Eisa Kohan-Baghkheirati - Department of Biology, Golestan University, Gorgan, Iran
Mohammad Bagherieh-Najjar - Department of Biology, Golestan University, Gorgan, Iran
Ahmad Abdolzadeh - Department of Biology, Golestan University, Gorgan, Iran
Jane Geisler-Lee - Department of Plant Biology, Southern Illinois University Carbondale, Carbondale, IL ۶۲۹۰۱, USA

Life-history traits and biometrics of plant development are greatly influenced by their changing environment. To survive under various stressful environments, plants develop a multifaceted regulatory network that is mainly governed by transcription factors, including the dehydration responsive element binding (DREB) family. The roles of DREB۱A have been investigated in responses of plants to various abiotic stresses, however, its effects on plant growth and development over the whole life cycle has not yet been fully described. Here, we studied detailed developmental characterizations of dreb۱a T-DNA insertional mutant alongside a previously reported DREB۱A over-expressing plants (OX۲۸) in Arabidopsis thaliana. Seed germination, vegetative and reproductive growth stages and plant yield were also investigated. Under normal growth conditions, both dreb۱a and OX۲۸ plants exhibited reduced seed germination and delayed early development. In addition, both dreb۱a and OX۲۸ plants showed prolonged vegetative growth and delayed transition from vegetative to reproductive development. At the reproductive phase, the time between the emergence of flower stem bolting and opening of the first flower in dreb۱a was ۱۵% shorter in comparison to wild type (WT-Col۰). In contrast, the OX۲۸ plant had a prolonged reproductive development with a remarkably increased number of flowers per plant. Interestingly, lateral branches on the main inflorescence stem showed a lower number in dreb۱a, as opposed to the OX۲۸ plant. Despite these observations, in both dreb۱a and OX۲۸ plants the total seed weight was decreased significantly. Our findings proposed that there was a relationship between a high expression level of the DREB۱A gene with the development and seed yield of A. thaliana.

Arabidopsis thaliana, DREB۱A, Seed germination, Early Development, Growth Phase Transition