Responses to Flooding Stress in Quinoa Seedlings Based on Metabolomic and Transcriptomic Analysis

Quinoa is a dicotyledonous annual herb has cold and drought resistance. However, there is little research on quinoa under flooding stress. We analyzed the metabolomics and transcriptomics of Dianli-1299 (flooding-resistant strain), Dianli-60 and Yuncaili-2 (non-flooding-resistant strains) quinoa seedlings. Through metabolome, we detected a total of 1058 metabolites. 337, 300, and 386 differential metabolites were found in Dianli-1299, Dianli-60, and Yuncaili-2, respectively. Transcriptome analysis showed the expression of saccharides and alcohols related genes in Dianli-1299 was higher than that in Dianli-60 and Yuncaili-2. Gene-LOC110708270 and gene-LOC110681806, which were related to UTP-glucose-1-phosphate uridylyltransferase (UGP2), were significantly expressed in Dianli-1299 treatment group (TR1), and the regulated galactinol content was significantly accumulated in TR1. Gene-LOC110736796 in Dianli-60 treatment group (TR2) was significantly higher than that in TR1, and the D-Ribose-5P content, which is regulated by gene-LOC110736796 was lower in TR2 than that in TR1. In Dianli-1299, the raffinose content regulated by gene-LOC110707988 and gene-LOC110725594 was higher than that in Dianli-60 and Yuncaili-2. The correlation coefficients of 18 differential metabolites and differential genes were greater than 0.9, which suggested these genes and metabolites might key factors for quinoa to cope with flooding stress. Our results may provide a basis for breeding and identifying quinoa flood-resistant varieties.