Comparison and Quantification of Metabolites and Their Antioxidant Activities in Young and Mature Leaves of Sugarcane

Abstract

Secondary metabolites perform diverse ecological functions in plants, providing defense against abiotic and biotic stresses and acting as a powerful antioxidant agent. The level of metabolites in each organ or tissue changes with time and the developmental stage of the plant, which determines its response to stress. However, few studies of the secondary metabolites of sugarcane, a major global crop, have been reported. This study focuses on the primary and secondary metabolites and their antioxidant activities in new and mature leaf blades of 12 sugarcane varieties. We observed that levels of primary metabolites such as amino acids, total glucose contents, and carbohydrates were higher in the young leaves than in mature leaves; in contrast, the mature sugarcane leaves showed a higher level of synthesis of secondary metabolites (such as phenolics, flavonoids, etc.) compared to that of new leaves. Interestingly, the antioxidant activities were higher in mature leaves than in new leaves. The mature leaves of Taitang172 and ROC22 possess a high total flavonoid content, and these varieties showed maximum antioxidant activities among 12 sugarcane varieties. This study provides a broad snapshot of secondary metabolites and their antioxidant activities in (new and mature leaves) different sugarcane varieties. It enhances our understanding of the metabolic localization in different leaf tissues. We speculate that exploring the metabolome through qualitative and quantitative profiling enables a more comprehensive examination of foliar metabolites.

Novel Insights into Anthocyanin Metabolism and Molecular Characterization of Associated Genes in Sugarcane Rinds Using the Metabolome and Transcriptome

“…In Arabidopsis and purple potato, the first step after anthocyanin biosynthesis is for glycosylation to form anthocyanin-3-O-glucoside and the downstream glycosylation alterations become entirely different. In sugarcane, the rind is the main organ that produces anthocyanins, and it is an important trait for long-term sugarcane breeding programs to acquire high anthocyanin contents [ 15 ]. Here, we tested 99 anthocyanins; among them, 43 anthocyanins and their derivatives were quantified in the sugarcane rind ( Table 1 ), whereas the other 56 anthocyanins were not observed in sugarcane rind (details were represented in Supplementary Table S1 ); perhaps the concentration of these anthocyanins was significantly lower than the detection limitations of the instrument.…”

“…Sugarcane is an excellent breeding material to enhance its anthocyanin content to extract more valuable anthocyanins for commercial uses [ 6 , 15 ]. Flavonoids and anthocyanins are naturally found in the Saccharum species such as S. barberi , S. robustum , S. officinarum , and their inter-generic and interspecific crosses.…”

Antioxidant Metabolites in Primitive, Wild, and Cultivated Citrus and Their Role in Stress Tolerance

“…Flavonoids are one of the major classes of secondary metabolites, which are extensively found in citrus fruit peel, fruit juice, leaves, and roots [ 84 , 85 ]. Among the secondary metabolites, flavonoids possess the highest antioxidant, antimicrobial, antiallergy, anti-inflammatory, and anticancer activities.…”

“…Flavonoids are localized in plant vacuoles and are considered the most powerful antioxidant compounds [ 84 ]. The relationship between flavonoid activity and ROS scavengers has been determined [ 84 , 85 ]. The catechol structure in the B ring (heterocyclic ring) is the key contributing factor for the scavenging activities of flavonoids [ 86 ].…”

Integrated Metabolomics and Transcriptome Analyses Unveil Pathways Involved in Sugar Content and Rind Color of Two Sugarcane Varieties

“…They can, besides, have potential impacts on other aspects of plant growth, development, and nutritional quality that are important in sugarcane production as well as different species and differ among plants of the same species, between diverse plant tissues (e.g., new and mature leaves, root, stem, fruit, etc.) ( Rao et al, 2021 ). Therefore, metabolites provide immense potential in molecular breeding program.…”