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Mathur P, Roy S. Insights into the plant responses to drought and decoding the potential of root associated microbiome for inducing drought tolerance. PHYSIOLOGIA PLANTARUM 2021; 172:1016-1029. [PMID: 33491182 DOI: 10.1111/ppl.13338] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Global increase in water scarcity is a serious problem for sustaining crop productivity. The lack of water causes the degeneration of the photosynthetic apparatus, an imbalance in key metabolic pathways, an increase in free radical generation as well as weakens the root architecture of plants. Drought is one of the major stresses that directly interferes with the osmotic status of plant cells. Abscisic acid (ABA) is known to be a key player in the modulation of drought responses in plants and involvement of both ABA-dependent and ABA-independent pathways have been observed during drought. Concomitantly, other phytohormones such as auxins, ethylene, gibberellins, cytokinins, jasmonic acid also confer drought tolerance and a crosstalk between different phytohormones and transcription factors at the molecular level exists. A number of drought-responsive genes and transcription factors have been utilized for producing transgenic plants for improved drought tolerance. Despite relentless efforts, biotechnological advances have failed to design completely stress tolerant plants until now. The root microbiome is the hidden treasure that possesses immense potential to revolutionize the strategies for inducing drought resistance in plants. Root microbiota consist of plant growth-promoting rhizobacteria, endophytes and mycorrhizas that form a consortium with the roots. Rhizospheric microbes are proliferous producers of phytohormones, mainly auxins, cytokinin, and ethylene as well as enzymes like the 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase) and metabolites like exopolysaccharides that help to induce systemic tolerance against drought. This review, therefore focuses on the major mechanisms of plant-microbe interactions under drought-stressed conditions and emphasizes the importance of drought-tolerant microbes for sustaining and improving the productivity of crop plants under stress.
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Affiliation(s)
- Piyush Mathur
- Microbiology Laboratory, Department of Botany, University of North Bengal, Raja Rammohunpur, India
| | - Swarnendu Roy
- Plant Biochemistry Laboratory, Department of Botany, University of North Bengal, Raja Rammohunpur, India
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Vaz ABM, Fonseca PLC, Silva FF, Quintanilha-Peixoto G, Sampedro I, Siles JA, Carmo A, Kato RB, Azevedo V, Badotti F, Ocampo JA, Rosa CA, Góes-Neto A. Foliar mycoendophytome of an endemic plant of the Mediterranean biome (Myrtus communis) reveals the dominance of basidiomycete woody saprotrophs. PeerJ 2020; 8:e10487. [PMID: 33344092 PMCID: PMC7719295 DOI: 10.7717/peerj.10487] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 11/12/2020] [Indexed: 11/20/2022] Open
Abstract
The true myrtle, Myrtus communis, is a small perennial evergreen tree that occurs in Europe, Africa, and Asia with a circum-Mediterranean geographic distribution. Unfortunately, the Mediterranean Forests, where M. communis occurs, are critically endangered and are currently restricted to small fragmented areas in protected conservation units. In the present work, we performed, for the first time, a metabarcoding study on the spatial variation of fungal community structure in the foliar endophytome of this endemic plant of the Mediterranean biome, using bipartite network analysis as a model. The local bipartite network of Myrtus communis individuals and their foliar endophytic fungi is very low connected, with low nestedness, and moderately high specialization and modularity. Similar network patterns were also retrieved in both culture-dependent and amplicon metagenomics of foliar endophytes in distinct arboreal hosts in varied biomes. Furthermore, the majority of putative fungal endophytes species were basidiomycete woody saprotrophs of the orders Polyporales, Agaricales, and Hymenochaetales. Altogether, these findings suggest a possible adaptation of these wood-decaying fungi to cope with moisture limitation and spatial scarcity of their primary substrate (dead wood), which are totally consistent with the predictions of the viaphytism hypothesis that wood-decomposing fungi inhabit the internal leaf tissue of forest trees in order to enhance dispersal to substrates on the forest floor, by using leaves as vectors and as refugia, during periods of environmental stress.
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Affiliation(s)
- Aline Bruna M Vaz
- Department of Microbiology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Paula Luize C Fonseca
- Department of Microbiology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Felipe F Silva
- Graduate Program of Bioinformatics, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Gabriel Quintanilha-Peixoto
- Graduate Program of Bioinformatics, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Inmaculada Sampedro
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, C.S.I.C., Granada, Spain
| | - Jose A Siles
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, C.S.I.C., Granada, Spain
| | - Anderson Carmo
- Department of Genetics, Ecology, and Evolution, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo B Kato
- Graduate Program of Bioinformatics, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Vasco Azevedo
- Department of Genetics, Ecology, and Evolution, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Fernanda Badotti
- Department of Chemistry, Centro Federal de Educação Tecnológica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Juan A Ocampo
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, C.S.I.C., Granada, Spain
| | - Carlos A Rosa
- Department of Microbiology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Aristóteles Góes-Neto
- Department of Microbiology, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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The Endophytic Fungus Chaetomium cupreum Regulates Expression of Genes Involved in the Tolerance to Metals and Plant Growth Promotion in Eucalyptus globulus Roots. Microorganisms 2019; 7:microorganisms7110490. [PMID: 31717780 PMCID: PMC6920756 DOI: 10.3390/microorganisms7110490] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/20/2019] [Accepted: 10/24/2019] [Indexed: 11/16/2022] Open
Abstract
The endophytic strain Chaetomium cupreum isolated from metal-contaminated soil was inoculated in Eucalyptus globulus roots to identify genes involved in metal stress response and plant growth promotion. We analyzed the transcriptome of E. globulus roots inoculated with C. cupreum. De novo sequencing, assembly, and analysis were performed to identify molecular mechanisms involved in metal stress tolerance and plant growth promotion. A total of 393,371,743 paired-end reads were assembled into 135,155 putative transcripts. It was found that 663 genes significantly changed their expression in the presence of treatment, of which 369 were up-regulated and 294 were down-regulated. We found differentially expressed genes (DEGs) encoding metal transporters, transcription factors, stress and defense response proteins, as well as DEGs involved in auxin biosynthesis and metabolism. Our results showed that the inoculation of C. cupreum enhanced tolerance to metals and growth promotion on E. globulus. This study provides new information to understand molecular mechanisms involved in plant–microbe interactions under metals stress.
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Dastogeer KMG. Influence of fungal endophytes on plant physiology is more pronounced under stress than well-watered conditions: a meta-analysis. PLANTA 2018; 248:1403-1416. [PMID: 30121874 DOI: 10.1007/s00425-018-2982-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 08/09/2018] [Indexed: 05/24/2023]
Abstract
A meta-analysis of published articles shows that the influence of fungal endophytes on plant performance is dependent on plant water status. The magnitude of endophytic effects is higher in plants grown in water-limiting environments than those in adequate watering environments. The outcome of plant-endophyte interactions depends on the identity of the plant host and fungal symbionts. Water limitation often hinders plant productivity in both natural and agricultural settings. Endophytic fungal symbionts can mediate plant water stress responses by enhancing drought tolerance and avoidance, but these effects have not been quantified across plant-endophyte studies. A meta-analysis of published studies was performed to determine how endophytic fungal symbionts influence plant response under non-stressed versus water-stressed conditions. A significantly positive or neutral overall effect of fungal endophyte was noted under water-stressed conditions. In contrast, under non-stressed conditions, the overall effect of fungi on plants was mostly neutral. In general, the presence of fungal endophytes increased plant's total biomass, chlorophyll content, and stomatal conductance irrespective of water availability. In addition, plant shoot biomass, tiller density, plant height, maximum quantum yield (Fv/Fm), net photosynthesis, relative water content (RWC), amounts of ascorbate peroxidase (APX), glutathione (GSH), polyphenol oxidase (PPO), superoxide dismutase (SOD), and phenolics were significantly increased by endophyte colonisation under stressed conditions. Malondialdehyde (MDA) and hydrogen peroxide (H2O2) were reduced in endophytic plants under stress as compared with non-endophytic counterparts. Categorical analysis revealed that accumulation in plant biomass is influenced by factors such as host and fungi identity, the magnitude of which is greater under stressed than non-stressed conditions.
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Affiliation(s)
- Khondoker M G Dastogeer
- Plant Biotechnology Group-Plant Virology and Plant-Microbe Interaction, Western Australian State Agricultural Biotechnology Centre, School of Veterinary and Life Sciences, Murdoch University, Perth, WA, 6150, Australia.
- Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh.
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