Tandem mass tag-based proteomics analysis to reveal growth stage-dependent pathways in Dendrobium nobile Lindl

Objective

This study aimed to analyze differentially proteins at various growth stages of Dendrobium nobile Lindl and attempt to find some possible functional proteins related to plant growth or pharmacological activity.

Methods

The samples were grouped into two categories based on their growth periods as 2–3 years (S1) and 7–8 years (S2), respectively. Tandem Mass Tag(TMT) labeling-based quantitative proteomics combined LC-MS/MS was applied to identify differential protein expression at various growth stages of Dendrobium nobile Lindl. Those proteins were analyzed by various bioinformatics methods. The activities of several antioxidant enzymes including superoxide dismutase(SOD), peroxidase (POD) and catalase (CAT) in the plant were specifically examined using commercially available assay kits.

Results

A total of 6032 proteins were identified with 283 differential proteins related to 168 up-regulated and 115 down-regulated. KEGG pathway enrichment analysis revealed that proteins involved in heat shock response, phenylpropanoid biosynthesis, and antioxidant activity showed significant changes across the growth stages. Specifically, a decrease in small heat shock proteins (sHSPs) was observed in older plants, potentially reducing their stress resilience, while proteins involved in lignin biosynthesis, such as SOD, CAT, and POD, were upregulated, suggesting improved stress response.

Conclusion

There are 283 differential proteins with diversiform function between different growth stages. Some upregulated antioxidant enzymes contribute to Dendrobium's ability to combat oxidative stress in older plants. These findings provide insights into how protein expression varies with growth stage, offering scientific support for determining optimal harvesting periods or pharmacological mechanism for Dendrobium nobile Lindl.