Proteomic changes may lead to yield alteration in maize under carbon dioxide enriched condition.

In the present study, the effect of elevated CO on growth, physiology, yield and proteome was studied on two maize ( L.) varieties grown under Free-air CO enrichment. Growth in high CO (530 ppm) did not affect either photosynthesis or pigment contents in both varieties. Reduced MDA content, antioxidant and antioxidative enzymes levels were observed in both varieties in response to high CO. PEHM-5 accumulated more biomass than SMH-3031 under eCO. PEHM-5 also had more seed starch and total soluble sugar than SMH-3031. However, SMH-3031 had increased number of seed per cob than PEHM-5. Interestingly, thousand seed weight was significantly increased in PEHM-5 only, while it was decreased in SMH-3031 under eCO. We observed increased seed size in PEHM-5, while the size of the SMH-3031 seeds remained unaltered. Leaf proteomics revealed more abundance of proteins related to Calvin cycle, protein synthesis assembly and degradation, defense and redox homeostasis in PEHM-5 that contributed to better growth and yield in elevated CO. While in SMH-3031 leaf, proteins related to Calvin cycle, defense and redox homeostasis were less abundant in elevated CO resulting in average growth and yield. The results showed a differential response of two maize varieties to eCO.