Integrative Analysis of the Metabolome and Transcriptome of Sorghum bicolor Reveals Dynamic Changes in Flavonoids Accumulation under Saline–Alkali Stress

Abstract

With the perpetuation of soil salinization, it is imperative to improve the salt and alkaline tolerance of crops. Sorghum bicolor, a C4 crop, is often grown in semiarid areas due to its high tolerance of various abiotic stresses. Whether to improve the resistance of the sorghum itself or that of other crops, it is necessary to understand the response of sorghum under saline–alkali stress. An integrative analysis of the metabolome and transcriptome of sorghum under normal conditions and treatments of moderate and severe saline–alkali stress was performed. Among the different accumulated metabolites (DAMs) and differentially expressed genes (DEGs), flavonoid-related DAMs and DEGs were clearly changed. The level of flavonoids was increased under saline–alkali stress, and the change in flavonoids was dynamic as to whether total flavonoids or most flavonoid components accumulated more under moderate saline–alkali stress compared to severe stress. Some flavonoid metabolites were significantly correlated with the expression of flavonoid biosynthesis genes. MYB transcription factors may also contribute to the regulation of flavonoids levels. These findings present the dynamic changes and possible molecular mechanisms of flavonoids under different saline–alkali stresses and provide a foundation for future research and crop improvement.

Multiomics Analyses of Two Sorghum Cultivars Reveal the Molecular Mechanism of Salt Tolerance

“…Our previous studies also explored dozens of DEGs related to salt tolerance in other sorghum genotypes planted in salt environments based on transcriptomic technology ( Cui et al, 2018 ). Although the salt stress condition is different, the outcomes of our study showed similarities from previous studies by Ma et al (2020) . Ma et al (2020) found that anthocyanin biosynthesis-related genes such as LOC8074150 which editing anthocyanidin synthase were up-regulated under moderate salt−alkali stress.…”

“…Although the salt stress condition is different, the outcomes of our study showed similarities from previous studies by Ma et al (2020) . Ma et al (2020) found that anthocyanin biosynthesis-related genes such as LOC8074150 which editing anthocyanidin synthase were up-regulated under moderate salt−alkali stress. In our work, the comparative analysis using RNA-Sequence revealed that a lot of the DEGs were located in the flavonoid biosynthesis pathway, indicating flavonoid may potentially confer protection against salt stress ( Figure 3A ).…”

“…The experimental designs and outcomes of our study showed differences as well as similarities from previous studies. In the previous studies ( Ma et al, 2020 ; Sun et al, 2020 ), integrated transcriptomic and metabolomic and transcriptomics techniques were used, respectively. In our work, three omics techniques were performed, to detect the differences in two different salt tolerance sorghum cultivars under salt stress, which help us improve the understanding of the biosynthetic networks more comprehensively ( Zhou et al, 2019 ).…”

“…In sorghum, the abundance of some flavonoid metabolites is significantly related to the expression of flavonoid biosynthesis genes ( Ma et al, 2020 ). Similar to the current study, flavonoids varied with the degree of stress and genotype, and the dynamic changes in flavonoid content at different genotypes were of great significance, particularly in the highly tolerant cultivar.…”

Physiological adjustment of pomegranate pericarp responding to sunburn and its underlying molecular mechanisms

“…The total phenolic content and antioxidant activity of pomegranate fruit with severe sunburn were lower than those of undamaged fruit [ 14 ]. This mechanism can also be expanded to other stress [ 25 ] and antioxidants [ 26 ].…”