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Zahra ST, Tariq M, Abdullah M, Zafar M, Yasmeen T, Shahid MS, Zaki HEM, Ali A. Probing the potential of salinity-tolerant endophytic bacteria to improve the growth of mungbean [ Vigna radiata (L.) Wilczek]. Front Microbiol 2023; 14:1149004. [PMID: 38111636 PMCID: PMC10725929 DOI: 10.3389/fmicb.2023.1149004] [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: 01/20/2023] [Accepted: 11/15/2023] [Indexed: 12/20/2023] Open
Abstract
Soil salinity is one of the major limiting factors in plant growth regulation. Salinity-tolerant endophytic bacteria (STEB) can be used to alleviate the negative effects of salinity and promote plant growth. In this study, thirteen endophytic bacteria were isolated from mungbean roots and tested for NaCl salt-tolerance up to 4%. Six bacterial isolates, TMB2, TMB3, TMB5, TMB6, TMB7 and TMB9, demonstrated the ability to tolerate salt. Plant growth-promoting properties such as phosphate solubilization, indole-3-acetic acid (IAA) production, nitrogen fixation, zinc solubilization, biofilm formation and hydrolytic enzyme production were tested in vitro under saline conditions. Eight bacterial isolates indicated phosphate solubilization potential ranging from 5.8-17.7 μg mL-1, wherein TMB6 was found most efficient. Ten bacterial isolates exhibited IAA production ranging from 0.3-2.1 μg mL-1, where TMB7 indicated the highest potential. All the bacterial isolates except TMB13 exhibited nitrogenase activity. Three isolates, TMB6, TMB7 and TMB9, were able to solubilize zinc on tris-minimal media. All isolates were capable of forming biofilm except TMB12 and TMB13. Only TMB2, TMB6 and TMB7 exhibited cellulase activity, while TMB2 and TMB7 exhibited pectinase production. Based on in vitro testing, six efficient STEB were selected and subjected to the further studies. 16S rRNA gene sequencing of efficient STEB revealed the maximum similarity between TMB2 and Rhizobium pusense, TMB3 and Agrobacterium leguminum, TMB5 and Achromobacter denitrificans, TMB6 and Pseudomonas extremorientalis, TMB7 and Bradyrhizobium japonicum and TMB9 and Serratia quinivorans. This is the first international report on the existence of A. leguminum, A. denitrificans, P. extremorientalis and S. quinivorans inside the roots of mungbean. Under controlled-conditions, inoculation of P. extremorientalis TMB6, B. japonicum TMB7 and S. quinivorans TMB9 exhibited maximum potential to increase plant growth parameters; specifically plant dry weight was increased by up to 52%, 61% and 45%, respectively. Inoculation of B. japonicum TMB7 displayed the highest potential to increase plant proline, glycine betaine and total soluble proteins contents by 77%, 78% and 64%, respectively, compared to control under saline conditions. It is suggested that the efficient STEB could be used as biofertilizers for mungbean crop productivity under saline conditions after field-testing.
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Affiliation(s)
- Syeda Tahseen Zahra
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Mohsin Tariq
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Muhammad Abdullah
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Marriam Zafar
- Department of Bioinformatics and Biotechnology, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Tahira Yasmeen
- Department of Environmental Sciences, Government College University Faisalabad, Faisalabad, Punjab, Pakistan
| | - Muhammad Shafiq Shahid
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
| | - Haitham E. M. Zaki
- Horticulture Department, Faculty of Agriculture, Minia University, El-Minia, Egypt
- Applied Biotechnology Department, University of Technology and Applied Sciences-Sur, Sur, Oman
| | - Amanat Ali
- Nuclear Institute of Agriculture (NIA), Tandojam, Pakistan
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Ali M, Sharif M, Ahmed I. Enhancement of Wheat Productivity and Zinc Accumulation Through Integrated Use of Zinc and Beneficial Microbes Under Irrigated and Rainfed Conditions. COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2023:1-12. [DOI: 10.1080/00103624.2023.2274034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 10/11/2023] [Indexed: 02/07/2024]
Affiliation(s)
- Murad Ali
- Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar, Pakistan
| | - Muhammad Sharif
- Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar, Pakistan
| | - Iftikhar Ahmed
- National Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad, Pakistan
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Mishra P, Mishra J, Arora NK. Biofortification revisited: Addressing the role of beneficial soil microbes for enhancing trace elements concentration in staple crops. Microbiol Res 2023; 275:127442. [PMID: 37437425 DOI: 10.1016/j.micres.2023.127442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 06/07/2023] [Accepted: 06/23/2023] [Indexed: 07/14/2023]
Abstract
Trace element deficiency is a pervasive issue contributing to malnutrition on a global scale. The primary cause of this hidden hunger is related to low dietary intake of essential trace elements, which is highly prevalent in numerous regions across the world. To address deficiency diseases in humans, fortification of staple crops with vital trace elements has emerged as a viable solution. Current methods for fortifying crops encompass chemical amendments, genetic breeding, and transgenic approaches, yet these approaches possess certain limitations, constraining their agricultural application. In contrast, fortifying staple crops through the utilization of soil-beneficial microbes has emerged as a promising and economically feasible approach to enhance trace element content in crops. A specific subset of these beneficial soil microbes, referred to as plant growth-promoting microbes, have demonstrated their ability to influence the interactions between plants, soil, and minerals. These microbes facilitate the transport of essential soil minerals, such as zinc, iron, and selenium, into plants, offering the potential for the development of tailored bioinoculants that can enhance the nutritional quality of cereals, pulses, and vegetable crops. Nevertheless, further research efforts are necessary to comprehensively understand the molecular mechanisms underlying the uptake, transport, and augmentation of trace element concentrations in staple crops. By delving deeper into these mechanisms, customized bioinoculants of soil-beneficial microbes can be developed to serve as highly effective strategies in combating trace element deficiency and promoting global nutritional well-being.
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Affiliation(s)
- Priya Mishra
- Department of Environmental Science, School of Earth and Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India
| | - Jitendra Mishra
- Department of Environmental Science, School of Earth and Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India
| | - Naveen Kumar Arora
- Department of Environmental Science, School of Earth and Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India.
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Ali M, Ahmed I, Tariq H, Abbas S, Zia MH, Mumtaz A, Sharif M. Growth improvement of wheat ( Triticum aestivum) and zinc biofortification using potent zinc-solubilizing bacteria. FRONTIERS IN PLANT SCIENCE 2023; 14:1140454. [PMID: 37251763 PMCID: PMC10213544 DOI: 10.3389/fpls.2023.1140454] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 04/11/2023] [Indexed: 05/31/2023]
Abstract
Zinc (Zn) is an indispensable element for proper plant growth. A sizeable proportion of the inorganic Zn that is added to soil undergoes a transformation into an insoluble form. Zinc-solubilizing bacteria (ZSB) have the potential to transform the insoluble Zn into plant-accessible forms and are thus promising alternatives for Zn supplementation. The current research was aimed at investigating the Zn solubilization potential of indigenous bacterial strains and to evaluate their impact on wheat growth and Zn biofortification. A number of experiments were conducted at the National Agriculture Research Center (NARC), Islamabad, during 2020-21. A total of 69 strains were assessed for their Zn-solubilizing ability against two insoluble Zn sources (ZnO and ZnCO3) using plate assay techniques. During the qualitative assay, the solubilization index and solubilization efficiency were measured. The qualitatively selected Zn-solubilizing bacterial strains were further tested quantitatively using broth culture for Zn and phosphorus (P) solubility. Tricalcium phosphate was used as insoluble source of P. The results showed that broth culture pH was negatively correlated with Zn solubilization, i.e., ZnO (r2 = 0.88) and ZnCO3 (r2 = 0.96). Ten novel promising strains, i.e., Pantoea sp. NCCP-525, Klebsiella sp. NCCP-607, Brevibacterium sp. NCCP-622, Klebsiella sp. NCCP-623, Acinetobacter sp. NCCP-644, Alcaligenes sp. NCCP-650, Citrobacter sp. NCCP-668, Exiguobacterium sp. NCCP-673, Raoultella sp. NCCP-675, and Acinetobacter sp. NCCP-680, were selected from the ecology of Pakistan for further experimentation on wheat crop based on plant growth-promoting rhizobacteria (PGPR) traits, i.e., solubilization of Zn and P in addition to being positive for nifH and acdS genes. Before evaluating the bacterial strains for plant growth potential, a control experiment was also conducted to determine the highest critical Zn level from ZnO to wheat growth using different Zn levels (0.1, 0.05, 0.01, 0.005, and 0.001% Zn) against two wheat varieties (Wadaan-17 and Zincol-16) in sand culture under glasshouse conditions. Zinc-free Hoagland nutrients solution was used to irrigate the wheat plants. As a result, 50 mg kg-1 of Zn from ZnO was identified as the highest critical level for wheat growth. Using the critical level (50 mg kg-1 of Zn), the selected ZSB strains were inoculated alone and in consortium to the seed of wheat, with and without the use of ZnO, in sterilized sand culture. The ZSB inoculation in consortium without ZnO resulted in improved shoot length (14%), shoot fresh weight (34%), and shoot dry weight (37%); with ZnO root length (116%), it saw root fresh weight (435%), root dry weight (435%), and Zn content in the shoot (1177%) as compared to the control. Wadaan-17 performed better on growth attributes, while Zincol-16 had 5% more shoot Zn concentration. The present study concluded that the selected bacterial strains show the potential to act as ZSB and are highly efficient bio-inoculants to combat Zn deficiency, and the inoculation of these strains in consortium performed better in terms of growth and Zn solubility for wheat as compared to individual inoculation. The study further concluded that 50 mg kg-1 Zn from ZnO had no negative impact on wheat growth; however, higher concentrations hampered wheat growth.
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Affiliation(s)
- Murad Ali
- National Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad, Pakistan
- Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar, Pakistan
- Cereal Crops Research Institute (CCRI), Pirsabak, Nowshera, Pakistan
| | - Iftikhar Ahmed
- National Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad, Pakistan
| | - Hamza Tariq
- National Culture Collection of Pakistan (NCCP), Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad, Pakistan
| | - Saira Abbas
- Department of Zoology, University of Science and Technology, Bannu, Pakistan
| | - Munir Hussain Zia
- Research and Development Department, Fauji Fertilizer Company (FFC) Limited, Rawalpindi, Pakistan
| | - Amer Mumtaz
- Food Sciences Research Institute (FSRI), National Agricultural Research Centre (NARC), Islamabad, Pakistan
| | - Muhammad Sharif
- Department of Soil and Environmental Sciences, The University of Agriculture, Peshawar, Pakistan
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