Extensive Transcriptome Changes During Natural Onset and Release of Vegetative Bud Dormancy in Populus

Area of Science:

• Plant biology
• Molecular biology
• Genomics

Background:

• Perennial plants enter endodormancy to survive winter, a state of suspended growth.
• Understanding the molecular mechanisms of endodormancy is crucial for plant survival and agricultural applications.

Purpose of the Study:

• To investigate gene expression changes associated with vegetative bud endodormancy in Populus trees.
• To identify key genes, transcription factors, and regulatory elements involved in dormancy transitions.

Main Methods:

• Analysis of gene expression using NimbleGen microarrays on Populus axillary buds in paradormant, endodormant, and ecodormant states.
• Identification of differentially expressed genes and associated regulatory motifs.
• Phytohormone and stress response gene analysis.

Main Results:

• Over 3% of Populus gene models (1,362) were differentially expressed across dormancy states.
• Dormancy transitions involve significant changes in DNA methylation and histone modifications, particularly via Polycomb Repressive Complex 2.
• Upregulated genes during endodormancy include those related to abiotic stress responses (ethylene, cold) and transcription factors like EIN3, ERF, and WRKY.
• Phytohormone analysis indicated significant changes in ethylene, auxin, and brassinosteroid signaling pathways.

Conclusions:

• Gene expression profiling provides critical insights into the molecular regulation of plant endodormancy.
• Chromatin remodeling and specific transcription factor networks play vital roles in establishing and maintaining endodormancy.
• The findings suggest conserved regulatory mechanisms between plant flowering and bud dormancy, involving genes like SPL, DAM, and SOC1.