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

农业和林业依赖的种子发芽率高，萌发后活力旺盛，生长同步。然而，这些行业遇到了与种子质量差和持续休眠有关的问题。例如，某些针叶(树)树种的种子，如黄柏，表现出明显的休眠，在扩散时表现出低萌发能力。我们已经定义了一些影响针叶树种子休眠和质量的机械因素，并开发了改进针叶树种子萌发和幼苗生长的工具。然而，我们最引人注目的发现是关于发芽抑制物脱落酸(ABA)的发现，以及一种名为ABI3的蛋白质，它有助于传递ABA信号。ABI3蛋白控制着许多对种子存活至关重要的事件。这包括食物储备的积累、休眠和种子组织对干燥的耐受性。我们已经从黄柏中分离出ABI3基因(CnABI3)，并确定了该蛋白的部分功能。此外，我们还鉴定了三种与CnABI3相互作用的黄柏蛋白，并进一步发现CnABI3可能在开花调控中发挥作用。在树木和其他植物物种中，ABI3蛋白可能发挥全球调节作用，调节植物生命周期的所有关键转变。然而，这种蛋白质的多种功能的潜在机制还不完全清楚。我们的目标是：(1)进一步了解(CN)ABI3作为植物生命周期重要转变的“守门人”的作用和机制，以及(2)研究(CN)ABI3在胁迫条件下作为保护措施的作用。这项研究将在机制水平上揭示ABI3在植物和种子中的作用，并将对林业和农业具有重要意义，在这些领域，种子质量、幼苗活力和抵抗逆境的能力至关重要。

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.