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采用RACE-PCR方法,以甘蔗心叶为材料克隆了甘蔗PSⅠ反应中心亚基Ⅱ基因全长,命名为SopsaD,GenBank登录号JX866950。该基因cDNA序列全长为904bp,编码200个氨基酸多肽,预测其分子质量和等电点分别为21.85ku和10.5,其中N端的1~44aa是叶绿体转运肽序列,62~199aa是保守的Pfam:PasD结构域。SopsaD与玉米(EU953246)、水稻(AY224449)、大麦(M98254)和短柄草(XM003564060)psaD基因核苷酸同源性分别为85%、85%、84%和81%,氨基酸序列的同源性分别为92%、88%、87%和85%。荧光定量PCR表明甘蔗在叶、花序、芽、茎和根中都能检测到SopsaD基因表达,其中在叶中表达量最高,其次是花序中,而在根中的表达量最低。甘蔗在工艺成熟期和生理成熟期SopsaD基因整体上表现为功能叶中基因表达量高,而老叶中基因表达量低,证实该基因参与光合作用反应。
The total length of subunit Ⅱ gene of PS Ⅰ reaction center of sugarcane was cloned by RACE-PCR from the leaves of sugarcane, and named as SopsaD, GenBank accession number JX866950. The cDNA sequence of this gene is 904bp in length and encodes a polypeptide of 200 amino acids. The predicted molecular mass and isoelectric point are 21.85ku and 10.5, respectively. The N-terminal 1 ~ 44aa is the chloroplast transit peptide sequence and the 62 ~ 199aa is conserved Pfam: PasD domain. The nucleotide homologies of SopsaD with the psaD gene of maize (EU953246), rice (AY224449), barley (M98254) and Brachycis (XM003564060) were 85%, 85%, 84% and 81% Sexuality was 92%, 88%, 87% and 85% respectively. Quantitative real-time PCR showed that SopsaD gene expression could be detected in leaves, inflorescences, shoots, stems and roots of sugarcane. Among them, the expression of SopsaD gene was highest in leaves, followed by inflorescences and lowest in roots. The sugarcane SopsaD gene showed a high gene expression level in the functional leaves and a low gene expression in the old leaves at the mature and physiological maturation stages of sugarcane, indicating that the gene is involved in the photosynthetic reaction.