Cross-compartment communication is critical for maintaining cellular homeostasis, which is essential for cell function and survival under stressful conditions. However, the cellular cues that trigger interorganellar communication remain poorly understood. Mitochondrial Ca2+ (mtCa2+) homeostasis is fundamental to mitochondrial function; yet, how mitochondrial Ca2+ (mtCa2+) homeostasis modulates nuclear gene expression to establish and maintain cellular homeostasis remains unclear. Here, we first characterize the critical role of the mitochondrial Ca2+ uniporter (MCU) in control of mtCa2+ uptake and maintaining mtCa2+ homeostasis in planta. Using gain-of-function and sextuple MCU knockdown mutants, we then analyzed the effects of impaired MCU-controlled mtCa2+ homeostasis (iMUCH). We find that iMUCH elicits an interorganellar transcription program that activates multiple compartment-specific unfolded protein responses (UPRs) and genes critical for mitochondrial and cytosolic proteostasis. Additionally, iMUCH induces a post-transcriptional program that selectively represses the synthesis of ribosomes and RNA modification proteins. Furthermore, eukaryotic initiation factor α (eIFα and its phosphorylation likely serve as a protective mechanism under long-term mitochondrial proteotoxic stress induced by iMUCH. Collectively, the data demonstrate that MCU-controlled mtCa2+ homeostasis plays a pivotal role in sustaining mitochondrial and cytosolic proteostasis through an interconnected organelle quality control system, which ultimately determines cell growth and fitness.

Mitogen-activated protein kinase (MAPK) cascades regulate growth, development, stress responses, and immunity in plants by transmitting signals from upstream regulators to downstream components. In this study, we identify a MAPK cascade composed of MAPK kinase kinase 19 (MKKK19), three MAPK kinases (MKK3/MKK5/MKK9), and MAPK 6 (or MPK6) that is involved in Arabidopsis leaf senescence. The kinase oxidative signal-inducible 1 (OXI1) functions upstream of the MKKK19-MKK3/MKK5/MKK9-MPK6 cascade to promote leaf senescence, whereas two of RESPIRATORY BURST OXIDASE HOMOLOGS (RBOHs), RBOHD and RBOHF, act downstream to mediate the accumulation of reactive oxygen species (ROS). Loss-of-function mutation of OXI1, MKKK19, MKK3/MKK5/MKK9, or MPK6 resulted in delayed leaf senescence associated with reduced ROS levels, whereas transgenic lines overexpressing OXI1, MKKK19, MKK3/MKK5/MKK9, or MPK6 displayed the opposite phenotypes. Epistatic analyses supported the involvement of OXI1, MKKK19, MKK3/MKK5/MKK9, MPK6, and RBOHD/RBOHF in the same signaling pathway for leaf senescence. In conclusion, genetic and biochemical analysis of the Arabidopsis MKKK19-MKK3/MKK5/MKK9-MPK6 cascade through OXI1 and RBOHD/RBOHF revealed a vital role for the MAPK cascade and ROS in natural leaf senescence.

Mitochondria support plant growth and adaptation via energy production and signaling pathways. However, how mitochondria control the transition between growth and stress response is largely unknown in plants. Using molecular approaches, we identified the histone H3K4me3 demethylase JMJ15 and the transcription factor CRF6 as targets of SnRK1 in Arabidopsis. By analyzing antimycin A (AA)-triggered mitochondrial stress, we explored how SnRK1, JMJ15, and CRF6 form a regulatory module that gauges mitochondrial status to balance growth and the oxidative stress response. SnRK1a1, a catalytic α-subunit of SnRK1, phosphorylates and destabilizes JMJ15 to inhibit its H3K4me3 demethylase activity. While SnRK1a1 does not phosphorylate CRF6, it promotes its degradation via the proteasome pathway. CRF6 interacts with JMJ15 and prevents its SnRK1a1 phosphorylation-dependent degradation, forming an antagonistic feedback loop. SnRK1a1, JMJ15, and CRF6 are required for transcriptional reprogramming in response to AA stress. The transcriptome profiles of jmj15 and crf6 mutants were highly correlated with those of plants overexpressing SnRK1a1 under both normal and AA stress conditions. Genetic analysis revealed that CRF6 acts downstream of SnRK1 and JMJ15. Our findings identify the SnRK1-JMJ15-CRF6 module that integrates energy and mitochondrial signaling for the growth-defense trade-off, highlighting an epigenetic mechanism underlying mitonuclear communication.

Organelle membrane (OM)-resident or -proximal proteins that face the cytosol play a critical role in the import and exchange of ions, metabolites, and proteins between subcellular compartments, thereby regulating organelle biogenesis and function. However, the identification and functional characterization of these proteins pose challenges due to their dynamic spatial and temporal nature. We introduce a proximity labeling system using biotin ligase-mediated protein biotinylation in live Arabidopsis thaliana cells. This chapter outlines a detailed step-by-step protocol for identifying cytosol-facing OM-resident or -proximal proteins of mitochondria, chloroplasts, and peroxisomes in plant cells. This protocol can be adapted to identify cytosol-facing OM-resident and/or proximal proteins of any subcellular compartments of interest, as well as to map their spatiotemporal profiles under various stress conditions. The protocol described includes the following key steps: (1) sample preparation; (2) optimization of biotin labeling conditions; (3) enrichment of biotinylated proteins for liquid chromatography-tandem mass spectrometry (LC-MS/MS); (4) validation of identified candidate proteins.

The cytosol-facing outer membrane (OM) of organelles communicates with other cellular compartments to exchange proteins, metabolites and signaling molecules. Cellular surveillance systems also target OM-resident proteins to control organellar homeostasis and ensure cell survival under stress. Using traditional approaches to discover OM proteins and identify their dynamically interacting partners remains challenging. In this study, we developed an OM proximity labeling (OMPL) system using biotin ligase-mediated proximity biotinylation to map the proximity proteome of the OMs of mitochondria, chloroplasts, and peroxisomes in living Arabidopsis ( Arabidopsis thaliana ) cells. We demonstrate the power of this system with the discovery of cytosolic factors and OM receptor candidates involved in local protein translation and translocation, membrane contact sites, and organelle quality control. This system also performed admirably for the rapid isolation of intact mitochondria and peroxisomes. Our data support the notion that TOM20-3 is a candidate for both a mitochondrial and a chloroplast receptor, and that PEX11D is a candidate for a peroxisome receptor for the coupling of protein translation and import. OMPL-generated OM proximity proteomes are valuable sources of candidates for functional validation and suggest directions for further investigation of important questions in cell biology.

Municipal solid waste incineration fly ash (MSWI FA) is categorized as a hazardous waste with significant implications on environmental safety and human health. This study tailored three types of alkali-activated materials (AAMs) by using ground granulated blast-furnace slag (GGBS) and metakaolin (MK) for the low-carbon stabilization/solidification (S/S) of MSWI FA. The intricate interactions between MSWI FA and AAMs synthesized from Al-rich precursors and Ca-rich precursors were investigated to elucidate the microstructural alterations of AAM-MSWI FA systems. Comprehensive characterization techniques were conducted, including isothermal calorimeter, thermal gravimetric analysis, Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and 27Al and 29Si nuclear magnetic resonance (NMR). The results revealed that the incorporation of MSWI FA significantly delayed alkali activation reactions, hindering the formation of aluminosilicate gel due to high contents of Cl and potentially toxic elements (PTEs) in the MSWI FA. High volume of dissolved Cl from MSWI FA would react with available Ca from MSWI FA and GGBS as well as Al from GGBS and MK to form Friedel’s salt, and this reaction was found to be more dominant in the Al-rich environment. Meanwhile, the C-(N-)A-S-H gel exhibited longer chain length in the Al-rich environment than in the Ca-rich environment. Overall, this study delivers microstructural insights into AAM-MSWI FA systems utilizing GGBS and MK as precursors. The results provide scientific groundwork for diverse practical applications of AAM-MSWI FA materials, thereby supporting the development of resource-efficient and low-carbon hazardous waste treatment strategies.

This paper proposes to prepare hydrophobic alkali-activated slag (AAS) mortars with methyl-terminated polydimethylsiloxane (PDMS), a hydrophobic polymer with low surface energy, to minimize its water sorptivity and efflorescence. To depict the efflorescence process of PDMS-modified AAS mortars, visual inspections of efflorescence features, the leaching behavior of sodium ions, water absorption characteristics of mortars and contact angle tests were conducted. Additionally, the hydration process, microscopic morphology, and chemical structure of PDMS-modified AAS mortars and pastes were examined by compressive strength, isothermal calorimetry, TEM, SEM, FT-IR, 29 Si NMR, enabling the explanation of PDMS working mechanisms. The results demonstrated that the addition of PDMS successfully mitigated esthetic issues and the spalling of mortars caused by efflorescence. Furthermore, PDMS reduced the risk of long-term durability issues of AAS mortars by restricting the loss of sodium ions after efflorescence. At the same time, the introduction of PDMS with dosage below 5 % did not significant retarder the hydration reaction process or the development of strength of AAS. However, it did alter the micromorphology and chemical structure of the hydration product. PDMS linked to the hydration products through covalent bonds and acted as a bridging role to alter the micromorphology of the hydration products. The resulting multi-structured material exhibited micropapillary and nano-coating layers with hydrophobic methyl functional groups, imparting hydrophobicity to the PDMS-AAS hydration product.

Ground granulated blast-furnace slag (GGBS) is widely used as supplementary cementitious material of interest for adjusting the performance of concrete. Unlike standard commercial products, characteristics of GGBS from different iron manufacturers vary significantly and assessment of its reactivity, especially at an early age, is not well-established despite numerous parameters specified in current standard systems. Three GGBSs with different setting features during the alkali-activated process were dissolved in either deionised (DI) water or NaOH solution in this study. To illustrate the fundamental processes of reaction kinetic, the dissolved ion concentrations, glassy structural changes, and chemically bound water were measured using ICP-OES, FTIR, and TG respectively. Meanwhile, thermodynamic calculations were carried out to estimate the precipitation of C-S-H gels, which is directly linked with setting behaviours. The results clearly show the differences in the dissolution of the three GGBSs, which could be used to indicate the activity of GGBS. The GGBS with higher activity (i.e. faster setting during alkali activation) tends to dissolve evenly in DI water, whilst those with lower activity show that the silicate groups with lower polymerisation dissolved faster. The chemically bound water determined by TG analysis and the effective saturation index (ESI) are promising parameters for reflecting the activity of GGBS during dissolution in the alkali media. Although this study demonstrated the dissolution rate of higher polymerised silicate groups in GGBS should be the root for the differences in its activity, more structural information on the glassy phase and the interactions of alkali with the surface of GGBS still require further understanding. It is speculated that the ratio of Al[IV]/Al[V] plays an important role in the activity of GGBS. This finding may shape a certain basic understanding of how GGBSs dissolve in neutral and high pH solutions and highlight a reevaluation of assumptions in thermodynamic simulation under different conditions.

Throughout legume–rhizobium symbiosis, nitrogen fixation occurs within the symbiosome, a membrane-bound organelle-like structure found in nodule cells. The symbiosome represents a temporary organelle in which rhizobia-encoded nitrogenase catalyzes dinitrogen conversion to ammonia in an oxygen-regulated microenvironment. Investigating symbiosome biology will undoubtedly improve our understanding of nitrogen fixation mechanisms and highlight novel targets for improving nitrogen fixation efficiency. Recent research advancements have taken place on regulatory aspects of symbiosome generation and functions, but obtaining spatiotemporally resolved symbiosome proteome and metabolomes, as well as tracking and deciphering its intracellular communication, is challenging. As a symbiotic interface, the symbiosome membrane proteome is largely composed of plant-derived proteins, while the symbiosome space between the symbiosome membrane and bacteria consists of proteins and metabolites from the rhizobium and plant. In the unique microenvironment, symbiosome proteins likely perform multiple tasks via their moonlighting functions, accounting for the many unsolved questions associated with symbiotic nitrogen fixation. In this review, we outline the current knowledge regarding the composition and potential moonlighting functions of symbiosome proteins. We highlight our current understanding of emergent symbiosome properties closely tied to nitrogen fixation activity. Ultimately, we discuss the challenges and opportunities for discovering new paradigms in symbiosome biology using recent technologies.

Spontaneous gain or loss of DNA methylation occurs in plant and animal genomes, and DNA methylation changes can lead to meiotically stable epialleles that generate heritable phenotypic diversity. However, it is unclear whether transgenerational epigenetic stability may be regulated by any cellular factors. Here, we examined spontaneously occurring variations in DNA methylation in wild-type and ros1 mutant Arabidopsis plants that were propagated for ten generations from single-seed descent. We found that the ros1 mutant, which is defective in active DNA demethylation, showed an increased transgenerational epimutation rate. The ros1 mutation led to more spontaneously gained methylation than lost methylation at individual cytosines, compared to the wild type which had similar numbers of spontaneously gained and lost methylation cytosines. Consistently, transgenerational differentially methylated regions were also biased toward hypermethylation in the ros1 mutant. Our results reveal a genetic contribution of the ROS1 DNA demethylase to transgenerational epigenetic stability and suggest that ROS1 may have an unexpected surveillance function in preventing transgenerational DNA methylation increases.

Upon the initial contact of hydrophilic cementitious materials with water, capillary absorption becomes the dominant phenomenon leading to durability deterioration of structures. The water absorption characteristics of such materials are governed by the interplay between pore structure and surface-free energies, with the latter being a factor often overlooked. In this study, advanced inverse gas chromatography (IGC) measurement techniques were employed to investigate the one-dimensional capillary water absorption of ordinary Portland cement (OPC) and alkali-activated slag (AAS). Results revealed water sorptivity values for OPC, AAS(NaOH), and AAS(Waterglass) as 0.0112, 0.0137, and 0.0187 mm/s0.5, respectively. This phenomenon can be attributed to the higher total surface-free energies observed at the liquid-solid interface in AAS materials, measuring 100.10 and 119.56 mJ/m2, compared with 74.25 mJ/m2 for OPC, consequently increasing capillary pressures. Moreover, it is observed that OPC exhibited a more complex pore tortuosity in comparison to AAS. This study underscores the dual role played by both capillary pressures and pore tortuosity in determining the water absorption characteristics of cementitious materials.

Pastes of white Portland cement (wPC) and wPC-30 % pulverized fuel ash (PFA), -60 % ground granulated blast furnace slag (GGBS), -30 % or 60 % inert filler (anatase-type TiO2) blends were prepared to investigate the dominant factors for morphological change of outer product (OP) C-A-S-H gel in blended cement systems. The OP C-A-S-H gel in SCMs-blended cements changes its morphology from fibrillar-like to mixed fine-fibrillar/foil-like when its Ca/(Si + Al) ratio < 1.30 and Al/Si ratio > 0.15. Meanwhile, the fine-fibrillar/foil-like C-A-S-H has the mean length of the aluminosilicate chain longer than 7– 8, of which, the [SiO4] bridging site occupancy factor (SOFBT) is higher than 0.6 and the [AlO4] SOFBT is higher than 0.3. The pore solutions show the characteristics of effective saturation index (ESI) of CH < −0.15 and ESI of jennite-based C-S-H gel < 0.10. The morphology of C-A-S-H gel in inert filler blends remains fibrillar throughout the hydration.

Plant stomata phenotypic traits can provide a basis for enhancing crop tolerance in adversity. Manually counting the number of stomata and measuring the height and width of stomata obviously cannot satisfy the high-throughput data. How to detect and recognize plant stomata quickly and accurately is the prerequisite and key for studying the physiological characteristics of stomata. In this research, we consider stomata recognition as a multi-object detection problem, and propose an end-to-end framework for intelligent detection and recognition of plant stomata based on feature weights transfer learning and YOLOv4 network. It is easy to operate and greatly facilitates the analysis of stomata phenotypic traits in high-throughput plant epidermal cell images. For different cultivars, multi-scales, rich background features, high density, and small stomata object images, the proposed method can precisely locate multiple stomata in microscope images and automatically give phenotypic traits of stomata. Users can also adjust the corresponding parameters to maximize the accuracy and scalability of automatic stomata detection and recognition. Experimental results on actual data provided by the National Maize Improvement Center show that the proposed method is superior to the existing methods in high stomata automatic detection and recognition accuracy, low training cost, strong generalization ability.

This paper aims to provide insights into the coupled influence of typical anti-freezing agents (AFAs) and cold environment on rheological performance of cement mortar with/without different superplasticizer (SP) and airentraining agent (AEA) components. Fresh mixtures were prepared with chemical admixtures singly or in groups (AFA; AFA/SP; AFA/SP/AEA) for the continuous measurement of their time-dependent rheological behavior at variable temperatures (24 & DEG;C; 0 & DEG;C; -5 & DEG;C; -10 & DEG;C). Hydration kinetics, pore solution and air-void system were systematically evaluated to provide evidences supporting for the variations in rheological parameters. It was found that the yield stress of mixture decreased and the plastic viscosity increased with the temperature falling from 24 & DEG;C to 0 & DEG;C, while both the yield stress and the plastic viscosity increased rapidly with the temperature falling from 0 & DEG;C to -10 & DEG;C. Temperature could affect the rheological parameters development by changing the interaction of SP with ions. For the SP-plasticized mixtures under low temperature, the dosage of calcium nitrite (CN) as AFA should be carefully restricted. For the air-entrained mixtures, the incorporation of CN enhanced the shear stress in the high shear rate region, while the incorporation of ethylene glycol (EG) showed a converse behavior. The results will provide theoretical supports for the manufacture and the early-age properties control of flowable concrete during winter construction.

Mitochondria produce signals besides energy and metabolites that influence plant growth and fitness. However, how mitochondrial signals are relayed to other cellular compartments is largely unknown. By applying poly(A)-site RNA-sequencing (PAS-seq) to wildtype Arabidopsis seedlings and a mutant in the histone demethylase JMJ30 treated with the mitochondrial electron transfer chain inhibitor antimycin A (AA), we identified a previously undefined mitochondrion-to-nucleus communication pathway by which mitochondrial functional state regulates co-transcriptionally alternative polyadenylation (APA) of nuclear mRNA. We observed a global shortening of 3′ untranslated regions (UTRs) as a molecular signature of AA-activated mitochondrial retrograde response (MRR), which contributed in part to translational regulation of auxin response and cell wall biogenesis. JMJ30 regulated AA-induced 3′ UTR shortening, resulting in more transcripts with shortened 3′ UTRs upon AA treatment in a JMJ30 gain-of-function mutant and overexpression lines. We also report on the JMJ30-interacting protein CPSF30, a cleavage and polyadenylation specificity factor that recruits JMJ30 to modulate H3K27me3 status at its target loci. Our study illustrates how epigenetic modification and APA coordinate mitochondrion-to-nucleus communication to allow cells to rapidly respond to changes in mitochondrial functional state and shape plant growth and fitness. One-sentence summary Epigenetic modification and APA coordinate mitochondrion-to-nucleus communication to allow cells to rapidly respond to changes in mitochondrial functional state and shape plant growth and fitness.

Low molecular weight protein tyrosine phosphatase (LWM-PTP), also known as acid phosphatase, is a highly conserved tyrosine phosphatase in living organisms. However, the function of LWM-PTP homolog has not been reported yet in plants. Here, we revealed a homolog of acid phosphatase, APH, in Arabidopsis plants, is a functional protein tyrosine phosphatase. The aph mutants are hyposensitive to ABA in post-germination growth. We performed an anti-phosphotyrosine antibody-based quantitative phosphoproteomics in wild-type and aph mutant and identified hundreds of putative targets of APH, including multiple splicing factors and other transcriptional regulators. Consistently, RNA-seq analysis revealed that the expression of ABA-highly-responsive genes is suppressed in aph mutants. Thus, APH regulates the ABA-responsive gene expressions by regulating the tyrosine phosphorylation of multiple splicing factors and other post-transcriptional regulators. We also revealed that Tyr383 in RAF9, a member of B2 and B3 RAF kinases that phosphorylate and activate SnRK2s in the ABA signaling pathway, is a direct target site of APH. Phosphorylation of Tyr383 is essential for RAF9 activity. Our results uncovered a crucial function of APH in ABA-induced tyrosine phosphorylation in Arabidopsis.

Mitochondrial Ca 2+ ( mt Ca 2+ ) homeostasis is essential to mitochondrial functions. However, how mt Ca 2+ homeostasis is achieved and the consequences of impaired mt Ca 2+ homeostasis in plants is poorly understood. Here, we demonstrate a critical role for mitochondrial Ca 2+ uniporter (MCU) in the control of mt Ca 2+ uptake for mt Ca 2+ homeostasis in planta by characterizing MCU mutants and overexpressed plants. Impaired MCU-controlled mt Ca 2+ homeostasis (iMUCH) in gain-of-function and loss-of-function MCU plants causes the misregulation of mitochondrial gene expression that triggers mitonuclear protein imbalance. Transcriptome integrated with proteomics analysis reveal activation of multiple compartmental UPR gene expression and decrease of cytosolic translation with selective repression of ribosome and RNA modification protein synthesis upon iMUCH. Intriguingly, TOR signalling is not involved in cytosolic translational response to iMUCH, but the reduction of eIFα phosphorylation is evident under iMUCH induced mitochondrial stress. Thus, our study unveils the essential functions of MCU proteins for mt Ca 2+ homeostasis, and the involvement of MCU-controlled mt Ca 2+ homeostasis in mitochondrial stress dependent regulation of protein synthesis for cellular proteostasis that is connected to plant growth and stress resistance.

Background and aims As drought threatens the yield and quality of maize ( Zea mays L.), it is important to dissect the molecular basis of maize drought tolerance. Flavonoids, participate in the scavenging of oxygen free radicals and alleviate stress-induced oxidative damages. This study aims to dissect the function of flavonoids in the improvement of maize drought tolerance. Methods Using far-infrared imaging screening, we previously isolated a drought overly insensitivity ( doi ) mutant from an ethyl methanesulfonate (EMS)-mutagenized maize library and designated it as doi57 . In this study, we performed a physiological characterization and transcriptome profiling of doi57 in comparison to corresponding wild-type B73 under drought stress. Results Under drought stress, doi57 seedlings displayed lower leaf-surface temperature (LST), faster water loss, and better performance in growth than B73. Transcriptome analysis reveals that key genes involved in flavonoid biosynthesis are enriched among differentially expressed genes in doi57 . In line with these results, more flavonols and less hydrogen peroxide (H 2 O 2 ) were accumulated in guard cells of doi57 than in those of B73 with the decrease of soil water content (SWC). Moreover, the capacity determined from doi57 seedling extracts to scavenge oxygen free radicals was more effective than that of B73 under the drought treatment. Additionally, doi57 seedlings had higher photosynthetic rates, stomatal conductance, transpiration rates, and water use efficiency than B73 exposed to drought stress, resulting in high biomass and greater root/shoot ratios in doi57 mutant plants. Conclusion Flavonoids may facilitate maize seedling drought tolerance by lowering drought-induced oxidative damage as well regulating stomatal movement.

本实验研究了偏高岭土掺量、碱当量及养护温度对碱激发矿渣/偏高岭土砂浆(AASM)干燥收缩性能的影响.结果表明:掺入50％(质量分数)偏高岭土的碱激发体系质量损失加大、内部相对湿度较低,但由于其游离水与基体产物中晶体含量增加,干缩对质量损失的敏感性显著降低.另外,适当提升养护温度可进一步改善产物中晶体成分,能够更好地降低体系干缩.值得注意的是,AASM易碳化,且过高碱当量(如10％)与过长高温养护时间都会降低改善干缩的效果.

Nitrogen (N) is one of the most important nutrients affecting maize productivity. The effects of osmotic stress on nitrogen assimilation still remain unclear. The aim of this study is to characterize the physiological and biochemical responses to the N level and examine the expression of the genes involved in the N assimilation pathway under osmotic stress. Maize seedlings were supplied with three N levels; low N (LN, 0.5 mM), moderate N (MN, 10 mM) and high N (HN, 20 mM) with or without 10% of PEG 6000 . Results showed that osmotic stress reduced photosynthesis, and transpiration rate as well as stomatal conductance while increased N assimilation at HN. The activities of NR and GPT enzymes were negatively correlated with the N level. However, a positive correlation was observed between the activities of other N assimilation related enzymes and HN level under osmotic stress. The relative expression of genes involved directly in nitrate transport, for example, ZmNRT1.2 , ZmNRT2.2 , and ZmNRT2.3 were higher at LN level. At LN application, the genes involved in the N assimilation pathway, like ZmGln4 , ZmGln5 , ZmGs1.3 , ZmGs1.4, and ZmSupp showed higher expression levels under osmotic stress. Overall, the expression level of osmotic-stress related genes was decreased at HN level. Taken together, we concluded that though the mRNA levels and enzymatic activities of N assimilation related enzymes were varied and not typically correlated at various nitrogen levels under osmotic stress. However, the expression level of major N assimilation related genes could be used as biomarkers for the identification of maize genotypes or mutants with high nitrogen assimilation under osmotic stress.