Expression analysis of candidate genes related to winter wheat vernalization

Introduction The yield of wheat (Triticum aestivum L.), is greatly reduced under environmental stress and decreased temperatures. Therefore, adaptation mechanisms and cold resistance are crucial in this plant. Vernalization is known as one of the essential mechanisms for grain adaptation to environmental conditions, whereby the plant can accelerate the flowering process or flower after a long cold period. Vernalization also plays a significant role in the acquisition of cold resistance in wheat plants. When exposed to low temperatures, certain genes related to vernalization are activated, leading to changes in the plant's physiology and allowing it to a better cold stress tolerance. This process involves complex regulatory mechanisms depending on the cultivar and environmental conditions. Understanding the molecular basis of vernalization and the genes involved in cold resistance could assist in developing new strategies to improve wheat productivity in adverse environments. Materials and methods In this research, we investigated the expression of three genes, NAC, ERF, and TCP, related to vernalization in two wheat cultivars named Baz and NorthStar, which known as spring and winter cultivars, respectively. The plant samples were preserved in growth racks and applied for vernalization treatment after the tillering stage. RNA extraction was performed at this stage. Real-Time PCR technique was then utilized to analyze the gene expression. To better understanding the function of these genes in response to cold stress, the promoter of the three studied genes was analyzed by screening 500 nucleotides upstream of the wheat TSS. The vernalization treatment was applied at two levels of 14 and 21 days and compared to the control plants under 4°C. Results and discussion The results showed that the expression of all three genes (TCP, NAC, and ERF) decreased under the vernalization treatment. However, the expression of the TCP and NAC genes increased after 14 and 21 days of treatment in the NorthStar and Baz varieties, respectively. In general, the decreased level of expression was shown by increasing in the number of vernalization days. Notably, the expression of the ERF gene reduced in both tested varieties with the increased number of vernalization days. This trend was also observed in the expression of the NAC gene. However, the vice versa was observed for NAC gene in the Baz variety by an increased expression. In the Baz variety, the expression rate of the TCP gene decreased with an increase in the number of vernalization days, whereas in the NorthStar variety, the gene expression increased and then decreased after 14 and 21 days of treatment. Based on the abundance and diversity of the identified elements resulting from the analysis of the promoters of the studied genes, 28 types of regulatory elements were identified, many of which are binding sites for transcription factors responding to biotic and abiotic stresses Top of Form. Conclusion Despite the similarity of the pattern of expression changes of all three genes in the two investigated cultivars, the intensity of the changes in the two cultivars was not same, which could be due to different reactions to cold stress. The results show the complexity of gene expression regulation in wheat vernalization. Additionally, the multiplicity of stress-responsive transcription factor binding sites in the promoter region of these genes could be a justification for the complexity of regulating their expression during vernalization and response to cold stress.