CAJ | 학술논문

高等植物叶绿素的生物合成对其正常光合作用起关键作用。本文根据前期芯片杂交结果,采用 RT-PCR 和RACE 技术克隆了3个茶树叶绿素合成相关基因,分别为谷氨酸-tRNA 还原酶基因(CsGluTR)、叶绿素合酶基因(CsChlS)、叶绿素酸醋氧化酶基因(CsCAO),对应的 GenBank 的登录号分别为 HQ660371、HQ660370、HQ660369。序列分析表明, CsGluTR 基因全长2165 bp,开放阅读框长1665 bp,编码554个氨基酸,推测的蛋白分子量约为60.6 kD,理论等电点为8.78； CsChlS 基因全长1463 bp,其中开放阅读框长1125 bp,编码374个氨基酸,推测的蛋白分子量约为40.5 kD,理论等电点为8.58； CsCAO 基因全长2146 bp,其中开放阅读框长1611 bp,编码536个氨基酸,推测的蛋白分子量约为60.8 kD,理论等电点为8.03。比对分析表明,3个基因编码的氨基酸序列与其他植物中同源基因的相似性均在70%以上。利用荧光定量 PCR 技术检测3个基因在不同白化阶段的表达,表明 CsChlS 和 CsCAO 基因具有明显的表达协同性,它们在叶片中的表达量与叶片的颜色变化高度同步；而 CsGluTR 在白化叶片和正常叶片中的表达差异相对较小,同时在新生芽叶转绿过程中最先恢复正常表达水平。说明在白化叶片中,叶绿素的合成机制受到较大影响,叶绿素合成受阻导致的叶片内色素类物质含量降低或消失是叶片白化的直接原因。
고등식물협록소적생물합성대기정상광합작용기관건작용。본문근거전기심편잡교결과,채용 RT-PCR 화RACE 기술극륭료3개다수협록소합성상관기인,분별위곡안산-tRNA 환원매기인(CsGluTR)、협록소합매기인(CsChlS)、협록소산작양화매기인(CsCAO),대응적 GenBank 적등록호분별위 HQ660371、HQ660370、HQ660369。서렬분석표명, CsGluTR 기인전장2165 bp,개방열독광장1665 bp,편마554개안기산,추측적단백분자량약위60.6 kD,이론등전점위8.78； CsChlS 기인전장1463 bp,기중개방열독광장1125 bp,편마374개안기산,추측적단백분자량약위40.5 kD,이론등전점위8.58； CsCAO 기인전장2146 bp,기중개방열독광장1611 bp,편마536개안기산,추측적단백분자량약위60.8 kD,이론등전점위8.03。비대분석표명,3개기인편마적안기산서렬여기타식물중동원기인적상사성균재70%이상。이용형광정량 PCR 기술검측3개기인재불동백화계단적표체,표명 CsChlS 화 CsCAO 기인구유명현적표체협동성,타문재협편중적표체량여협편적안색변화고도동보；이 CsGluTR 재백화협편화정상협편중적표체차이상대교소,동시재신생아협전록과정중최선회복정상표체수평。설명재백화협편중,협록소적합성궤제수도교대영향,협록소합성수조도치적협편내색소류물질함량강저혹소실시협편백화적직접원인。
Chlorophyll is one of the main pigments participating in photosynthesis in plant chloroplasts, and its biosynthesis is crucial for higher plant. In this article, we cloned and characterized three important genes involved in the biosynthesis of chloro-phyll which were CsGluTR, CsChlS, and CsCAO (GenBank accession number HQ660371, HQ660370, and HQ660369) lead on the results of cDNA microarray hybridization. The full-length cDNA of CsGluTR was 2165 bp, containing a 1665 bp ORF encod-ing a 554 amino acids protein, and its 3′ untranslated region had an obvious polyadenylation signal. The deduced protein molecu-lar weight was 60.6 kD and its theoretical isoelectric point was 8.78. The obtained cDNA of CsChlS was 1463 bp in length, con-taining a 1125 bp ORF which encoded 374 amino acid residues. The deduced protein molecular weight was 40.5 kD and its theo-retical isoelectric point was 8.58. The full-length of CsCAO was 2146 bp, containing a 1611 bp ORF encoding a 536 amino acids protein. The deduced amino acid sequence of CsGluTR, CsChlS, and CsCAO from tea plant shared high identity with those of other species, for instance the similarity of 79%, 90%, and 77 % with Vitis vinifera, respectively. The result of Real-time RT-PCR analysis showed a coordinated expression of CsChlS and CsCAO, which was corresponded with the change of the albino pheno-type. However, there were small changes in the expression level of CsGluTR between the normal and albino leaves. These results implied that the biosynthesis of chlorophyll is completely hindered in albino leaves, causing the decline of pigment content and the albino phenotype.