Agave macroacantha Transcriptome Reveals Candidate CNGC Genes Responsive to Cold Stress in Agave

Agave, with its unique appearance and ability to produce hard fibers, holds high economic value. However, low temperatures during winter can restrict its growth and even damage the leaves, causing a loss of ornamental appeal or affecting the fiber quality. Conversely, the plant <i>cyclic nucleotide-gated channel</i> (<i>CNGC</i>) family plays an important role in the growth and development of plants and the response to stress. Studying the <i>CNGC</i> family genes is of great importance for analyzing the mechanism by which agave responds to cold stress. This research conducted a transcriptomic analysis of the ornamental plant <i>Agave macroacantha</i>. Through assembly via Illumina sequencing, 119,911 transcripts were obtained, including 78,083 unigenes. In total, 6, 10, 11, and 13 <i>CNGC</i> genes were successfully identified from <i>A. macroacantha</i>, <i>Agave.</i> H11648, <i>Agave. deserti</i>, and <i>Agave. tequilana</i>, respectively. These <i>CNGC</i> genes could be divided into four groups (I, II, III, and IV), and group IV could be divided into two subgroups (IV-A and IV-B). The relative expression levels were quantified by qRT-PCR assays, which revealed that <i>AhCNGC4.1</i> was significantly upregulated after cold treatment and Ca(NO₃)₂ treatment, suggesting its importance in cold stress and calcium signaling. Additionally, the Y2H assay has preliminarily identified interacting proteins of AhCNGC4.1, including AhCML19 and AhCBSX3. This study has established a completely new transcriptome dataset of <i>A. macroacantha</i> for the first time, enriching the bioinformatics of agave's transcriptome. The identified <i>CNGC</i> genes are of great significance for understanding the evolution of agave species. The cloned <i>CNGC</i> genes, expression pattern analysis, and protein interaction results laid a foundation for future research related to the molecular functions of agave <i>CNGC</i> genes in cold tolerance.