Overexpression of the ascorbate peroxidase through enhancer‐trapped pSB111 bar vector for alleviating drought stress in rice

Abstract

Rice (Oryza sativa L.) plant growth and productivity is adversely affected by various stress factors. Overexpression of drought tolerance‐related genes is one of the best approaches for developing drought‐resistant transgenics. Agrobacterium tumefaciens has been widely used in generating transgenic plants through plasmid vector to obtain desired characteristics and to know the specific expression profiles of genes in the plant. The enhancer trap method was developed to know the specific expression of genes at different stages of growth by entrapping the genes of an organism. In the present study, we designed a vector molecule with a feature of promoting the expression of a specific gene more than four times than its normal expression and it is useful for efficient transformation to higher plants by utilizing the trans configuration of vir genes of the plasmid A. tumefaciens, to transfer right and left sequence bordered of transferred DNA (T‐DNA) into the nuclear genome of plants. We developed a binary vector consisting of 1.8‐kb green fluorescent protein (GFP) cassette as a reporter gene and 1.4‐kb tetramer of CaMv35S enhancer (4XEn) were cloned at HindIII site of pSB11 bar intermediate vector to tag and know the genes and their expression profiles, then mobilized into A. tumefaciens to produce a super‐binary vector pSB111‐bar‐4XEn‐GFP. The resultant construct was confirmed by polymerase chain reaction and restriction digestion methods. Finally, we discuss the role of overexpressed ascorbate peroxidase in drought stress.