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Research Progress on Role of Transcription Factor TGA in Nitrogen Absorption, Transport and Assimilation in Plants
LIUZheyang, FENGDianxing, ZOULiangping, RUANMengbin, YUXiaoling, LIShuxia, LIWenbin, ZHAOPingjuan
Chin Agric Sci Bull ›› 2026, Vol. 42 ›› Issue (2) : 65-70.
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Abbreviation (ISO4): Chin Agric Sci Bull
Editor in chief: Yulong YIN
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Research Progress on Role of Transcription Factor TGA in Nitrogen Absorption, Transport and Assimilation in Plants
Nitrogen is one of the critical nutrient element for plant growth and development, and its uptake, transport, and assimilation are finely regulated by multiple transcription factors. Among the bZIP transcription factor family, the TGACG motif-binding factor (TGA) has been confirmed to play a central regulatory role in plant nitrogen metabolism. To clarify its molecular regulatory pathways, this review systematically summarizes the molecular characteristics of TGA transcription factors, with a focus on their core functions in nitrate uptake, root development regulation, and nitrogen assimilation. We further analyze the molecular mechanisms by which TGA participates in nitrogen metabolism through hormone signaling pathways—including salicylic acid (SA), jasmonic acid (JA)/ethylene (ET), and abscisic acid (ABA), as well as redox modifications. The results indicate that: (1) TGA transcription factors belong to subfamily D of the bZIP family, and are divided into five subgroups. They are highly conserved in various plants such as Arabidopsis and rice; (2) they positively promote nitrogen uptake and transport by activating the expression of NRT family genes and modulating root development, and form regulatory networks with factors such as NLP7 (NIN-like protein 7); (3) through hormone signaling crosstalk and redox modifications, TGA factors respond to stresses such as low nitrogen and help maintain nitrogen metabolic homeostasis. In summary, TGA transcription factors serve as key nodes in the regulatory network of plant nitrogen metabolism, coordinately regulating nitrogen uptake, transport, and assimilation through multiple pathways. Future studies should integrate multi-omics and gene-editing technologies to elucidate the organ-specific functions, interaction networks, and species-specific variations of TGA, thereby providing a theoretical basis and breeding strategies for improving nitrogen-use efficiency in crops.
nitrogen / uptake and translocation / assimilation / TGACG motif-binding factor (TGA) / hormonal regulation / redox modification
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Nitrogen is a crucial element for all living organisms especially plants which rely on substantial nitrogen quantities to sustain their growth and productivity. Crop production is greatly influenced by nitrogen consumption efficiency and a significant amount of nitrogen fertilizers is used to increase yield. Approximately half of N fertilizers are not utilized by the crops and are lost to the environment by polluting water sources or by releasing pollutants into the atmosphere. From the rhizosphere, plants absorb nitrogen in the form of nitrate (NO3-), ammonium (NH4+), or organic nitrogen (amino acids and urea). Plants exhibit an array of sensing and adaptive mechanisms to respond to the diverse nitrogen nutrition conditions which include morphological and physiological responses. Two primary systems govern nitrogen uptake in plants: the High-affinity transport system (HATS) and the Low-affinity transport system (LATS). Nitrate transporters fall into two categories, Nitrate Transporter 1 (NRT1) and Nitrate Transporter 2 (NRT2) transporters, Chloride Channel Family (CLC) transporters and Slow Anion Associated Channel Homologs (SLAC/SLAHs). The ammonium transporter family includes Ammonium Transporter 1 (AMT1) and Ammonium Transporter 2 (AMT2) transporters. The uptake of organic nitrogen is facilitated through amino acid and urea uptake and transport systems. In fluctuating environmental conditions, plants employ nitrogen response mechanisms to fine-tune homeostasis. A comprehensive understanding of these regulatory mechanisms holds the potential to yield valuable insights for the development of crops with enhanced nitrogen use efficiency.
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Nitrate signaling improves plant growth under limited nitrate availability and, hence, optimal resource use for crop production. Whereas several transcriptional regulators of nitrate signaling have been identified, including the Arabidopsis thaliana transcription factor NIN-LIKE PROTEIN7 (NLP7), additional regulators are expected to fine-tune this pivotal physiological response. Here, we characterized Arabidopsis NLP2 as a top-tier transcriptional regulator of the early nitrate response gene regulatory network. NLP2 interacts with NLP7 in vivo and shares key molecular features such as nitrate-dependent nuclear localization, DNA binding motif, and some target genes with NLP7. Genetic, genomic, and metabolic approaches revealed a specific role for NLP2 in the nitrate-dependent regulation of carbon and energy-related processes that likely influence plant growth under distinct nitrogen environments. Our findings highlight the complementarity and specificity of NLP2 and NLP7 in orchestrating a multi-tiered nitrate regulatory network that links nitrate assimilation with carbon and energy metabolism for efficient nitrogen use and biomass production.© American Society of Plant Biologists 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Nitrogen (N) is a critical factor for crop growth and yield. Improving N use efficiency (NUE) in agricultural systems is crucial for sustainable food production. However, the underlying regulation of N uptake and utilization in crops is not well known. Here, we identified OsSNAC1 (stress-responsive NAC 1) as an upstream regulator of OsNRT2.1 (nitrate transporter 2.1) in rice (Oryza sativa) by yeast 1-hybridization screening. OsSNAC1 was mainly expressed in roots and shoots and induced by N deficiency. We observed similar expression patterns of OsSNAC1, OsNRT2.1/2.2, and OsNRT1.1A/B in response to NO3− supply. Overexpression of OsSNAC1 resulted in increased concentrations of free NO3− in roots and shoots, as well as higher N uptake, higher NUE, and N use index (NUI) in rice plants, which conferred increased plant biomass and grain yield. On the contrary, mutations in OsSNAC1 resulted in decreased N uptake and lower NUI, which inhibited plant growth and yield. OsSNAC1 overexpression significantly upregulated OsNRT2.1/2.2 and OsNRT1.1A/B expression, while the mutation in OsSNAC1 significantly downregulated OsNRT2.1/2.2 and OsNRT1.1A/B expression. Y1H, transient co-expression, and ChIP assays showed OsSNAC1 directly binds to the upstream promoter regions of OsNRT2.1/2.2 and OsNRT1.1A/1.1B. In conclusion, we identified a NAC transcription factor in rice, OsSNAC1, with a positive role in regulating NO3− uptake through direct binding to the upstream promoter regions of OsNRT2.1/2.2 and OsNRT1.1A/1.1B and activating their expression. Our results provide a potential genetic approach for improving crop NUE in agriculture.
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The TGA transcription factors, a subfamily of bZIP group D, play crucial roles in various biological processes, including the regulation of growth and development as well as responses to pathogens and abiotic stress. In this study, 27 genes were identified in the soybean genome. The expression patterns of genes showed that several genes are differentially expressed under drought and salt stress conditions. Among them, was strongly induced by both stress, which were verificated by the promoter-GUS fusion assay. encodes a nuclear-localized protein with transcriptional activation activity. Heterologous and homologous overexpression of enhanced tolerance to drought and salt stress in both transgeinc plants and soybean hairy roots. However, RNAi hairy roots silenced for exhibited an increased sensitivity to drought and salt stress. In response to drought or salt stress, transgenic plants had an increased chlorophyll and proline contents, a higher ABA content, a decreased MDA content, a reduced water loss rate, and an altered expression of ABA- responsive marker genes compared with WT plants. In addition, transgenic plants were more sensitive to ABA in stomatal closure. Similarly, measurement of physiological parameters showed an increase in chlorophyll and proline contents, with a decrease in MDA content in soybean seedlings with overexpression hairy roots after drought and salt stress treatments. The opposite results for each measurement were observed in RNAi lines. This study provides new insights for functional analysis of soybean TGA transcription factors in abiotic stress.
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黎春红, 汪开拓, 雷长毅, 等. 桃TGA家族鉴定及BABA诱导的抗病表达分析[J]. 园艺学报, 2022, 49(2):265-280.
以高度保守的BRLZ（PF07716）和DOG1（PF14144）结构域为种子序列,通过生物信息分析共鉴定得到15个桃TGA（TGACG motif-binding factor）家族基因,这些基因分布于桃的4条染色体上,其编码蛋白大小介于333 ~ 546 aa,分子量介于37.07 ~ 61.47 kD,等电点介于6.01 ~ 8.59,均定位于细胞核上。根据系统进化关系,拟南芥、大豆、番茄、水稻和桃的 TGA 家族分为5 个亚族,其中桃 TGA 家族成员主要分布于第Ⅰ、Ⅱ和Ⅳ亚族。对桃TGA家族成员启动子区域的顺式调控元件进行预测分析,其启动子区含有至少1个激素或逆境胁迫响应元件。经RNA-seq 数据分析可知,β-氨基丁酸（β- aminobutyric acid,BABA）处理和匍枝根霉（Rhizopus stolonifer）侵染能诱导桃TGA成员表达,其中PpTGA1-1在处理后12 h内上调最为显著;显著表达的PpTGA1-1通过与PpNPR1蛋白相互作用赋予PpNPR1蛋白DNA结合功能,启动一系列病程相关（pathogenesis-related,PR）基因的表达,从而诱导果实敏化（priming）抗性。桃 TGA 家族成员（尤其PpTGA1-1）可直接响应激发子诱导和病原菌侵染,并通过修饰PpNPR1蛋白从而在防卫反应中发挥重要调控作用。
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田义, 张彩霞, 康国栋, 等. 植物TGA转录因子研究进展[J]. 中国农业科学, 2016, 49(4):632-642.
TGA基因家族是bZIP转录因子家族中十分重要的一组，其能够与靶基因启动子上的as-1区域相结合，激活或抑制下游靶标基因的转录，从而调控植株抗性或花器官发育。自烟草中首个TGA基因被鉴定以来，从拟南芥、水稻和苹果等多个物种中均有该家族基因被分离和鉴定出来。拟南芥基因组中共有10个TGA转录因子，依据其序列相似性可将其分为5组（Ⅰ组包含TGA1与TGA4；TGA2、TGA5与TGA6组成第Ⅱ组；TGA3与TGA7组成第Ⅲ组；TGA9和TGA10构成第Ⅳ组；PAN为第Ⅴ组）。其中Ⅰ、Ⅱ与Ⅲ组成员广泛参与植株的抗病反应。酵母双杂交和pull-down等结果显示，TGA1—TGA7均可与水杨酸信号途径关键调节因子NPR1相互作用。EMSA结果表明，这种相互作用能够促进TGA对下游PR1启动子的结合并上调其表达，提高植株抗病性。但这3组基因在植物基础抗性与系统获得抗性中的作用有所不同：tga3突变体对病菌的基础抗性存在缺陷，但植株诱导抗性却并不受影响;TGA1与TGA4对基础抗性和系统抗性均有一定影响；TGA2、TGA5与TGA6之间存在功能冗余，仅tga2/5/6三突变体才表现出与npr1突变体类似的系统获得性抗性缺乏的表型。酵母双杂交筛选发现：Ⅱ组TGA能够与谷氧还蛋白GRX480相互作用并介导SA对JA途径标记基因的抑制作用，同时，该组蛋白还能够与GRAS家族蛋白SCL14相互作用，增强下游CYP81D11与GSTU7等解毒相关基因的表达，以一种不依赖于NPR1的信号途径提高植物对外源化学物质毒害的耐性。此外，tga1/4双突变体与nrt2.1/2.2双突变体的初生根和侧生根生长在低氮条件下较野生型显著下降，ChIP和酵母单杂交结果显示，TGA1能够与硝酸盐转运蛋白基因NRT2.1及NRT2.2的启动子相互结合，通过调节这两个基因的表达来调节植物的氮响应。而TGA3在镉长距离运输中发挥重要作用。Ⅳ与Ⅴ组成员在调控花器官发育中具有重要作用。tga9/10表现出与roxy1/2双突变体类似的花药发育缺陷的表型；PAN能够与NPR1类蛋白BOP1和BOP2相互作用，并且pan与bop1/2双突变体均可表现出5枚萼片的表型，暗示花发育与抗病可能具有类似的信号调节机制。在文章最后介绍了翻译后修饰对TGA功能的影响，并对TGA未来的研究方向进行了探讨，以期为该领域研究者提供参考。
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The plant immune system encompasses an arsenal of defense genes that is activated upon recognition of a pathogen. Appropriate adjustment of gene expression is mediated by multiple interconnected signal transduction cascades that finally control the activity of transcription factors. These sequence-specific DNA-binding proteins act at the interface between the DNA and the regulatory protein network. In 1989, tobacco TGA1a was cloned as the first plant transcription factor. Since then, multiple studies have shown that members of the TGA family play important roles in defense responses against biotrophic and necrotrophic pathogens and against chemical stress. Here, we review 22 years of research on TGA factors which have yielded both consistent and conflicting results.
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Tiller angle is an important determinant of plant architecture in rice (Oryza sativa L.). Auxins play a critical role in determining plant architecture, however the underlying metabolic and signaling mechanisms are still largely unknown. In this study, we have identified a member of the bZIP family of TGA class transcription factors, OsbZIP49, that participates in the regulation of plant architecture and is specifically expressed in gravity-sensing tissues, including the shoot base, nodes and lamina joints. Transgenic rice plants overexpressing OsbZIP49 displayed a tiller-spreading phenotype with reduced plant height and internode lengths. In contrast, CRISPR/Cas9 mediated knockout of OsbZIP49 resulted in a compact architecture. Follow-up studies indicated that the effects of OsbZIP49 on tiller angles are mediated through changes in shoot gravitropic responses. Additionally, we provide evidence that OsbZIP49 activates the expression of indole-3-acetic acid-amido synthetases OsGH3-2 and OsGH3-13 by directly binding to TGACG motifs located within the promoters of both genes. Increased GH3-catalysed conjugation of IAA in rice transformants overexpressing OsbZIP49 resulted in the increased accumulation of IAA-Asp and IAA-Glu, and a reduction in local free auxin, tryptamine and IAA-Glc levels. Exogenous IAA or NAA partially restored shoot gravitropic responses in OsbZIP49-overexpressing plants. Knockout of OsbZIP49 led to reduced expression of both OsGH3-2 and OsGH3-13 within the shoot base, and increased accumulation of IAA and increased OsIAA20 expression levels were observed in transformants following gravistimulation. Taken together, the present results reveal the role transcription factor OsbZIP49 plays in determining plant architecture, primarily due to its influence on local auxin homeostasis.This article is protected by copyright. All rights reserved.
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Polycyclic aromatic compounds (PACs) are known due to their mutagenic activity. Among them, 2-nitrobenzanthrone (2-NBA) and 3-nitrobenzanthrone (3-NBA) are considered as two of the most potent mutagens found in atmospheric particles. In the present study 2-NBA, 3-NBA and selected PAHs and Nitro-PAHs were determined in fine particle samples (PM 2.5) collected in a bus station and an outdoor site. The fuel used by buses was a diesel-biodiesel (96:4) blend and light-duty vehicles run with any ethanol-to-gasoline proportion. The concentrations of 2-NBA and 3-NBA were, on average, under 14.8 µg g−1 and 4.39 µg g−1, respectively. In order to access the main sources and formation routes of these compounds, we performed ternary correlations and multivariate statistical analyses. The main sources for the studied compounds in the bus station were diesel/biodiesel exhaust followed by floor resuspension. In the coastal site, vehicular emission, photochemical formation and wood combustion were the main sources for 2-NBA and 3-NBA as well as the other PACs. Incremental lifetime cancer risk (ILCR) were calculated for both places, which presented low values, showing low cancer risk incidence although the ILCR values for the bus station were around 2.5 times higher than the ILCR from the coastal site.
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Leaves of Nagafu No. 6 were transformed by the Agrobacterium tumefaciens-mediated method, and 158 hyg-resistant buds were obtained. Using fresh leaf tissue, seven positive lines were obtained by polymerase chain reaction (PCR) with total DNA, and four by reverse transcriptase–polymerase chain reaction (RT–PCR) with total RNA. The results showed that the MhTGA2 gene was successfully transformed into Nagafu No. 6 plants and expressed. At 4 months after transplanting, photosynthetic parameters of young leaves were determined using transgenic and control plants prior to the determination of leaf surface characteristics (epidermal structure and stomatal distribution) by scanning electronic microscopy. The results showed that the net photosynthesis rate, the instantaneous carboxylation rate and stomatal conductance of transgenic plants were higher than the control, whereas the internal carbon dioxide (CO2) concentrations of the transgenic plants were lower. Under non-saline conditions, the stomata of the transgenic plants were better distributed than in the control. Under saline conditions, the epidermal structure of the control leaves was severely hypohydrated and the quantity of stomata was significantly decreased. Conversely, the epidermal structure of transgenic leaves was not significantly altered, indicating salt-stress tolerance. The overall results suggested that MhTGA2 may play a crucial role in the response to salt stress in Nagafu No. 6.
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Transcriptional reprogramming during induction of salicylic acid (SA)-mediated defenses is regulated primarily by NPR1 (NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1), likely through interactions with TGA bZIP transcription factors. To ascertain the contributions of clade I TGA factors (TGA1 and TGA4) to defense responses, a tga1-1 tga4-1 double mutant was constructed and challenged with Pseudomonas syringae and Hyaloperonospora arabidopsidis. Although the mutant displayed enhanced susceptibility to virulent P. syringae, it was not compromised in systemic acquired resistance against this pathogen or resistance against avirulent H. arabidopsidis. Microarray analysis of nonelicited and SA-treated plants indicated that clade I TGA factors regulate fewer genes than NPR1. Approximately half of TGA-dependent genes were regulated by NPR1 but, in all cases, the direction of change was opposite in the two mutants. In support of the microarray data, the NPR1-independent disease resistance observed in the autoimmune resistance (R) gene mutant snc1 is partly compromised by tga1-1 tga4-1 mutations, and a triple mutant of clade I TGA factors with npr1-1 is more susceptible than either parent. These results suggest that clade I TGA factors are required for resistance against virulent pathogens and avirulent pathogens mediated by at least some R gene specificities, acting substantially through NPR1-independent pathways.
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Dynamic reprogramming of gene regulatory networks (GRNs) enables organisms to rapidly respond to environmental perturbation. However, the underlying transient interactions between transcription factors (TFs) and genome-wide targets typically elude biochemical detection. Here, we capture both stable and transient TF-target interactions genome-wide within minutes after controlled TF nuclear import using time-series chromatin immunoprecipitation (ChIP-seq) and/or DNA adenine methyltransferase identification (DamID-seq). The transient TF-target interactions captured uncover the early mode-of-action of NIN-LIKE PROTEIN 7 (NLP7), a master regulator of the nitrogen signaling pathway in plants. These transient NLP7 targets captured in root cells using temporal TF perturbation account for 50% of NLP7-regulated genes not detectably bound by NLP7 in planta. Rapid and transient NLP7 binding activates early nitrogen response TFs, which we validate to amplify the NLP7-initiated transcriptional cascade. Our approaches to capture transient TF-target interactions genome-wide can be applied to validate dynamic GRN models for any pathway or organism of interest.
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Nitrogen (N) is vital for crop growth and yield, impacting food quality. However, excessive use of N fertilizers leads to high agricultural costs and environmental challenges. This review offers a thorough synthesis of the genetic and molecular regulation of N uptake, assimilation, and remobilization in maize, emphasizing the role of key genes and metabolic pathways in enhancing N use efficiency (NUE). We summarize the genetic regulators of N transports for nitrate (NO) and ammonium (NH) that contribute to efficient N uptake and transportation. We further discuss the molecular mechanisms by which root system development adapts to N distribution and how N influences root system development and growth. Given the advancements in high-throughput microbiome studies, we delve into the impact of rhizosphere microorganisms on NUE and the complex plant-microbe interactions that regulate maize NUE. Additionally, we conclude with intricate regulatory mechanisms of N assimilation and remobilization in maize, involving key enzymes, transcription factors, and amino acid transporters. We also scrutinize the known N signaling perception and transduction mechanisms in maize. This review underscores the challenges in improving maize NUE and advocates for an integrative research approach that leverages genetic diversity and synthetic biology, paving the way for sustainable agriculture.Copyright © 2024 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.
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To cope with environmental stress caused by global climate change and excessive nitrogen application, it is important to improve water and nitrogen use efficiencies in crop plants. It has been reported that higher nitrogen uptake could alleviate the damaging impact of drought stress. However, there is scant evidence to explain how nitrogen uptake affects drought resistance. In this study we observed that bZIP transcription factor AtTGA4 (TGACG motif-binding factor 4) was induced by both drought and low nitrogen stresses, and that overexpression of AtTGA4 simultaneously improved drought resistance and reduced nitrogen starvation in Arabidopsis. Following drought stress there were higher nitrogen and proline contents in transgenic AtTGA4 plants than in wild type controls, and activity of the key enzyme nitrite reductase (NIR) involved in nitrate assimilation processes was also higher. Expressions of the high-affinity nitrate transporter genes NRT2.1 and NRT2.2 and nitrate reductase genes NIA1 and NIA2 in transgenic plants were all higher than in wild type indicating that higher levels of nitrate transport and assimilation activity contributed to enhanced drought resistance of AtTGA4 transgenic plants. Thus genetic transformation with AtTGA4 may provide a new approach to simultaneously improve crop tolerance to drought and low nitrogen stresses. Copyright © 2015 Elsevier Inc. All rights reserved.
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Unlike plants in the field, which experience significant temporal fluctuations in environmental conditions, plants in the laboratory are typically grown in controlled, stable environments. Therefore, signaling pathways evolved for survival in fluctuating environments often remain functionally latent in laboratory settings. Here, we show that TGA1 and TGA4 act as hub transcription factors through which the expression of genes involved in high-affinity nitrate uptake are regulated in response to shoot-derived phloem mobile polypeptides, CEP DOWNSTREAM 1 (CEPD1), CEPD2 and CEPD-like 2 (CEPDL2) as nitrogen (N) deficiency signals, and Glutaredoxin S1 (GrxS1) to GrxS8 as N sufficiency signals. CEPD1/2/CEPDL2 and GrxS1-S8 competitively bind to TGA1/4 in roots, with the former acting as transcription coactivators that enhance the uptake of nitrate, while the latter function as corepressor complexes together with TOPLESS (TPL), TPL-related 1 (TPR1) and TPR4 to limit nitrate uptake. Arabidopsis plants deficient in TGA1/4 maintain basal nitrate uptake and exhibit growth similar to wild-type plants in a stable N environment, but are impaired in regulation of nitrate acquisition in response to shoot N demand, leading to defective growth under fluctuating N environments where rhizosphere nitrate ions switch periodically between deficient and sufficient states. TGA1/4 are crucial transcription factors that enable plants to survive under fluctuating and challenging N environmental conditions.© 2024. The Author(s).
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金丹丹, 陈玥, 战莘晔, 等. 水稻氮素吸收利用及水杨酸的调节效应[J]. 东北农业科学, 2021, 46(4):38-42.
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罗正英. 外源激素对黑穗病菌侵染后甘蔗生理生化及基因表达的影响[D]. 昆明: 云南农业大学, 2023.
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Abscisic acid (ABA) regulates key plant processes, including seed germination, dormancy, and abiotic stress responses. While its physiological role in germination is well-documented, the molecular mechanisms are still poorly understood. To address this, we analyzed transcriptomic and metabolomic changes in ABA-treated germinating barley (Hordeum vulgare) embryos. To map ABA-responsive gene expression across embryonic tissues, we employed the Visium Spatial Transcriptomics (10× Genomics). This approach, which remains technically challenging to be applied in plant tissues, enabled the precise localization of gene expression across six embryo regions, offering insights into tissue-specific expression patterns that cannot be resolved by traditional RNA-seq.
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Abscisic acid (ABA) signaling is crucial for plant responses to various abiotic stresses. The Arabidopsis (Arabidopsis thaliana) transcription factor ABA INSENSITIVE 5 (ABI5) is a central regulator of ABA signaling. ABI5 BINDING PROTEIN 1 (AFP1) interacts with ABI5 and facilitates its 26S-proteasome-mediated degradation, although the detailed mechanism has remained unclear. Here, we report that an ABA-responsive U-box E3 ubiquitin ligase, PLANT U-BOX 35 (PUB35), physically interacts with AFP1 and ABI5. PUB35 directly ubiquitinated ABI5 in a bacterially reconstituted ubiquitination system and promoted ABI5 protein degradation in vivo. ABI5 degradation was enhanced by AFP1 in response to ABA treatment. Phosphorylation of the T201 and T206 residues in ABI5 disrupted the ABI5–AFP1 interaction and affected the ABI5–PUB35 interaction and PUB35-mediated degradation of ABI5 in vivo. Genetic analysis of seed germination and seedling growth showed that pub35 mutants were hypersensitive to ABA as well as to salinity and osmotic stresses, whereas PUB35 overexpression lines were hyposensitive. Moreover, abi5 was epistatic to pub35, whereas the pub35-2 afp1-1 double mutant showed a similar ABA response to the two single mutants. Together, our results reveal a PUB35–AFP1 module involved in fine-tuning ABA signaling through ubiquitination and 26S-proteasome-mediated degradation of ABI5 during seed germination and seedling growth.
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张云秀, 吕雪梅, 张燕, 等. 外源γ-氨基丁酸调控小麦灌浆生理机制[J]. 麦类作物学报, 2023, 43(2):233-240.
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Abscisic acid (ABA) is a natural hormone produced in plants, which plays an important role in plant growth and development and in response to adversity. Increasing research indicates that ABA is involved in plant response to cold stress and enhances the cold tolerance of plants through various pathways. Therefore, the roles, regulator mechanisms and regulator pathways of ABA in plant response to cold stress are summarized. In this paper, we first discuss the mechanism of cold damage in plants. Second, we review the important roles of ABA in enhancing plant cold tolerance, including the interactions between endogenous and exogenous ABA, ABA and other substances, ABA and specific genes and transcription factors, and ABA and phosphorylation. On the whole, the involvement of ABA in the plant’s response to cold stress constitutes a complex and multi-dimensional system. ABA interacts with various factors, including hormones, enzymes, genes and so on, to establish a regulatory network that enhances plant resistance to cold injury. Finally, we also provide some perspectives for future research on plant ABA, and we hope that this paper can provide some lessons for future research on the mechanism of ABA involvement in plant adversity stress.
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| [45] |
Nitrate is both an important nutrient and a critical signaling molecule that regulates plant metabolism, growth, and development. Although several components of the nitrate signaling pathway have been identified, the molecular mechanism of nitrate signaling remains unclear. Here, we showed that the growth-related transcription factors HOMOLOG OF BRASSINOSTEROID ENHANCED EXPRESSION2 INTERACTING WITH IBH1 (HBI1) and its three closest homologs (HBIs) positively regulate nitrate signaling in Arabidopsis thaliana. HBI1 is rapidly induced by nitrate through NLP6 and NLP7, which are master regulators of nitrate signaling. Mutations in HBIs result in the reduced effects of nitrate on plant growth and approximately 22% nitrate-responsive genes no longer to be regulated by nitrate. HBIs increase the expression levels of a set of antioxidant genes to reduce the accumulation of reactive oxygen species (ROS) in plants. Nitrate treatment induces the nuclear localization of NLP7, whereas such promoting effects of nitrate are significantly impaired in the hbi-q and cat2 cat3 mutants, which accumulate high levels of H2O2. These results demonstrate that HBI-mediated ROS homeostasis regulates nitrate signal transduction through modulating the nucleocytoplasmic shuttling of NLP7. Overall, our findings reveal that nitrate treatment reduces the accumulation of H2O2, and H2O2 inhibits nitrate signaling, thereby forming a feedback regulatory loop to regulate plant growth and development.© The Author(s) 2021. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.
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| [46] |
The TGACG motif-binding factor1 (TGA1) transcription factor, in which belongs to the bZIP transcription factor family and has vast application potential in plant growth and development. Here, we cloned the gene of the MtTGA1 transcription factor from Medicago truncatula. The MtTGA1 promoter region contains a diverse range of photoregulatory and hormonal regulatory elements. The expression profile of MtTGA1 indicated its highest expression in the root. Additionally, the expression level of MtTGA1 was significantly upregulated after SA and BR treatments and showed a downward trend after GA and ABA treatments. To explore the potential function of MtTGA1, we treated the transgenic plants with salt treatment for 15 days, and the results showed that transgenic plants demonstrated significantly longer root lengths and heightened activities of antioxidant enzymes such as ascorbic acid catalase (APX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) in their roots and leaves. The levels of endogenous hormones, including ABA and BR were improved in transgenic plants, with a marked change in the morphology of their leaf cells. Transcriptome analysis identified a total of 193 differentially expressed genes, which were significantly enriched in the pathways of “Brassinosteroid biosynthesis”, “Ascorbate and aldarate metabolism”, and “Plant hormone signal transduction”. Furthermore, MtTGA1 was found to interact with the SPX domain-containing protein 1 (SPX1) in Medicago truncatula. In conclusion, these results are beneficial for further studies about the plant growth and development regulatory network mediated by the TGA1 transcription factor family.
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| [47] |
宋丹华, 焦永刚, 石琳琪, 等. 断营养影响青梗菜硝酸盐含量的转录组学分析[J]. 华北农学报, 2023, 38(1):74-83.
为降低青梗菜硝酸盐含量,在采收前对其进行断营养处理。生理分析发现,断营养5 d青梗菜产量无明显变化,但根、叶柄和叶片的硝酸盐含量分别降低了49.77%,23.90%,33.39%。转录组比较发现,断营养5 d青梗菜根、叶柄和叶片分别鉴定出301,2 270,2 271个差异表达基因(DEGs)。基因本体论(GO)分析表明,这些DEGs均主要富集在氮(N)代谢、碳(C)代谢和活性氧(ROS)代谢过程中。在N代谢过程中,根、叶柄和叶片硝酸盐摄取转运蛋白NPF7.2基因下调表达;叶柄和叶片NPF7.2的上游调控因子ERF104下调表达;叶片硝酸盐再转运蛋白NPF2.13和NPF1.1基因上调表达;根和叶片硝酸盐同化关键酶谷氨酰胺合成酶(GS)基因上调表达。在C代谢过程中,叶柄和叶片蔗糖合成关键酶磷酸蔗糖合酶(SPS)基因上调表达。在ROS代谢过程中,根的超氧化物歧化酶(SOD)基因和抗坏血酸过氧化物酶(APX)基因上调表达;叶柄和叶片细胞色素P450、过氧化物酶体和脂肪氧化酶下调表达;叶片过氧化氢酶(CAT)基因和过氧化物酶(POD)基因上调表达。综上,在青梗菜采收前5 d进行断营养处理,不仅可以保证产量不受影响,还可以降低硝酸盐含量,提高品质。
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