Effect of Cadmium on Peroxidase Isozyme Activity in Roots of Two Oryza Sativa Cultivars

鎘對兩個不同栽培品系水稻根部之過氧化同功異構酶活性的影響

張敏郎(Min-Lang Chang) ； 陳南瑛(Nan-Ying Chen) ； 廖麗貞(Li-Jen Liao) ； 卓忠隆(Chung-Lung Cho) ； 劉景煌(Zin-Huang Liu)

《Botanical Studies》 53卷1期 (2012/01) Pp. 31-44

摘要

鎘處理之水稻（Oryza sativa L. cv. Taichung Native 1 and O. sativa L. cv. Tainung 67）幼苗根的生長受到抑制，根組織內過氧化酶活性亦有增加。台農67 號（Japonica type）之水稻根部鎘處理後可能藉調控啟動子區域，影響過氧化酶基因表現或是藉由將過氧化酶糖基化，引發過氧化酶活性的增加，加強根部組織清除由鎘引起之過氧化氫的能力，同時合成較多木質素。台中在來一號（Indica type）水稻品系則在鎘處理後，過氧化酶增加量少，造成較多的過氧化氫之累積，並且生成的木質素較少，故台中在來一號（Indica type）水稻對於鎘較敏感。因此，台農67 號（Japonica type）之水稻對鎘耐受性較台中在來一號（Indica type）佳。由過氧化酶基因啟動子區域之分析，台農67 號（Japonica type）之水稻根部細胞內過氧化酶基因含有十個重金屬反應元素（CURE），而台中在來一號（Indica type）則含八個重金屬反應元素（CURE）。我們推測台農67 號（Japonica type）之水稻可能較容易接受重金屬鎘之刺激的訊息，進而調控更多的過氧化酶之合成，進而應付鎘之衝擊。

關鍵字

鎘 ； 過氧化氫 ； 木質素 ； 水稻 ； 過氧化酶 ； 氧化逆境 ； 啟動子

並列摘要

Cadmium (Cd) decreased the growth of rice expressed as fresh weight. Root growth was inhibited more severely in Taichung Native 1 rice than in Tainung 67. The differences in peroxidase (POX) activity and lignin content between Cd-tolerant and Cd-sensitive rice varieties were compared. In our study, POX activity in Tainung 67 increased significantly in Cd-treated tissues. However, enhanced POX activity in Cd-treated tissues was accompanied by a H2O2 decrease. The H2O2 accumulation in the Cd-treated tissues of Taichung Native 1 rice may be due to the lower amount of POX enhancement induced by Cd. The increased activity in cationic (pI 8.6) and anionic (pI 4.5) POXs correlated with the increase in POX transcripts, and therefore was mostly due to the de novo synthesis of the cationic (pI 8.6) and anionic (pI 4.5) POXs in Cd-treated roots of Tainung 67. For promoter analysis, Tainung 67 (Japonica type) owned ten conserved cores of CURECORECR sequence (5´-GTAC-3´), a copper-response element (CuRE), involved in heavy metals response. Taichung Native 1 (Indica type) had only eight CURE. This implies that a Cd-tolerant cultivar, Tainung 67 (Japonica type), may receive more signals with Cd treatment, enhancing more POX synthesis, which leads to the production of more lignin to deal with Cd stress.

並列關鍵字

Cadmium ； Lignin ； Oryza sativa ； Oxidative stress ； Peroxidase ； Promoter