前人研究發現蛋白酶抑制子(proteinase inhibitor)在植物遭受逆境時會大量表現,與植物對逆境的耐受性有關。刺角瓜(Cucumis metuliferus)Cm1蛋白屬於絲氨酸蛋白酶抑制子(serine proteinase inhibitor),為瞭解Cm1蛋白是否參與對逆境的調控,本研究利用農桿菌轉殖法(Agrobacterium-mediated transformation)將刺角瓜的Cm1基因轉殖於圓葉菸草(Nicotiana benthamiana)中,分別獲得具有一套及兩套Cm1轉基因之植株Y1與Y2。將轉殖植株與種子分別處理鹽分及乾旱逆境,結果發現在250 mM NaCl鹽分逆境處理十天後,Y1與Y2相較於對照組其發芽比率提高55.6-73.3%,而在400 mM Mannitol乾旱逆境處理五天後,則提高63-75%。另外在29% PEG的乾旱逆境處理六天後,帶有兩套Cm1的Y2轉殖株葉圓片總葉綠素含量比對照組約高10%,推測Cm1在乾旱逆境下與防止葉綠素降解有關。本研結果顯示轉殖刺角瓜Cm1基因可能有助於提高植物在鹽害及乾旱逆境下的耐性並且提升種子發芽比率。
Horned melon Cm1 gene belongs to serine proteinase inhibitor and could be induced by biotic and abiotic stresses. To evaluate the function of Cm1 gene under salt and drought stresses, transgenic plants with one copy and two copies of Cm1 gene tobacco, Y1 and Y2, by Agrobacterium-mediated transformation in "Nicotiana benthamiana". The germination rate of the two transgenic lines increased dramatically about 55.6% to 73.3%, higher than wild type (WT) under 250 mM NaCl salt stress after ten days treatment. The increase of 63% to 75% than WT under 400 mM Mannitol drought stress after five days was detected in Y1 and Y2 plants. In addition, the chlorophyll content of leaf discs in transgenic lines with two copies of Cm1 gene, Y2, was 10% higher than WT under 29% PEG drought stress after six days treatment. These results indicated that horned melon Cm1 protein could increase tolerance and also improve the germination rate in "N. benthamiana" under salt and drought stresses.