Park J H, Oh S A, Kim Y H, Woo H R, Nam H G
Department of Life Science and School of Environmental Engineering, Pohang University of Science and Technology, Kyungbuk, South Korea.
Plant Mol Biol. 1998 Jun;37(3):445-54. doi: 10.1023/a:1005958300951.
Four cDNA clones, named pSEN2, pSEN3, pSEN4, and pSEN5, for mRNAs induced during leaf senescence in Arabidopsis thaliana were characterized. The clones were isolated from a cDNA library of detached leaves incubated in darkness for 2 days to accelerate senescence, first by differential screening and then by examining expression of the primarily screened clones during age-dependent leaf senescence. Transcript levels detected by these cDNA clones, thus, were up-regulated in an age-dependent manner and during dark-induced leaf senescence. In contrast, when leaf senescence was induced by ethylene, ABA or methyljasmonate, the transcript level detected by the clones was differentially regulated depending on the senescence-inducing hormones. The transcript level for pSEN4 increased during senescence induced by all three hormones, while the transcript detected by the pSEN2 clone did not increase during senescence induced by ethylene. The transcript level for pSEN5 was increased upon ABA-induced senescence but decreased during ethylene-induced senescence. The pSEN3 clone detected multiple transcripts that are differentially regulated by these factors. The results show that, although the apparent senescence symptoms of Arabidopsis leaf appear similar regardless of the senescence-inducing factors, the detailed molecular state of leaf cells during senescence induced by different senescence-inducing factors is different. The pSEN3 clone encodes a polyubiquitin and the pSEN4 clone encodes a peptide related to endoxyloglucan transferase. This result is consistent with the expected roles of senescence-induced genes during leaf senescence.
对拟南芥叶片衰老过程中诱导产生的mRNA的四个cDNA克隆（命名为pSEN2、pSEN3、pSEN4和pSEN5）进行了表征。这些克隆是从在黑暗中培养2天以加速衰老的离体叶片cDNA文库中分离得到的，首先通过差异筛选，然后通过检测主要筛选出的克隆在依赖年龄的叶片衰老过程中的表达情况。因此，这些cDNA克隆检测到的转录水平在依赖年龄的过程以及黑暗诱导的叶片衰老过程中呈上调状态。相比之下，当用乙烯、脱落酸或茉莉酸甲酯诱导叶片衰老时，这些克隆检测到的转录水平根据衰老诱导激素的不同而受到差异调节。pSEN4的转录水平在由所有三种激素诱导的衰老过程中均升高，而pSEN2克隆检测到的转录本在乙烯诱导的衰老过程中未升高。pSEN5的转录水平在脱落酸诱导的衰老过程中升高，但在乙烯诱导的衰老过程中降低。pSEN3克隆检测到多个受这些因素差异调节的转录本。结果表明，尽管无论衰老诱导因子如何，拟南芥叶片的明显衰老症状看起来相似，但在不同衰老诱导因子诱导的衰老过程中，叶片细胞的详细分子状态是不同的。pSEN3克隆编码一种多聚泛素，pSEN4克隆编码一种与内切木葡聚糖转移酶相关的肽。这一结果与衰老诱导基因在叶片衰老过程中的预期作用一致。
