Oxidative stress is a major threat for plants exposed to various environmental stresses especially in heat stress. Previously, the CAT1 gene from heat-tolerant “Shin-Fa 1208” (SF1208) broccoli was cloned and up-regulated in response to heat-sensitive “Green Magic” broccoli under the heat stress conditions. Full-length of the broccoli CAT1 cDNA was 1768 bp, including 1479 bp of an open reading frame. In addition, CAT2 was a type of isoform to CAT1 from SF1208 under heat-induced environment, and was cloned in the current study.
The objective of this study was to transfer the CAT1 and CAT2 cDNAs under the control of ubiquitin promoter to the host plants via Agrobacterium tumefaciens strain LBA4404 and EHA105. RT-qPCR analysis demonstrates that both BoCAT1 and BoCAT2 were over-expressed in the transgenic Arabidopsis. The CAT activity of AtCAT2-2 transgenic line was approximately 12.3-times higher than non-transgenic plant under the heat stress. The CAT protein of AtCAT2-2 was also shown highly accumulation in western blotting analysis. Compared with non-transgenic plants, lower level of heat-induced H2O2 accumulation was detected in leaves of transgenic plants with high level of CAT activity using DAB staining. These results indicate that overexpression of CAT gene in Arabidopsis could enhance the tolerance under heat stress by elimination of H2O2.
