Transcriptomic Analysis Reveals Calcium and Ethylene Signaling Pathway Genes in Response to Cold Stress in Cinnamomum camphora

Cinnamomum camphora is one of the most dominant broad-leaved evergreen trees in tropical and subtropical regions. Understanding its response to cold stress is crucial for enhancing its resilience to climate changes and expanding the cultivation range. Cold stress response is a vital strategy for plants to withstand cold stress, typically involving transcriptional changes across various pathways. In this study, RNA-Sequencing (RNA-Seq) was conducted on the leaves of C. camphora subjected to different cold stress treatments (0 h, 2 h, and 12 h). Transcriptome analyses revealed that short-term cold stress treatment rapidly induced the upregulation of genes associated with calcium and ethylene signaling pathways, including GLR2.7, CaM, CPK7, and ERF1/3/4/5/7. Subsequently, 12 h cold response treatment further activated genes related to the cold response, jasmonic acid signaling pathways, and the negative regulation of cellular biosynthetic processes, such as CBF2 and CBF4. Notably, ERFs emerged as the most differentially expressed transcription factors in this study. A total of 133 ERF family members from C. camphora were identified through phylogenetic analysis, and these ERFs were classified into 12 clusters. Many of these ERFs are likely to play pivotal roles in the cold response of C. camphora, especially ERF1/3/4/5/7. These findings offer novel insights into the mechanisms underlying the cold response and present valuable candidates for further research, advancing our understanding of plant responses to cold stress.