Artemin molecular chaperone from Artemia urmiana improves tolerance of Arabidopsis thaliana to abiotic stress.

Abstract

Artemia is a genus of aquatic microcrustaceans that belong to the class Branchiopoda. Encysted Artemia urmiana embryos are resistant to harsh environmental stressors, including repeated desiccation, prolonged anoxia, extreme temperatures, and high levels of UV radiation. The protein artemin has a chaperone activity and is believed to play a crucial role in protecting the organism against such stresses. To elucidate the potential functional roles of artemin in plants, the cDNA sequence of artemin was cloned into the pZPY122 binary plant expression vector. Agrobacterium -mediated transformation and the floral-dip technique were used to introduce this construct into Arabidopsis thaliana . Three independent transgenic lines (art1 , art2 , art3 ) were generated and subjected to heat stress at 45°C. Results showed a significant interaction between heat stress and genotype for germination rate, germination speed, vigor index, and seedling and root length. The transgenic lines with the artemin transgene (ART ) exhibited remarkable heat stress tolerance compared with wild-type plants. They also had markedly lower levels of electrolyte leakage, hydrogen peroxide content, higher activities of catalase, superoxide dismutase and peroxidase, greater total protien content, and increased accumulation of proline. Under heat stress conditions, the expression of two key abiotic stress-responsive genes, DREB2A and HSFA3 , was significantly upregulated in the ART lines compared to the wild-type . These findings suggest that the ART gene from A. urmiana may act as molecular chaperone when expressed in Arabidopsis , thereby enhancing the plant's tolerance to heat stress.