OsEIL1 is involved in the response to heterogeneous high ammonium in rice: A split-root analysis.

Ammonium (NH4+) concentrations in rice fields show heterogeneous spatial distribution under the combined influences of nitrogen fertilizer application and modern agronomic practices. However, the characteristics and mechanisms of rice roots in response to heterogeneous NH4+ supply are not well understood. Here, we found a systemic response of rice roots to heterogeneous and high (10 mM) NH4+ supply using a split-root experiment, and show root growth on the NH4+-free (NO3-) side was also inhibited by localized high-NH4+ supply. Moreover, OsEIL1 (encoding a core transcription factor in the ethylene signaling pathway) was found to be involved in the response of rice roots to heterogeneous NH4+. OsEIL1 mutation significantly increased the inhibitory effect of localized high-NH4+ on root growth of the NO3- side, as well as significantly increased NH4+ efflux there. Furthermore, our results indicate that the mitigating effect of OsEIL1 on NH4+ efflux is related to the regulated expression of OsVTC1-3 (encoding a GDP-mannose pyrophosphorylase). These findings provide insight into the mechanisms by which OsEIL1 responds to heterogeneous high NH4+ and contribute to our understanding of rice adaptation to heterogeneous NH4+ supply.

Possible hazards from biodegradation of soil plastic mulch: Increases in microplastics and CO2 emissions.

Biodegradable mulches are widely recognized as ecologically friendly substances. However, their degradation percentage upon entering soils may vary based on mulch type and soil microbial activities, raising concerns about potential increases in microplastics (MPs). The effects of using different types of mulch on soil carbon pools and its potential to accelerate their depletion have not yet well understood. Therefore, we conducted an 18-month experiment to investigate mulch biodegradation and its effects on CO2 emissions. The experiment included burying soil with biodegradable mulch made of polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT), and control treatments with traditional mulch (PE) and no mulch (CK). The results indicated that PE did not degrade, and the degradation percentage of PLA and PBAT were 46.2% and 88.1%, and the MPs produced by the degradation were 6.7 × 104 and 37.2 × 104 items/m2, respectively. Biodegradable mulch, particularly PLA, can enhance soil microbial diversity and foster more intricate bacterial communities compared to PE. The CO2 emissions were 0.58, 0.74, 0.99, and 0.86 g C/kg in CK, PE, PLA, , PBAT, respectively. A positive correlation was observed between microbial abundance and diversity with CO2 emissions, while a negative correlation was observed with soil total organic carbon. Biodegradable mulch enhanced the transformation of soil organic C into CO2 by stimulating microbial activity.

Plant iron status regulates ammonium-use efficiency through protein N-glycosylation.

Improving nitrogen-use efficiency (NUE) is an important path toward enhancing crop yield and alleviating the environmental impacts of fertilizer use. Ammonium (NH4+) is the energetically preferred inorganic N source for plants. The interaction of NH4+ with other nutrients is a chief determinant of ammonium-use efficiency (AUE) and of the tipping point toward ammonium toxicity, but these interactions have remained ill-defined. Here, we report that iron (Fe) accumulation is a critical factor determining AUE and have identified a substance that can enhance AUE by manipulating Fe availability. Fe accumulation under NH4+ nutrition induces NH4+ efflux in the root system, reducing both growth and AUE in Arabidopsis (Arabidopsis thaliana). Low external availability of Fe and a low plant Fe status substantially enhance protein N-glycosylation through a Vitamin C1 (VTC1)-independent pathway, thereby reducing NH4+ efflux to increase AUE during the vegetative stage in Arabidopsis under elevated NH4+ supply. We confirm the validity of the iron-ammonium interaction in the important crop species lettuce (Lactuca sativa). We further show that dolomite can act as an effective substrate to subdue Fe accumulation under NH4+ nutrition by reducing the expression of Low Phosphate Root 2 (LPR2) and acidification of the rhizosphere. Our findings present a strategy to improve AUE and reveal the underlying molecular-physiological mechanism.

The Roles of GRETCHEN HAGEN3 (GH3)-Dependent Auxin Conjugation in the Regulation of Plant Development and Stress Adaptation.

The precise control of free auxin (indole-3-acetic acid, IAA) gradient, which is orchestrated by biosynthesis, conjugation, degradation, hydrolyzation, and transport, is critical for all aspects of plant growth and development. Of these, the GRETCHEN HAGEN 3 (GH3) acyl acid amido synthetase family, pivotal in conjugating IAA with amino acids, has garnered significant interest. Recent advances in understanding GH3-dependent IAA conjugation have positioned GH3 functional elucidation as a hot topic of research. This review aims to consolidate and discuss recent findings on (i) the enzymatic mechanisms driving GH3 activity, (ii) the influence of chemical inhibitor on GH3 function, and (iii) the transcriptional regulation of GH3 and its impact on plant development and stress response. Additionally, we explore the distinct biological functions attributed to IAA-amino acid conjugates.

Nitrogen-loss and carbon-footprint reduction by plant-rhizosphere exudates.

Low-carbon approaches to agriculture constitute a pivotal measure to address the challenge of global climate change. In agroecosystems, rhizosphere exudates are significantly involved in regulating the nitrogen (N) cycle and facilitating belowground chemical communication between plants and soil microbes to reduce direct and indirect emissions of greenhouse gases (GHGs) and control N runoff from cultivated sites into natural water bodies. Here, we discuss specific rhizosphere exudates from plants and microorganisms and the mechanisms by which they reduce N loss and subsequent N pollution in terrestrial and aquatic environments, including biological nitrification inhibitors (BNIs), biological denitrification inhibitors (BDIs), and biological denitrification promoters (BDPs). We also highlight promising application scenarios and challenges in relation to rhizosphere exudates in terrestrial and aquatic environments.

A lignin-derived material improves plant nutrient bioavailability and growth through its metal chelating capacity.

The lignocellulosic biorefinery industry can be an important contributor to achieving global carbon net zero goals. However, low valorization of the waste lignin severely limits the sustainability of biorefineries. Using a hydrothermal reaction, we have converted sulfuric acid lignin (SAL) into a water-soluble hydrothermal SAL (HSAL). Here, we show the improvement of HSAL on plant nutrient bioavailability and growth through its metal chelating capacity. We characterize HSAL's high ratio of phenolic hydroxyl groups to methoxy groups and its capacity to chelate metal ions. Application of HSAL significantly promotes root length and plant growth of both monocot and dicot plant species due to improving nutrient bioavailability. The HSAL-mediated increase in iron bioavailability is comparable to the well-known metal chelator ethylenediaminetetraacetic acid. Therefore, HSAL promises to be a sustainable nutrient chelator to provide an attractive avenue for sustainable utilization of the waste lignin from the biorefinery industry.

The biomineralization of silica induced stress tolerance in plants: a case study for aluminum toxicity.

Biomineralization in plant roots refers to the process of cell-induced self-assembly to form nanostructures on the root surface. Silicon (Si) is the second most abundant element in soils, and beneficial to plant growth. Meanwhile, silicon is shown to participate in the process of biomineralization, which is useful for improving mechanical strength and alleviating biotic and abiotic stress, for example silicic acid polymerizes to form amorphous silica (SiO2-nH2O) in the process of growing to resist fungi and environmental stress. This process alters physical and chemical properties of cell wall. However, the mechanistic basis of this process remains unclear. Aluminum toxicity is a major constraint affecting plant performance in acid soil. This paper summarizes recent research advances in the field of plant biomineralization and describes the effects of silicon biomineralization on plant aluminum tolerance and its adaptive significance, using aluminum toxicity as a case study.

Interaction of ammonium nutrition with essential mineral cations.

Plant growth and development depend on sufficient nutrient availability in soils. Agricultural soils are generally nitrogen (N) deficient, and thus soils need to be supplemented with fertilizers. Ammonium (NH4+) is a major inorganic N source. However, at high concentrations, NH4+ becomes a stressor that inhibits plant growth. The cause of NH4+ stress or toxicity is multifactorial, but the interaction of NH4+ with other nutrients is among the main determinants of plants' sensitivity towards high NH4+ supply. In addition, NH4+ uptake and assimilation provoke the acidification of the cell external medium (apoplast/rhizosphere), which has a clear impact on nutrient availability. This review summarizes current knowledge, at both the physiological and the molecular level, of the interaction of NH4+ nutrition with essential mineral elements that are absorbed as cations, both macronutrients (K+, Ca2+, Mg2+) and micronutrients (Fe2+/3+, Mn2+, Cu+/2+, Zn2+, Ni2+). We hypothesize that considering these nutritional interactions, and soil pH, when formulating fertilizers may be key in order to boost the use of NH4+-based fertilizers, which have less environmental impact compared with nitrate-based ones. In addition, we are convinced that better understanding of these interactions will help to identify novel targets with the potential to improve crop productivity.

The wall-associated kinase gene family in pea (Pisum sativum) and its function in response to B deficiency and Al toxicity.

Plant cell walls are embedded in a pectin matrix which is physically linked with the wall-associated kinases (WAKs), a subfamily of receptor-like kinases that participate in the cell wall integrity (CWI) sensing. Since cell walls are also the main binding sites for boron (B) and aluminum (Al), WAK may be potentially associated with the regulation of plant responses to Al toxicity and B deficiency. Using pea as a model species, we have identified a total of 28 WAK genes in the genome and named them according to its chromosomal location. All the PsWAKs were phylogenetically grouped into three clades. Phylogenetic relationship and synteny analysis showed that the PsWAKs in pea and Glycine max or Medicago truncatula shared a relatively conserved evolutionary history. Protein domain, motif, and transmembrane analysis indicated that all PsWAK proteins were predicted to be localized to the plasma membrane, and most PsWAKs shared a similar structure to their homologs. The RNA-seq data showed that the expression pattern of WAK genes in response to B deficiency was similar to that of Al toxicity, with most of PsWAKs being up-regulated. The qRT-PCR results further confirmed that PsWAK5, PsWAK9 and PsWAK14 were more specific for both B-deficiency and Al toxicity, and the expression levels of PsWAK5, PsWAK9 and PsWAK14 were significantly higher in the Al-sensitive cultivar Hyogo than in the Al-resistant cultivar Alaska under Al toxicity. This study provided an important basis for the functional and evolutionary analysis of PsWAKs and linked them to responses to cell wall damage induced by B-deficiency and Al toxicity, suggesting that PsWAKs may play a key role in the perception of cell wall integrity under Al toxicity or B-deficiency, as well as in the regulation of Al tolerance in pea.

PIN2/3/4 auxin carriers mediate root growth inhibition under conditions of boron deprivation in Arabidopsis.

The mechanistic basis by which boron (B) deprivation inhibits root growth via the mediation of root apical auxin transport and distribution remains elusive. This study showed that B deprivation repressed root growth of wild-type Arabidopsis seedlings, which was related to higher auxin accumulation (observed with DII-VENUS and DR5-GFP lines) in B-deprived roots. Boron deprivation elevated the auxin content in the root apex, coinciding with upregulation of the expression levels of auxin biosynthesis-related genes (TAA1, YUC3, YUC9, and NIT1) in shoots, but not in root apices. Phenotyping experiments using auxin transport-related mutants revealed that the PIN2/3/4 carriers are involved in root growth inhibition caused by B deprivation. B deprivation not only upregulated the transcriptional levels of PIN2/3/4, but also restrained the endocytosis of PIN2/3/4 carriers (observed with PIN-Dendra2 lines), resulting in elevated protein levels of PIN2/3/4 in the plasma membrane. Overall, these results suggest that B deprivation not only enhances auxin biosynthesis in shoots by elevating the expression levels of auxin biosynthesis-related genes but also promotes the polar auxin transport from shoots to roots by upregulating the gene expression levels of PIN2/3/4, as well as restraining the endocytosis of PIN2/3/4 carriers, ultimately resulting in auxin accumulation in root apices and root growth inhibition.

Metalla-Claisen Rearrangement in Gold-Catalyzed [4+2] Reaction: A New Elementary Reaction Suggested for Future Reaction Design.

We report here computational evidence for a metalla-Claisen rearrangement (MCR) in the case of gold-catalyzed [4+2] cycloaddition reaction of yne-dienes. The [4+2] reaction starts from exo cyclopropanation, followed by MCR and reductive elimination. The cyclopropane moiety formed in the first step is crucial for a low barrier of the MCR step. In addition, the importance of an appropriate combination of the tether group and the terminal substituent on alkyne in the yne-diene substrates was studied. The mechanism of rhodium-catalyzed [4+2] reaction of yne-dienes was also investigated to see whether an MCR mechanism is involved or not. The findings and new understanding hereby reported represent an important advance in the catalysis field.

Smallholder vegetable farming produces more soil microplastics pollution than large-scale farming.

Microplastics (MPs) accumulation in farmland has attracted global concern. Smallholder farming is the dominant type in China's agriculture. Compared with large-scale farming, smallholder farming is not constrained by restrictive environmental policies and public awareness about pollution. Consequently, the degree to which smallholder farming is associated with MP pollution in soils is largely unknown. Here, we collected soil samples from both smallholder and large-scale vegetable production systems to determine the distribution and characteristics of MPs. MP abundance in vegetable soils was 147.2-2040.4 MP kg-1 (averaged with 500.8 MP kg-1). Soil MP abundance under smallholder cultivation (730.9 MP kg-1) was twice that found under large-scale cultivation (370.7 MP kg-1). MP particle sizes in smallholder and large-scale farming were similar, and were mainly <1 mm. There were also differences in MP characteristics between the two types of vegetable soils: fragments (60%) and fibers (34%) were dominant under smallholder cultivation, while fragments (42%), fibers (42%), and films (11%) were dominant under large-scale cultivation. We observed a significant difference in the abundance of fragments and films under smallholder versus large-scale cultivation; the main components of MPs under smallholder cultivation were PP (34%), PE (28%), and PE-PP (10%), while these were PE (29%), PP (16%), PET (16%), and PE-PP (13%) under large-scale cultivation. By identifying the shape and composition of microplastics, it can be inferred that agricultural films were not the main MP pollution source in vegetable soil. We show that smallholder farming produces more microplastics pollution than large-scale farming in vegetable soil.

The nitrification inhibitor 1,9-decanediol from rice roots promotes root growth in Arabidopsis through involvement of ABA and PIN2-mediated auxin signaling.

1,9-decanediol (1,9-D) is a biological nitrification inhibitor secreted in roots, which effectively inhibits soil nitrifier activity and reduces nitrogen loss from agricultural fields. However, the effects of 1,9-D on plant root growth and the involvement of signaling pathways in the plant response to 1,9-D have not been investigated. Here, we report that 1,9-D, in the 100-400 µM concentration range, promotes primary root length in Arabidopsis seedlings at 3d and 5d, by 10.1%-33.3% and 6.9%-32.6%, and, in a range of 50-200 µM, leads to an increase in the number of lateral roots. 150 µM 1,9-D was found optimum for the positive regulation of root growth. qRT-PCR analysis reveals that 1,9-D can significantly increase AtABA3 gene expression and that a mutation in ABA3 results in insensitivity of root growth to 1,9-D. Moreover, through pharmacological experiments, we show that exogenous addition of ABA (abscisic acid) with 1,9-D enhances primary root length by 23.5%-63.3%, and an exogenous supply of 1,9-D with the ABA inhibitor Flu reduces primary root length by 1.0%-14.3%. Primary root length of the pin2/eir1-1 is shown to be insensitive to both exogenous addition of 1,9-D and ABA, indicating that the auxin carrier PIN2/EIR1 is involved in promotion of root growth by 1,9-D. These results suggest a novel for 1,9-D in regulating plant root growth through ABA and auxin signaling.

Development of a sensor-based site-specific N topdressing algorithm for a typical leafy vegetable.

Precise and site-specific nitrogen (N) fertilizer management of vegetables is essential to improve the N use efficiency considering temporal and spatial fertility variations among fields, while the current N fertilizer recommendation methods are proved to be time- and labor-consuming. To establish a site-specific N topdressing algorithm for bok choy (Brassica rapa subsp. chinensis), using a hand-held GreenSeeker canopy sensor, we conducted field experiments in the years 2014, 2017, and 2020. Two planting densities, viz, high (123,000 plants ha-1) in Year I and low (57,000 plants ha-1) in Year II, whereas, combined densities in Year III were used to evaluate the effect of five N application rates (0, 45, 109, 157, and 205 kg N ha-1). A robust relationship was observed between the sensor-based normalized difference vegetation index (NDVI), the ratio vegetation index (RVI), and the yield potential without topdressing (YP0) at the rosette stage, and 81-84% of the variability at high density and 76-79% of that at low density could be explained. By combining the densities and years, the R 2 value increased to 0.90. Additionally, the rosette stage was identified as the earliest stage for reliably predicting the response index at harvest (RIHarvest), based on the response index derived from NDVI (RINDVI) and RVI (RIRVI), with R 2 values of 0.59-0.67 at high density and 0.53-0.65 at low density. When using the combined results, the RIRVI performed 6.12% better than the RINDVI, and 52% of the variability could be explained. This study demonstrates the good potential of establishing a sensor-based N topdressing algorithm for bok choy, which could contribute to the sustainable development of vegetable production.

Citric acid modified biochar application at a low dosage can synchronically mitigate the nitrogenous gas pollutants emission from rice paddy soils.

Raw biochar with high pH possibly stimulated ammonia (NH3) volatilization in the agricultural soil. We hypothesized that the modified biochar (MBC) with low pH can synchronically decrease the NH3 and nitrous oxide (N2O) losses. We performed a two-year experiment to clarify how citric acid MBC influence the NH3 volatilization and N2O emission as well as the underlying mechanisms. Two typical paddy soils, i.e., Hydragric Anthrosol and Haplic Acrisol, receiving equal urea N with 240 kg ha-1 but varied rates of MBC with 0, 5, 10, and 20 t ha-1 (named Urea, Urea + MBC5, Urea + MBC10, and Urea + MBC20, respectively) were studied. The results showed that MBC-amended treatments effectively mitigated the NH3 volatilization from Hydragric Anthrosol and Haplic Acrisol by 29.6%-57.9% and 30.5%-62.4% in 2017, and by 16.5%-21.0% and 24.5%-35.0% in 2018, respectively, compared to Urea treatment. In addition, significantly lower N2O emissions with averaged 38.3% and 43.1% in 2017, and 51.7% and 26.7% were recorded under Hydragric Anthrosol and Haplic Acrisol, respectively, following the MBC application (P < 0.05). Increased MBC addition performed higher efficacy on mitigating NH3 volatilization, particularly in the first rice season, while this "dosage effect" was not found for N2O reduction. Lowered pH in overlying water, enhanced adsorption of NH4+-N and its nitrification rate likely contributed to the lower NH3 volatilization as result of MBC addition. The nirS and nosZ gene copies were not changed by MBC, while the nirK gene copies were decreased as result of MBC amendment by 8.3%-25.2% under Hydragric Anthrosol and by 21.8%-24.9% under Haplic Acrisol. Consequent lower ratio of nirK/(nirS + nosZ) explained the mitigation effect of MBC on N2O emission. In conclusion, the present two-year study recommends that MBC applied at a low dosage can perform positive effect on controlling the nitrogenous gas pollutants from paddy soil.

TaSRO1 plays a dual role in suppressing TaSIP1 to fine tune mitochondrial retrograde signalling and enhance salinity stress tolerance.

Initially discovered in yeast, mitochondrial retrograde signalling has long been recognised as an essential in the perception of stress by eukaryotes. However, how to maintain the optimal amplitude and duration of its activation under natural stress conditions remains elusive in plants. Here, we show that TaSRO1, a major contributor to the agronomic performance of bread wheat plants exposed to salinity stress, interacted with a transmembrane domain-containing NAC transcription factor TaSIP1, which could translocate from the endoplasmic reticulum (ER) into the nucleus and activate some mitochondrial dysfunction stimulon (MDS) genes. Overexpression of TaSIP1 and TaSIP1-∆C (a form lacking the transmembrane domain) in wheat both compromised the plants' tolerance of salinity stress, highlighting the importance of precise regulation of this signal cascade during salinity stress. The interaction of TaSRO1/TaSIP1, in the cytoplasm, arrested more TaSIP1 on the membrane of ER, and in the nucleus, attenuated the trans-activation activity of TaSIP1, therefore reducing the TaSIP1-mediated activation of MDS genes. Moreover, the overexpression of TaSRO1 rescued the inferior phenotype induced by TaSIP1 overexpression. Our study provides an orchestrating mechanism executed by the TaSRO1-TaSIP1 module that balances the growth and stress response via fine tuning the level of mitochondria retrograde signalling.

Being applied at rice or wheat season impacts biochar's effect on gaseous nitrogen pollutants from the wheat growth cycle.

Biochar (BC) application to agricultural soil can impact two nitrogen (N) gases pollutants, i.e., the ammonia (NH3) and nitrous oxide (N2O) losses to atmospheric environment. Under rice-wheat rotation, applied at which growth cycle may influence the aforementioned effects of BC. We conducted a soil column (35 cm in inner diameter and 70 cm in height) experiment to evaluate the responses of wheat N use efficiency (NUE), NH3 volatilization, and N2O emission from wheat season to biochar applied at rice (R) or wheat (W) growth cycle, meanwhile regarding the effect of inorganic fertilizer N input rate, i.e., 72, 90, and 108 kg ha-1 (named N72, N90, and N108, respectively). The results showed that BC application influenced the wheat growth and grain yield. In particular, BC applied at rice season increased the wheat grain yield when receiving 90 and 108 kg N ha-1. The improved wheat grain yield was attributed to that N90 + BC(R) and N108 + BC(R) enhanced the wheat NUE by 53.8% and 52.8% over N90 and N108, respectively. More N input led to higher NH3 volatilization and its emission factor. Interestingly, 19.7%-34.0% lower NH3 vitalizations were recorded under treatments with BC applied in rice season, compared with the treatments only with fertilizer N. BC applied at rice season exerted higher efficiency on mitigating N2O emission than that applied at wheat season under three N input rates, i.e., 60.5%-77.6% vs 29.8%-34.8%. Overall, considering the crop yield and global warming potential resulting from NH3 volatilization and N2O emission of wheat season, N90 + BC(R) is recommended. In conclusion, farmers should consider the application time and reduce inorganic fertilizer N rate when using BC.

The Role of Plant Growth Regulators in Modulating Root Architecture and Tolerance to High-Nitrate Stress in Tomato.

Plant growth regulators are known to exert strong influences on plant performance under abiotic stress, including exposure to high nitrate, as occurs commonly in intensive vegetable production. However, direct comparative evaluations of growth regulators under otherwise identical conditions in major crop species are scarce. In this study, tomato (Solanum lycopersicum L.) was used as a model crop, and the roles of four common exogenously applied plant growth regulators (MT, melatonin; SA, salicylic acid; HA, humic acid; SNP, sodium nitroprusside) in regulating crop growth were studied under high-nitrate stress. We provide a particular focus on root system architecture and root physiological responses. Our data show that all four growth regulators improve tomato tolerance under high nitrate, but that this occurs to differing extents and via differing mechanisms. Optimal concentrations of MT, SA, HA, and SNP were 50 µmol L-1, 25 µmol L-1, 25 mg L-1, and 50 µmol L-1, respectively. MT and SNP produced the strongest effects. MT enhanced root growth while SNP enhanced above-ground growth. Growth of coarse and thin lateral roots was significantly improved. Furthermore, an enhancement of root vitality and metabolism, improved integrity of root cell membranes, and an increase in antioxidant enzyme activities were found, but regulatory mechanisms were different for each growth regulator. Our results show that in particular the application of MT and SNP can improve growth of tomato in intensive vegetable production under high-nitrate stress and that root growth stimulation is of special importance in procuring these beneficial effects.

OsEIL1 protects rice growth under NH4+ nutrition by regulating OsVTC1-3-dependent N-glycosylation and root NH4+ efflux.

Rice is known for its superior adaptation to ammonium (NH4+ ) as a nitrogen source. Compared to many other cereals, it displays lower NH4+ efflux in roots and higher nitrogen-use efficiency on NH4+ . A critical role for GDP-mannose pyrophosphorylase (VTC1) in controlling root NH4+ fluxes was previously documented in Arabidopsis, but the molecular pathways involved in regulating VTC1-dependent NH4+ efflux remain unclear. Here, we report that ETHYLENE-INSENSITIVE3-LIKE1 (OsEIL1) acts as a key transcription factor regulating OsVTC1-3-dependent NH4+ efflux and protein N-glycosylation in rice grown under NH4+ nutrition. We show that OsEIL1 in rice plays a contrasting role to Arabidopsis-homologous ETHYLENE-INSENSITIVE3 (AtEIN3) and maintains rice growth under NH4+ by stabilizing protein N-glycosylation and reducing root NH4+ efflux. OsEIL1 constrains NH4+ efflux by activation of OsVTC1-3, but not OsVTC1-1 or OsVTC1-8. OsEIL1 binds directly to the promoter EIN3-binding site (EBS) of OsVTC1-3 in vitro and in vivo and acts to increase the transcription of OsVTC1-3. Our work demonstrates an important link between excessive root NH4+ efflux and OsVTC1-3-mediated protein N-glycosylation in rice grown under NH4+ nutrition and identifies OsEIL1 as a direct genetic regulator of OsVTC1-3 expression.

MicroRNAs Are Involved in Regulating Plant Development and Stress Response through Fine-Tuning of TIR1/AFB-Dependent Auxin Signaling.

Auxin, primarily indole-3-acetic acid (IAA), is a versatile signal molecule that regulates many aspects of plant growth, development, and stress response. Recently, microRNAs (miRNAs), a type of short non-coding RNA, have emerged as master regulators of the auxin response pathways by affecting auxin homeostasis and perception in plants. The combination of these miRNAs and the autoregulation of the auxin signaling pathways, as well as the interaction with other hormones, creates a regulatory network that controls the level of auxin perception and signal transduction to maintain signaling homeostasis. In this review, we will detail the miRNAs involved in auxin signaling to illustrate its in planta complex regulation.