Survey on Gene Expression of Phytocystatin from Local Taro (Colocasia esculenta) Plants

芋頭中植物性半胱氨酸蛋白水解酶抑制劑之基因表現

10.30061/CEB.200506.0004

楊藹華(Ai-Hua Yang)；葉開溫(Kai-Wun Yeh)

半胱氨酸蛋白酶抑制劑 ； 芋頭 ； 球莖 ； 周皮層 ； Cysteine proteinase inhibitor ； Taro ； Corm ； Periderm

作物、環境與生物資訊

2卷2期（2005 / 06 / 01）

123 - 130

英文

針對臺灣地區四種芋頭(Colocasia esculenta (L.) Schott.)栽培品系進行半胱氨酸蛋白酶抑制劑(cystatin; cysteine proteinase inhibitor)的測試調查，首先利用明膠凝膠活性電泳測試法(gelatin/SDS-PAGE)分析四種芋頭球莖中的蛋白質粗抽取液，其中高雄一號(Kaosiung No.1)具有強烈的半胱氨酸蛋白水解酶抑制劑的活性，及赤芽芋(Ch'ih-Ya-Yu)有一點活性之外，其他二種品系狗蹄芋(Kou-Ti-Yu)及檳榔心(Pin-Lang-Hsin)則不具此活性。以南方轉印法分析此基因拷貝數，發現高雄一號基因組(genome)中含有一個以上的基因拷貝數(gene copy)；北方轉印的分析顯示，此基因只特定表現於芋頭球莖中，尤其在球莖的周皮組織(periderm)特別豐富，其他組織如葉部及葉柄皆不表現；即使採收後的球莖儲存至第四週此基因仍有極強表現量。從這些調查結果顯示，雖然芋頭的cystatin基因其演化來源未知，但卻可作為分辨高雄一號品系的DNA marker，其在高雄一號中獨特存在及豐富的表現量，可能是此品系較其餘三種品系具有抗病蟲力的主要原因。

An investigation on the cystein protease inhibitor (cystatin) activity of the local taro (Colocasia esculenta (L.) Schott.) cultivars was carried out. Interestingly, the cultivar Kaohsiung No. 1 showed great positive and Ch'ih-Ya-Yu showed little activity. The other two cultivars, i.e., Pin-Lang-Hsin and Kou-Ti-Yu, never showed the inhibitory activities. Southern gel blot revealed that more than one copy of cystatin gene was present in the haploid genome of Kaohsiung No 1 cultivar. This result indicated that cystatin gene can be an useful marker to differentiate Kaohsiung No 1 cultivar from others. Further studies demonstrated that cystatin genes are differentially expressed in corm organ, and more abundant in the periderm tissue of corm. They are able to retain active expression for four weeks long during storage condition. Therefore, the significance of cystatin gene expression is considered to be closely related with the resistance of pest invasion.