Overexpression of AtEXPA18 in Arabidopsis thaliana

root hairs play a role in the uptake of water and nutrients from the rhizosphere and serve as a site of interaction with soil microorganisms. The process of root hair formation is well characterized in Arabidopsis (Arabidopsis thaliana). The events of cell elongation and maturation occurring in the root have been suggested to be controlled by the extensibility of the cell wall and the turgor pressure inside the cell. Expansins are mainly considered as a primary agent for cell wall loosening and extension. These proteins are encoded by a superfamily of genes that are organized into four families on a phylogenetic tree α-expansin (EXPA), β-expansin (EXPB), expansin-like A (EXLA) and expansin-like B (EXLB). It has been demonstrated the expression of a root-specific Arabidopsis expansin gene (AtEXP18) is tightly linked to root hair initiation. In this study, Full length AtEXPA18 was amplified using High fidelity and primers having SacI and BamHI overhangs. Then it was cloned into pGEMT vector. To make the final construct, both recombinant pGEMT carrying AtEXPA18 and pBI121 were digested with restriction enzymes and finally the AtEXPA18 fragment was inserted into the binary plant expression vector pBI121 under the control of a constitutive promoter, Cauliflower mosaic virus 35S (CaMV35S) and a terminator, NOS (nopaline synthase gene). This construct was then transferred into Agrobacterium tumefaciens strain LBA4404 and subsequently transformed into Arabidopsis thaliana via Floral dip method. Transformed Arabidopsis plants were selected on selective medium containing Kanamycin, and were confirmed with RT-PCR using Neomycin Phosphotransferase (nptII) and AtEXP 18 primers.