Primary Root Length Research Articles

Stimulating microorganisms in the cultivation and improvement of vegetable plants

Research objective: In this study, the possibility of using different microbial types inoculated into the growing medium was evaluated in order to assess the growth-promoting potential of certain vegetable species. Materials and Methods: The plants were grown in pots under controlled conditions; 30 seedlings per thesis, divided into 3 replications of 10 plants each, were planted in early November 2023. The plants used in the trial were Cichorium intybus and Allium ampeloprasum. All plants were fertilised with a slow-release fertiliser (2 kg m-3 of Osmocote Pro® for 6 months) introduced into the growing medium at the time of transplanting. The six experimental groups in cultivation were: i) group without microorganisms, irrigated with water and previously fertilised substrate; ii) group with Pacilomyces lilacinus; iii) group with Azospirillum sp.; iv) group with Glomus sp.; v) group with Trichoderma viride; vi) group with mix Bacillus subtilis, Pseudomonas sp. and Trichoderma viride. On 11 January 2024, plant height, number of leaves, total leaf area per plant (mm2), primary root length (mm), biomass of the aerial and root system, and number of dead plants were recorded. Results and Discussion: The experiment showed that the use of microbial strains of various types can indeed significantly improve the vegetative and root growth of Cichorium intybus and Allium ampeloprasum. All treatments showed a significant improvement over the untreated control for the agronomic parameters analysed, but the Azospirillum sp. and Glomus sp. treatments were statistically the best. Improvements were also found in plant height, number of leaves, leaf area, vegetative and root biomass and root length. A very interesting aspect was also the ability of the microbial products to reduce plant mortality, particularly the application of Trichoderma viride in Cichorium intibus and all microbial treatments on Allium ampeloprasum. Conclusions: This experiment highlights other interesting and innovative aspects of the use of microorganisms, which have already been highlighted in previous trials on various vegetable and ornamental species. Given the importance of the application of microbial inoculums in plants, the new agricultural experiments are very important because they could enable the development of new products to be used in organic and sustainable farming systems and enable better results.

GhAGL16 (AGAMOUS-LIKE16) Negatively Regulates Tolerance to Water Deficit in Transgenic Arabidopsis and Cotton.

Cotton is one of the most economically important crops in the world, and drought is a key abiotic factor that can significantly reduce cotton yield. MADS-box transcription factors play essential roles in various aspects of plant growth and development as well as responses to biotic and abiotic stress. However, the use of MADS-box transcription factors to regulate water stress responses has not been fully explored in cotton. Here, we showed that GhAGL16 acts as a negative regulator of water deficit in cotton, at least in part by regulating ABA signaling. GhAGL16-overexpressing (GhAGL16-OE) transgenic Arabidopsis had lower survival rates and relative water contents (RWCs) under water stress. Isolated leaves of GhAGL16-OE Arabidopsis had increased water loss rates, likely attributable to their increased stomatal density. GhAGL16-OE Arabidopsis also showed reduced primary root lengths in response to mannitol treatment and decreased sensitivity of seed germination to ABA treatment. By contrast, silencing GhAGL16 in cotton enhanced tolerance to water deficit by increasing proline (Pro) content, increasing superoxide dismutase (SOD) and peroxidase (POD) activities, and reducing malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents under water stress. Subcellular localization and transcriptional activation assays confirmed that GhAGL16 is a nuclear protein that lacks transcriptional self-activation activity. The expression of ABA biosynthesis-related genes (GhNCED3/7/14), a catabolism-related gene (GhCYP707A), and a gene related to the ABA signaling pathway (GhABF4) was altered in GhAGL16-silenced plants. Taken together, our data demonstrate that GhAGL16 plays an important role in cotton resistance to water stress.

Meta-topolin and silica nanoparticles induced vigorous carnation plantlet via regulation of antioxidant status and mineral absorption

This study is an attempt to explore the potential of meta-topolin (MT) and silica nanoparticles (SiNPs) in carnation micropropagation - an in vitro vitrification sensitive cut flower. Among MT concentrations (0.5 mg/L - 3.0 mg/L), 1.0 mg/L MT treatment showed a significant increase in shoot height, leaf length, chlorophyll content, dry weight and dry matter index (DM). However, MT concentration > 2.5 mg/L resulted in increased number of shoots and vitrification. Beside different concentrations SiNPs (0.1 mg/L - 3.0 mg/L) were tested in shoot multiplication, chlorophyll content and DM increased; in contrast, the number of shoots, shoot height and other growth indicators all decreased significantly. The results indicated that MT improved shoot multiplication and reduced vitrification, while SiNPs were less suitable for this stage due to limited water absorption of shoots. Interestingly, SiNPs induced compact shoot structure and stimulated root system development, as well as induced densely closed stomata. Furthermore, the presence of SiNPs increased the activities of antioxidant enzymes Catalase (CAT), Superoxide dismutase (SOD) and Ascorbate peroxidase (APX); besides, SiNPs showed negative correlation with Cu, K and Ca uptake but significantly improved Mg, Fe and Si uptake. However, the plantlets derived from SiNPs showed 2.1–2.8-fold decrease in shoot height compared to the control but significantly increased chlorophyll content, DM index, primary root length and diameter as well as lateral root formation. At the highly tested concentrations of 2.0 mg/L - 3.0 mg/L SiNPs, a decrease in growth, uptake of Mg, Fe, Si and explosion of CAT, APX and SOD antioxidant activity was found, which presumably express stress-induced SiNPs. Nevertheless, carnation plantlets derived from SiNPs showed almost complete survival and well growth in greenhouse conditions. These findings suggest that MT and SiNPs can be used to stimulate growth, reduce vitrification, and harden carnation plantlet in practical micropropagation.

Response of Barley (Hordeum Vulgare L.) Genotypes to Soil Acidity, at Hula District, Sidama Region, Ethiopia

Barley (Hordeum vulgare L.) was domesticated at about 8000 B.C. It is one of the most important cereal crops in Ethiopia, accounting for over 60% of the food of the peoples living in the highlands of Ethiopia. Soil acidity is expanding in its scope, about 43 % out of the total cultivated land in Ethiopia, is dominated with acidic soil, as a sensitive highland crop, barley productivity is decreasing due to soil acidity and in areas where the problem is severe the crop is going out of production. A greenhouse pot experiment was conducted with the objective of performance comparison and screening of soil acidity-tolerant barley genotypes. The treatments consisted of two lime levels (with and without lime) and ten barley genotypes making up a total of 20 treatments laid out in a completely randomized design with six replications. Crop phenology, growth parameters, yield and yield components were evaluated. Primary root length, lateral root length, lateral root number, and root dry weight were significantly (P < 0.05) affected by the application of lime. Stand count at harvest, above-ground biomass, plant height, total seed number per pot, and seed number per plant were significantly (P < 0.05) affected by the application of lime. Accession 215454a, has shown a greater value of relative root length measurement with 73.76 centimeter. The study revealed the impact of soil acidity could be so severe it can result to the extent of having no yield as compared to lime-treated soils. This necessitates the use of lime in areas that are prone to acidic soils. Overall, the accession that showed relative tolerance from early stage screening can be candidate for further breeding program to develop barley variety that is tolerant to acidic soils.

Emergence and initial growth of Celosia argentea L. cultivated under irrigation with brackish water

Emergence and initial growth of Celosia argentea L. cultivated under irrigation with brackish water

Effect of treatment with thiamethoxam and cyantraniliprole on the germination and storage of forest tree seeds

ABSTRACT: Seed predation is a problem that limits the use of direct sowing of tree species, and it is necessary to develop studies involving products used in seed treatment. The objectives of this study were to evaluate the effects of treatment with insecticides on the storage and germination of seeds of six forest species. Seeds were treated with thiamethoxam and cyantraniliprole and germinated on paper and sand substrates at 25 °C under constant light. For storage, the seeds were treated and analyzed at 0, 3 and 6 months. For both tests, the following variables were evaluated: germination, mortality, hard seeds, abnormal seedlings, average length of shoot and primary root, and germination speed index (GSI). For Senna multijuga, treatment with insecticides had no effect. Peltophorum dubium and Enterolobium contortisiliquum showed positive effects of the treatments on seedling vigor and development, while Guazuma ulmifolia displayed a negative effect on primary root length. Bowdichia virgilioides and Hymenaea courbaril seeds were sensitive to the treatments. It is possible to treat and store P. dubium and E. contortisiliquum seeds with thiamethoxam for up to six months.

Characterization of Bacillus amyloliquefaciens BA-4 and its biocontrol potential against Fusarium-related apple replant disease.

Apple replant disease (ARD), caused by Fusarium pathogens, is a formidable threat to the renewal of apple varieties in China, necessitating the development of effective and sustainable control strategies. In this study, the bacterial strain BA-4 was isolated from the rhizosphere soil of healthy apple trees in a replanted orchard, demonstrating a broad-spectrum antifungal activity against five crucial apple fungal pathogens. Based on its morphology, physiological and biochemical traits, utilization of carbon sources, and Gram stain, strain BA-4 was tentatively identified as Bacillus amyloliquefaciens. Phylogenetic analysis using 16S rDNA and gyrB genes conclusively identified BA-4 as B. amyloliquefaciens. In-depth investigations into B. amyloliquefaciens BA-4 revealed that the strain possesses the capacity to could secrete cell wall degrading enzymes (protease and cellulase), produce molecules analogous to indole-3-acetic acid (IAA) and siderophores, and solubilize phosphorus and potassium. The diverse attributes observed in B. amyloliquefaciens BA-4 underscore its potential as a versatile microorganism with multifaceted benefits for both plant well-being and soil fertility. The extracellular metabolites produced by BA-4 displayed a robust inhibitory effect on Fusarium hyphal growth and spore germination, inducing irregular swelling, atrophy, and abnormal branching of fungal hyphae. In greenhouse experiments, BA-4 markedly reduced the disease index of Fusarium-related ARD, exhibiting protective and therapeutic efficiencies exceeding 80% and 50%, respectively. Moreover, BA-4 demonstrated plant-promoting abilities on both bean and Malus robusta Rehd. (MR) seedlings, leading to increased plant height and primary root length. Field experiments further validated the biocontrol effectiveness of BA-4, demonstrating its ability to mitigate ARD symptoms in MR seedlings with a notable 33.34% reduction in mortality rate and improved biomass. Additionally, BA-4 demonstrates robust and stable colonization capabilities in apple rhizosphere soil, particularly within the 10-20 cm soil layer, which indicates that it has long-term effectiveness potential in field conditions. Overall, B. amyloliquefaciens BA-4 emerges as a promising biocontrol agent with broad-spectrum antagonistic capabilities, positive effects on plant growth, and strong colonization abilities for the sustainable management of ARD in apple cultivation.

Physiological effects of Acmella ciliata essential oil on root development of Nicotiana tabacum

In this study, the essential oil of Acmella ciliata, characterized by the presence of significant amounts of spilanthol, α-phellandrene epoxide, and carvotanacetone, was assessed for its influence on the growth of Nicotiana tabacum cv. Xanthi, with the focus primarily on root hair density and primary root length. Following its extraction through microwave-assisted hydrodistillation, the oil was stored at 4°C in amber vials, distinguishable by its unique yellowish-reddish hue, with a refractive index of 1.3478 and a density of 0.847 g cm-3. Among the various dilutions evaluated, the undiluted oil (T3) and the dilution 1.5:0.5 (Oil:EtOH) (T6) demonstrated the most prominent effects. The T3 and T6 treatments markedly enhanced root hair numbers, with T6 additionally promoving root length compared to other treatments. Considering the presence of bioactive alkamides such as spilanthol in the oil, these compounds may have contributed to the observed root growth modulation. When compared against the positive control, affinin, Acmella ciliata essential oil displayed a more pronounced effect on root hair proliferation, while affinin predominantly boosted primary root elongation. The findings highlight the differential effects of the essential oil on specific plant growth parameters.

Оценка посевных качеств семян сортов зернового сорго при применении хелатных микроудобрений

Recently, the cultivation of grain sorghum has become increasingly popular in modern agriculture. Grain sorghum is a valuable agricultural crop, the peculiarity of which is consistently high productivity even under conditions of abnormal drought, which is especially important in arid agriculture. Another feature of grain sorghum is its suitability for food use. The grain of this crop serves as a valuable raw material for gluten-free products. Currently, the area of cultivation of grain sorghum is actively expanding, which extends to countries in Africa, Asia, South and North America, Europe and Australia. It should be noted that grain sorghum responds well to the use of agrotechnical techniques, including fertilizer systems, both in organic and mineral forms, as well as to the use of pre-sowing, leaf treatments with various humic, chelate and growth-regulating preparations. However, the effect of chelated micronutrients in the pre-sowing treatment of grain sorghum seeds has not been studied widely enough. This circumstance was the reason for the research. The article notes the significant effect of chelated preparations on the germination energy and germination of seeds of grain sorghum varieties. A tendency to increase the degree of grain swelling, as well as the length of primary roots and primary seedlings, was revealed when using preparations in chelated form. Keywords: GRAIN SORGHUM, VARIETY, CHELATED MICRO FERTILIZERS, WATER CONSUMPTION, SWELLING, GERMINATION ENERGY, GERMINATION, PRIMARY ROOTS, SEEDLINGS

Heterologous Expression of a Ferritin Homologue Gene PpFer1 from Prunus persica Enhances Plant Tolerance to Iron Toxicity and H2O2 Stress in Arabidopsis thaliana.

In plants, ferritin proteins play an important role in iron (Fe) storage which contributes to plant growth and development. However, the biological functions of ferritins in fruit trees are essentially unknown. In this study, three Ferritin genes were isolated from 'Zhentong No. 3' peach, which were named PpFer1-PpFer3. The expression levels of these genes were different in distinct tissues/organs. Notably, PpFer1 was the most abundantly expressed Ferritin family gene in all tested tissues of 'Zhentong No. 3' peach; its expression levels were significantly enhanced throughout the entire peach seedling under Fe toxicity and H2O2 stress, particularly in the leaves. In addition, over-expression of PpFer1 was effective in rescuing the retarded growth of Arabidopsis fer1-2 knockout mutant, embodied in enhanced fresh weight, primary root length, lateral root numbers, total root length, total leaf chlorophyll, stomatal conductance (Gs), net photosynthetic rate (Pn), transpiration rate, and tissue Fe concentration. This study provides insights into understanding the molecular mechanisms of Fe storage and sequestration in perennial fruit trees.

Arthrospira promotes plant growth and soil properties under high salinity environments.

Salt stress detrimentally impacts plant growth, imperiling crop yield and food quality. Ameliorating plant resilience and productivity in saline environments is critical for global food security. Here, we report the positive effect of Arthrospira (Spirulina) on plant growth and salt tolerance in Arabidopsis and sweet sorghum. Arthrospira application greatly promotes seed germination and seedling growth in both species under salt stress conditions in a dosage-dependent manner. Application of 6 mg Arthrospira per plate significantly enhances K+/Na+ equilibrium and reactive oxygen species (ROS) scavenging in Arabidopsis, reducing salt-induced toxicity. The primary root length, survival rate, chlorophyll content, photosynthesis, plant height, biomass and yield were all improved in both species. Concurrently, Arthrospira demonstrated the synthesis of compatible solutes, such as trehalose (Tre) and glucosylglycerol (GG), contributing to heightened stress tolerance when co-cultivated with Arabidopsis on plates. Transcriptome analysis revealed dramatic up-/down- regulation of genes involved in phytohormone signal transduction, chlorophyll and photosynthesis metabolism, and phenylpropanoid metabolism in Arabidopsis. Furthermore, the application of Arthrospira exerted a positive influence on the rhizosphere bacteriome structure in sweet sorghum, crucial for nutrient cycling and soil health enhancement. Our findings uncovered the underlying mechanisms of algae-plants interaction in saline soil, proposing strategies to enhance crop productivity and soil quality, thereby addressing the urgent need for sustainable agriculture practices to mitigate salinity's repercussions amidst climate change challenges.

Arabidopsis seedlings respond differentially to nutrient efficacy of three rock meals by regulating root architecture and endogenous auxin homeostasis

BackgroundPlants show developmental plasticity with variations in environmental nutrients. Considering low-cost rock dust has been identified as a potential alternative to artificial fertilizers for more sustainable agriculture, the growth responses of Arabidopsis seedlings on three rock meals (basalt, granite, and marlstone) were examined for the different foraging behavior, biomass accumulation, and root architecture.ResultsCompared to ½ MS medium, basalt and granite meal increased primary root length by 13% and 38%, respectively, but marlstone caused a 66% decrease, and they all drastically reduced initiation and elongation of lateral roots but lengthened root hairs. Simultaneous supply of organic nutrients and trace elements increased fresh weight due to the increased length of primary roots and root hairs. When nitrogen (N), phosphorus (P), and potassium (K) were supplied individually, N proved most effective in improving fresh weight of seedlings growing on basalt and granite, whereas K, followed by P, was most effective for those growing on marlstone. Unexpectedly, the addition of N to marlstone negatively affected seedling growth, which was associated with repressed auxin biosynthesis in roots.ConclusionsOur data indicate that plants can recognize and adapt to complex mineral deficiency by adjusting hormonal homeostasis to achieve environmental sensitivity and developmental plasticity, which provide a basis for ecologically sound and sustainable strategies to maximize the use of natural resources and reduce the production of artificial fertilizers.

Effect of mycorrhization on growth and physiology performance of Quercus species

The development of mycorrhiza could contribute to strengthening the resilience of forest ecosystems to climate change. Several mycorrhizal fungi are known for their valuable effect in increasing plant performances and adaptation to stressful environmental conditions. Thereby, this research aims to investigate how Terfezia boudieri (Chatin) mycorrhizal fungi affects the growth (primary root length, above-ground plant weight) and the physiological behaviour (net photosynthesis, responses to intercellular [CO2] and the intensity of photosyntically active radiation) of Quercus subsp. coccifera and Q. suber L. Inoculated and non-inoculated seedlings of the two Quercus species were grown in one-liter pots in the greenhouse, with a temperature that ranged from 25 to 30 °C, natural lighting and an irrigation applied twice a week with top water. Results revealed that primary root length and the above-ground biomass increased with mycorrhization. In addition, mycorrhization promoted net photosynthesis (at 400 ppm and at saturation point), the apparent quantum yield, the water use efficiency, and the photosynthetic pigments contents. However, inoculation decreased the light compensation point for both species. Effectiveness of T. boudieri inoculation on Quercus sp. performance, highlights the potential of the mycorrhization process to improve forest management and resilience to climate change.

OsmiRNA5488 Regulates the Development of Embryo Sacs and Targets OsARF25 in Rice (Oryza sativa L.).

Small RNAs are a class of non-coding RNAs that typically range from 20 to 24 nucleotides in length. Among them, microRNAs (miRNAs) are particularly important regulators for plant development. The biological function of the conserved miRNAs has been studied extensively in plants, while that of the species-specific miRNAs has been studied in-depth. In this study, the regulatory role of a rice-specific OsmiRNA5488 (OsmiR5488) was characterized with the miR5488-overexpressed line (miR5488-OE) and miR5488-silenced line (STTM-5488). The seed-setting rate was notably reduced in miR5488-OE lines, but not in STTM-5488 lines. Cytological observation demonstrated the different types of abnormal mature embryo sacs, including the degeneration of embryo sacs and other variant types, in miR5488-OE lines. The percentage of the abnormal mature embryo sacs accounted for the reduced value of the seed-setting rate. Furthermore, OsARF25 was identified as a target of OsmiR5488 via RNA ligase-mediated 3'-amplifification of cDNA ends, dual luciferase assays, and transient expression assays. The primary root length was decreased with the increases in auxin concentrations in miR5488-OE lines compared to wild-type rice. Summarily, our results suggested that OsmiR5488 regulates the seed-setting rate and down-regulates the targeted gene OsARF25.

Genome wide association analysis reveals multiple QTLs controlling root development in maize

Maize root system plays a crucial role in the development of the aboveground plant and determines the yield via the uptake of water and nutrients in the field. However, the genetic architecture of the maize root system is largely unknown mainly due to the complexity of maize root system and the interaction between genotype and environment. Using a high-throughput semi-automatic hydroponic platform with stable conditions, we comprehensively characterized the root system in a core population of 518 diverse inbred lines of maize. Population structure analysis revealed that the panel has a stratification and linkage disequilibrium decay distance was less than 50 Kb. Based on the genotyping with the high density of 600 K SNPs, we conducted a genome wide association analysis (GWAS) and identified nine SNPs and seven candidate genes significantly associated with 24 traits. A candidate gene GRMZM2G400533 located at the upstream 5 Kb region from the leading SNP (AX-91771718) was significantly associated with primary root length and preferentially expressed in primary root and crown root. The expression of GRMZM2G400533 increased as the primary root developed but negatively correlated with primary root elongation. We also identified three functional variants and eight allelic haplotypes based on candidate gene analysis of GRMZM2G400533. The present study will broaden our understanding of maize root development and provide a theoretical basis for maize improvement through optimizing root system.

Pengaruh Tinggi Tapak Timbun Terhadap Distribusi Akar Kelapa Sawit (Elaeis guineensis Jacq.) Umur 10 Tahun Pada Lahan Mineral

One of the reasons for the low productivity of oil palm is the lack of proper technical culture implementation. The implementation of technical culture practices that can be carried out includes stem mounding by creating mound platforms for the oil palm. This study aims to determine the effect of mound bed height on the growth and development of roots in 10-year-old oil palm plants. The research was conducted experimentally using a Non-Factorial Randomized Complete Block Design with 5 levels of mound bed height: 20 cm, 25 cm, 30 cm, 35 cm, and 40 cm. Each treatment was replicated five times, resulting in 25 experimental units. Each experimental unit consisted of three sample plants, making a total of 75 sample plants. The observed parameters included fresh root weight, dry root weight, the number of primary roots, the length of primary roots, the number of secondary roots, the length of secondary roots, and the number of tertiary roots. The results of the study indicated that the mound bed treatment on 10-year-old oil palm plants in mineral soil, particularly at a height of 40 cm, tended to increase the fresh root weight by 2.45 g, the dry root weight by 0.65 g, the number of tertiary roots by 5.26 strands, the number of primary roots by 2.80 strands, the length of primary roots by 10.0 cm, the number of secondary roots by 2.26 strands, and the length of secondary roots by 2.61 cm.

INORT: Biofertilizer based on Inula viscosa L. (Dittrichia viscosa L.), algae and micro-organisms for growth, Fusarium oxysporum defence and water stress resistance of Plumeria frangipani

Research objective: In this study, the possibility of using INORT, a biostimulant based on Inula viscosa L. (Dittrichia viscosa L.), algae and microorganisms to improve growth, defence against Fusarium oxysporum and resistance to water stress, on Plumeria frangipani plants grown in open field was evaluated. Materials and Methods: The experiments, started in January 2023, were conducted in the greenhouses of CREA-OF in Pescia (Pt), on Plumeria frangipani plants cvs “California sunset and “Super round”. The plants were grown in open field. The five experimental groups in cultivation were: group without biostimulant (CTRL); group with microrganisms; group with algae; group with Inula viscosa; group with (INORT) (mix Microorganisms + Inula viscosa + Algae).The product INORT was supplied by the Francesco Attanasio farm. On 15 September 2023, plant height, number of leaves, number of branches, total leaf area per plant (mm2), primary root length (mm), aerial and root system biomass were recorded. In addition, plant mortality as a result of Fusarium oxysporum attacks and water stress was assessed in the experiment. Results and Discussion: The experiment showed that the use of the biostimulant based on Inula viscosa, microorganisms and algae (INORT) can indeed significantly improve the vegetative and root growth of Plumeria frangipani plants grown in the open field. Improvements were also found in plant height, number of leaves, number of floral branches, leaf area, vegetative and root biomass and root length at different irrigation frequencies of 3 and 6 days. A very interesting aspect was also the ability of the biostimulant based on Inula viscosa, microorganisms and algae to significantly reduce the incidence of Fusarium oxysporum attacks on leaves. Conclusions: Given the importance of Inula viscosa from a medicinal, pollination and biodiversity point of view, new agricultural experiments are very important as they could allow the development of new biofertiliser products that can be used in organic and sustainable farming systems

Integrated BSA-seq and RNA-seq analysis to identify candidate genes associated with nitrogen utilization efficiency (NUtE) in rapeseed (Brassica napus L.)

Rapeseed (Brassica napus L.) is one of the important oil crops, with a high demand for nitrogen (N). It is essential to explore the potential of rapeseed to improve nitrogen utilization efficiency (NUtE). Rapeseed is an allotetraploid crop with a relatively large and complex genome, and there are few studies on the mapping of genes related to NUtE regulation. In this study, we used the combination of bulk segregant analysis sequencing (BSA-Seq) and RNA sequencing (RNA-Seq) to analyze the N-efficient genotype ‘Zheyou 18’ and N-inefficient genotype ‘Sollux’, to identify the genetic regulatory mechanisms. Several candidate genes were screened, such as the high-affinity nitrate transporter gene NRT2.1 (BnaC08g43370D) and the abscisic acid (ABA) signal transduction-related genes (BnaC02g14540D, BnaA03g20760D, and BnaA05g01330D). BnaA05g01330D was annotated as ABA-INDUCIBLE bHLH-TYPE TRANSCRIPTION FACTOR (AIB/bHLH17), which was highly expressed in the root. The results showed that the primary root length of the ataib mutant was significantly longer than that of the wild type under low N conditions. Overexpression of BnaA5.AIB could reduce the NUtE under low N levels in Arabidopsis (Arabidopsis thaliana). Candidate genes identified in this study may be involved in the regulation of NUtE in rapeseed, and new functions of AIB in orchestrating N uptake and utilization have been revealed. It is indicated that BnaA5.AIB may be the key factor that links ABA to N signaling and a negative regulator of NUtE. It will provide a theoretical basis and application prospect for resource conservation, environmental protection, and sustainable agricultural development.

Promotional Properties of ACC Deaminase-Producing Bacterial Strain DY1-3 and Its Enhancement of Maize Resistance to Salt and Drought Stresses.

Salt stress and drought stress can decrease the growth and productivity of agricultural crops. Plant growth-promoting bacteria (PGPB) may protect and promote plant growth at abiotic stress. The aim of this study was to search for bacterial strains that can help crops resist rises in drought and salt stresses, to improve crop seed resistance under drought and salt stresses, and to investigate the effect of bacterial strains that can help crop resist external stresses under different stress conditions. Pseudomonas DY1-3, a strain from the soil under the glacier moss community of Tien Shan No. 1, was selected to investigate its growth-promoting effects. Previous studies have shown that this strain is capable of producing ACC (1-aminocyclopropane-1-carboxylic acid) deaminase. In this experiment, multifunctional biochemical test assays were evaluated to determine their potential as PGPB and their bacterial growth-promoting properties and stress-resistant effects on maize plants were verified through seed germination experiments and pot experiments. The results showed that strain DY1-3 has good salt and drought tolerance, as well as the ability to melt phosphorus, fix nitrogen, and produce iron carriers, IAA, EPS, and other pro-biomasses. This study on the growth-promoting effects of the DY1-3 bacterial strain on maize seeds revealed that the germination rate, primary root length, germ length, number of root meristems, and vigor index of the maize seeds were increased after soaking them in bacterial solution under no-stress, drought-stress, and salt-stress environments. In the potting experiments, seedlings in the experimental group inoculated with DY1-3 showed increased stem thicknesses, primary root length, numbers of root meristems, and plant height compared to control seedlings using sterile water. In the study on the physiological properties of the plants related to resistance to stress, the SOD, POD, CAT, and chlorophyll contents of the seedlings in the experimental group, to which the DY1-3 strain was applied, were higher than those of the control group of seedlings to which the bacterial solution was not applied. The addition of the bacterial solution reduced the content of MDA in the experimental group seedlings, which indicated that DY1-3 could positively affect the promotion of maize seedlings and seeds against abiotic stress. In this study, it was concluded that strain DY1-3 is a valuable strain for application, which can produce a variety of pro-biotic substances to promote plant growth in stress-free environments or to help plants resist abiotic stresses. In addition to this, the strain itself has good salt and drought tolerance, making it an option to help crops grown in saline soils to withstand abiotic stresses, and a promising candidate for future application in agricultural biofertilizers.

Silicon improves root system and canopy physiology in wheat under drought stress

AimsRoot system is an important regulator for unevenly distributed below-ground resource acquisition. In a rainfed cropping environment, drought stress (DS) significantly restricts root growth and moisture uptake capacity. The fact that silicon (Si) alleviates DS in wheat is widely reported, but its effects on the wheat root system remain unclear.MethodsThe present study investigated the effect of pre-sowing Si treatment on two contrasting wheat cultivars (RAC875, drought-tolerant; Kukri, drought-susceptible) at early growth stages. The cultivars were grown in a glasshouse in a complete randomized design with four replications and two watering treatments. Various root traits and physiological data, including non-destructive infrared thermal imaging for water stress indices, were recorded.ResultsUnder DS and Si (DSSi), Kukri had a significant increase in primary root length (PRL,44%) and lateral root length (LRL,28.1%) compared with RAC875 having a substantial increase in PRL (35.2%), but non-significant in LRL. The Si-induced improvement in the root system positively impacted canopy physiology and significantly enhanced photosynthesis, stomatal conductance and transpiration in Kukri and RAC875 under DSSi. Canopy temperature was reduced significantly in Kukri (4.24%) and RAC875 (6.15%) under DSSi, while canopy temperature depression was enhanced significantly in both the cultivars (Kukri,78.6%; RAC875, 58.6%) under DSSi.ConclusionThese results showed that Si has the potential to influence below-ground traits, which regulate the moisture uptake ability of roots for cooler canopy and improved photosynthesis under DS. It also suggests a future direction to investigate the underlying mechanisms involved in wheat’s Si-induced root growth and moisture uptake ability.