Roots Of Seedlings Research Articles

Qualitative and Quantitative Analyses of 1-Aminocyclopropane-1-carboxylic Acid Concentrations in Plants Organs Using Phenyl Isothiocyanate Derivatization.

1-Aminocyclopropane-1-carboxylic acid (ACC) is a direct precursor of phytohormone ethylene. We used a phenyl isothiocyanate (PITC) derivatization modification method combined with spectrographic analysis to isolate and identify three products of the derivatization reactions of ACC and PITC. The MRM+ mode of UPLC-MS/MS was used to establish the analysis of 6-phenyl-5-thioxo-4,6-diazaspiro[2.4]heptan-7-one (PTH-ACC). Three fragment ions detected at the precursor ion (m/z 219.10) were selected for qualitative analysis (m/z 98.10, 77.15, and 72.10), and the most abundant product ion (m/z 98.10) was selected for quantitative analysis. The conditions for the derivatization reaction for the main product PTH-ACC were analyzed and optimized using response surface methodology, resulting in the optimal derivatization conditions being a reaction temperature of 90 °C, a reaction time of 1.5 h, and a formic acid (FA) concentration of 40%. ACC concentrations in 25-200 mg rice samples was successfully determined. Moreover, the ACC concentrations in the shoots, seeds, and roots of rice, maize, and cotton seedlings were all analyzed. The ACC concentrations were found to exhibit tissue specificity. Interestingly, during the ripening process in tomato and mango fruits, the concentrations of ACC in the fruits showed an initial increase, followed by a decrease. In black nightshade fruits, ACC content was the highest in the immature stage, decreased with fruit ripening, and remained stable from the semimature to mature stages. These results provide a reliable analysis technology foundation for the study of ethylene.

Regulation of photosynthetic characteristics carbon and nitrogen metabolism and growth of maize seedlings by graphene oxide coating

Maize seedlings in cold regions and high latitude often face abiotic stress. As a result, weak seedlings affect maize production, The commonly used seed coating agents in production are mainly to prevent biological stress of pests and diseases, and have little effect on seedling vigor and abiotic resistance. In this experiment, the combination of graphene oxide (GO) and seed coating agent can effectively prevent pests and diseases and increase the growth of seedlings.The effects of different concentrations of composite GO seed coating agent on photosynthetic carbon and nitrogen metabolism activity of maize were verified by pot experiments. It provides a reference for the application of nanomaterials in maize seed adjuvant technology and the improvement of maize seedling quality. Using maize as a model plant, the study evaluates, 22 g/L(T1), 44 g/L(T2), 66 g/L(T3), and 88 g/L(T4), GO were add respectively. Commercial seed coating agent as control (Con). Under the conditions of this experiment, GO thickened the stem by regulating the nutrients absorption of the roots in maize seedlings. The leaf thickness and vascular bundle area were increased, the photosynthetic efficiency of leaves were improved. Finally, it promoted the carbon and nitrogen metabolism of maize seedling leaves. Therefore, 44 g/L GO is the most suitable concentration as a coating agent in this experiment.

Morphological responses of shoots and fine roots to weed control in Abies sachalinensis and Picea jezoensis seedlings

ABSTRACT A mechanistic understanding of how morphological traits of seedlings are relevant to their functions against competition is the basis for managing vegetation in plantations. This study evaluated the growth responses and functional traits of shoots and fine roots in seedlings of boreal silvicultural species to manual weed control. Aboveground morphological traits reflecting competitive ability, including the total number of shoots per individual, length and weight per current shoot, area and weight per current leaf, and their ratio were evaluated. The fine roots were classified as pioneer roots or fibrous roots and were evaluated for diameter and specific root length (SRL). Compared with Picea jezoensis, Abies sachalinensis has superior competitive ability by reducing the total number of shoots by approximately 40%, preserving shoot length, and increasing specific leaf area by approximately 30% under competition. This finding is partly inconsistent with conventional strategies against shade, and A. sachalinensis is tolerant and partly avoidant of competing vegetation compared with P. jezoensis. The lack of interspecies differences in growth responses to weed control indicates that individual growth cannot be explained by aboveground responses alone. Thinner and higher SRL of fibrous roots in competing conditions were observed only in A. sachalinensis. However, thinner and higher SRL of pioneer roots in competing conditions were observed in both species. Altogether, these results highlighted that the fine root system widely adopts an avoidance strategy against competition regardless of aboveground competitive strategies. Because soil resources can be depleted, the preemptive strategy to access soil space against competition is responsible.

Spatial-Temporal Dynamics of Adventitious Roots of Typha domingensis Pers. Seedlings Grown with Auxin/Cytokinin.

The spatial-temporal dynamics of an in vitro radicular system of Typha domingensis for the development of rhizofiltration technologies, with the potential for use as a phytotreatment of eutrophicated water, were studied for the first time in the roots of seedlings and in rhizotron systems. The effect of indole-3-acetic acid (AIA) in combination with kinetin (CIN) or 6-benzylaminopurine (BAP) on seedlings cultivated in the light and dark in three radicular systems and in a rhizotrophic regime for the screening of dynamic rhizogenic lines, by weekly allometric measurements of the length and number of roots, were studied. Inhibition of the elongation and branching velocities of roots by BAP and light was observed but CIN increased elongation and branching. In rhizotrons cultivated in light and dark conditions with different AIA/CIN ratios, isolated root explants remained inactive; however, roots attached to a meristematic base presented a significant increase in growth development, with values comparable to those of roots attached to seedlings cultivated in light without hormones. The results revealed that six adventitious rhizogenic root lines with basal meristems have the potential for use in a wide range of environmental and innovative applications in phytotreatment technologies involving eutrophicated water.

Draft genomes and assemblies of the ectomycorrhizal basidiomycetes Scleroderma citrinum hr and S. yunnanense jo associated with chestnut trees.

The earthball Scleroderma, an ectomycorrhizal basidiomycete belonging to the Sclerodermataceae family, serves as a significant mutualistic tree symbiont globally. Originally, two genetically sequenced strains of this genus were obtained from fruiting bodies collected under chestnut trees (Castanea mollissima). These strains were utilized to establish in vitro ectomycorrhizal roots of chestnut seedlings. The genome sequences of these strains share characteristics with those of other ectomycorrhizal species in Boletales order, including a restricted set of genes encoding carbohydrate-active enzymes. The genome sequences presented here will aid in further exploring the factors contributing to the establishment of ectomycorrhizal symbiosis in chestnut trees.

Diversity, Extracellular Enzyme Activity and Growth Promoting Potential of Fungal Isolates from the Roots of Coleus aromaticus Benth.

ABSTRACT: Coleus aromaticus Benth. a member of Lamiaceae family is a herbaceous plant with numerous medicinal properties. The present study was aimed at the isolation, characterization, extracellular enzyme activity and growth promoting ability of endophytic fungi from the roots of C. aromaticus collected from different parts of Palakkad, Kerala, India. A total of nine cultures grouped into five morphotypes including one non-sporulating taxa mostly belonging to Ascomycota were isolated. Their colonization rate and diversity index was determined. Extracellular enzyme activity and plant growth promotion studies were also carried out. Amylase activity was exhibited by all isolates, while none of them showed tyrosinase, protease, or laccase activity. Among the isolates, Fusarium sp. exhibited significant root and shoot length promotion in Vigna radiata seedlings, and its identification was confirmed through sequence analysis as Fusarium solani. The results indicated that the endophytic association has a positive role in promoting plant growth and revealed diverse mycoflora in the roots of Coleus aromaticus with various biological activities, highlighting the potential for further research into endophytes and their metabolites as a promising field.

Endophytic Bacteria Enterobacter cloacae PN7 Promotes Biosynthesis and Accumulation of Saponins in Panax notoginseng.

Panax notoginseng is an important Chinese medicinal plant. Saponins are the major bioactive secondary metabolites with a wide range of medicinal and commercial value in P. notoginseng, so it is crucial to develop environmentally friendly methods to increase their production. The symbiotic relationship between endophytic bacteria and host plants offers a sustainable approach to enhance secondary metabolite biosynthesis. In this study, it was reported that the co-cultivation of an endophytic bacterium Enterobacter cloacae PN7, isolated from P. notoginseng and its host plant could greatly promote saponin accumulation in the root of seedlings. After six days of PN7 treatment, the total saponin concentration reached 21.64mg/g, representing a 2.01-fold increase over the control. Transcriptome sequencing revealed that PN7 induction upregulated key genes in the saponin biosynthetic pathway (including DXS, HMGR, PMK, DS, CYP450, and GTs), modulated 253 plant hormone signaling genes (such as those related to JA, ETH, and ABA), and affected 284 transcription factor genes and 47 ABC transporter genes. Co-expression network analysis identified DEGs related to plant hormone signaling, transcription factors, and ABC transporters in saponin biosynthesis and distribution. The results suggested that JA signaling, mediated by transcription factors, such as bHLH and MYBs, and its interaction with ETH, played crucial roles in saponin biosynthesis. Additionally, potential ABC transporter candidates involved in saponin transport were identified. This study highlights the role of endophytic bacteria in enhancing saponin production in P. notoginseng and opens avenues for further research on microbial-plant interactions in secondary metabolite production.

Exploring Drought Resistance Genes from the Roots of the Wheat Cultivar Yunhan1818.

The root is an important organ by which plants directly sense variation in soil moisture. The discovery of drought stress-responsive genes in roots is very important for the improvement of drought tolerance in wheat varieties via molecular approaches. In this study, transcriptome sequencing was conducted on the roots of drought-tolerant wheat cultivar YH1818 seedlings at 0, 2, and 7 days after treatment (DAT). Based on a weighted gene correlation network analysis of differentially expressed genes (DEGs), 14 coexpression modules were identified, of which five modules comprising 3107 DEGs were related to 2 or 7 DAT under drought stress conditions. A total of 223,357 single-nucleotide polymorphisms (SNPs) of these DEGs were retrieved from public databases. Using the R language package and GAPIT program, association analysis was performed between the 223,357 SNPs and the drought tolerance coefficient (DTC) values of six drought resistance-related traits in 114 wheat germplasms. The results revealed that 18 high-confidence SNPs of 10 DEGs, including TaPK, TaRFP, TaMCO, TaPOD, TaC3H-ZF, TaGRP, TaDHODH, TaPPDK, TaLectin, and TaARF7-A, were associated with drought tolerance. The RT-qPCR results confirmed that these genes were significantly upregulated by drought stress at 7 DAT. Among them, TaARF7-A contained three DTC-related SNPs, which presented two haplotypes in the tested wheat germplasms. YH1818 belongs to the Hap1 allele, which is involved in increased drought tolerance. This study revealed key modules and candidate genes for understanding the drought-stress response mechanism in wheat roots.

SlNAC12, a novel NAC-type transcription factor, confers salt stress tolerance in tomato.

SlNAC12 enhances salt stress tolerance of transgenic tomato by regulating ion homeostasis, antioxidant activity and flavonoids biosynthesis Soil salinization is a major environmental factor that adversely affects plant growth and development. NAC (NAM, ATAF1/2, and CUC2) is a large family of plant-specific transcription factors that play crucial roles in stress response. Here, we investigated the role of a novel NAC transcription factor, SlNAC12, in conferring salt stress tolerance in tomato (Solanum lycopersicum). Subcellular localization and yeast assays studies revealed that SlNAC12 is localized in the nucleus with weak transcriptional activity. SlNAC12 transcript was induced by salt stress in the leaves and roots of tomato seedlings. Overexpression of SlNAC12 in tomato led to significantly reduced plant height and root length. Transgenic tomato lines overexpressing of SlNAC12 (OE#1 and OE#3) exhibited enhanced tolerance to salinity, as evidenced by reduced the inhibitory effect of growth parameters under salt stress compared to wild type (WT). Overexpression of SlNAC12 in tomato affected Na+ and K+ homeostasis, leading to reduced Na+/K+ ratio, enhanced activity of antioxidant enzymes and decreased reactive oxygen species (ROS) accumulation under salt stress. Furthermore, the transcript levels of several genes involved in flavonoids metabolism and the levels of flavonoids accumulation were increased in SlNAC12-overexpressing tomato lines. Collectively, this study suggests that SlNAC12 transcription factor enhances salt stress tolerance in tomato is correlated with ion homeostasis, antioxidant enzyme systems, and flavonoids accumulation.

Investigating the mechanism of auxin-mediated fulvic acid-regulated root growth in Oryza sativa through physiological and transcriptomic analyses.

As rice is one of the most crucial staple food sources worldwide, enhancing rice yield is paramount for ensuring global food security. Fulvic acid (FA), serving as a plant growth promoter and organic fertilizer, holds significant practical importance in studying its impact on rice root growth for improving rice yield and quality. This study investigated the effects of different concentrations of FA on the growth of rice seedlings. The results indicated that 0.05 g/L FA could promote the growth of rice seedlings, while 0.5 g/L FA inhibited root growth, reduced cell activity and enzyme activity in the root tips, and accumulated reactive oxygen species in root cells. To further elucidate the molecular mechanisms underlying these effects, we performed transcriptomic analysis and found that auxin (Aux) may be involved in the growth process mediated by FA. Furthermore, transcriptome heatmap analysis revealed a significant upregulation of the Aux/indoleacetic acid (Aux/IAA) gene family after FA treatment, suggesting that this gene family plays a crucial role in the impact of FA on root growth. Additionally, by detecting endogenous Aux content and adding exogenous Aux inhibitors, we confirmed the involvement of FA in rice seedling root growth as well as in the synthesis and transduction pathway of Aux.

Dynamics of rice seed-borne bacteria from acquisition to seedling colonization

BackgroundRice cultivation relies on planting grains harboring beneficial microbiota. However, the origination, distribution, and transmission dynamics of grain-borne bacteria remain unclear.ResultsUsing rice grain as a model system, this study investigates the primary sources, major niches in seeds, and the dynamics of community acquisition, maintenance, and transmission between generations of grain-borne bacteria. Quantitative PCR and 16S rRNA gene sequencing demonstrate rice grains acquiring bacteria primarily from the external environment during panicle heading and flowering. These bacteria concentrate between the caryopsis and glumes, establishing sizable communities in developing seeds. The dominant taxa included Pantoea, Pseudomonas, and Sphingomonas. Throughout seed development and storage, community structure remains consistent while abundance fluctuates within one order of magnitude. Upon germination under axenic conditions, seed bacteria successfully colonize shoots and roots of offspring seedlings. However, bacteria transmitted solely through internal routes fail to form comparably large communities. Analysis of taxonomic composition uncovers dramatic reshaping from seeds to seedlings, potentially reflecting functional adaptation.ConclusionsWe clarify seed-borne bacterial origination, acquisition timing, seed colonization, intergenerational transmission, and seedling diversification. Our findings provide novel insights into rice seed bacterial dynamics critical for microbiome management.9FJ-hzomPrM-V3Zi4Nmp4KVideo

5-Aminolevulinic Acid (5-ALA)-Induced Drought Resistance in Maize Seedling Root at Physiological and Transcriptomic Levels.

Drought stress seriously affects the growth, development, yield, and quality of maize. This study aimed to investigate the effects of exogenous 5-ALA on root morphology and physiological changes in maize seedlings and to detect its regulatory network. The results showed that adding 25 mg/L 5-ALA accelerated root morphogenesis (root average diameter, main root length, total root length, and root surface area) and promoted dry matter accumulation and free radical removal. Transcriptome analysis showed that after applying exogenous 5-ALA, differently expressed genes (DEGs) were mainly involved in histidine metabolism, amino acid biosynthesis, plasma membrane components, secondary active sulfate transmembrane transporter activity, and anion reverse transporter activity. Two inbred lines specifically responded to organelle and structural molecular activity, and 5-ALA may regulate maize roots to achieve drought tolerance through these two pathways. In addition, candidate genes that may regulate maize root growth were screened by weighted gene co-expression network analysis (WGCNA). These genes may play important roles in alleviating drought stress through lignin synthesis, heat shock proteins, iron storage and transport, calcium binding proteins, and plasma membrane regulation of exogenous regulator 5-ALA. Our results may provide a theoretical basis for clarifying the response of maize seedling roots to drought and the mechanism of exogenous hormones in alleviating drought.

Genome editing in almond using hairy root transformation system

Woody plant species are often challenging to transform, which complicates gene function studies using molecular biology techniques. To develop an effective gene editing tool for almond (Prunus dulcis, syn. Prunus amygdalus), we established a new method for inducing hairy roots in almond seedlings based on the injection of agrobacterial culture. We generated composite plants comprising wild-type shoots and transgenic hairy roots. This approach was also successful in almond x peach hybrids. The hairy root transformation system was used alongside Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 gene editing to target two transcription factor genes (ETHYLENE RESPONSE FACTOR 74 and GIBBERELLIC ACID INSENSITIVE). We successfully generated hairy roots with knockouts of the target genes and evaluated the efficiency of guide RNAs for gene editing in almond. Our transgenic root method could be a valuable tool for routine gene function studies in almond.

WAG1 과다발현에 의한 애기장대 유식물 뿌리의 굴곡 생장 및 측근 형성 억제

The protein kinase WAG1, together with WAG2 and PINOID, regulates auxin transport by phosphorylating PIN auxin efflux carriers. In this study, we examined the changes in wavy root growth and lateral root development in Arabidopsis seedlings overexpressing WAG1. When WAG1-overexpressing seedlings were grown vertically, wavy root growth was suppressed compared to the wild-type controls. Even under 45-degree slanted growth conditions, which promote wavy root growth, the roots of WAG1-overexpressing seedlings showed strong suppression of wavy growth, growing straight unlike the wild type. Furthermore, in the roots of WAG1-overexpressing seedlings, both wavy root growth and lateral root formation were inhibited, revealing a correlation between the intensity of wavy root growth and the rate of lateral root formation in Arabidopsis seedlings. YFP-WAG1 protein was found to localize to the plasma membrane and nucleus of root epidermal cells, confirming its association with the membrane-localized PIN proteins.

Effect of Zinc Oxide Nanoparticles on Growth and Germination of Mung Bean Seeds (Vigna radiata L.)

The globe is currently experiencing a micronutrient shortage, which is being addressed with various chemical fertilizers that harm the environment and human health. Research is shifting toward nanotechnology to overcome this and using nano fertilizer has sparked scientists’ interest. In this study, we examined the effect of zinc oxide nanoparticles (ZnO NPs) dosage on the growth and seed germination of mu ngbean (Vigna radiata L.). This experiment was designed to study the impact of ZnO NPs, obtained from Curcuma longa leaves extract, on seedling vigour index, root, shoot length and chlorophyll content for Vigna radiata species. Three concentrations (3, 6 and 9 mg/mL) of ZnO NPs were examined at the seed germination stage. Significant enhancement of the germination percentage values was observed after the treatment of mungbean seeds with ZnO NPs in comparison with untreated seeds. Green-produced ZnO nanoparticles positively impacted the development and germination of Vigna radiata, indicating a beneficial impact on agricultural productivity. The response to ZnO NPs was dose-dependent, though, therefore more research is needed to determine the ideal dosages for increased agricultural production and human nutrition.

Acetoin Promotes Plant Growth and Alleviates Saline Stress by Activating Metabolic Pathways in Lettuce Seedlings.

Acetoin is a volatile organic compound, which is a class of metabolites produced by plant growth-promoting rhizobacteria. The mechanisms underlying plant growth promotion by acetoin and its potential to induce saline stress tolerance in plants are poorly understood. Lettuce (Lactuca sativa L. var. ramosa Hort.) seedlings in hydronics and pots under non-saline or saline conditions were foliar-sprayed with 10 mL of 0 or 1 mg·mL-1 acetoin at 7 and 14 d after transplantation and harvested 7 d after the second spray. Shoots and roots of hydroponic lettuce seedlings were harvested at 6 and 24 h after treatment for RNA sequencing. Seedlings sprayed with acetoin showed more vigorous growth, with higher shoot and root biomass than those of the controls, in both hydronic and pot modes. The transcriptomic analysis revealed acetoin application resulted in 177 differentially expressed genes (39 upregulated and 138 downregulated) in shoots and 397 differentially expressed genes (112 upregulated and 285 downregulated) in roots. These DEGs, mainly involved in plant hormone signal transduction and the mitogen-activated protein kinase, have the potential to trigger plants' responses to various environmental stimuli, including stress and developmental signals. Under saline conditions, acetoin-treated plants showed increased net leaf photosynthesis and activities of several defense enzymes, indicating that acetoin enhances both fundamental growth and the plant's stress defenses, especially against salinity. In summary, acetoin appears to act through a complex interplay of genetic and biochemical mechanisms, influencing key signaling pathways and physiological processes that lead to improved growth and stress tolerance in lettuce seedlings.

PRE-GERMINATION TREATMENTS IN BRAZILWOOD SEEDS IN SEEDLING EMERGENCE AND DEVELOPMENT

Brazilwood (Caesalpinia echinata) is a species from the Atlantic Forest considered a national symbol of Brazil. The wood is heavy, smooth and hard and highly resistant to wood-eating organisms. Brazilwood seeds may present dormancy and initial germination difficulties. The objective of this study was to evaluate different methods to stimulate the emergence and development of Brazilwood seedlings. The research was carried out in the nursery of IFES-Campus Santa Teresa. The seeds were subjected to the following immersion treatments for 60 minutes: natural water (26°C) as control; gibberellin solution at 1000 mg.L-1, 2000 mg.L-1, 3000 mg.L-1 and 4000 mg.L-1; NaCl solution 9 gL-1; KCl solution 50 gL-1 and coconut water. They were then sown in 150 mL tubes containing commercial substrate. The experimental design was randomized blocks with 8 treatments and four replicates. After 30 days from the beginning of emergence, the emergence percentage was evaluated and, after 90 days from emergence, the number of leaves; plant height; stem diameter; root length; green mass of the aerial part; dry mass of the aerial part; green mass of the root; dry mass of the root were evaluated. Immersion in coconut water promoted the highest percentage of seedling emergence. The dose of 4000 mg.L-1 of GA3, 9 gL-1 of NaCl solution and 50 gL-1 of KCL provided the highest values ​​related to growth and greater production of dry mass of leaves and roots in the brazilwood seedlings.

Reduction of Plasmodiophora brassicae infection on Brassica rapa through host-induced gene silencing of two secreted genes.

Clubroot disease caused by the biotrophic pathogen Plasmodiophora brassicae, is one of the most serious threats to cruciferous crops production worldwide. P. brassicae is known for rapid adaptive evolution to overcome resistance in varieties. It is urgent to establish alternative management to control P. brassicae. In this study, we identified two P. brassicae secretory proteins that were up-regulated during infection and effected plant defense. We established a method for transient expression in the roots of seedlings and demonstrated that P. brassicae could take up substances from the environment of root cells. Using a RNA interference (RNAi)-based host-induced gene silencing (HIGS) by expression of hairpin RNAi constructs with sequence homology to P. brassicae effector Pb48 or Pb52 in susceptible Brassica rapa plants enhanced host disease resistance. After silencing these two effectors, the transcription levels of cytokinin biosynthesis gene IPT1 and the regulation gene of auxin homeostasis GH3.5 were down-regulated. These results suggested that RNAi-based HIGS of effectors has a great practical application of improving crop resistance against P. brassicae and can contribute to environmentally sustainable agriculture.

Concentration of Nutrients in Individual Organs of European Beech (Fagus sylvatica L.) Seedlings and Root System Development as a Result of Different Fertilization

The large-scale dieback of spruce monocultures, especially in the lower alpine, has become a significant problem and has necessitated the restoration of these areas, mainly using seedlings produced in forest nurseries. The primary source of nutrients for seedlings can be slow-release fertilizers and an appropriate dose of fertilizer improves the efficiency of its use and minimizes the negative environmental impact associated with the excessive use of mineral fertilizers. Aims: This study aimed to evaluate the effect of applying different fertilizer dose combinations on the accumulation of macronutrients in different parts of the seedlings (roots, shoots, and leaves) and on the morphology and development of fine roots. Methods: This research was carried out on producing beech seedlings with the application of starter soil fertilization with Yara Mila Complex (YMC) and Osmocote Exact Standard 3-4M (OES) fertilizers in four varying doses. Results: No deficiency of the analyzed macronutrients was noted in any of the tested fertilization variants. The highest content of all analyzed macronutrients was recorded in the leaves of beech seedlings, with values in roots and shoots being several times lower. The mixed fertilization variant OES 1.0 + YMC 1.0 shows a positive correlation with all analyzed elements and the parameters DQI (Dickson Quality Index), SA (Surface Area), RV (Root Volume), and mass. Conclusions: Results confirm the hypothesis that applying a mixture of fast-acting (YMC) and slow-acting (OES) fertilizer positively affects the nutrition and accumulation of macronutrients and the development of root systems in beech seedlings compared to fertilization with a single fertilizer.

OsABT Negatively Regulates the Abscisic Acid Signal Transduction Pathway in Rice Seedling Roots

Rice (Oryza sativa L.) is a main food crop in China and is crucial for the maintenance of national food security. The growth of rice seedling roots is regulated by a variety of genes and is closely related to abscisic acid (ABA) metabolism and ABA signaling pathways. In this study, we found that OsABT could increase the length of rice root tip meristem cells and upregulate root development-related genes, thereby alleviating ABA’s inhibitory effects on rice root growth and seed germination. The overexpression of OsABT reduced the ABA content by downregulating ABA synthesis genes (OsNCED3 and OsNCED5) and upregulating the ABA catabolic gene (OsABA8ox2). In addition, OsABT interacted with OsPYL4, OsPYL10, and OsABIL2 via the ABA signal transduction pathway. By inhibiting the expression of positive regulatory genes (OsPYL9 and Rab16a) and increasing the expression of a negative regulatory gene (OsABIL1), OsABT negatively regulates the ABA signal transduction pathway. Transcriptome analysis revealed that OsABT inhibited the activity of Gene Ontology entries in response to ABA. Thus, OsABT increased the length of the rice root meristem, reduced the accumulation of ABA in the roots, and negatively regulated the ABA signal transduction pathway by interacting with key proteins in this pathway, ultimately relieving the inhibitory effect of ABA on rice root length and seed germination.