Multiomics Combined Analysis of Low-Phosphorus and Drought Stresses in Lotus Japonicus

Abstract BackgroundLotus japonicus is a perennial herb in Leguminosae. It is a good feed source and improves soil. It is also an excellent honey source and medicinal plant. Low-phosphorus and drought stresses are among the main abiotic stress factors limiting the production of pulse roots. MethodsIn this experiment, the effects of low-phosphorus and drought stresses on Baimai roots were analyzed under three treatments: control (zl1), low-phosphorus stress (zl2) and drought stress (zl3). Results A total of 2176, 3026 and 2980 differentially expressed genes were screened in zl1 vs. zl2, zl1 vs. zl3 and zl2 vs. zl3, respectively. The differentially expressed genes were enriched in functions related to cells, membranes, ion binding, enzyme activity and resistance to low-phosphorus and drought stresses. The enriched KEGG pathways included the MAPK signaling pathway-plant, flavor biosynthesis, starch and sucrose metabolism and plant hormone signal transmission. In particular, a large number of differentially expressed genes were enriched in the response to plant hormone signal transmission pathways among different treatments, and gene expression changes were analyzed. In addition, the differentially expressed genes identified under drought stress and the phase response genes identified under osmotic stress were upregulated. Differential metabolites were mainly enriched in the important metabolic pathways of flavonoid biosynthesis, arginine and proline metabolism and starch and sucrose metabolism. Differentially expressed proteins were mainly enriched in GO terms related to cell, membrane, ion binding and enzyme activity functions, and the main enriched KEGG pathways included the ribosome, starch and sucrose metabolism and plant hormone signal transmission pathways. ConclusionIn conclusion, these results of transcriptome, metabolome and proteome sequencing are helpful for understanding the response mechanisms, gene changes, metabolite changes and protein changes in Baimai roots under low-phosphorus and drought stress conditions to lay a foundation for future research on Lotus japonicus.