植物通常會暴露在不同的環境逆境下，如：強光、低溫、鹽害、高溫、淹水等，其中熱逆境為世界上許多地區所存在的農業問題。在先前的研究中，於熱逆境下，耐熱品種結球白菜“亞蔬二號”相較於不耐熱品種“瑞農720”有較高的ascorbate peroxidase (APX)活性及基因表現量。其BcAPX1 基因之cDNA 全長為1056 bps，轉譯框架區域為753 bps。而在本研究中，已從“亞蔬二號”中再選殖出BcAPX2 及BcAPX3，為BcAPX1 的同功酶基因。本研究之目的是將BcAPX1、 BcAPX2及BcAPX3在ubiquitin啟動子調控下，經由農桿菌GV3101 轉殖到阿拉伯芥中。結果顯示轉殖BcAPX1、 BcAPX2 及BcAPX3於阿拉伯芥之轉殖率分別為1%、0.6%、0.6%。轉殖阿拉伯芥植株以PCR、RT-PCR 分析之結果顯示轉基因存在於轉殖植株中，並且可轉錄mRNA。APX 酵素活性分析及西方墨點之結果顯示，阿拉伯芥轉殖株APX 活性及表現量均較未轉殖株顯著增加。將轉殖株及未轉植株進行高溫處理，外表型態及生理測定之結果顯示，轉殖株比未轉殖株具有較高耐熱性。
Most of the time, plants are exposed to diverse environmental stresses, such as high light intensity, cold, salt, heat, drought, and waterlogging . Among these stresses, heat stress is an agricultural problem in many areas of the world. Previously, the APX activity and gene expression of heat-tolerant “ASVEG2” Chinese cabbage was significantly higher than those of heat-sensitive RN720 plants under the heat-stress conditions . Full-length of the BcAPX1 cDNA was 1056 bp,including 753 bp of an open reading frame in the APX gene. In addition, BcAPX2 and BcAPX3 were a type of isoform to BcAPX1 from ASVEG2 under heat induced environment, and were cloned in the current study.
The objective of this study was to transfer the BcAPX1, BcAPX2 and BcAPX3 cDNAs under the control of ubiquitin promoter to Arabidopsis via Agrobacterium tumefaciens strain GV3101. The transformation rate of BcAPX1, BcAPX2 and BcAPX3 in arabidopsis were 1%, 0.6% and 0.6%, respectively. The results from PCR and RT-PCR indicated that the transgenes had been transferred into arabidopsis genomes, and transcribed as well. The results from APX activity assay and Western blot revealed that activity and expression of APX in transgenic line were higher than those of non-transgenic plants under the heat stress. The results of physiological assay and appearance showed that transformants were higher resistance to the heat treatment compared to non-transforment under heat stress.
