Effects of cold and methyl jasmonate on the expression of miRNAs and target genes in response to vernalisation in two wheat cultivars (Triticum aestivum L.)

Wheat undergoes significant physiological changes during winter, driven by processes such as cold acclimation and vernalisation that are regulated by gene expression and phytohormones. We investigate the effects of methyl jasmonate (MeJA) and cold treatments on the expression of three specific miRNAs and the associated target genes in Baz spring wheat and Norstar winter wheat using qRT-PCR analysis. Our objective was to examine the impact of MeJA on vernalisation and cold adaptation in these genotypes. Results showed that MeJA had no significant impact on vernalisation and acclimation in Baz, while the compound decreased these traits in Norstar. Additionally, the expression of miRNAs in Norstar was significantly reduced after a 2-day cold treatment, particularly for miR156 and further reduced after 14days for miR172 and miR319 . In contrast, Baz showed varied gene expression responses, with an increase in miRNA levels after the 14-day cold treatment. MeJA combined with a 2-day cold treatment suppressed the expression of SPL , AP2 and MYB3 target genes, with the most pronounced suppression observed in SPL . However, AP2 was induced after 14-day cold treatment in both cultivars. The study highlighted an inverse relationship between miRNAs and target genes under vernalisation conditions, underscoring the complex regulatory interactions between genotype, miRNAs and the associated target genes. Therefore, these findings provide new insights into how MeJA and cold treatments modulate miRNA and gene expression, enhancing our understanding of wheat's adaptive response mechanisms.