Investigating the novel roles of a conifer ABI3 gene as a gatekeeper of key transitions during the plant lifecycle and a 'safeguard' in stress conditions

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The agricultural and forest industries rely upon seeds that exhibit high germinability and vigorous, synchronous growth after germination. However, these industries encounter problems related to poor seed quality and persistent dormancy. For example, the seeds of certain conifer (tree) species such as yellow-cedar develop pronounced dormancy, exhibiting a low capacity for germination upon dispersal. We have defined some of the mechanistic factors that underlie the dormancy and quality of conifer seeds, and have developed tools for improving conifer seed germination and seedling growth. However, our most striking discoveries are those concerning the germination inhibitor abscisic acid (ABA), and a protein called ABI3, which helps to relay ABA signals. ABI3 proteins control many events that are critical to seed survival. This includes the deposition of food reserves, dormancy imposition and the acquisition of a tolerance of seed tissues to desiccation. We have isolated the ABI3 gene from yellow-cedar (CnABI3) and have defined some of the functions of this protein. In addition, we have identified three yellow-cedar proteins that interact with CnABI3, and further have made the exciting discovery that CnABI3 may play a role in the regulation of flowering. In trees and other plant species, the ABI3 protein may function as a global regulator, acting to regulate all key transitions of the plant lifecycle. However, the mechanisms underlying the multiple functions of this protein are not fully understood. Our objectives are: (1) To further our understanding of the role and mechanisms of (Cn)ABI3 as a 'gatekeeper' of important transitions of the plant lifecycle and (2) To investigate the role of (Cn)ABI3 as a safeguard in stress conditions. This research will uncover novel findings at a mechanistic level of the role of ABI3 in plants and seeds and will have significance to forestry and agriculture, in which seed quality, seedling vigour and the ability to resist stresses are of utmost importance.