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Kanda T, Srivastava R, Yadav S, Singh N, Prajapati R, Singh PK, Yadav S, Atri N. Pretilachlor-induced physiological, biochemical and morphological changes in Indian paddy field agroecosystem inhabited Anabaena doliolum. ENVIRONMENTAL RESEARCH 2023; 238:117201. [PMID: 37775005 DOI: 10.1016/j.envres.2023.117201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/24/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023]
Abstract
Pretilachlor is a systemic, pre-emergence herbicide applied in the paddy fields to kill narrow and broadleaf weeds. The present study evaluates the toxicity of pretilachlor on the non-target diazotrophic free-living cyanobacterium Anabaena doliolum, commonly found in the paddy fields of eastern Uttar Pradesh (India) and used as a biofertilizer. A.doliolum was subjected to several doses (0, 2, 5, 7, 10, 20 and 40 μg/ml) of pretilachlor and its effects were examined in terms of alterations in cellular morphology, ultrastructure, physiology, and biochemical attributes. The treatment of pretilachlor decreased the growth, total pigment content and photosynthetic efficiency of the test organism in a dose-dependent manner. The decline in growth was observed on 20th day at 2, 5, 7, 10, 20 and 40 μg/ml of pretilachlor concentration by 4, 9, 26, 47, 71 and 92%, respectively. Furthermore, Chlorophyll a and phycocyanin levels were noticeably declined. As a result, the photosynthetic performance also registered a similar decline as measured by chlorophyll fluorescence. However, carotenoid content increased by 13%, 41% and 53% at 5, 10 and 20 μg/ml on 5th day reflecting its protective property. A marked increase in fluorescence intensity and malondialdehyde content by 2.65 and 2.45 folds at 10 and 20 μg/ml on 7th day was registered. The enzymatic antioxidants (SOD and CAT) and a concurrent increase in glutathione reductase activity were registered (1.75 and 2.11-fold at 20 and 40 μg/ml on 5th day), indicating pretilachlor mediated ROS generation. Moreover, ultrastructural studies done by SEM and TEM revealed plasma membrane and thylakoid membrane damage and fragmentation. These findings have contributed to the broader comprehension of the stress responses triggered by pretilachlor in cyanobacteria. Moreover, they can aid in the evaluation of the detrimental impact of pretilachlor on A. doliolum, given their crucial function as a nitrogen contributor in paddy fields.
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Affiliation(s)
- Tripti Kanda
- Department of Botany, MMV, Banaras Hindu University, Varanasi, U.P., 221005, India
| | - Rupanshee Srivastava
- Department of Botany, MMV, Banaras Hindu University, Varanasi, U.P., 221005, India
| | - Sadhana Yadav
- Department of Botany, MMV, Banaras Hindu University, Varanasi, U.P., 221005, India
| | - Nidhi Singh
- Department of Botany, MMV, Banaras Hindu University, Varanasi, U.P., 221005, India
| | - Rajesh Prajapati
- Department of Botany, Government College of Art's and Commerce, Beohari, Shahdol, M.P, 48774, India
| | - Prashant Kumar Singh
- Department of Biotechnology, Mizoram University (A Central University), Pacchunga University College Campus, Aizawl, 796001, Mizoram, India
| | - Shivam Yadav
- Department of Botany, University of Allahabad, Prayagraj, U.P., 211002, India.
| | - Neelam Atri
- Department of Botany, MMV, Banaras Hindu University, Varanasi, U.P., 221005, India.
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Sachu M, Kynshi BL, Syiem MB. Cyanobacterial degradation of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D): Its response to the oxidative stress induced by the primary degradation product 2,4-dichlorophenol (2,4-DCP). Comp Biochem Physiol C Toxicol Pharmacol 2023; 273:109739. [PMID: 37659610 DOI: 10.1016/j.cbpc.2023.109739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/21/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
Excessive use of herbicides in agricultural fields has become a major environmental concern due to the negative effects on the ecosystem. Microbial degradation has been well-known as an effective approach for combating such non-natural substances in soil. In the present study, the degradation of 2,4-Dichlorophenoxyacetic acid (2,4-D) as a result of metabolic activities of a cyanobacterium Nostoc muscorum Meg 1 was investigated using GC-MS analysis. After seven days of 2,4-D exposure, the main residue obtained was 2,4-dichlorophenol (2,4-DCP) at RT: 8.334 (confirmed using NIST library). The effects of 2,4-DCP were studied in a cyanobacterium Nostoc muscorum Meg 1 isolated from a rice field where 2,4-D is commonly used. Exposure to 2,4-DCP at 20, 40, and 80 ppm significantly increased ROS production in the cyanobacterium by 74, 107, and 211 % (p < 0.001). With rising 2,4-DCP concentrations in the surroundings, lipid peroxidation and protein oxidation in the organism correspondingly increased, indicating cellular injury. The mRNA and protein contents, and also the activities of different oxidant neutralizing enzymes such as CAT, SOD, GR, and GPx and the non-enzymatic antioxidants (proline, GSH, thiol and phytochelatin content) were found augmented in 20 ppm 2,4-DCP exposed cultures. However, in the presence of 40 and 80 ppm 2,4-DCP, most enzymatic and non-enzymatic antioxidants were severely compromised. At higher exposures, the organism's attempt to mitigate the oxidants was still visible, as both proline and TSH levels increased. SEM and TEM analysis aided in visualizing the effects of 2,4-DCP on the morphology and ultrastructures of the organism.
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Affiliation(s)
- Meguovilie Sachu
- Department of Biochemistry, North-Eastern Hill University, Shillong 793022, Meghalaya, India
| | | | - Mayashree B Syiem
- Department of Biochemistry, North-Eastern Hill University, Shillong 793022, Meghalaya, India.
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Perez LM, Mauleon R, Arick MA, Magbanua ZV, Peterson DG, Dean JFD, Tseng TM. Transcriptome analysis of the 2,4-dichlorophenoxyacetic acid (2,4-D)-tolerant cotton chromosome substitution line CS-B15sh and its susceptible parental lines G. hirsutum L. cv. Texas Marker-1 and G. barbadense L. cv. Pima 379. FRONTIERS IN PLANT SCIENCE 2022; 13:910369. [PMID: 36072333 PMCID: PMC9441920 DOI: 10.3389/fpls.2022.910369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
The cotton chromosome substitution line, CS-B15sh, exhibits 41% lower injury from 2,4-D when applied at the field recommended rate of 1.12 kg ae ha-1 (1×) than does Texas Marker-1 (TM-1). CS-B15sh was developed in the genetic background of Gossypium hirsutum L. cv TM-1 and has chromosome introgression on the short arm of chromosome 15 from Gossypium barbadense L. cv. Pima 379. In a previous experiment, we observed reduced translocation of [14C]2,4-D outside the treated leaf tissue in CS-B15sh, which contrasted with an increased translocation of the herbicide in the tissues above and below the treated leaf in TM-1. Our results indicate a potential 2,4-D tolerance mechanism in CS-B15sh involving altered movement of 2,4-D. Here, we used RNA sequencing (RNA-seq) to determine the differential expression of genes between 2,4-D-challenged and control plants of the tolerant (CS-B15sh) and susceptible lines (TM-1 and Pima 379). Several components of the 2,4-D/auxin-response pathway-including ubiquitin E3 ligase, PB1|AUX/IAA, ARF transcription factors, and F-box proteins of the SCFTIR1/AFB complex-were upregulated with at least threefold higher expression in TM-1 compared with CS-B15sh, while both Pima 379 and TM-1 showed the same fold change expression for PB1|AUX/IAA mRNA. Some genes associated with herbicide metabolism, including flavin monooxygenase (Gohir.A01G174100) and FAD-linked oxidase (Gohir.D06G002600), exhibited at least a twofold increase in CS-B15sh than in TM-1 (the gene was not expressed in Pima 379), suggesting a potential relationship between the gene's expression and 2,4-D tolerance. It is interesting to note that glutathione S-transferase was differentially expressed in both CS-B15sh and Pima 379 but not in TM-1, while cytochrome P450 and other genes involved in the oxidation-reduction process were significantly expressed only in CS-B15sh in response to 2,4-D. Gene set enrichment analysis on the union DEGs of the three cotton genotypes revealed the depletion of transcripts involved in photosynthesis and enrichment of transcripts involved in ABA response and signaling.
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Affiliation(s)
- Loida M. Perez
- Department of Biochemistry, Molecular Biology, Entomology & Plant Pathology, Mississippi State University, Starkville, MS, United States
| | - Ramil Mauleon
- Faculty of Science and Engineering, Southern Cross University, East Lismore, NSW, Australia
| | - Mark A. Arick
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Starkville, MS, United States
| | - Zenaida V. Magbanua
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Starkville, MS, United States
| | - Daniel G. Peterson
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Starkville, MS, United States
| | - Jeffrey F. D. Dean
- Department of Biochemistry, Molecular Biology, Entomology & Plant Pathology, Mississippi State University, Starkville, MS, United States
| | - Te Ming Tseng
- Department of Plant and Soil Sciences, Mississippi State University, Starkville, MS, United States
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Flores E, Romanovicz DK, Nieves-Morión M, Foster RA, Villareal TA. Adaptation to an Intracellular Lifestyle by a Nitrogen-Fixing, Heterocyst-Forming Cyanobacterial Endosymbiont of a Diatom. Front Microbiol 2022; 13:799362. [PMID: 35369505 PMCID: PMC8969518 DOI: 10.3389/fmicb.2022.799362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
The symbiosis between the diatom Hemiaulus hauckii and the heterocyst-forming cyanobacterium Richelia intracellularis makes an important contribution to new production in the world's oceans, but its study is limited by short-term survival in the laboratory. In this symbiosis, R. intracellularis fixes atmospheric dinitrogen in the heterocyst and provides H. hauckii with fixed nitrogen. Here, we conducted an electron microscopy study of H. hauckii and found that the filaments of the R. intracellularis symbiont, typically composed of one terminal heterocyst and three or four vegetative cells, are located in the diatom's cytoplasm not enclosed by a host membrane. A second prokaryotic cell was also detected in the cytoplasm of H. hauckii, but observations were infrequent. The heterocysts of R. intracellularis differ from those of free-living heterocyst-forming cyanobacteria in that the specific components of the heterocyst envelope seem to be located in the periplasmic space instead of outside the outer membrane. This specialized arrangement of the heterocyst envelope and a possible association of the cyanobacterium with oxygen-respiring mitochondria may be important for protection of the nitrogen-fixing enzyme, nitrogenase, from photosynthetically produced oxygen. The cell envelope of the vegetative cells of R. intracellularis contained numerous membrane vesicles that resemble the outer-inner membrane vesicles of Gram-negative bacteria. These vesicles can export cytoplasmic material from the bacterial cell and, therefore, may represent a vehicle for transfer of fixed nitrogen from R. intracellularis to the diatom's cytoplasm. The specific morphological features of R. intracellularis described here, together with its known streamlined genome, likely represent specific adaptations of this cyanobacterium to an intracellular lifestyle.
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Affiliation(s)
- Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC, Universidad de Sevilla, Seville, Spain
| | - Dwight K Romanovicz
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - Mercedes Nieves-Morión
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC, Universidad de Sevilla, Seville, Spain
| | - Rachel A Foster
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Tracy A Villareal
- Department of Marine Science and Marine Science Institute, The University of Texas at Austin, Port Aransas, TX, United States
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