Later Growth Cessation and Increased Freezing Tolerance Potentially Result in Later Dormancy in Evergreen Iris Compared with Deciduous Iris

Abstract

Winter dormancy is a protective survival strategy for plants to resist harsh natural environments. In the context of global warming, the progression of dormancy has been significantly affected in perennials, which requires further research. Here, a systematic study was performed to compare the induction of dormancy in two closely related iris species with an ecodormancy-only process, the evergreen Iris japonica Thunb. and the deciduous Iris tectorum Maxim. under artificial conditions. Firstly, morphological and physiological observations were evaluated to ensure the developmental status of the two iris species. Furthermore, the expression patterns of the genes involved in key pathways related to plant winter dormancy were determined, and correlation analyses with dormancy marker genes were conducted. We found that deciduous iris entered dormancy earlier than evergreen iris under artificial dormancy induction conditions. Phytohormones and carbohydrates play roles in coordinating growth and stress responses during dormancy induction in both iris species. Moreover, dormancy-related MADS-box genes and SnRKs (Snf1-related protein kinase) might represent a bridge between carbohydrate and phytohormone interaction during iris dormancy. These findings provide a hypothetical model explaining the later dormancy in evergreen iris compared with deciduous iris under artificial dormancy induction conditions and reveal some candidate genes. The findings of this study could provide new insights into the research of dormancy in perennial plants with an ecodormancy-only process and contribute to effectively managing iris production, postharvest storage, and shipping.

Transcription Control Mechanisms for Plant Stress Responses

“…Three original articles describe the discovery and characterization of gene-specific transcription factors from cotton, strawberry, and iris [ 1 , 2 , 3 ]. In addition, the review article by Chen et al [ 4 ] provides comprehensive information about mediator complexes, which connect gene-specific transcription factors and general transcription factors to control target gene expression. Furthermore, Nguyen et al [ 5 ] reviewed recent findings on the epigenetic mechanism underlying transcriptional stress memory and the transgenerational inheritance of drought tolerance in plants.…”

“…Mediator complexes transmit signals delivered by gene-specific transcription factors to the transcription machinery assembled at promoters to control transcription initiation. Chen et al [ 4 ] present a comprehensive review of recent advances in the study of the structure and function of plant mediator complexes. The authors reviewed studies on the roles of Mediator complexes in plant adaptive responses to a wide spectrum of environmental stresses.…”