Integrated transcriptome and metabolome analysis reveals the response mechanisms of soybean to aluminum toxicity

Background and aims

Exchangeable aluminum (Al) released from acidic soil (pH < 5.5) inhibits root elongation and reduces crop yield. This study aimed to explore the possible mechanism of soybean response to Al toxicity stress.

Methods

An integrated analysis of transcriptome and metabolome was applied to compare Al-tolerant (NN99-6) and Al-sensitive (ZD32) soybean germplasms in response to Al toxicity.

Results

The root growth of NN99-6 genotype was less inhibited under Al toxicity compared to ZD32 genotype. Following a three-day Al toxicity treatment, both the relative primary root elongation and relative total root length were greater in NN99-6 than in ZD32. Transcriptome analysis identified 2555 differentially expressed genes (DEGs) in NN99-6 and 2577 DEGs in ZD32, respectively. 140 differentially expressed metabolites (DEMs) in NN99-6 and 161 DEMs in ZD32 were respectively detected by metabolome analysis. Based on the integrated transcriptome and metabolome analysis, DEGs and DEMs were primarily enriched in lignin and aldarate biosynthesis, isoflavonoid biosynthesis, ASA-GSH and SAM cycle. Compared to ZD32, most DEGs and DEMs were mainly up-regulated in NN99-6. The proposed model showed that the high expression level of DEGs and DEMs in enriched pathways may benefit the synthesis and repair of the cell wall and improve the antoxidation in NN99-6, ultimately alleviating Al toxicity.

Conclusion

This study offers an effective strategy to explore DEGs and DEMs in response to Al toxicity, clarifying the mechanism of Al toxicity resistance by improving the synthesis and repair of cell wall and antoxidation in soybean.