scholarly journals Biofilms Positively Contribute to Bacillus amyloliquefaciens 54-induced Drought Tolerance in Tomato Plants

2019 ◽  
Vol 20 (24) ◽  
pp. 6271 ◽  
Author(s):  
Da-Cheng Wang ◽  
Chun-Hao Jiang ◽  
Li-Na Zhang ◽  
Lin Chen ◽  
Xiao-Yun Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Root Colonization ◽  
Stomatal Closure ◽  
Defense Responses ◽  
Antioxidant Enzyme Activities ◽  
Elevated Concentration ◽  
Tomato Plants

Drought stress is a major obstacle to agriculture. Although many studies have reported on plant drought tolerance achieved via genetic modification, application of plant growth-promoting rhizobacteria (PGPR) to achieve tolerance has rarely been studied. In this study, the ability of three isolates, including Bacillus amyloliquefaciens 54, from 30 potential PGPR to induce drought tolerance in tomato plants was examined via greenhouse screening. The results indicated that B. amyloliquefaciens 54 significantly enhanced drought tolerance by increasing survival rate, relative water content and root vigor. Coordinated changes were also observed in cellular defense responses, including decreased concentration of malondialdehyde and elevated concentration of antioxidant enzyme activities. Moreover, expression levels of stress-responsive genes, such as lea, tdi65, and ltpg2, increased in B. amyloliquefaciens 54-treated plants. In addition, B. amyloliquefaciens 54 induced stomatal closure through an abscisic acid-regulated pathway. Furthermore, we constructed biofilm formation mutants and determined the role of biofilm formation in B. amyloliquefaciens 54-induced drought tolerance. The results showed that biofilm-forming ability was positively correlated with plant root colonization. Moreover, plants inoculated with hyper-robust biofilm (ΔabrB and ΔywcC) mutants were better able to resist drought stress, while defective biofilm (ΔepsA-O and ΔtasA) mutants were more vulnerable to drought stress. Taken altogether, these results suggest that biofilm formation is crucial to B. amyloliquefaciens 54 root colonization and drought tolerance in tomato plants.

scholarly journals Comparative Genomics Within the Bacillus Genus Reveal the Singularities of Two Robust Bacillus amyloliquefaciens Biocontrol Strains

2015 ◽  
Vol 28 (10) ◽  
pp. 1102-1116 ◽  
Author(s):  
M. C. Magno-Pérez-Bryan ◽  
P. M. Martínez-García ◽  
J. Hierrezuelo ◽  
P. Rodríguez-Palenzuela ◽  
E. Arrebola ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Communication Systems ◽  
Defense Mechanisms ◽  
Ad Hoc ◽  
Cell Communication ◽  
Defense Responses ◽  
Microbial Pathogens ◽  
Stimulate Plant Growth

Bacillus amyloliquefaciens CECT 8237 and CECT 8238, formerly known as Bacillus subtilis UMAF6639 and UMAF6614, respectively, contribute to plant health by facing microbial pathogens or inducing the plant’s defense mechanisms. We sequenced their genomes and developed a set of ad hoc scripts that allowed us to search for the features implicated in their beneficial interaction with plants. We define a core set of genes that should ideally be found in any beneficial Bacillus strain, including the production of secondary metabolites, volatile compounds, metabolic plasticity, cell-to-cell communication systems, and biofilm formation. We experimentally prove that some of these genetic elements are active, such as i) the production of known secondary metabolites or ii) acetoin and 2-3-butanediol, compounds that stimulate plant growth and host defense responses. A comparison with other Bacillus genomes permits us to find differences in the cell-to-cell communication system and biofilm formation and to hypothesize variations in their persistence and resistance ability in diverse environmental conditions. In addition, the major protection provided by CECT 8237 and CECT 8238, which is different from other Bacillus strains against bacterial and fungal melon diseases, permits us to propose a correlation with their singular genetic background and determine the need to search for additional blind biocontrol-related features.

scholarly journals Drought Stress in Grain Legumes: Effects, Tolerance Mechanisms and Management

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2374
Author(s):  
Marium Khatun ◽  
Sumi Sarkar ◽  
Farzana Mustafa Era ◽  
A. K. M. Mominul Islam ◽  
Md. Parvez Anwar ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Association Studies ◽  
Stomatal Closure ◽  
Grain Legumes ◽  
Grain Legume ◽  
Developmental Cycle ◽  
Genome Wide Association Studies ◽  
Tolerance Mechanisms ◽  
Drought Tolerant

Grain legumes are important sources of proteins, essential micronutrients and vitamins and for human nutrition. Climate change, including drought, is a severe threat to grain legume production throughout the world. In this review, the morpho-physiological, physio-biochemical and molecular levels of drought stress in legumes are described. Moreover, different tolerance mechanisms, such as the morphological, physio-biochemical and molecular mechanisms of legumes, are also reviewed. Moreover, various management approaches for mitigating the drought stress effects in grain legumes are assessed. Reduced leaf area, shoot and root growth, chlorophyll content, stomatal conductance, CO2 influx, nutrient uptake and translocation, and water-use efficiency (WUE) ultimately affect legume yields. The yield loss of grain legumes varies from species to species, even variety to variety within a species, depending upon the severity of drought stress and several other factors, such as phenology, soil textures and agro-climatic conditions. Closure of stomata leads to an increase in leaf temperature by reducing the transpiration rate, and, so, the legume plant faces another stress under drought stress. The biosynthesis of reactive oxygen species (ROS) is the most detrimental effect of drought stress. Legumes can adapt to the drought stress by changing their morphology, physiology and molecular mechanism. Improved root system architecture (RSA), reduced number and size of leaves, stress-induced phytohormone, stomatal closure, antioxidant defense system, solute accumulation (e.g., proline) and altered gene expression play a crucial role in drought tolerance. Several agronomic, breeding both conventional and molecular, biotechnological approaches are used as management practices for developing a drought-tolerant legume without affecting crop yield. Exogenous application of plant-growth regulators (PGRs), osmoprotectants and inoculation by Rhizobacteria and arbuscular mycorrhizal fungi promotes drought tolerance in legumes. Genome-wide association studies (GWASs), genomic selection (GS), marker-assisted selection (MAS), OMICS-based technology and CRISPR/Cas9 make the breeding work easy and save time in the developmental cycle to get resistant legumes. Several drought-resistant grain legumes, such as the chickpea, faba bean, common bean and pigeon pea, were developed by different institutions. Drought-tolerant transgenic legumes, for example, chickpeas, are developed by introgressing desired genes through breeding and biotechnological approaches. Several quantitative trait loci (QTLs), candidate genes occupying drought-tolerant traits, are identified from a variety of grain legumes, but not all are under proper implementation. Hence, more research should be conducted to improve the drought-tolerant traits of grain legumes for avoiding losses during drought.

scholarly journals miR2105 regulates ABA biosynthesis via OsbZIP86-OsNCED3 module to contribute to drought tolerance in rice

2021 ◽  
Author(s):  
Weiwei Gao ◽  
Mingkang Li ◽  
Songguang Yang ◽  
Chunzhi Gao ◽  
Yan Su ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Transgenic Rice ◽  
Crucial Role ◽  
Agronomic Traits ◽  
Stomatal Closure ◽  
Plant Tolerance ◽  
Rice Plants ◽  
Transgenic Rice Plants ◽  
Aba Biosynthesis

AbstractInduced abscisic acid (ABA) biosynthesis plays an important role in plant tolerance to abiotic stresses, including drought, cold and salinity. However, regulation pathway of the ABA biosynthesis in response to stresses is unclear. Here, we identified a rice miRNA, osa-miR2105 (miR2105), which plays a crucial role in ABA biosynthesis under drought stress. Analysis of expression, transgenic rice and cleavage site showed that OsbZIP86 is a target gene of miR2105. Subcellular localization and luciferase activity assays showed that OsbZIP86 is a nuclear transcription factor. In vivo and in vitro analyses showed that OsbZIP86 directly binds to the promoter of OsNCED3, and interacts with OsSAPK10, resulting in enhanced-expression of OsNCED3. Transgenic rice plants with knock-down of miR2105 or overexpression of OsbZIP86 showed higher ABA content, more tolerance to drought, a lower rate of water loss, more stomatal closure than wild type rice ZH11 under drought stress. These rice plants showed no penalty with respect to agronomic traits under normal conditions. By contrast, transgenic rice plants with miR2105 overexpression, OsbZIP86 downregulation, or OsbZIP86 knockout displayed less tolerance to drought stress and other phenotypes. Collectively, our results show that a regulatory network of ‘miR2105-OsSAPK10/OsbZIP86-OsNCED3’ control ABA biosynthesis in response to drought stress.One-sentence summary‘miR2105-OsbZIP86-OsNCED3’ module plays crucial role in mediating ABA biosynthesis to contribute to drought tolerance with no penalty with respect to agronomic traits under normal conditions.

scholarly journals Arabidopsis thaliana trehalose-6-phosphate phosphatase gene TPPI enhances drought tolerance by regulating stomatal apertures

2020 ◽  
Vol 71 (14) ◽  
pp. 4285-4297 ◽  
Author(s):  
Qingfang Lin ◽  
Song Wang ◽  
Yihang Dao ◽  
Jianyong Wang ◽  
Kai Wang
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Stomatal Closure ◽  
Primary Root ◽  
Stomatal Aperture ◽  
Wild Type ◽  
Trehalose Metabolism ◽  
Use Efficiency ◽  
Responsive Element ◽  
Primary Root Length

Abstract Transpiration occurs through stomata. The alteration of stomatal apertures in response to drought stress is an important process associated with water use efficiency (WUE). Trehalose-6-phosphate phosphatase (TPP) family genes have been reported to participate in adjustment of stomatal aperture. However, there have been no reports of the trehalose metabolism pathway genes improving WUE, and the upstream signalling pathway modulating these genes is not clear. Here, we demonstrate that a member of the TPP gene family, AtTPPI, confers drought resistance and improves WUE by decreasing stomatal apertures and improving root architecture. The reduced expression of AtTPPI caused a drought-sensitive phenotype, while its overexpression significantly increased drought tolerance. Abscisic acid (ABA)-induced stomatal closure experiments confirmed that AtTPPI mutation increased the stomatal aperture compared with that of wild-type plants; in contrast, overexpression plants had smaller stomatal apertures than those of wild-type plants. Moreover, AtTPPI mutation also caused stunted primary root length and compromised auxin transport, while overexpression plants had longer primary root lengths. Yeast one-hybrid assays showed that ABA-responsive element-binding factor1 (ABF1), ABF2, and ABF4 directly regulated AtTPPI expression. In summary, the way in which AtTPPI responds to drought stress suggests that AtTPPI-mediated stomatal regulation is an important mechanism to cope with drought stress and improve WUE.

scholarly journals 2R,3R-Butanediol, a Bacterial Volatile Produced by Pseudomonas chlororaphis O6, Is Involved in Induction of Systemic Tolerance to Drought in Arabidopsis thaliana

2008 ◽  
Vol 21 (8) ◽  
pp. 1067-1075 ◽  
Author(s):  
Song Mi Cho ◽  
Beom Ryong Kang ◽  
Song Hee Han ◽  
Anne J. Anderson ◽  
Ju-Young Park ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Root Colonization ◽  
Stomatal Closure ◽  
Primary Role ◽  
Pseudomonas Chlororaphis ◽  
Biotic And Abiotic Stresses ◽  
Arabidopsis Mutant ◽  
Mutant Lines ◽  
Reduced Water ◽  
Dependent Mechanism

Root colonization of plants with certain rhizobacteria, such as Pseudomonas chlororaphis O6, induces tolerance to biotic and abiotic stresses. Tolerance to drought was correlated with reduced water loss in P. chlororaphis O6-colonized plants and with stomatal closure, indicated by size of stomatal aperture and percentage of closed stomata. Stomatal closure and drought resistance were mediated by production of 2R,3R-butanediol, a volatile metabolite of P. chlororaphis O6. Root colonization with bacteria deficient in 2R,3R-butanediol production showed no induction of drought tolerance. Studies with Arabidopsis mutant lines indicated that induced drought tolerance required the salicylic acid (SA)-, ethylene-, and jasmonic acid-signaling pathways. Both induced drought tolerance and stomatal closure were dependent on Aba-1 and OST-1 kinase. Increases in free SA after drought stress of P. chlororaphis O6-colonized plants and after 2R,3R-butanediol treatment suggested a primary role for SA signaling in induced drought tolerance. We conclude that the bacterial volatile 2R,3R-butanediol was a major determinant in inducing resistance to drought in Arabidopsis through an SA-dependent mechanism.

Effects of exogenous abscisic acid on foliar anthocyanin accumulation and drought tolerance in purple rice

Biologia ◽  
2015 ◽  
Vol 70 (7) ◽  
Author(s):  
Parinyaphorn Ploenlap ◽  
Wattana Pattanagul
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Reproductive Organs ◽  
Antioxidant Enzyme Activities ◽  
Rice Cultivars ◽  
Anthocyanin Accumulation ◽  
Exogenous Aba ◽  
Antioxidant Mechanism ◽  
Effects Of Drought ◽  
Dpph Scavenging

AbstractThe effects of drought and exogenous ABA on foliar anthocyanin accumulation and its role in drought tolerance were studied in two purple rice cultivars GS. No. 00621 and GS. No. 21427. The seedlings were grown for 14 days and separated into four groups including control (well-watered), drought (withholding water), ABA (foliar sprayed with 20 mg L−1 ABA and well-watered), ABA and drought (foliar sprayed with 20 mg L−1 ABA and withholding water). Drought was imposed by withholding water for 7 days. The results showed that drought significantly reduced root and shoot growth in GS. No. 00621, while had little effect on GS. No. 21427. Drought stress also induced anthocyanin overaccumulation in GS. No. 21427, whereas its content was reduced in GS. No. 00621. Exogenous ABA had no effect on anthocyanin in both wellwatered and drought conditions in both cultivars. Higher anthocyanin in GS. No. 21427 was coincided with higher DPPH scavenging ability, antioxidant enzyme activities as well as higher relative water content. It is, therefore, concluded that drought-induced anthocyanin overaccumulation may be different between purple rice cultivars and anthocyanin is beneficial for the response to drought stress by protecting plant antioxidant mechanism. Unlike anthocyanin in plant reproductive organs, exogenous ABA has no effect on foliar anthocyanin accumulation in purple rice. It is possible that anthocyanin accumulation in leaf and reproductive organs may be regulated differently or triggered by different mechanisms.

scholarly journals Amplification of early drought responses caused by volatile cues emitted from neighboring plants

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jieyang Jin ◽  
Mingyue Zhao ◽  
Ting Gao ◽  
Tingting Jing ◽  
Na Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Density ◽  
Stomatal Closure ◽  
Induced Volatiles ◽  
Positive Regulators ◽  
Tea Plants ◽  
Aba Content ◽  
Volatile Cues

AbstractPlants have developed sophisticated mechanisms to survive in dynamic environments. Plants can communicate via volatile organic compounds (VOCs) to warn neighboring plants of threats. In most cases, VOCs act as positive regulators of plant defense. However, the communication and role of volatiles in response to drought stress are poorly understood. Here, we showed that tea plants release numerous VOCs. Among them, methyl salicylate (MeSA), benzyl alcohol, and phenethyl alcohol markedly increased under drought stress. Interestingly, further experiments revealed that drought-induced MeSA lowered the abscisic acid (ABA) content in neighboring plants by reducing 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, resulting in inhibition of stomatal closure and ultimately decreasing early drought tolerance in neighboring plants. Exogenous application of ABA reduced the wilting of tea plants caused by MeSA exposure. Exposure of Nicotiana benthamiana to MeSA also led to severe wilting, indicating that the ability of drought-induced MeSA to reduce early drought tolerance in neighboring plants may be conserved in other plant species. Taken together, these results provide evidence that drought-induced volatiles can reduce early drought tolerance in neighboring plants and lay a novel theoretical foundation for optimizing plant density and spacing.

scholarly journals Kandelia candel Thioredoxin f Confers Osmotic Stress Tolerance in Transgenic Tobacco

2020 ◽  
Vol 21 (9) ◽  
pp. 3335 ◽  
Author(s):  
Xiaoshu Jing ◽  
Jun Yao ◽  
Xujun Ma ◽  
Yanli Zhang ◽  
Yuanling Sun ◽  
...  
Keyword(s):  
Drought Stress ◽  
Transgenic Plants ◽  
Drought Tolerance ◽  
Osmotic Stress ◽  
Transgenic Tobacco ◽  
Stomatal Closure ◽  
H2o2 Production ◽  
Kandelia Candel ◽  
Ros Scavenging ◽  
Thioredoxin F

Water deficit caused by osmotic stress and drought limits crop yield and tree growth worldwide. Screening and identifying candidate genes from stress-resistant species are a genetic engineering strategy to increase drought resistance. In this study, an increased concentration of mannitol resulted in elevated expression of thioredoxin f (KcTrxf) in the nonsecretor mangrove species Kandelia candel. By means of amino acid sequence and phylogenetic analysis, the mangrove Trx was classified as an f-type thioredoxin. Subcellular localization showed that KcTrxf localizes to chloroplasts. Enzymatic activity characterization revealed that KcTrxf recombinant protein possesses the disulfide reductase function. KcTrxf overexpression contributes to osmotic and drought tolerance in tobacco in terms of fresh weight, root length, malondialdehyde (MDA) content, and hydrogen peroxide (H2O2) production. KcTrxf was shown to reduce the stomatal aperture by enhancing K+ efflux in guard cells, which increased the water-retaining capacity in leaves under drought conditions. Notably, the abscisic acid (ABA) sensitivity was increased in KcTrxf-transgenic tobacco, which benefits plants exposed to drought by reducing water loss by promoting stomatal closure. KcTrxf-transgenic plants limited drought-induced H2O2 in leaves, which could reduce lipid peroxidation and retain the membrane integrity. Additionally, glutathione (GSH) contributing to reactive oxygen species (ROS) scavenging and transgenic plants are more efficient at regenerating GSH from oxidized glutathione (GSSG) under conditions of drought stress. Notably, KcTrxf-transgenic plants had increased glucose and fructose contents under drought stress conditions, presumably resulting from KcTrxf-promoted starch degradation under water stress. We conclude that KcTrxf contributes to drought tolerance by increasing the water status, by enhancing osmotic adjustment, and by maintaining ROS homeostasis in transgene plants.

scholarly journals Contribution of Bacillomycin D in Bacillus amyloliquefaciens SQR9 to Antifungal Activity and Biofilm Formation

2012 ◽  
Vol 79 (3) ◽  
pp. 808-815 ◽  
Author(s):  
Zhihui Xu ◽  
Jiahui Shao ◽  
Bing Li ◽  
Xin Yan ◽  
Qirong Shen ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Root Colonization ◽  
Antagonistic Activity ◽  
Vital Role ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Bacillomycin D

ABSTRACTBacillus amyloliquefaciensstrains are capable of suppressing soilborne pathogens through the secretion of an array of lipopeptides and root colonization, and biofilm formation ability is considered a prerequisite for efficient root colonization. In this study, we report that one of the lipopeptide compounds (bacillomycin D) produced by the rhizosphere strainBacillus amyloliquefaciensSQR9 not only plays a vital role in the antagonistic activity againstFusarium oxysporumbut also affects the expression of the genes involved in biofilm formation. When the bacillomycin D and fengycin synthesis pathways were individually disrupted, mutant SQR9M1, which was deficient in the production of bacillomycin D, only showed minor antagonistic activity againstF. oxysporum, but another mutant, SQR9M2, which was deficient in production of fengycin, showed antagonistic activity equivalent to that of the wild-type strain ofB. amyloliquefaciensSQR9. The results fromin vitro, rootin situ, and quantitative reverse transcription-PCR studies demonstrated that bacillomycin D contributes to the establishment of biofilms. Interestingly, the addition of bacillomycin D could significantly increase the expression levels ofkinCgene, but KinC activation is not triggered by leaking of potassium. These findings suggest that bacillomycin D contributes not only to biocontrol activity but also to biofilm formation in strainB. amyloliquefaciensSQR9.

scholarly journals Sulfate-Based Fertilizers Regulate Nutrient Uptake, Photosynthetic Gas Exchange, and Enzymatic Antioxidants to Increase Sunflower Growth and Yield Under Drought Stress

2021 ◽  
Author(s):  
Bilal Ahamid Shafiq ◽  
Fahim Nawaz ◽  
Sadia Majeed ◽  
Muhammad Aurangzaib ◽  
Abdullah Al Mamun ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Nutrient Uptake ◽  
Photosynthetic Apparatus ◽  
Growth And Yield ◽  
Antioxidant Enzyme Activities ◽  
Guaiacol Peroxidase ◽  
Enzymatic Antioxidants ◽  
Photosynthetic Gas Exchange ◽  
Gypsum Application

AbstractThe challenging impact of drought to agricultural productivity requires the adoption of mitigation strategies with a better understanding of underlying mechanisms responsible for drought tolerance. The present study aimed at investigating the effects of sulfur-based fertilizers on mitigation of drought stress in sunflower. Sulfate-containing fertilizers, viz., ammonium sulfate, zinc sulfate, magnesium sulfate, potassium sulfate, and gypsum, were initially evaluated at two different rates (10 and 20 mg kg−1 soil equivalent to 20 and 40 kg ha−1, respectively) for nutrient uptake and growth-promoting traits in sunflower seedlings (cv. Hysun-33). The best performing fertilizer (gypsum) was then selected to evaluate the response of sunflower under drought stress imposed at flowering stage for three weeks (25–30% water holding capacity). Results indicated significant amelioration of drought stress with higher activity of photosynthetic apparatus, upregulation of antioxidative enzymes, and increased achene yield by gypsum application. In comparison to control, gypsum-treated plants (20 mg kg−1 soil) exhibited higher water status (32%), leaf photosynthetic rate (29%), transpiration rate (67%), and stomatal conductance (118%) under drought stress. The antioxidant enzyme activities of catalase, guaiacol peroxidase, and superoxide dismutase were also increased by 67%, 62%, and 126%, respectively, resulting in higher achene yield (19%) under water-deficit conditions. This study indicates that the application of sulfur-based fertilizers (gypsum) can be used to induce drought tolerance and obtain high sunflower yields under drought stress, and furthermore, it is a cost-effective strategy resulting in high benefit–cost ratio with respect to no gypsum application.

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