Beyond Protein Abundance: Proteoform Diversity and Phosphoproteome Remodeling in Maize (Zea mays L.) Responding to Drought and Heat Stresses

Summary

This narrative review synthesizes two decades of mass spectrometry-based proteomic and phosphoproteomic studies on maize drought and heat stress responses. Rather than focusing on individual protein abundance changes, the authors argue for a shift toward proteoform-centered biology—recognising how post-translational modifications, proteolytic processing, and genetic variation generate distinct molecular species with differential functions. The review identifies critical methodological gaps (predominance of bottom-up approaches, underrepresentation of combined-stress and reproductive tissue studies) and advocates for integrated top-down proteomics, phosphoproteomics, and proteogenomics to resolve functionally distinct stress-adaptive networks in maize.

Regional applicability

This review addresses fundamental molecular mechanisms of climate stress tolerance in a globally important cereal crop. Findings are applicable to United Kingdom agriculture where drought and heat stress events are increasing; however, the molecular insights require translation into breeding or agronomic strategies for temperate maize and barley systems. The proteoform-resolved approaches discussed may inform development of climate-resilient crop varieties relevant to UK farming.

Key measures

Protein abundance, phosphorylation patterns, proteoform diversity, oxidative modifications, proteolytic processing, alternative splicing variants, phosphoproteomic network remodeling

Outcomes reported

The review synthesizes knowledge on proteomic and phosphoproteomic responses of maize to drought and heat stresses, emphasizing how phosphorylation, oxidative modifications, proteolytic processing, alternative splicing, and genetic variation generate proteoform diversity and expand functional complexity of the stress proteome. It evaluates methodological limitations and proposes future directions integrating top-down proteomics, phosphoproteomics, and proteogenomics for stress-responsive molecular networks.

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