Synthetic nitrogen fertilizers have greatly increased crop yields, yet much of the applied nitrogen is lost from agroecosystems and contributes to environmental pollution and higher economic costs. Improving nitrogen uptake efficiency (NUpE) benefits from understanding how root system architecture (RSA) governs soil nitrogen capture. Although root traits have seldom been explicit breeding targets, selection for variation in above-ground nitrogen accumulation has also likely shaped differences in RSA. The Illinois Protein Strain Recombinant Inbred population, derived from more than a century of divergent selection for seed protein concentration, offers a powerful resource for dissecting RSA variation. Using multi-year field phenotyping of excavated root crowns and genome-wide association analysis, we identified a quantitative trait locus on chromosome 10 containing E1OGDH1, which encodes the E1 subunit of the 2-oxoglutarate dehydrogenase (OGDH) complex. OGDH performs a key step in the tricarboxylic acid cycle that also modulates 2-oxoglutarate, an important entry point into nitrogen metabolism and a co-factor for enzymes involved in hormone and secondary product synthesis. Long-read sequencing of inbreds derived from the divergent IHP and ILP parental populations revealed promoter polymorphisms defining E1OGDH1 alleles and differed in E1OGDH1 expression in root tissue. Field experiments in IPSRI lines carrying IHP- or ILP-associated E1OGDH1 alleles showed differences in root architectural traits over two years. CRISPR-Cas9 knockout mutants confirmed a functional role for E1OGDH1 in whole-plant performance and nitrogen-responsive root development. Mutants were shorter, had reduced biomass, and exhibited altered architectural responses to soil nitrogen levels. Transcriptome analysis further showed that loss of E1OGDH1 altered basal and nitrogen-responsive expression of genes associated with root development and nitrogen uptake and metabolism. Together, these findings identify E1OGDH1 as a strong candidate quantitative regulator of maize RSA and nitrogen plasticity, suggesting that central carbon–nitrogen metabolic genes can contribute to root developmental responses relevant to NUpE.
Potato is a globally important food crop, but its production faces major challenges related to inefficient nitrogen fertilizer use. Excessive nitrogen application, particularly in intensive agricultural systems, compromises sustainability and increases environmental and health risks. Improving nitrogen use efficiency (NUE), defined as the capacity of plants for nitrogen uptake and assimilation, is therefore essential to optimize fertilization practices and enhance sustainable crop production. In this study, we analyzed candidate genes associated with NUE in a diploid potato diversity panel (Solanum tuberosum Group Phureja) by evaluating morphological, physiological, and biochemical variables under contrasting nitrogen levels. Association analyses were performed between these variables and genetic polymorphisms within NUE-related genes. Single nucleotide polymorphisms (SNPs) were identified in three candidate genes: AMT1.1 (ammonium transporter), 2OGDD (2-oxoglutarate-dependent dioxygenase), and PPR (pentatricopeptide repeat protein gene). These variants explained 8–20% of the phenotypic variation in traits such as relative chlorophyll content, aerial biomass, and NUE. Notably, a missense variant (Lys → Glu) in 2OGDD was associated with a 30.5% reduction in NUE under low nitrogen conditions, suggesting distinct adaptive strategies. Specific SNPs were associated with NUE-related traits, representing candidate variants for future functional validation and marker-assisted breeding.
A. Jiménez-Medrano, Johana Carolina Soto-Sedano, S. Magnitskiy et al.· ACS Agricultural Science &am...· 0 citations
The findings suggest that GmRD22 has undergone directional selection during soybean domestication and improvement, and offer new insights into the genetic control of SNF and establish promising targets for breeding soybean varieties with improved nitrogen fixation efficiency.
Hanyu Zhao, Jiaying Zhong, Chao Ma et al.· Plants· 0 citations
Increasing atmospheric carbon dioxide (CO2) is transforming the climate space in which plants grow, severely affecting crop physiology and crop productivity. Elevated CO2 enhances photosynthesis and biomass; however, it can nitrogen (N) metabolism, inhibiting the nutritional value and the yield capacity of crops. The most important central N-regulated protein machineries are: transporters, nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, glutamate dehydrogenase, and urease which control N assimilation, distribution and remobilization in crop plants. With high CO2, these molecular components exhibit altered expression and activities mostly due to the reduction in N concentration. Complex systemic plant responses under N control like adaptation of photosynthetic capacity, flowering time, reproductive development and seed nutrient profiles further support the complexity of the interactions between C and N signaling. The high CO2 environment requires a more holistic analysis of the regulatory networks of N metabolism and anticipative crop improvement strategies. Future breeding and crop improvement strategies should focus on enhancing the resilience of N assimilation by optimizing the N transporter function and maintaining C-N stoichiometry, thereby sustaining crop performance and nutritive quality under changing climatic conditions. The present review identifies the molecular processes that regulate N responses in crops grown under elevated CO2, highlighting the differences between legume versus non-legume and C3 versus C4 plant responses and providing details that can ensure mitigation against negative impacts and outline future perspectives on crop improvement.
R. Sreeharsha, D. Unnikrishnan, Shalini Mudalkar et al.· Physiologia Plantarum : An I...· 0 citations
The A allele (Hap1) was significantly associated with increased plant height, SPAD value, grain number, nitrogen accumulation, nitrogen accumulation, and biomass under LN stress, suggesting that SORBI_3001G116400 as a candidate gene requiring functional validation and testing in additional genetic backgrounds.
Fangfang Fan, Xiaoqiang Cheng, Yao Wang et al.· Agronomy· 0 citations
The results suggest that OsCYP51H9 participates in the phytosterol-BR pathway and plays a positive role in rice adaptation to low-nitrogen environments, providing a potential target for molecular breeding.
Zhengli Jiao, Jianyi Li, Weijuan Xu et al.· Plant physiology and biochem...· 0 citations
In natural and agricultural ecosystems, nitrogen deficiency is often a major limiting factor for plant growth, while research on the molecular genetic basis of nitrogen uptake and utilization in slash pine remains scarce. This study explored the regulatory mechanisms of pine needles under different conditions by comparing the differences in nitrogen response of needles from different slash pine families at different time points under varying nitrogen concentrations, aiming to better understand the expression profile of nitrogen uptake and utilization in slash pine needles. Three key results were obtained: (1) A total of 2353 differentially expressed genes were identified, mainly including transcription factors families, such as C3H, bHLH, MYB, and others. These genes have been reported to be associated with nitrogen uptake and utilization in plants. (2) The nitrogen uptake and utilization pathway contains 36 DEGs encoding 10 types of proteins. (3) Weighted Gene Co-expression Network Analysis showed a strong correlation between ground diameter of slash pine and module gene expression, and the hub gene Pee07g026510 exhibited high connectivity with other nitrogen metabolism genes. This confirms that Pee07g026510 can affect Diameter growth by regulating GAD expression—specifically, generating GABA to alleviate ammonium toxicity under high-nitrogen conditions and prioritizing the efficiency of the GS/GOGAT cycle under low-nitrogen conditions. This is consistent with the theory that nitrogen deficiency inhibits biomass accumulation, providing a fundamental reference for the management and genetic improvement of slash pine plantations.
Shaoze Wu, X. Ding, Q. Luan et al.· Frontiers in Plant Science· 0 citations
