Yap Mee-Ngan, Lee Ruey-Hua, Huang Yih-Jong, Liao Chao-Jan, Chen Shu-Chen Grace
Institute of Botany, Academia Sinica, Taipei, Taiwan.
Plant Mol Biol. 2003 Mar;51(4):471-81. doi: 10.1023/a:1022334820332.
The structure and expression of a novel senescence-associated gene (SPA15) of sweet potato were characterized. The protein coding region of the gene consists of 13 exons encoding 420 amino acids. Apparent homologues of this sweet potato gene are found in a variety of dicot and monocot plants, but not in animals or microorganisms. Examination of the expression patterns of the SPA15 gene in sweet potato reveals that the transcripts of SPA15 are specifically induced in the senescing leaves, and the temporal profile of SPA15 protein accumulation is correlated with that of SPA15 transcripts. Studies on the distribution of SPA15 homologue in rice plants also indicate that SPA15 homologue is up-regulated specifically in senescing rice leaves. Treatment of detached sweet potato leaves with phytohormones including ethylene, methyl jasmonate, salicylic acid and abscisic acid resulted in a high-level induction of SPA15. Immunoelectron microscopic analysis demonstrates that SPA15 is specifically associated with the cell wall. The potential role for SPA15 during leaf senescence is discussed.
对甘薯一种新的衰老相关基因（SPA15）的结构和表达进行了表征。该基因的蛋白质编码区由13个外显子组成，编码420个氨基酸。在多种双子叶和单子叶植物中发现了该甘薯基因的明显同源物，但在动物或微生物中未发现。对甘薯中SPA15基因表达模式的研究表明，SPA15的转录本在衰老叶片中被特异性诱导，并且SPA15蛋白积累的时间特征与SPA15转录本的时间特征相关。对水稻植株中SPA15同源物分布的研究也表明，SPA15同源物在衰老的水稻叶片中特异性上调。用包括乙烯、茉莉酸甲酯、水杨酸和脱落酸在内的植物激素处理离体甘薯叶片，导致SPA15的高水平诱导。免疫电子显微镜分析表明，SPA15与细胞壁特异性相关。讨论了SPA15在叶片衰老过程中的潜在作用。
