Physiological and molecular responses of potato tuber formation regulated by nitrogen (PRJCA049164)
In order to explore the key factors of nitrogen regulating potato tuber formation, the response of potato tuber formation to nitrogen was systematically analyzed from the perspective of physiology and transcriptomics. We conducted pot experiments on potato plants under nitrogen deficiency, normal nitrogen level and sufficient nitrogen level. The results showed that nitrogen deficiency led to the thickening of cell wall and plasma membrane, the increase of intercellular space and the decrease of mitochondria in stolon, which significantly reduced plant height, chlorophyll content, dry matter quality and nitrogen accumulation. the tuber number per plant, tuber weight per plant and commodity rate were significantly reduced. Excessive nitrogen can significantly increase plant height, chlorophyll content, dry matter quality and nitrogen accumulation, resulting in late plant maturity and excessive formation of small potatoes. Finally, the tuber number per plant and the quality of tubers per plant were significantly higher than those of nitrogen deficiency treatment. Transcriptome and weighted gene co-expression network analysis showed that there were 3019 differentially expressed genes (DEGs) related to nitrogen stress, which were mainly enriched in pathways related to material transport, cell division and carbohydrate metabolism, and played an important role in tuber formation. During tuber formation, there are a series of hub genes responding to nitrogen stress, including Polyubiquitin-like, auxin response factor 7-like, and protein RRP6-like 2. It has been reported that these hub genes may co-regulate potato tuber formation through synergistic effects. In addition, by constructing a co-expression network, multiple transcription factors (TFs) are involved in the regulation of tuber formation-related hub genes, such as C2H2, WRKY, and ARF. These TFs may be key regulators of the transcriptional network, regulating tuber formation-related gene expression under nitrogen stress. Overall, our comprehensive study revealed hub genes and potential pathways for potato tuber formation under different nitrogen conditions. It provides a new idea for further study on improving nitrogen use efficiency of potato.