Expression of the Apx gene family during leaf senescence of Arabidopsis thaliana
Expression of the Apx gene family during leaf senescence of Arabidopsis thaliana
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DOI：
10.1007/s00425-005-0028-8
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发表时间：
2005-11-01
期刊：
影响因子：
4.3
通讯作者：
Volkov, RA
中科院分区：
文献类型：
--
作者：
Panchuk, II;Zentgraf, U;Volkov, RA
氧自由基被认为在衰老中起着重要作用。因此，分析了编码H2 O2清除酶抗坏血酸过氧化物酶（APX; EC 1.11.1.11）的小基因家族在拟南芥（L.）嘿应用实时RT-PCR，对拟南芥基因组中鉴定的三种胞质（APX 1，APX 2，APX 6），两种叶绿体类型（基质sAPX，类囊体tAPX）和三种微粒体（APX 3，APX 4，APX 5）亚型的mRNA水平进行定量。叶绿体类囊体结合的tAPX和微粒体APX 4的基因表现出强烈的年龄相关的mRNA水平的下降，来自一个莲座丛以及来自不同年龄的植物叶片。与tAPX相比，sAPX的mRNA仅在老植株的老叶中减少。微粒体APX 3和APX 5，以及胞质APX 1，APX 2和APX 6的mRNA水平没有显示出显着的年龄相关的变化。这些数据表明，在衰老过程中，个别APX基因的表达受到不同的调节，这表明可能的各自同工酶的功能特化。过氧化氢水平似乎在植物发育期间的不同细胞隔室中被非常精确地控制。
Oxygen-free radicals are thought to play an essential role in senescence. Therefore, the expression patterns of the small gene family encoding the H2O2 scavenging enzymes ascorbate peroxidase (APX; EC 1.11.1.11) were analyzed during senescence of Arabidopsis thaliana (L.) Heinh. Applying real-time RT-PCR, the mRNA levels were quantified for three cytosolic (APX1, APX2, APX6), two chloroplastic types (stromal sAPX, thylakoid tAPX), and three microsomal (APX3, APX4, APX5) isoforms identified in the genome of Arabidopsis. The genes of chloroplastic thylakoid-bound tAPX and the microsomal APX4 exhibit a strong age-related decrease of mRNA level in leaves derived from one rosette as well as in leaves derived from plants of different ages. In contrast to the tAPX, the mRNA of sAPX was only reduced in old leaves of old plants. The microsomal APX3 and APX5, and the cytosolic APX1, APX2, and APX6 did not show remarkable age-related changes in mRNA levels. The data show that expression of the individual APX genes is differentially regulated during senescence indicating possible functional specialization of respective isoenzymes. The hydrogen peroxide levels seem to be controlled very precisely in different cell compartments during plant development.