Integrative Transcriptomic and Metabolomic Analysis Reveals Quinoa Leaf Response Mechanisms to Different Phosphorus Concentrations During Filling Stage

Quinoa is an annual self-pollinating plant rich in polyphenols, flavonoids, saponins, and amino acids; its protein balance closely aligns with the ideal recommendation set by the Food and Agriculture Organization. Therefore, quinoa is considered the most suitable "all-nutrient food". Phosphorus fertilization plays an important role in restricting the growth and development of quinoa; however, the effects of phosphorus fertilizer on quinoa growth remain unclear. Therefore, we conducted metabolome and transcriptome analyses on quinoa leaves during the filling stage, subjecting plants to different doses of phosphorus fertilizer. Overall, phosphorus treatment exerted a significant impact on the phenotypic characteristics of quinoa. Specifically, through a combined analysis of ultra-performance liquid chromatography-tandem mass spectrometry and transcriptome analysis, we identified the alteration and regulation of specific metabolites and genes within flavonoid biosynthesis pathways; this comprehensive evaluation helped elucidate the response mechanism of quinoa leaves during the grouting stage under various phosphorus conditions. Ultimately, the results of this study provide a reference for the selection of quinoa cultivars that exhibit tolerance to low- or high-phosphorus stress; additionally, we offer a theoretical basis for the rational application of phosphorus fertilizer and the enhancement of phosphorus utilization efficiency.