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Abstract Global crop production faces increasing threats from the rise in frequency, duration, and intensity of drought and heat stress events due to climate change. Most staple food crops, including wheat, rice, soybean, and corn that provide over half of the world's caloric intake, are not well-adapted to withstand heat or drought. Efforts to breed or engineer stress-tolerant crops have had limited success due to the complexity of tolerance mechanisms and the variability of agricultural environments. Effective solutions require a shift towards fundamental research that incorporates realistic agricultural settings and focuses on practical outcomes for farmers. This review explores the genetic and environmental factors affecting heat and drought tolerance in major crops, examines the physiological and molecular mechanisms underlying these stress responses, and evaluates the limitations of current breeding programs and models. It also discusses emerging technologies and approaches that could enhance crop resilience, such as synthetic biology, advanced breeding techniques, and high-throughput phenotyping. Finally, this review emphasizes the need for interdisciplinary research and collaboration with stakeholders to translate fundamental research into practical agricultural solutions. 

Mass spectrometry (MS)-based top-down characterization of integral membrane proteins (IMPs) is crucial for understanding their functions in biological processes. However, it is technically challenging due to their low solubility in typical MS-compatible buffers. In this work, for the first time, we developed an efficient capillary zone electrophoresis (CZE)-tandem MS (MS/MS) method for the top-down proteomics (TDP) of IMPs enriched from mouse brains. Our technique employs a sample buffer containing 30% (v/v) formic acid and 60% (v/v) methanol for solubilizing IMPs and utilizes a separation buffer of 30% (v/v) acetic acid and 30% (v/v) methanol for maintaining the solubility of IMPs during CZE separation. Single-shot CZE-MS/MS identified 51 IMP proteoforms from the mouse brain sample. Coupling size exclusion chromatography (SEC) to CZE-MS/MS enabled the identification of 276 IMP proteoforms from the mouse brain sample containing 1-4 transmembrane domains. This proof-of-concept work demonstrates the high potential of CZE-MS/MS for the large-scale TDP of IMPs. 

Abstract Maize (Zea mays) production systems are heavily reliant on the provision of managed inputs such as fertilizers to maximize growth and yield. Hence, the effective use of nitrogen (N) fertilizer is crucial to minimize the associated financial and environmental costs, as well as maximize yield. However, how to effectively utilize N inputs for increased grain yields remains a substantial challenge for maize growers that requires a deeper understanding of the underlying physiological responses to N fertilizer application. We report a multiscale investigation of five field-grown maize hybrids under low or high N supplementation regimes that includes the quantification of phenolic and prenyl-lipid compounds, cellular ultrastructural features, and gene expression traits at three developmental stages of growth. Our results reveal that maize perceives the lack of supplemented N as a stress and, when provided with additional N, will prolong vegetative growth. However, the manifestation of the stress and responses to N supplementation are highly hybrid-specific. Eight genes were differentially expressed in leaves in response to N supplementation in all tested hybrids and at all developmental stages. These genes represent potential biomarkers of N status and include two isoforms of Thiamine Thiazole Synthase involved in vitamin B1 biosynthesis. Our results uncover a detailed view of the physiological responses of maize hybrids to N supplementation in field conditions that provides insight into the interactions between management practices and the genetic diversity within maize. 

This article is a Commentary onMorelliet al. (2023),237: 1696–1710. 

Abstract We present a large‐scale top‐down proteomics (TDP) study of plant leaf and chloroplast proteins, achieving the identification of over 4700 unique proteoforms. Using capillary zone electrophoresis coupled with tandem mass spectrometry analysis of offline size‐exclusion chromatography fractions, we identify 3198 proteoforms for total leaf and 1836 proteoforms for chloroplast, with 1024 and 363 proteoforms having post‐translational modifications, respectively. The electrophoretic mobility prediction of capillary zone electrophoresis allowed us to validate post‐translational modifications that impact the charge state such as acetylation and phosphorylation. Identified modifications included Trp (di)oxidation events on six chloroplast proteins that may represent novel targets of singlet oxygen sensing. Furthermore, our TDP data provides direct experimental evidence of the N‐ and C‐terminal residues of numerous mature proteoforms from chloroplast, mitochondria, endoplasmic reticulum, and other sub‐cellular localizations. With this information, we suggest true transit peptide cleavage sites and correct sub‐cellular localization signal predictions. This large‐scale analysis illustrates the power of top‐down proteoform identification of post‐translational modifications and intact sequences that can benefit our understanding of both the structure and function of hundreds of plant proteins.