAS- ADH protein was mainly involved with translation. Electronic expression analysis revealed that the ScASADH gene was constitutively expressed in the sugarcane root tip, seedling, inflorescence, leaf and stein, and the expression of this gene in the stem of sugarcane was much higher than that in all the other four types of sugarcane tissues, the ex- pression of this gene was regulated under the stresses of Gluconacetobacter and Colletotrichum falcatum.