Uncovering the transcription factors and metabolic pathways unique to proso millet and foxtail millet under salt stress through a comparative transcriptome approach

Salt stress causes major losses to crop production all over the globe. Millets being the climate-resilient crop possess the potential to overcome adverse abiotic stress conditions including salinity in comparison with other crops. Molecular level understanding of gene expressions that confer resistance to salt stress will increase food production as well as security. In addition to climatic resilient properties, they provide a high level of protein as well as important minerals like magnesium, phosphorus, and iron. In this study, we have compared the salt resistance responsible genes between proso millet and foxtail millet. The findings of this study compare the responses of foxtail and proso millets to salt stress and reveal a common metabolic network with 137 metabolic pathways that support salt tolerance. Pathways such as amino sugar and nucleotide sugar metabolism, phenylpropanoid biosynthesis, and different fundamental metabolism and energy-generating routes are examples of shared metabolic pathways. Salt stress signal conversion and energy metabolism under stress are both explained by the shared "Calcium signaling pathway" and "Oxidative phosphorylation pathway", respectively. Both species have distinctive metabolic pathways, which may indicate that they have each evolved differently in response to environmental forces. Notably, the species-specific transcription factors such as HD-ZIP and NAC in foxtail millet, and bHLH, ERF, and MYB-related in proso millet, highlight unique regulatory networks tailored to their environmental adaptations. The study also identified important transcription factors, including WRKY, bHLH, GRAS, Dof, and C3H, emphasizing their potential roles in increasing salinity tolerance and modifying stress responses. The enzymatic landscape includes both typical and unusual enzymes that take part in various pathways and are essential for metabolic adaptation.