Aluminum Stress Research Articles

GmWRKY21, a Soybean WRKY Transcription Factor Gene, Enhances the Tolerance to Aluminum Stress in Arabidopsis thaliana.

The WRKY transcription factors (TFs) are one of the largest families of TFs in plants and play multiple roles in plant growth and development and stress response. In this study, GmWRKY21 encoding a WRKY transcription factor was functionally characterized in Arabidopsis and soybean. The GmWRKY21 protein containing a highly conserved WRKY domain and a C2H2 zinc-finger structure is located in the nucleus and has the characteristics of transcriptional activation ability. The GmWRKY21 gene presented a constitutive expression pattern rich in the roots, leaves, and flowers of soybean with over 6-fold of relative expression levels and could be substantially induced by aluminum stress. As compared to the control, overexpression of GmWRKY21 in Arabidopsis increased the root growth of seedlings in transgenic lines under the AlCl3 concentrations of 25, 50, and 100 μM with higher proline and lower MDA accumulation. The results of quantitative real-time polymerase chain reaction (qRT-PCR) showed that the marker genes relative to aluminum stress including ALMT, ALS3, MATE, and STOP1 were induced in GmWRKY21 transgenic plants under AlCl3 treatment. The stress-related genes, such as KIN1, COR15A, COR15B, COR47, GLOS3, and RD29A, were also upregulated in GmWRKY21 transgenic Arabidopsis under aluminum stress. Similarly, stress-related genes, such as GmCOR47, GmDREB2A, GmMYB84, GmKIN1, GmGST1, and GmLEA, were upregulated in hair roots of GmWRKY21 transgenic plants. In summary, these results suggested that the GmWRKY21 transcription factor may promote the tolerance to aluminum stress mediated by the pathways regulating the expression of the acidic aluminum stress-responsive genes and abiotic stress-responsive genes.

GsMYB7 encoding a R2R3-type MYB transcription factor enhances the tolerance to aluminum stress in soybean (Glycine max L.)

BackgroundMYB transcription factor (TF) is one of the largest families of TFs in plants and play essential roles in plant growth and development, and is involved in responses to biological and abiotic stress. However, there are few reports on GsMYB7 gene in soybean under aluminum acid stress, and its regulatory mechanism remains unclear.ResultsThe GsMYB7 protein is localized in the nucleus and has transcriptional activation ability. Quantitative real-time PCR (qRT-PCR) results showed that GsMYB7 held a constitutive expression pattern rich in roots. When AlCl3 concentration was 25 µM, the total root surface area (SA) of GsMYB7 transgenic lines were 34.97% higher than that of wild-type Huachun 6 (HC6). While the accumulation of Al3+ in root tip of transgenic plants after aluminum treatment was 17.39% lower than that of wild-type. RNA-sequencing analysis indicated that over 1181 genes were regulated by GsMYB7 and aluminum stress. Among all the regulated genes, the expression levels of glutathione peroxidase, protein kinase, cytochrome and other genes in the transgenic lines were significantly higher than those in wild type by acidic aluminum stress. The bioinformatics and qRT-PCR results showed that 9 candidate genes were induced under the treatments of acidic aluminum stress which were indirectly and/or directly regulated by GsMYB7. After AlCl3 treatments, the transcripts of these genes in GsMYB7 transgenic seedlings were significantly higher than those of wide-type HC6.ConclusionsThe results suggested that GsMYB7 may enhance soybean tolerance to acidic aluminum stress by regulating the downstream genes.

Malate-mediated CqMADS68 enhances aluminum tolerance in quinoa seedlings through interaction with CqSTOP6, CqALMT6 and CqWRKY88

Aluminum (Al) stress in acidic soils has severe negative effects on crop productivity. In this study, the alleviating effect and related mechanism of malate on Al stress in quinoa (Chenopodium quinoa) seedlings were investigated. The findings indicated that malate alleviated the growth inhibition of quinoa seedlings under Al stress, maintained the enzymatic and nonenzymatic antioxidant systems, and aided resistance to the damage caused by excessive reactive oxygen species (ROS). Under Al stress, malate significantly increased the contents of chlorophyll and carotenoids in quinoa shoots by 103.8% and 240.7%, and significantly increased the ratios of glutathione (GSH)/oxidized glutathione (GSSG), and ascorbate (AsA)/dehydroascorbate (DHA) in roots by 59.9% and 699.2%, respectively. However, malate significantly decreased the superoxide radical (O2•-), hydrogen peroxide (H2O2), malondialdehyde (MDA) and Al contents in quinoa roots under Al stress by 32.7%, 60.9%, 63.1% and 49%, respectively. Moreover, the CqMADS family and the Al stress-responsive gene families (CqSTOP, CqALMT, and CqWRKY) were identified from the quinoa genome. Comprehensive expression profiling identified CqMADS68 as being involved in malate-mediated Al resistance. Transient overexpression of CqMADS68 increased Al tolerance in quinoa seedlings. More importantly, we found that CqMADS68 regulated the expression of CqSTOP6, CqALMT6 and CqWRKY88 and further demonstrated the interaction of CqMADS68 with CqSTOP6, CqALMT6 and CqWRKY88 by bimolecular fluorescence complementation (BIFC) experiments. Moreover, transient overexpression and physiological and biochemical analyses demonstrated that CqSTOP6, CqALMT6 and CqWRKY88 could also improve Al tolerance by maintaining the antioxidant capacity of quinoa seedlings. Taken together, these findings reveal that CqMADS68, CqSTOP6, CqALMT6 and CqWRKY88 may be important contributors to the Al tolerance regulatory network in quinoa, providing new insights into Al stress resistance.

PROTECTIVE ROLE OF RESVERATROL AGAINST OXIDATIVESTRESS INDUCED BY ALUMINIUM AND FLUORIDE IN RAT BRAIN

Aluminium and Fluoride, known to form a strong complex, are being used widely in many industries. Both elements are involved in the pathogenesis of neurodegenerative disorders by inducing oxidative stress. Many experimental studies reported neuroprotective properties of resveratrol (Res). In this study, we examined the ameliorative effects of resveratrol on aluminiumfluoride-induced oxidative stress in the conventional and preclinical models. AlCl3 (100 mg/kg bw)+ NaF (10 mg/kg bw), AlCl3 (100 mg/kg bw) + NaF (10 mg/kg bw) + Res (30 mg/kg bw), and Res (30mg/kg bw) were administered for II, III and IV groups respectively and group-I was served as control for 8 weeks. The results showed considerable (p<0.05) alterations in protein content andoxidative markers (GPx, GST, GR, GSSH) in group-II whereas a significant (p<0.05) reversal was observed in group III. Taken together, the above findings indicate that resveratrol significantly alleviated the aluminium and fluoride-induced oxidative stress through its ameliorative efficacy.

Identification of aluminum-activated malate transporters (ALMT) family genes in hydrangea and functional characterization of HmALMT5/9/11 under aluminum stress.

Hydrangea (Hydrangea macrophylla (Thunb.) Ser.) is a famous ornamental plant species with high resistance to aluminum (Al). The aluminum-activated malate transporter (ALMT) family encodes anion channels, which participate in many physiological processes, such as Al tolerance, pH regulation, stomatal movement, and mineral nutrition. However, systematic studies on the gene family have not been reported in hydrangea. In this study, 11 candidate ALMT family members were identified from the transcriptome data for hydrangea, which could be divided into three clusters according to the phylogenetic tree. The protein physicochemical properties, phylogeny, conserved motifs and protein structure were analyzed. The distribution of base conservative motifs of HmALMTs was consistent with that of other species, with a highly conserved WEP motif. Furthermore, tissue-specific analysis showed that most of the HmALMTs were highly expressed in the stem under Al treatment. In addition, overexpression of HmALMT5, HmALMT9 and HmALMT11 in yeasts enhanced their tolerance to Al stress. Therefore, the above results reveal the functional role of HmALMTs underlying the Al tolerance of hydrangea. The present study provides a reference for further research to elucidate the functional mechanism and expression regulation of the ALMT gene family in hydrangea.

Arabidopsis ETHYLENE INSENSITIVE 3 directly regulates the expression of PG1β-like family genes in response to aluminum stress.

The genes in the subfamily PG1β (beta subunit of poly-galacturonase isoenzyme 1) have a clear effect on the biosynthesis pathway of pectin, a main component of the cell wall. However, the detailed functions of the PG1β-like gene members in Arabidopsis (AtPG1-3) have not yet been determined. In this study, we investigated their functional roles in response to aluminum (Al) stress. Our results indicate that the PG1β-like gene members are indeed involved in the Al-stress response and they can modulate its accumulation in roots to achieve optimum root elongation and hence better seedling growth. We found that transcription factor EIN3 (ETHYLENE INSENSITIVE 3) alters pectin metabolism and the EIN3 gene responds to Al stress to affect the pectin content in the root cell walls, leading to exacerbation of the inhibition of root growth, as reflected by the phenotypes of overexpressing lines. We determined that EIN3 can directly bind to the promoter regions of PG1-3, which act downstream of EIN3. Thus, our results show that EIN3 responds to Al stress in Arabidopsis directly through regulating the expression of PG1-3. Hence, EIN3 mediates their functions by acting as a biomarker in their molecular biosynthesis pathways, and consequently orchestrates their biological network in response to Al stress.

Transcriptome Analysis of Response to Aluminum Stress in Pinus massoniana

Pinus massoniana is a vital kind of coniferous species rich in rosin. Aluminum stress is a severe problem for P. massoniana growth in acidic soil causing root poisoning. However, the molecular mechanisms of aluminum-responsive are still unclear. We performed a transcriptome analysis of the P. massoniana root in response to aluminum stress. Through WGCNA analysis, we identified 338 early and 743 late response genes to aluminum stress. Gene Ontology analysis found many critical functional pathways, such as carbohydrate binding, cellulase activity, and phenylalanine ammonia-lyase activity. In addition, KEGG analysis revealed a significant enrichment of phenylpropanoid biosynthesis pathways. Further analysis showed that the expression of lignin synthesis genes 4CL, CAD, and COMT were up-regulated, indicating that they may play a crucial role in the process of aluminum tolerance in P. massoniana roots. These results provide method support for studying the regulation mechanism of P. massoniana aluminum stress.

GsERF1 enhances Arabidopsis thaliana aluminum tolerance through an ethylene-mediated pathway

Ethylene response factor (ERF) transcription factors constitute a subfamily of the AP2/ERF superfamily in plants and play multiple roles in plant growth and development as well as in stress responses. In this study, the GsERF1 gene from the wild soybean BW69 line (an Al-resistant Glycine soja line) was rapidly induced in response to aluminum stress. Quantitative real-time PCR (qRT–PCR) analysis showed that the GsERF1 gene maintained a constitutive expression pattern and was induced in soybean in response to aluminum stress, with increased amounts of transcripts detected in the roots. The putative GsERF1 protein, which contains an AP2 domain, was located in the nucleus and maintained transactivation activity. In addition, under AlCl3 treatment, GsERF1 overexpression increased the relative growth rate of the roots of Arabidopsis and weakened the hematoxylin staining of hairy roots. Ethylene synthesis-related genes such as ACS4, ACS5 and ACS6 were upregulated in GsERF1 transgenic lines compared with the wild type under AlCl3 treatment. Furthermore, the expression levels of stress/ABA-responsive marker genes, including ABI1, ABI2, ABI4, ABI5 and RD29B, in the GsERF1 transgenic lines were affected by AlCl3 treatment, unlike those in the wild type. Taken together, the results indicated that overexpression of GsERF1 may enhance aluminum tolerance of Arabidopsis through an ethylene-mediated pathway and/or ABA signaling pathway, the findings of which lay a foundation for breeding soybean plants tolerant to aluminum stress.

Genome-Wide Identification and Transcriptional Expression Profiles of PP2C in the Barley (Hordeum vulgare L.) Pan-Genome.

The gene family protein phosphatase 2C (PP2C) is related to developmental processes and stress responses in plants. Barley (Hordeum vulgare L.) is a popular cereal crop that is primarily utilized for human consumption and nutrition. However, there is little knowledge regarding the PP2C gene family in barley. In this study, a total of 1635 PP2C genes were identified in 20 barley pan-genome accessions. Then, chromosome localization, physical and chemical feature predictions and subcellular localization were systematically analyzed. One wild barley accession (B1K-04-12) and one cultivated barley (Morex) were chosen as representatives to further analyze and compare the differences in HvPP2Cs between wild and cultivated barley. Phylogenetic analysis showed that these HvPP2Cs were divided into 12 subgroups. Additionally, gene structure, conserved domain and motif, gene duplication event detection, interaction networks and gene expression profiles were analyzed in accessions Morex and B1K-04-12. In addition, qRT-PCR experiments in Morex indicated that seven HvMorexPP2C genes were involved in the response to aluminum and low pH stresses. Finally, a series of positively selected homologous genes were identified between wild accession B1K-04-12 and another 14 cultivated materials, indicating that these genes are important during barley domestication. This work provides a global overview of the putative physiological and biological functions of PP2C genes in barley. We provide a broad framework for understanding the domestication- and evolutionary-induced changes in PP2C genes between wild and cultivated barley.

Evolution of phosphate metabolism in Tibetan wild barley to adapt to aluminum stress

Evolution of phosphate metabolism in Tibetan wild barley to adapt to aluminum stress

Integrative Transcriptomics and Proteomics Elucidate the Regulatory Mechanism of Hydrangea macrophylla Flower-Color Changes Induced by Exogenous Aluminum

The mechanism through which Hydrangea macrophylla are able to change color has been the focus of investigation for many studies. However, the molecular mechanism involved in the complexation of aluminum ions and anthocyanins to regulate the color change remains unclear. Here, the color-changing mechanism was investigated in Hydrangea macrophylla plants under aluminum stress using proteome and transcriptome sequencing methods. Catalase, peroxidase, superoxide dismutase, 3-O-delphinidin and Al3+ contents in sepal were significantly upregulated upon Al3+ treatment. Moreover, 1628 differentially expressed genes and 448 differentially expressed proteins were identified between the treated and untreated conditions. GO and KEGG enrichment analyses revealed that the differentially expressed genes and differentially expressed proteins were enriched in categories related to the cell wall, peroxidase activity, and peroxisome pathways. Importantly, eight genes involved in anthocyanin biosynthesis were significantly downregulated at the transcript and protein levels under aluminum stress. These results suggest that aluminum ions induce expression changes of related key genes, which regulate the hydrangea’s flower color. Overall, this study provides a valuable reference for the molecular mechanism relating to the color change and adaptation of Hydrangea macrophylla in response to aluminum stress.

Genome-wide identification and expression analysis of the AhTrx family genes in peanut

Thioredoxins (Trx) are small multifunctional redox proteins that contain thioredoxin conserved domain and active site WCXXC. The Trx family has an important role in multiple processes, including electron transport, seed germination, redox regulation, biotic and abiotic stresses resistance, etc. Although Trx genes have been extensively characterized in some plants, they have not been reported in peanut until now. The identification of AhTrx genes provides potential candidate genes for studying their effects and regulatory mechanisms in peanut (Arachis hypogaea L.) growth and development, especially under aluminium (Al) stress. It is also helpful to further analyze the Al resistance pathway in plants. Seventy AhTrx genes were identified using a genome-wide search method and conservative domain analysis. Then the basic physicochemical properties, phylogenetic relationship, gene structure, chromosomal localization, and promoter prediction were studied by the bioinformatic methods. Furthermore, the expressions of AhTrx genes under different Al treatment times in two peanut cultivars were tested using a real-time quantitative polymerase chain reaction. Seventy AhTrx genes were identified and characterized. Phylogenetic tree analysis showed that all AhTrx members could be classified into 9 groups with different conserved domains. Motif 1 was found to exist in every sequence, with an active site. Furthermore, the gene structures showed that the AhTrx family was complicated and changeable during evolution. The chromosomal localization indicated that the distribution and density of the Trx family on 20 peanut chromosomes were uneven. Predictive promoter analysis indicated that AhTrx proteins might play a role in phytohormones synthesis and stress response. Finally, the expression patterns of the AhTrx genes showed that every gene was differently expressed under Al treatment in different peanut cultivars, some were obvious, others had no significant difference, some were at a high level, while others were at a low level. This study systematically identifies the Trx gene family in peanut, providing some candidates for further study on its effects and regulatory mechanism under Al stress in peanut.

The influence of milling induced residual stress on fatigue life of aluminum alloys

The effect of machining strategies on the surface integrity have received minimal consideration as this fluid situation develops, specifically, the machining induced residual stress generated in the material during milling. This study investigates the presence of machining induced residual stress in Aluminum 7075 and its effects on fatigue life. The testing consists of a layer removal process to measure residual stress followed by a three-point bending fatigue test. The study finds that an increase in feed per tooth in combination with a reduction in cutting speed increases compressive residual stress at the surface in the material. The fatigue testing concludes that this increase in compressive stress improves fatigue life with varying effects on long crack and short crack propagation.

Repression of Mitochondrial Citrate Synthase Genes by Aluminum Stress in Roots of Secale cereale and Brachypodium distachyon.

Aluminum (Al) toxicity in acid soils influences plant development and yield. Almost 50% of arable land is acidic. Plants have evolved a variety of tolerance mechanisms for Al. In response to the presence of Al, various species exudate citrate from their roots. Rye (Secale cereale L.) secretes both citrate and malate, making it one of the most Al-tolerant cereal crops. However, no research has been done on the role of the mitochondrial citrate synthase (mCS) gene in Al-induced stress in the rye. We have isolated an mCS gene, encoding a mitochondrial CS isozyme, in two S. cereale cultivars (Al-tolerant cv. Ailés and Al-sensitive inbred rye line Riodeva; ScCS4 gene) and in two Brachypodium distachyon lines (Al-tolerant ABR8 line and Al-sensitive ABR1 line; BdCS4 gene). Both mCS4 genes have 19 exons and 18 introns. The ScCS4 gene was located on the 6RL rye chromosome arm. Phylogenetic studies using cDNA and protein sequences have shown that the ScCS4 gene and their ScCS protein are orthologous to mCS genes and CS proteins of different Poaceae plants. Expression studies of the ScCS4 and BdSC4 genes show that the amount of their corresponding mRNAs in the roots is higher than that in the leaves and that the amounts of mRNAs in plants treated and not treated with Al were higher in the Al-tolerant lines than that in the Al-sensitive lines of both species. In addition, the levels of ScCS4 and BdCS4 mRNAs were reduced in response to Al (repressive behavior) in the roots of the tolerant and sensitive lines of S. cereale and B. distachyon.

Cloning and functional characterization of a citrate synthase gene of Rhododendron micranthum Turcz

Citrate synthase (CS) is a rate-limiting enzyme in tricarboxylic acid (TCA) cycle, which is related to numerous plant physiological events, like mitochondrial energy metabolism and stress resistance, and has a key function in aluminum (Al) stress response. Rhododendron micranthum Turcz. has been used as ornamental plants worldwide. This species prefers acidic soils, and thus its growth and ornamental quality are often limited by Al toxicity. In the present work, the full-length cDNA encoding a CS (here designated RmCS) was isolated and characterized. The RmCS contained the conserved CS domain and a N-terminal PWPN-box. RmCS protein was predicted to be localized to the cytoplasm and mitochondria. A neighbor-joining tree indicated that RmCS was similar to CS proteins of Actinidia chinensis var. chinensis and Vitis riparia the most. RmCS was highly expressed in stems; particularly, it shows predominant expression in flowers in the first flowering period, whereas in leaves peak expression levels were detected in September. Southern blotting analysis demonstrated that one to three copies of RmCS were successfully integrated in the genome of transgenic tobacco. Overexpression of RmCS significantly increased salt, alkali, drought, and Al tolerance, but reduced the plant height and leaf area, of transgenic tobacco. Roots of RmCS-overexpressing tobacco plants secreted higher concentrations of malic acid, citric acid, and tartaric acid. Decreased malonaldehyde while elevated proline contents in the leaf suggested that the improved abiotic stress tolerance conferred by RmCS was associated with decreased membrane damage and improved osmotic adjustment. The above findings indicated the potentially vital function of RmCS in abiotic stress responses of R. micranthum, and lays certain theoretical foundation for improving stress resistance of R. micranthum.

Seed priming with pyroligneous acid mitigates aluminum stress, and promotes tomato seed germination and seedling growth

Aluminum (Al) toxicity in acidic soils is a major constraint for seed germination and crop growth. Pyroligneous acid (PA) is rich in bioactive compounds that can enhance crop growth and tolerance to environmental stresses including toxic trace elements, but under studied. In this study, we investigated the effect of tomato (Solanum lycopersicum L. ‘Scotia’) seed priming with different rates of PA (i.e., 0, 0.5:100, 1:100, 1:300, 1:600, 1:900, 1:1200, and 2:100 PA/ddH2O (v/v)) on germination and seedling growth under different growing medium Al concentrations (i.e., 0, 0.5, and 1.25 mM aluminum chloride termed Al). The results showed that priming tomato seed with 2:100 PA for 24 hr significantly (p < 0.01) enhanced seed germination indices and seedling growth. PA significantly (p < 0.05) improved seed germination index and seedling vigor irrespective of the imposed Al stress compared to the control, but not seed germination percentage. Priming with PA also increased the total lengths and surface areas of seedling hypocotyls and roots, root volume, and seedling fresh weight. In most cases, seedling growth of both the control and the PA primed groups were not affected by the 0.5 mM Al. Additionally, hydrogen peroxide and malonaldehyde contents of seedlings were reduced while proline and soluble protein contents were significantly (p < 0.001) increased in PA primed seedlings compared to the control. Furthermore, PA-primed seedlings exhibited enhanced peroxidase (POD) activities, and relatively high expression of auxin response factor and antioxidant genes (i.e., glutathione reductase, POD, superoxide dismutase, catalase, and ascorbate peroxidase 1). These findings suggest that seed priming with PA can mitigates Al stress, and improve tomato seed germination and seedling growth via improving antioxidant defense system against Al-induced oxidative stress. Future studies will be required to investigate molecular mechanisms.

Transcription Factor Crz1 from Cryptococcus humicola Conferred Aluminum Resistance and Interacted with Calcineurin.

Calcineurin was activated by aluminum stress and increased aluminum resistance. To investigate how the calcineurin pathway regulates aluminum stress in Cryptococcus humicola, the expressions of Crz1 under stresses were analyzed by quantitative real-time PCR. Calcium, cadmium, and aluminum induced the expression of Crz1. Cna1, calcineurin catalytic subunit A (CNA1) encoding gene, was constructed into pGBKT7 and Crz1 gene was constructed into pGADT7. The resultant plasmids, pGADT7-Crz1 and pGBKT7-Cna1, were transformed into Y2HGold and Y187 yeast strain, respectively. Yeast two-hybridization results showed an interaction between CNA1 and Crz1. The role of Crz1 gene in stresses resistance including hydrogen peroxide, calcium, cadmium, and aluminum was assayed by constructing transgenic yeast. The growth of Crz1 transgenic yeasts was much better than that of the control yeast under these stress conditions. These results suggested that Crz1 participated in resistance to stresses and Crz1 showed an interaction with CNA1.

Involvement of cytokinins in STOP1-mediated resistance to proton toxicity

STOP1 (sensitive to proton rhizotoxicity1) is a master transcription factor that governs the expression of a set of regulatory and structural genes involved in resistance to aluminum and low pH (i.e., proton) stresses in Arabidopsis. However, the mechanisms and regulatory networks underlying STOP1-mediated resistance to proton stresses are largely unclear. Here, we report that low-pH stresses severely inhibited root growth of the stop1 plants by suppressing root meristem activities. Interestingly, the stop1 plants were less sensitive to exogenous cytokinins at normal and low pHs than the wild type. Significantly, low concentrations of cytokinins promoted root growth of the stop1 mutant under low-pH stresses. Moreover, lateral and adventitious root formation was stimulated in stop1 and by low-pH stresses but suppressed by cytokinins. Further studies of the expression patterns of a cytokinin signaling reporter suggest that both the loss-of-function mutation of STOP1 and low-pH stresses suppressed cytokinin signaling outputs in the root. Furthermore, the expression of critical genes involved in cytokinin biosynthesis, biodegradation, and signaling is altered in the stop1 mutant in response to low-pH stresses. In conclusion, our results reveal a complex network of resistance to low-pH stresses, which involves coordinated actions of STOP1, cytokinins, and an additional low-pH-resistant mechanism for controlling root meristem activities and root growth upon proton stresses.

An Evaluation of Aluminum Tolerant Pseudomonas aeruginosa A7 for In Vivo Suppression of Fusarium Wilt of Chickpea Caused by Fusarium oxysporum f. sp. ciceris and Growth Promotion of Chickpea.

Chickpea wilt, caused by Fusarium oxysporum f. sp. ciceris, is a disease that decreases chickpea productivity and quality and can reduce its yield by as much as 15%. A newly isolated, moss rhizoid-associated Pseudomonas aeruginosa strain A7, demonstrated strong inhibition of Fusarium oxysporum f. sp. ciceris growth. An in vitro antimicrobial assay revealed A7 to suppress the growth of several fungal and bacterial plant pathogens by secreting secondary metabolites and by producing volatile compounds. In an in vivo pot experiment with Fusarium wilt infection in chickpea, the antagonist A7 exhibited a disease reduction by 77 ± 1.5%, and significantly reduced the disease incidence and severity indexes. Furthermore, A7 promoted chickpea growth in terms of root and shoot length and dry biomass during pot assay. The strain exhibited several traits associated with plant growth promotion, extracellular enzymatic production, and stress tolerance. Under aluminum stress conditions, in vitro growth of chickpea plants by A7 resulted in a significant increase in root length and plant biomass production. Additionally, hallmark genes for antibiotics production were identified in A7. The methanol extract of strain A7 demonstrated antimicrobial activity, leading to the identification of various antimicrobial compounds based on retention time and molecular weight. These findings strongly suggest that the strain’s significant biocontrol potential and plant growth enhancement could be a potential environmentally friendly process in agricultural crop production.

Boron-mediated aluminium stress tolerance under aluminium toxicity at germination and early seedling stages of wheat

Aluminium stress is one of the major problems of wheat production that significantly reduces the growth and development. Al toxicity can be recovered by exogenous application of different growth inducing nutrient elements. Thus, this study was conducted to evaluate the ameliaration effect of B under Al toxicity. Therefore, a petri dish and hydroponic culture experiment of wheat was conducted at Crop Physiology Laboratory, Department of Crop Botany, Bangladesh Agricultural University, Mymensingh during the period from January 2016 to February 2017 to investigate the effect of boron on amelioration of aluminium toxicity in germination and seedling stage. Both the experiments were designed in completely randomized design (CRD) with three replications. The experiments were comprised of four levels of boron and aluminium concentrations viz., 0 µM B + 0 µM Al (control), 0 µM Al + 40 µM B, 200 µM Al + 40 µM B and 0 µM B + 200 µM Al and five wheat varieties viz; BARI Gom-23, BARI Gom-24, BARI Gom-28, BARI Gom-27 and BARI Gom-30. Results indicated that germination percentage, radicle and plumule length, root and shoot length, leaf length, fresh and dry mass plant-1 were greater in 0 µM Al + 40 µM B treated plants than 0 µM B + 200 µM Al induced conditions. It indicates that wheat seedlings are susceptible to aluminium and boron can ameliorate aluminium toxicity. However, among the studied varieties, the reduction of dry mass under aluminium stress was minimum in BARI Gom-28 followed by BARI Gom-23 indicating BARI Gom-28 was more tolerant to aluminium stress than the other varieties. On the contrary, the varieties, BARI Gom-27 and BARI Gom-24 were more susceptible to aluminium stress. So it indicates that aluminium stress severely affects the growth and developments especially in the sensitive varieties and tolerant varieties have the self-ability to grow and develop even under aluminium stress condition.&#x0D; Progressive Agriculture 32 (2): 127-139, 2021