Combined Transcriptome and Metabolome Analysis of Lupinus polyphyllus Response to PEG Stress

Abstract

Drought stress is a common abiotic stress, and Lupinus polyphyllus presents strong adaptability, but its drought resistance mechanism has not been explored. This study used PEG-6000 to simulate drought stress, and the H2O2 content, O2− generation rate and MDA content were determined. Transcriptome sequencing and untargeted metabolome analyses were also carried out on an Iceland germplasm and American B germplasm under different drought stress durations. The results showed that the gene regulation range in the American B germplasm was greater, whether genes were upregulated or downregulated. And the number of genes in the American B germplasm was higher than that in the Iceland germplasm. Additionally, the Iceland germplasm produced less peroxide under PEG stress than the Iceland germplasm. The Iceland germplasm was more stable than the American B germplasm under PEG stress, which can be shown in two aspects: peroxide content and gene regulation quantity. Joint transcriptomics and metabolomics analysis showed that genes and metabolites related to secondary and carbon metabolism were mainly involved in the response of Lupinus polyphyllus to PEG-simulated drought stress. The metabolites mainly included phenylalanine, tyrosine, trans-2-hydroxycinnamate, starch synthase, 1,4-alpha glucan branching enzyme and glycogen phosphorylase, and genes mainly included COMT, F5H, REF1, CAD, UGT72E and TPS. These results provided genetic resources and a theoretical basis for further molecular breeding of Lupinus polyphyllus.