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Anuar MSK, Hashim AM, Ho CL, Wong MY, Sundram S, Saidi NB, Yusof MT. Synergism: biocontrol agents and biostimulants in reducing abiotic and biotic stresses in crop. World J Microbiol Biotechnol 2023; 39:123. [PMID: 36934342 DOI: 10.1007/s11274-023-03579-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/12/2023] [Indexed: 03/20/2023]
Abstract
In today's fast-shifting climate change scenario, crops are exposed to environmental pressures, abiotic and biotic stress. Hence, these will affect the production of agricultural products and give rise to a worldwide economic crisis. The increase in world population has exacerbated the situation with increasing food demand. The use of chemical agents is no longer recommended due to adverse effects towards the environment and health. Biocontrol agents (BCAs) and biostimulants, are feasible options for dealing with yield losses induced by plant stresses, which are becoming more intense due to climate change. BCAs and biostimulants have been recommended due to their dual action in reducing both stresses simultaneously. Although protection against biotic stresses falls outside the generally accepted definition of biostimulant, some microbial and non-microbial biostimulants possess the biocontrol function, which helps reduce biotic pressure on crops. The application of synergisms using BCAs and biostimulants to control crop stresses is rarely explored. Currently, a combined application using both agents offer a great alternative to increase the yield and growth of crops while managing stresses. This article provides an overview of crop stresses and plant stress responses, a general knowledge on synergism, mathematical modelling used for synergy evaluation and type of in vitro and in vivo synergy testing, as well as the application of synergism using BCAs and biostimulants in reducing crop stresses. This review will facilitate an understanding of the combined effect of both agents on improving crop yield and growth and reducing stress while also providing an eco-friendly alternative to agroecosystems.
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Affiliation(s)
- Muhammad Salahudin Kheirel Anuar
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, UPM, Selangor, 43400, Malaysia
| | - Amalia Mohd Hashim
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, UPM, Selangor, 43400, Malaysia
| | - Chai Ling Ho
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, UPM, Selangor, 43400, Malaysia
| | - Mui-Yun Wong
- Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, UPM, Selangor, 43400, Malaysia
| | - Shamala Sundram
- Biology Research Division, Malaysian Palm Oil Board, Kajang, Selangor, 43000, Malaysia
| | - Noor Baity Saidi
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, UPM, Selangor, 43400, Malaysia
| | - Mohd Termizi Yusof
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, UPM, Selangor, 43400, Malaysia.
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Ganugi P, Fiorini A, Tabaglio V, Capra F, Zengin G, Bonini P, Caffi T, Puglisi E, Trevisan M, Lucini L. The Functional Profile and Antioxidant Capacity of Tomato Fruits Are Modulated by the Interaction between Microbial Biostimulants, Soil Properties, and Soil Nitrogen Status. Antioxidants (Basel) 2023; 12:antiox12020520. [PMID: 36830078 PMCID: PMC9951999 DOI: 10.3390/antiox12020520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 02/12/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
The application of microbial biostimulants to plants has revealed positive effects related to nutrients uptake, stress tolerance, root development and phenological growth. However, little information is available exploiting the potential synergistic biostimulant action of microbes on the functional quality of the yields. The current research elucidated the effect of single or coupled action of biostimulants, associated with either optimal or reduced nitrogen application, on the functional quality of tomato fruits. Chemical assays and untargeted metabolomics were applied to investigate Rhizoglomus irregulare and Funneliformis mosseae administration (both being arbuscular mycorrhiza, AMF), under optimal or low N input conditions, alone or coupled to Trichoderma atroviride application. The coupling of AMF and Trichoderma fungal inoculations resulted in a synergistic biostimulant effect on tomato fruits under sub-optimal fertility, revealing improved concentrations of carotenoid compounds-B-carotene (0.647 ± 0.243 mg/100 g), Z-carotene (0.021 ± 0.021 mg/100 g), 13-z-lycopene (0.145 ± 0.052 mg/100 g) and all-trans-lycopene (12.586 ± 1.511 mg/100 g), and increased values for total phenolic content (12.9 ± 2.9 mgGAE/g), total antioxidant activity (phosphomolybdenum, 0.9 ± 0.2 mmolTE/g), radical scavenging activity (DPPH, 3.4 ± 3.7 mgTE/g), reducing power (FRAP, 23.6 ± 6.3 mgTE/g and CUPRAC, 37.4 ± 7.6 mg TE/g), and enzyme inhibitory activity (AChE, 2.4 ± 0.1 mg GALAE/g), when compared to control. However, evidence of carotenoid and bioactive compounds were exclusively observed under the sub-optimal fertility and no significant differences could be observed between the biostimulant treatment and control under optimal fertility.
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Affiliation(s)
- Paola Ganugi
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Andrea Fiorini
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Vincenzo Tabaglio
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Federico Capra
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Gokhan Zengin
- Department of Biology, Faculty of Science, Selcuk University, Konya Campus, 8300 Konya, Turkey
| | | | - Tito Caffi
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Edoardo Puglisi
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Marco Trevisan
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
| | - Luigi Lucini
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
- Correspondence:
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Mechanisms and Applications of Bacterial Inoculants in Plant Drought Stress Tolerance. Microorganisms 2023; 11:microorganisms11020502. [PMID: 36838467 PMCID: PMC9958599 DOI: 10.3390/microorganisms11020502] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 02/19/2023] Open
Abstract
Agricultural systems are highly affected by climatic factors such as temperature, rain, humidity, wind, and solar radiation, so the climate and its changes are major risk factors for agricultural activities. A small portion of the agricultural areas of Brazil is irrigated, while the vast majority directly depends on the natural variations of the rains. The increase in temperatures due to climate change will lead to increased water consumption by farmers and a reduction in water availability, putting production capacity at risk. Drought is a limiting environmental factor for plant growth and one of the natural phenomena that most affects agricultural productivity. The response of plants to water stress is complex and involves coordination between gene expression and its integration with hormones. Studies suggest that bacteria have mechanisms to mitigate the effects of water stress and promote more significant growth in these plant species. The underlined mechanism involves root-to-shoot phenotypic changes in growth rate, architecture, hydraulic conductivity, water conservation, plant cell protection, and damage restoration through integrating phytohormones modulation, stress-induced enzymatic apparatus, and metabolites. Thus, this review aims to demonstrate how plant growth-promoting bacteria could mitigate negative responses in plants exposed to water stress and provide examples of technological conversion applied to agroecosystems.
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Lakho MA, Jatoi MA, Solangi N, Abul-Soad AA, Qazi MA, Abdi G. Optimizing in vitro nutrient and ex vitro soil mediums-driven responses for multiplication, rooting, and acclimatization of pineapple. Sci Rep 2023; 13:1275. [PMID: 36690671 PMCID: PMC9870889 DOI: 10.1038/s41598-023-28359-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
A comprehensive study was carried out on in vitro multiplication and rooting using the medium enriched with different plant growth regulators and acclimatization of pineapple cv. 'Smooth Cayenne' using different soil growing substrates. The significantly highest shoot buds (Avg. 16.7) were obtained on the medium comprising 2.0 mg L-1 BA (6-Benzylaminopurine). Results showed that 1.0 mg L-1 IBA (Indole-3-butyric acid) increased the thickness and length of white adventitious roots and resulted in a significantly highest number of roots (Avg. 8) and root length (6.15 cm). Plantlets with healthy, multiple roots were transplanted in several soil combinations of river silt, bolhari (yellow sand), and peat moss. However, the significantly highest survival (100%) of plantlets in the greenhouse was obtained on the soil medium containing only peat moss. Furthermore, soil mixtures of bolhari and peat moss (1:1) and river silt alone exhibited 98.9% and 95.1% survivability of plantlets, which was also considered equally significant (at 5% probability level). The in vitro and ex vitro protocols optimized in the current study can be applied commercially for pineapple crop worldwide.
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Affiliation(s)
- Maqsood Ahmed Lakho
- Department of Botany/Date Palm Research Institute, Shah Abdul Latif University, Khairpur, Sindh, Pakistan
| | - Mushtaque Ahmed Jatoi
- Department of Botany/Date Palm Research Institute, Shah Abdul Latif University, Khairpur, Sindh, Pakistan.
| | - Najamuddin Solangi
- Department of Botany/Date Palm Research Institute, Shah Abdul Latif University, Khairpur, Sindh, Pakistan
| | - Adel Ahmed Abul-Soad
- Tropical Fruit Department, Horticulture Research Institute, Agricultural Research Center, Cairo, Egypt
| | - Muneer Ahmed Qazi
- Institute of Microbiology, Shah Abdul Latif University, Khairpur, Sindh, Pakistan
| | - Gholamreza Abdi
- Department of Biotechnology, Persian Gulf Research Institute, Persian Gulf University, Bushehr, 75169, Iran.
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Sani MNH, Yong JWH. Harnessing Synergistic Biostimulatory Processes: A Plausible Approach for Enhanced Crop Growth and Resilience in Organic Farming. BIOLOGY 2021; 11:biology11010041. [PMID: 35053039 PMCID: PMC8773105 DOI: 10.3390/biology11010041] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/24/2021] [Accepted: 12/26/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Demand for organically grown crops has risen globally due to its healthier and safer food products. From a sustainability perspective, organic farming offers an eco-friendly cultivation system that minimizes agrochemicals and producing food with little or no environmental footprint. However, organic agriculture’s biggest drawback is the generally lower and variable yield in contrast to conventional farming. Compatible with organic farming, the selective use of biostimulants can close the apparent yield gap between organic and conventional cultivation systems. A biostimulant is defined as natural microorganisms (bacteria, fungi) or biologically active substances that are able to improve plant growth and yield through several processes. Biostimulants are derived from a range of natural resources including organic materials (composts, seaweeds), manures (earthworms, fish, insects) and extracts derived from microbes, plant, insect or animal origin. The current trend is indicative that a mixture of biostimulants is generally delivering better growth, yield and quality rather than applying biostimulant individually. When used correctly, biostimulants are known to help plants cope with stressful situations like drought, salinity, extreme temperatures and even certain diseases. More research is needed to understand the different biostimulants, key components, and also to adjust the formulations to improve their reliability in the field. Abstract Demand for organically grown food crops is rising substantially annually owing to their contributions to human health. However, organic farm production is still generally lower compared to conventional farming. Nutrient availability, content consistency, uptake, assimilation, and crop responses to various stresses were reported as critical yield-limiting factors in many organic farming systems. In recent years, plant biostimulants (BSs) have gained much interest from researchers and growers, and with the objective of integrating these products to enhance nutrient use efficiency (NUE), crop performance, and delivering better stress resilience in organic-related farming. This review gave an overview of direct and indirect mechanisms of microbial and non-microbial BSs in enhancing plant nutrient uptake, physiological status, productivity, resilience to various stressors, and soil-microbe-plant interactions. BSs offer a promising, innovative and sustainable strategy to supplement and replace agrochemicals in the near future. With greater mechanistic clarity, designing purposeful combinations of microbial and non-microbial BSs that would interact synergistically and deliver desired outcomes in terms of acceptable yield and high-quality products sustainably will be pivotal. Understanding these mechanisms will improve the next generation of novel and well-characterized BSs, combining microbial and non-microbial BSs strategically with specific desired synergistic bio-stimulatory action, to deliver enhanced plant growth, yield, quality, and resilience consistently in organic-related cultivation.
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Affiliation(s)
- Md. Nasir Hossain Sani
- School of Natural Sciences, Bangor University, Bangor LL57 2DG, UK
- Correspondence: (M.N.H.S.); (J.W.H.Y.)
| | - Jean W. H. Yong
- Department of Biosystems and Technology, Swedish University of Agricultural Sciences, 234 56 Alnarp, Sweden
- Correspondence: (M.N.H.S.); (J.W.H.Y.)
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da Silva MSRDA, Dos Santos BDMS, da Silva CSRDA, da Silva CSRDA, Antunes LFDS, Dos Santos RM, Santos CHB, Rigobelo EC. Humic Substances in Combination With Plant Growth-Promoting Bacteria as an Alternative for Sustainable Agriculture. Front Microbiol 2021; 12:719653. [PMID: 34777275 PMCID: PMC8589081 DOI: 10.3389/fmicb.2021.719653] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
Plant growth-promoting bacteria (PGPB) and humic substances (HSs) are promising options for reducing the use of pesticides and mineral fertilizers. Although many studies have shown the effects of PGPB and HSs separately, little information is available on plant responses to the combined application of these biostimulants despite the great potential for the simultaneous action of these biological inputs. Thus, the objective of this review is to present an overview of scientific studies that addressed the application of PGPB and HSs to different crops. First, we discuss the effect of these biostimulants on biological nitrogen fixation, the various effects of the inoculation of beneficial bacteria combined with the application of HSs on promoting the growth of nonleguminous plants and how this combination can increase bacterial colonization of plant hosts. We also address the effect of PGPB and HSs on plant responses to abiotic stresses, in addition to discussing the role of HSs in protecting plants against pathogens. There is a lack of studies that address the role of PGPB + HSs in biocontrol. Understanding the factors involved in the promotion of plant growth through the application of PGPB and HSs can assist in the development of efficient biostimulants for agricultural management. This approach has the potential to accelerate the transition from conventional cultivation to sustainable agrosystems.
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Affiliation(s)
| | | | - Camilla Santos Reis de Andrade da Silva
- Department of Soil, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil.,National Agrobiology Research Center, Embrapa Agrobiologia, Seropédica, Brazil
| | | | | | | | | | - Everlon Cid Rigobelo
- Department of Agricultural Production Sciences, Universidade Estadual Paulista, Jaboticabal, Brazil
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Effect of Vermicompost on Growth, Plant Nutrient Uptake and Bioactivity of Ex Vitro Pineapple (Ananas comosus var. MD2). AGRONOMY-BASEL 2020. [DOI: 10.3390/agronomy10091333] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vermicompost is a nutrient-rich organic waste produced from earthworms that is beneficial in enhancing the soil condition and has been reported to aid in improving the crop yield and quality. In the present study, a field trial was conducted using a randomized complete block design with four replicates to elucidate the effects of vermicompost application (compared to supplementation with chemical fertilizer and no fertilizer) on the productivity of ex vitro MD2 pineapple plants. Vermicompost was applied on the sandy loam soils at transplanting followed by a second application at 7 months after planting (MAP) at the rate of 10 t·ha−1, while chemical fertilizer was applied based on the recommended cultivation practice. Data analysis revealed that there was no significant difference between the plants treated with vermicompost and chemical fertilizer in terms of the plant height, number of leaves, length and width of D-leaves, stomatal density and stomatal size. However, the fruits produced with vermicompost amendment were smaller in size but contained higher total soluble solids, titratable acidity, total solids, ascorbic acid and total chlorophyll content compared to the fruits produced from plants supplied with chemical fertilizer. Based on the DPPH, ABTS and FRAP assays, the methanolic fruit extracts from the control plants showed the highest antioxidant potential, followed by those of plants treated with vermicompost and chemical fertilizer. On the other hand, the application of vermicompost reduced soil acidity and produced macro- and micronutrient contents (N, P, K, Mg, Ca, S, Fe, Zn, B and Al) in the soil and plants that were comparable to or higher than those produced by the chemical fertilizer treatment. However, some of the nutrient contents observed in all treatments were lower than the recommended range for pineapple plant growth, suggesting that vermicompost or chemical fertilizer should not be used alone as a source of nutrients for ex vitro MD2 pineapple plants under these soil and field conditions. However, vermicompost can be used as a supplement to increase the fruit chemical quality and maintain the soil quality for agricultural sustainability.
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Khan MA, Asaf S, Khan AL, Jan R, Kang SM, Kim KM, Lee IJ. Extending thermotolerance to tomato seedlings by inoculation with SA1 isolate of Bacillus cereus and comparison with exogenous humic acid application. PLoS One 2020; 15:e0232228. [PMID: 32353077 PMCID: PMC7192560 DOI: 10.1371/journal.pone.0232228] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/09/2020] [Indexed: 12/12/2022] Open
Abstract
Heat stress is one of the major abiotic stresses that impair plant growth and crop productivity. Plant growth-promoting endophytic bacteria (PGPEB) and humic acid (HA) are used as bio-stimulants and ecofriendly approaches to improve agriculture crop production and counteract the negative effects of heat stress. Current study aimed to analyze the effect of thermotolerant SA1 an isolate of Bacillus cereus and HA on tomato seedlings. The results showed that combine application of SA1+HA significantly improved the biomass and chlorophyll fluorescence of tomato plants under normal and heat stress conditions. Heat stress increased abscisic acid (ABA) and reduced salicylic acid (SA) content; however, combined application of SA1+HA markedly reduced ABA and increased SA. Antioxidant enzymes activities revealed that SA1 and HA treated plants exhibited increased levels of ascorbate peroxidase (APX), superoxide dismutase (SOD), and reduced glutathione (GSH). In addition, heat stress markedly reduced the amino acid contents; however, the amino acids were increased with co-application of SA1+HA. Similarly, inductively-coupled plasma mass-spectrometry results showed that plants treated with SA1+HA exhibited significantly higher iron (Fe+), phosphorus (P), and potassium (K+) uptake during heat stress. Heat stress increased the relative expression of SlWRKY33b and autophagy-related (SlATG5) genes, whereas co-application of SA1+HA augmented the heat stress response and reduced SlWRKY33b and SlATG5 expression. The heat stress-responsive transcription factor (SlHsfA1a) and high-affinity potassium transporter (SlHKT1) were upregulated in SA1+HA-treated plants. In conclusion, current findings suggest that co-application with SA1+HA can be used for the mitigation of heat stress damage in tomato plants and can be commercialized as a biofertilizer.
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Affiliation(s)
- Muhammad Aaqil Khan
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Sajjad Asaf
- Natural and Medical Plants Research Center, University of Nizwa, Nizwa, Oman
| | - Abdul Latif Khan
- Natural and Medical Plants Research Center, University of Nizwa, Nizwa, Oman
| | - Rahmatullah Jan
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Sang-Mo Kang
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Kyung-Min Kim
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - In-Jung Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
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Integrated Use of Humic Acid and Plant Growth Promoting Rhizobacteria to Ensure Higher Potato Productivity in Sustainable Agriculture. SUSTAINABILITY 2019. [DOI: 10.3390/su11123417] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In sustainable agriculture, seeking eco-friendly methods to promote plant growth and improve crop productivity is a priority. Humic acid (HA) and plant growth promoting rhizobacteria (PGPR) are among the most effective methods that utilize natural biologically-active substances. The aim of the present study was to analyze the effect of the presence of HA on potato (Solanum tuberosum L.) inoculation with PGPR (Bacillus megatorium and Bacillus subtilis) when compared to control and recommended doses of NPK. Seed tubers treated by humic acid (200, 400, and 600 kg ha−1) and PGPR, separately or in combination, and NPK (50% and 100%) were planted into soil and untreated soil. Treatments were assessed for plant growth, classified tuber yields, quality, and mineral contents of potato tubers. There were highly significant increases in potato growth, tuber yields, and quality in PGPR and HA inoculated crops. Tuber size, weight, specific gravity, dry matter, starch, protein, and mineral contents (except Cu) were improved with PGPR treatments and further increased when administered with humic acids. Inoculation with PGPR mixed culture and 400 kg ha−1 HA increased total potato tuber yield by about 140% while conventional single treatment of 100% NPK fertilizer only led to an increase in potato production of 111% when compared to the control. The results demonstrated that this integrated approach has the potential to accelerate the transformation from conventional to sustainable potato production.
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Rouphael Y, Colla G. Synergistic Biostimulatory Action: Designing the Next Generation of Plant Biostimulants for Sustainable Agriculture. FRONTIERS IN PLANT SCIENCE 2018; 9:1655. [PMID: 30483300 PMCID: PMC6243119 DOI: 10.3389/fpls.2018.01655] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 10/25/2018] [Indexed: 05/18/2023]
Abstract
Over the past 10 years, interest in plant biostimulants (PBs) has been on the rise compelled by the growing interest of scientists, extension specialists, private industry, and growers in integrating these products in the array of environmentally friendly tools that secure improved crop performance and yield stability. Based on the new EU regulation PBs are defined through claimed agronomic effects, such as improvement of nutrient use efficiency, tolerance to abiotic stressors and crop quality. This definition entails diverse organic and inorganic substances and/or microorganisms such as humic acids, protein hydrolysates, seaweed extracts, mycorrhizal fungi, and N-fixing bacteria. The current mini-review provides an overview of the direct (stimulatory on C and N metabolism) and indirect (enhancing nutrient uptake and modulating root morphology) mechanisms by which microbial and non-microbial PBs improve nutrient efficiency, plant performance, and physiological status, resilience to environmental stressors and stimulate plant microbiomes. The scientific advances underlying synergistic and additive effects of microbial and non-microbial PBs are compiled and discussed for the first time. The review identifies several perspectives for future research between the scientific community and private industry to design and develop a second generation of PBs products (biostimulant 2.0) with specific biostimulatory action to render agriculture more sustainable and resilient.
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Affiliation(s)
- Youssef Rouphael
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
- *Correspondence: Youssef Rouphael, ;
| | - Giuseppe Colla
- Department of Agriculture and Forest Sciences, University of Tuscia, Viterbo, Italy
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Castro RA, Dourado MN, Almeida JRD, Lacava PT, Nave A, Melo ISD, Azevedo JLD, Quecine MC. Mangrove endophyte promotes reforestation tree (Acacia polyphylla) growth. Braz J Microbiol 2018; 49:59-66. [PMID: 28774638 PMCID: PMC5790640 DOI: 10.1016/j.bjm.2017.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 03/24/2017] [Accepted: 04/19/2017] [Indexed: 11/30/2022] Open
Abstract
Mangroves are ecosystems located in the transition zone between land and sea that serve as a potential source of biotechnological resources. Brazil's extensive coast contains one of the largest mangrove forests in the world (encompassing an area of 25,000km2 along all the coast). Endophytic bacteria were isolated from the following three plant species: Rhizophora mangle, Laguncularia racemosa and Avicennia nitida. A large number of these isolates, 115 in total, were evaluated for their ability to fix nitrogen and solubilize phosphorous. Bacteria that tested positive for both of these tests were examined further to determine their level of indole acetic acid production. Two strains with high indole acetic acid production were selected for use as inoculants for reforestation trees, and then the growth of the plants was evaluated under field conditions. The bacterium Pseudomonas fluorescens (strain MCR1.10) had a low phosphorus solubilization index, while this index was higher in the other strain used, Enterobacter sp. (strain MCR1.48). We used the reforestation tree Acacia polyphylla. The results indicate that inoculation with the MCR1.48 endophyte increases Acacia polyphylla shoot dry mass, demonstrating that this strain effectively promotes the plant's growth and fitness, which can be used in the seedling production of this tree. Therefore, we successfully screened the biotechnological potential of endophyte isolates from mangrove, with a focus on plant growth promotion, and selected a strain able to provide limited nutrients and hormones for in plant growth.
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Affiliation(s)
- Renata Assis Castro
- University of São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Department of Genetics, Piracicaba, SP, Brazil; University of São Paulo, Center for Nuclear Energy in Agriculture (CENA), Piracicaba, SP, Brazil
| | - Manuella Nóbrega Dourado
- University of São Paulo, Biomedical Science Institute, Department of Microbiology, São Paulo, SP, Brazil.
| | - Jaqueline Raquel de Almeida
- University of São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Department of Genetics, Piracicaba, SP, Brazil
| | - Paulo Teixeira Lacava
- Federal University of São Carlos (UFSCar), Center for Biological and Health Sciences, Department of Morphology and Pathology, São Carlos, SP, Brazil
| | - André Nave
- BIOFLORA Comercial LTDA, Piracicaba, SP, Brazil
| | - Itamar Soares de Melo
- EMBRAPA Environment, Laboratory of Environmental Microbiology, Jaguariuna, SP, Brazil
| | - João Lucio de Azevedo
- University of São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Department of Genetics, Piracicaba, SP, Brazil; University of São Paulo, Center for Nuclear Energy in Agriculture (CENA), Piracicaba, SP, Brazil
| | - Maria Carolina Quecine
- University of São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Department of Genetics, Piracicaba, SP, Brazil
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Farhat MB, Boukhris I, Chouayekh H. Mineral phosphate solubilization by Streptomyces sp. CTM396 involves the excretion of gluconic acid and is stimulated by humic acids. FEMS Microbiol Lett 2015; 362:fnv008. [PMID: 25743071 DOI: 10.1093/femsle/fnv008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The actinomycetes isolates (128) which were taken from agricultural soil samples and collected near a rock phosphate processing unit were screened for mineral phosphate-solubilizing (MPS) ability. A significant MPS activity was observed for 30 isolates on various phosphate sources when grown in the National Botanical Research Institute's phosphate broth. CTM396 and CTM397 strains which showed the highest MPS abilities were identified by 16S rDNA sequencing as members of the genus Streptomyces. Their MPS activity was proved to be concomitant with a drop in pH due to the secretion of gluconic acid (GA). This was correlated with the simultaneous detection by PCR of genes gdh [encoding the glucose dehydrogenase (GDH) responsible for GA production from glucose] and pqq (involved in biosynthesis of the pyrroloquinoline quinone cofactor of GDH), as well as the highlighting of GHD enzyme activity, for the first time in a Streptomyces sp. strain producing GA. Furthermore, the 0.05% of humic acids proved to have a stimulatory effect on the growth and the ability of CTM396 to solubilize Gafsa rock phosphate. According to this study, it is possible to use humic acids and Gafsa rock phosphate in association with spores of ad hoc Streptomyces strains as natural and efficient amendments to improve plant growth with no need of costly and pollutant transformation of Gafsa rock phosphate.
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Affiliation(s)
- Mounira Ben Farhat
- Laboratoire de Microorganismes et de Biomolécules, Centre de Biotechnologie de Sfax, Université de Sfax, BP '1177' 3018 Sfax, Tunisie
| | - Ines Boukhris
- Laboratoire de Microorganismes et de Biomolécules, Centre de Biotechnologie de Sfax, Université de Sfax, BP '1177' 3018 Sfax, Tunisie
| | - Hichem Chouayekh
- Laboratoire de Microorganismes et de Biomolécules, Centre de Biotechnologie de Sfax, Université de Sfax, BP '1177' 3018 Sfax, Tunisie
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