Nitrogen is one of the most powerful levers in modern agriculture. When supplies are inadequate, crops often produce less biomass, fewer seeds and smaller grains. Yet applying more nitrogen is not a simple solution. Crops commonly absorb only a fraction of the fertilizer supplied to fields; the remainder can leach into waterways, escape as nitrous oxide or undergo chemical transformations that contribute to air and climate pollution. Farmers therefore face a biological paradox: plants need enough nitrogen to build a productive canopy, but excessive applications are expensive and can damage ecosystems. Nitrogen-use efficiency, or NUE, describes how effectively a plant converts available nitrogen into harvestable yield. According to the review by Dmitry Veselov, Jiangzhe Zhao, Alla Korobova and colleagues, improving NUE will require understanding not just how nitrate enters roots, but how plants interpret its presence and coordinate their entire body in response.

The first step is nitrate perception. Plant roots use transporter proteins to acquire nitrate from soil, but some of these transporters also act as “transceptors”—molecules that combine transport activity with sensory functions. One of the best studied is NRT1.1, also known as CHL1 or NPF6.3 in Arabidopsis. Its activity changes with nitrate concentration, allowing roots to respond across a broad range of nutrient availability. At low nitrate levels, high-affinity NRT2 transporters help capture scarce ions; at higher concentrations, other transport systems become more important. NRT1.1 can also influence the distribution of auxin, another plant hormone, thereby altering the formation and elongation of lateral roots. This allows a plant to proliferate roots in nutrient-rich patches rather than spending the same amount of energy everywhere. Once nitrate is detected, calcium signals, protein phosphorylation and transcription factors such as NLP6 and NLP7 help activate a rapid nitrogen-response program.

Cytokinins add a second layer of control to this nutrient-sensing network. These hormones are produced in roots and shoots, and their concentration depends on a balance between biosynthesis, transport and breakdown. Nitrate availability can stimulate the expression of isopentenyl transferase, or IPT, enzymes involved in cytokinin production. In particular, nitrate-responsive changes in root IPT activity can increase the synthesis of cytokinin precursors, including forms that are converted into trans-zeatin, a biologically active cytokinin. Other enzymes, including cytokinin oxidases and dehydrogenases known as CKXs, remove or deactivate the hormones. The result is a dynamic system rather than a simple on–off switch: a change in nitrate supply can alter cytokinin production, chemical form and movement through the plant. Recent evidence highlighted in the review suggests that fluctuations in nitrate may even influence IPT3 through changes in chromatin and histone modification, allowing roots to adjust hormone production as nutrient conditions shift.

The direction of cytokinin movement is crucial. Root-derived cytokinins can travel upward through the xylem, carrying information about soil conditions to leaves and growing shoots. Transporters such as ABCG14 and related proteins help load and move cytokinin compounds over long distances, while purine permeases and other transport systems contribute to local distribution and hormone homeostasis. The shoot is not simply a passive recipient of this chemical message. It also sends information back to the roots through sugars, nitrogen-containing metabolites and mobile peptides. CEP peptides produced in roots under nitrogen limitation can be processed into signals that travel upward and stimulate shoot-to-root messages, including CEPD-like proteins that regulate nitrate uptake. Cytokinins therefore participate in a two-way conversation: roots report the availability of nitrate, while shoots communicate their demand for additional nitrogen. This feedback prevents the plant from absorbing nutrients indiscriminately when its leaves cannot use them efficiently.

The most visible consequence of this communication appears below ground, where nitrate and cytokinin signals help reshape root architecture. When nitrate is scarce, plants may favor deeper or more extensive roots capable of exploring a larger volume of soil. In a localized nitrate-rich patch, they can stimulate lateral root growth near the nutrient source. Cytokinins interact with auxin in this process, often exerting opposing effects on root and shoot development. High cytokinin activity in some root zones can limit primary root elongation, while reduced cytokinin levels may permit a larger root system. This explains why genetically or chemically reducing cytokinin degradation in roots can produce plants with enhanced root growth, improved mineral accumulation in shoots and greater drought tolerance. The effect is context-dependent, however. A root that grows farther is not automatically more efficient; constructing and maintaining extra tissue requires carbon. The plant must balance the energetic cost of exploration against the expected benefit of finding and absorbing more nitrate.

Above ground, cytokinins help determine whether newly acquired nitrogen becomes productive leaf area or is diverted elsewhere. Adequate cytokinin signaling promotes cell division, leaf expansion and chloroplast development, the process by which cells build the photosynthetic machinery that captures light. In rice, wheat and other cereals, higher cytokinin status has been associated with increased photosynthetic capacity under favorable nitrogen conditions. This connection is chemically logical: nitrogen is required to build chlorophyll and many photosynthetic proteins, including Rubisco, the enzyme that fixes carbon dioxide. Cytokinins can also influence stomatal behavior, chlorophyll maintenance and the expression of genes involved in carbon assimilation. By coordinating nitrogen uptake with photosynthetic activity, the plant can convert absorbed nitrate into sugars more efficiently. Those sugars, in turn, provide energy and carbon skeletons for nitrate assimilation, creating a feedback loop between carbon and nitrogen metabolism.

The review also draws attention to cytokinin’s role in delaying leaf senescence, the orderly deterioration of leaves as plants age or face nutrient stress. During grain filling, cereal crops depend heavily on flag leaves to continue producing carbohydrates that are transported into developing seeds. Nitrogen availability and cytokinin signaling can help maintain these leaves for longer, preserving photosynthetic activity at a stage when grain weight is being determined. At the same time, cytokinin metabolism must be carefully controlled. Excessive or poorly timed signaling can disrupt the balance between vegetative growth and reproduction. Enzymes such as CKXs act as important regulators of this balance. Research in rice has shown that altering CKX activity can affect grain number, grain filling and the relationship between carbohydrate-producing leaves and developing grains. Some transport proteins may even carry both sugar and cytokinin, linking the movement of energy and growth signals directly within developing cereal grains.

Nitrogen and cytokinin signaling may also help crops cope with drought, salinity, heat and flooding—stresses that are becoming more consequential as climates change. Nitrate can influence stress-related gene expression, antioxidant defenses and the production of reactive oxygen species, molecules that serve as signals at controlled levels but can damage cells when they accumulate excessively. Cytokinins interact with abscisic acid, the hormone strongly associated with drought responses, as well as with ethylene and other signaling pathways. Under water deficit, changes in cytokinin production and transport can alter the balance between shoot growth and root investment, helping plants conserve resources while continuing to search for water. In some systems, stress-induced cytokinin synthesis has been linked to coordinated regulation of carbon and nitrogen assimilation. Nitrate nutrition has also been associated with improved tolerance to salinity and heat, although the benefits depend on dose, timing, species and environmental conditions. Too much nitrogen can intensify stress by stimulating growth that the plant cannot support with available water.

The authors emphasize that these findings do not justify simply adding hormones or more fertilizer to fields. Cytokinins are powerful regulators, and their effects vary with tissue, developmental stage, nitrate concentration and interactions with other hormones. Instead, the review points toward precision strategies that might match fertilizer placement and timing to the plant’s signaling capacity. Localized fertilizer application could encourage roots to forage in nutrient-rich zones without saturating the entire soil profile. Breeding or gene editing might target nitrate sensors, cytokinin transporters, IPT biosynthetic enzymes or CKX catabolic enzymes to create crops that maintain productivity with less nitrogen. Beneficial soil microbes that produce or modify cytokinins could provide another route, particularly under drought or nutrient stress, although field performance remains difficult to predict. The central message is that future high-efficiency crops may be designed not only to absorb more nitrate, but to make better decisions about when, where and why to use it. By treating nitrate as both food and information, agriculture could move closer to producing more grain with less fertilizer—and make the plant’s own communication network part of the solution.

Subject of Research: Interaction between nitrate signaling and cytokinin hormones in plant nitrogen-use efficiency, growth, stress resistance and crop productivity

Article Title: Interaction between nitrates and cytokinins in the regulation of nitrogen use efficiency, plant growth, abiotic stress resistance and productivity

Article References: Veselov, D., Zhao, J., Korobova, A. et al. “Interaction between nitrates and cytokinins in the regulation of nitrogen use efficiency, plant growth, abiotic stress resistance and productivity.” Plant and Soil (2026). Original research page

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09011-7

Keywords: nitrate uptake, nitrogen-use efficiency, cytokinin signaling, cytokinin transporters, root architecture, crop productivity, drought resistance, cereal grain filling

Cysteine proteases are a group of enzymes that play crucial roles in protein degradation and processing in a wide range of biological systems. Their functions in plants are vital for growth, development, and the response to environmental stimuli. The significance of the cysteine protease gene family in maize cannot be overstated, as they are involved in critical processes such as senescence, disease resistance, and stress tolerance. Wang and colleagues’ meticulous work marks an important step toward deciphering the complex interactions and regulatory mechanisms involving these enzymes.

Through advanced genomic techniques, the research team performed a genome-wide analysis of the cysteine protease gene family in maize. This involved mining the maize genome for the identification and annotation of cysteine protease genes, followed by a detailed characterization of their sequences and structures. The researchers employed bioinformatics tools to analyze the phylogenetic relationships among these genes, providing insights into their evolutionary history and functional divergence.

One of the key findings from the study was the identification of a considerable number of cysteine protease genes within the maize genome, highlighting the complexity and diversity of this gene family. The researchers found that these genes are not only abundant but also show differential expression patterns across various developmental stages and environmental conditions. Such expression profiling is crucial for understanding how maize responds to stressors, which is particularly relevant in the context of climate change and food security.

Moreover, the research identified specific cysteine protease genes that are upregulated in response to environmental stresses such as drought and pathogen attack. This information points to potential targets for genetic engineering and breeding programs aimed at enhancing stress tolerance in maize. The ability to manipulate these genes could lead to the development of maize varieties that are more resilient and yield more effectively under adverse conditions.

Another fascinating aspect of the study was the exploration of the regulatory networks influencing the expression of cysteine protease genes. The researchers examined the promoter regions of these genes to identify cis-regulatory elements that may be involved in their expression. This investigation underscores the intricacies of gene regulation in plants and the role of regulatory elements in orchestrating the expression of genes in response to various stimuli.

In addition to the technical advancements in genomics, the study also delved into the functional analysis of selected cysteine protease genes. By using transcriptomics and proteomics approaches, the team was able to correlate gene expression levels with functional outcomes in maize. This integrative approach laid the groundwork for future experiments aimed at elucidating the biological functions of individual cysteine proteases, further enriching the understanding of their roles in plant physiology.

As agriculture faces increasing pressures from climate change, the findings of this research provide a roadmap for enhancing crop resilience through genetic and biotechnological interventions. By focusing on the molecular underpinnings of the cysteine protease gene family in maize, Wang and colleagues have opened doors to innovative strategies that could lead to sustainable agricultural practices.

The implications of this research extend beyond maize as well. The methodologies and insights gained from this study can be applied to other crops and plant species, potentially aiding in the global effort to improve food security and agricultural sustainability. Understanding the role of cysteine proteases in different plant systems may unveil novel approaches for enhancing crop performance in various environmental contexts.

As the scientific community continues to explore the complexities of plant genetics, studies like this one are vital in paving the way for future discoveries. The integration of genomic data with functional studies will remain critical for advancing plant biology and addressing the challenges facing modern agriculture.

In conclusion, the comprehensive characterization and expression profiling of the cysteine protease gene family in maize represent a significant milestone in plant genomics. By revealing the intricate relationships between these genes and their broader biological functions, Wang, Guan, and Zheng are contributing to a deeper understanding of plant resilience and adaptation. Such research is invaluable as we strive to build a more sustainable agricultural future.

In essence, the work serves as a clarion call for continued research into plant gene families and their applications in crop improvement. As we stand at the cusp of a new era in agricultural science, findings like these not only enhance our basic scientific understanding but also fuel hope for innovations that can meet the food demands of a growing global population.

Ultimately, as we look forward to further studies and potential applications arising from this research, the role of cysteine proteases in maize could prove to be a linchpin in the future of crop resilience and productivity, underscoring the importance of molecular characterization and expression profiling in plant science.

Subject of Research: Cysteine protease gene family in maize

Article Title: Genome-wide molecular characterization and expression profiling of the cysteine protease gene family in maize.

Article References:

Wang, T., Guan, M., Zheng, Y. et al. Genome-wide molecular characterization and expression profiling of the cysteine protease gene family in maize. BMC Genomics 26, 789 (2025). https://doi.org/10.1186/s12864-025-12003-z

Image Credits: AI Generated

DOI: 10.1186/s12864-025-12003-z

Keywords: Cysteine protease, maize, gene family, molecular characterization, expression profiling, plant resilience, stress tolerance, genomics.