铝胁迫对木薯生长和根系分泌物的影响OA

[Objective]This study aimed to investigate effects of aluminum stress on cassava growth and root exu-dates,thereby providing theoretical references for elucidating toxic effects of aluminum stress on cassava,investigating re-sponse mechanism of cassava to aluminum stress,and breeding cassava germplasms tolerant to aluminum toxicity.[Method]Taking seedlings of cassava SC205 at 47 d after cutting as experimental materials,their plant height,leaf malon-dialdehyde(MDA)content,and root proline(Pro)content were determined after treated with 200 mmol/L aluminum chloride solution for 19 d,seedlings without stress treatment were taken as the control group.Ultra-high performance li-quid chromatography mass spectrometry(UPLC-MS/MS)was used to determine the types and compositions of root exu-dates of the treatment groups and control,and effects of aluminum treatment on root exudates were analyzed using untar-geted metabolomics.Differential metabolites were screened to perform functional annotation and enrichment analysis of metabolic pathways based on databases such as HMDB,Lipidmaps,and KEGG.[Result]After aluminum treatment,the cassava leaves gradually wilted,with their plant height significantly lower than that of the control(P<0.05,the same be-low),and leaf MDA content and root Pro content significantly increased.A total of 2948 metabolites were detected from cassava root exudates,and 1882 differential metabolites were screened,among which 768 differential metabolites up-regulated and 1114 differential metabolites down-regulated.The KEGG enrichment results showed that metabolites with high differential significance were mainly distributed in seven pathways:pantothenate and CoA biosynthesis;β-alanine metabolism;glycine,serine,and threonine metabolism;pyrimidine metabolism;phenylalanine,tyrosine,and trypto-phan biosynthesis;purine metabolism;and tyrosine metabolism.Metabolites like N,N-dimethylglycine,acetoacetate,4-aminobutanoate,oxalic acid,xanthosine,phenol,adenine,L-tyrosine,L-phenylalanine,L-tryptophan,L-aspartic acid,L-histidine,and L-glutamine significantly up-regulated,among which four matabolites(N,N-dimethylglycine,acetoace-tate,4-aminobutanoate,and oxalic acid)exhibited up-regulated fold changes of more than 35.40;while choline,3-phosphonooxypyruvate phosphate,L-dopachrome,glyceric acid,and panthenol significantly down-regulated,among which choline exhibited a down-regulated fold change of 33.75.[Conclusion]Aluminum stress has obviously toxic effects on cassava,leading to damage of cell membrane lipids,inhibition of normal growth,causing significant changes in compo-sition of cassava root metabolites,as obvious changes are found in important metabolites such as pantothenate,amino acids,and oxalic acid.