Browsing by Author "Swarnmala Samal"

Now showing 1 - 13 of 13

Alternaria host-specific (HSTs) toxins: An overview of chemical characterization, target sites, regulation and their toxic effects
(Elsevier Inc., 2019) Mukesh Meena; Swarnmala Samal
Alternaria causes pathogenic disease on various economically important crops having saprophytic to endophytic lifecycle. Pathogenic fungi of Alternaria species produce many primary and secondary metabolites (SMs). Alternaria species produce more than 70 mycotoxins. Several species of Alternaria produce various phytotoxins that are host-specific (HSTs) and non-host-specific (nHSTs). These toxins have various negative impacts on cell organelles including chloroplast, mitochondria, plasma membrane, nucleus, Golgi bodies, etc. Non-host-specific toxins such as tentoxin (TEN), Alternaric acid, alternariol (AOH), alternariol 9-monomethyl ether (AME), brefeldin A (dehydro-), Alternuene (ALT), Altertoxin-I, Altertoxin-II, Altertoxin-III, zinniol, tenuazonic acid (TeA), curvularin and alterotoxin (ATX) I, II, III are known toxins produced by Alternaria species. In other hand, Alternaria species produce numerous HSTs such as AK-, AF-, ACT-, AM-, AAL- and ACR-toxin, maculosin, destruxin A, B, etc. are host-specific and classified into different family groups. These mycotoxins are low molecular weight secondary metabolites with various chemical structures. All the HSTs have different mode of actions, biochemical reactions, and signaling mechanisms to causes diseases in the host plants. These HSTs have devastating effects on host plant tissues by affecting biochemical and genetic modifications. Host-specific mycotoxins such as AK-toxin, AF-toxin, and AC-toxin have the devastating effect on plants which causes DNA breakage, cytotoxic, apoptotic cell death, interrupting plant physiology by mitochondrial oxidative phosphorylation and affect membrane permeability. This article will elucidate an understanding of the disease mechanism caused by several Alternaria HSTs on host plants and also the pathways of the toxins and how they caused disease in plants. © 2019 The Authors
Endophytic actinomycetes in bioactive compounds production and plant defense system
(Elsevier, 2019) Mohd Aamir; Krishna Kumar Rai; Andleeb Zehra; Manish Kumar Dubey; Swarnmala Samal; Mukesh Yadav; Ram Sanmukh Upadhyay
Endophytic actinomycetes colonizing inside plant tissue have received much attention due to their potential use in stimulation of plant growth as well as in the management of soil and plant survival by producing certain functional metabolites and simultaneously counteracting pathogenic microbes residing within same plant species. Advancement in the "omics" technology such as computational biology, metabolic engineering, and proteomics has provided an efficient way to unravel mechanisms behind revelation of biosynthesis of these bioactive compounds and also provided efficient ways for the identification of gene clusters form unexplored actinomycetes. Plethora of researches on endophytic microorganisms has evidenced the existence of new and untouched endophytic actinomycetes producing discrete bioactive compounds within distinct tissues of several medicinal plants. Howbeit, till date sporadic reports are available on their biodiversity, phylogenetic distribution, and their probable association with traditional plants along with their specific environments. This chapter mainly focuses on different protective and signaling mechanisms used by the endophytic actinomycetes to promote plant growth and soil health. The chapter also examines the current biochemical status of endophytic actinomycetes and intervention of "omics" approaches used in revealing their full potential and lastly, it also sharpens the knowledge about newly discovered potential bioactive compounds and their possible exploitation by agricultural and pharmaceutical industries. © 2020 Elsevier Inc. All rights reserved.
Endophytic Fusarium and their association with plant growth
(Elsevier, 2022) Swarnmala Samal; Shalini Rai; Ram Sanmukh Upadhaya
Most Fusarium endophytes develop a diverse association with plants, including as commensals, a mutualistic symbiont, and the most prevalent act as pathogens in different crops. These interactions between plants and microbes depend on environmental biotic and abiotic conditions, the host genotype, and the interacting microorganism. Endophytic microbiota and the various associations amongst members profoundly impact the sustainable agriculture and agro-ecological balance. This chapter briefly discusses the peculiarities and resemblances between nonpathogenic and pathogenic Fusarium endophytes, their response, and their mode of colonization in the host plant. In addition, Fusarium secreted bioactive compounds, mycotoxin, and their impact on host plant as well as their interaction being a pathobiont within plant microbiota are discussed too. Moreover, endophytic Fusarium bioactive secondary metabolites have demonstrated significant importance in agriculture not only as biocontrol agents but also as phytostimulants through the production of fungicidal and nematicidal chemicals and activation of defense responses. To combat the climate change and agriculture problems, the emerging role of endophytic Fusarium has been presented as the best option for the development of bioformulations, biopesticides, and biostimulants. © 2023 Elsevier Inc. All rights reserved.
First report of Lasiodiplodia pseudotheobromae causing postharvest brown fruit rot on plum in India
(Springer Nature, 2025) Swarnmala Samal; Dinesh V. Singh
Brown rot disease of Plum (Prunus salicina) was prevalent year-round, peaking in May, with symptoms of brown rot on plum fruits. The pathogen, isolated in May 2023–2024 in New Delhi, India, was identified as Lasiodiplodia pseudotheobromae through morphological and phylogenetic characterization. This is the first report of L.pseudotheobromae causing brown rot on Plum in India. © The Author(s) under exclusive licence to Australasian Plant Pathology Society Inc. 2025.
First Report of Phytopythium vexans Causing Gummosis and Root Rot of Khasi Mandarin (Citrus reticulata) in North Eastern States of India
(American Phytopathological Society, 2024) Dinesh Singh; Sapna Sharma; Amrita Das; Dwipendra Thakuria; Lingaraj Sahoo; L.L. Kharbikar; Swarnmala Samal; Gireesh Chand; Amar Bahadur; R.C. Shakywar
[No abstract available]
First report on Obelidium megarhizum (Chytridiaceae) from India
(Springer, 2019) Manish Kumar Dubey; Andleeb Zehra; Swarnmala Samal; Ram Sanmukh Upadhyay
In the present report, Obelidium megarhizum Willoughby was isolated, described and illustrated based on morphological traits. The species is mainly recognized by the presence of conspicuous sub-apical spine or barb bearing thin-walled sporangium and relatively coarse rhizoidal system. Short description, comments, color photo, and illustration, accompanied by its comparison with other allied taxa of the genus are provided in this paper for this relatively rare species. To the best of our knowledge, this is the first generic record of O. megarhizum outside UK, USA, and Poland. © 2019, Society for Plant Research.
Hydrolytic genes of antagonistic rhizobacteria strains on Fusarium udum causing wilt disease in pigeonpea
(Springer Science and Business Media Deutschland GmbH, 2024) Swarnmala Samal; Dinesh Singh; Ram Sanmukh Upadhyay; P. Lokesh Babu; Neelam Geat
Pigeaonpea is attacked by various diseases, including the wilt disease of pigeonpea caused by Fusarium udum. This disease is a severe pathogen to this crop. This study aims to identify the potential biocontrol agent against wilt disease as a fungicide alternative. Forty-seven isolates were evaluated for antagonistic activity against F. udum by dual culture method. Interaction of F. udum and antagonistic bacteria was studied in potato dextrose agar (PDA) under in vitro conditions and lysis of fungal hyphae was observed by using Scanning Electron Microscope. Dry weight of F. udum mycelium was recorded after 3 days of co-inoculation with the rhizobacteria in PDB. Potential antagonistic bacterial isolates were further used for enzymatic assay in vitro conditions. Molecular characterization of bacteria was done by using primers based on hydrolytic genes like chitinase and 1,3-glucanase related genes, amplified at 402 and 750 bp, respectively. Out of forty-seven bacterial isolates used to assess their antagonistic activity, only eight isolates, viz., Bacillus amyloliquefaciens CFLB 31, Bacillus velezensis CFLB 24, Bacillus subtilis CFLB 11, Stenotrophomonas rhizophila CFLB 26, S. matalophila CFLB 47, Microbacteria sp. CFLB 28, G.nicotiana CFLB 18 and Pseudoarthrobacter sp. CFLB 36 showed the promising antagonistic activity against F. udum with 70–84% inhibition in a dual culture plate assay. Among them, three Bacillus species (B. amyloliquefaciens, B. velezensis, B. subtilis) and S. maltophilia CFLB 47 were found to be the most effective biocontrol agent against F. udum under in vitro conditions. Lysis of fungal hyphae was also noted during interaction of fungus and bacteria on PDA. These isolates were screened for production of hydrolytic enzymes activities and they showed positive for production of pectinase, protease and cellulase under in vitro conditions. These isolates amplified chitinase and β-1, 3-glucanase-related genes at 402 and 750 bp, respectively. In addition, bacterial strains reduced the mycelium weight of F. udum with the range of 58.42 − 86.84% during co-inoculation in PDB. However, B. amyloliquefaciens had the highest percentage of biomass reduction, up to 86.84%. Bacterial treatments are considered beneficial and nature-friendly. The results propose that the eight potential strains and their hydrolytic enzymatic properties made them promise to manage wilt disease of pigeonpea. © The Author(s) under exclusive licence to Società Italiana di Patologia Vegetale (S.I.Pa.V.) 2024.
Hydrolytic genes of antagonistic rhizobacteria strains on Fusarium udum causing wilt disease in pigeonpea
(Springer Science and Business Media Deutschland GmbH, 2025) Swarnmala Samal; Dinesh V. Singh; Ram Sanmukh Upadhyay; P. Lokesh Babu; Neelam Geat
Pigeaonpea is attacked by various diseases, including the wilt disease of pigeonpea caused by Fusarium udum. This disease is a severe pathogen to this crop. This study aims to identify the potential biocontrol agent against wilt disease as a fungicide alternative. Forty-seven isolates were evaluated for antagonistic activity against F. udum by dual culture method. Interaction of F. udum and antagonistic bacteria was studied in potato dextrose agar (PDA) under in vitro conditions and lysis of fungal hyphae was observed by using Scanning Electron Microscope. Dry weight of F. udum mycelium was recorded after 3 days of co-inoculation with the rhizobacteria in PDB. Potential antagonistic bacterial isolates were further used for enzymatic assay in vitro conditions. Molecular characterization of bacteria was done by using primers based on hydrolytic genes like chitinase and 1,3-glucanase related genes, amplified at 402 and 750 bp, respectively. Out of forty-seven bacterial isolates used to assess their antagonistic activity, only eight isolates, viz., Bacillus amyloliquefaciens CFLB 31, Bacillus velezensis CFLB 24, Bacillus subtilis CFLB 11, Stenotrophomonas rhizophila CFLB 26, S. matalophila CFLB 47, Microbacteria sp. CFLB 28, G.nicotiana CFLB 18 and Pseudoarthrobacter sp. CFLB 36 showed the promising antagonistic activity against F. udum with 70–84% inhibition in a dual culture plate assay. Among them, three Bacillus species (B. amyloliquefaciens, B. velezensis, B. subtilis) and S. maltophilia CFLB 47 were found to be the most effective biocontrol agent against F. udum under in vitro conditions. Lysis of fungal hyphae was also noted during interaction of fungus and bacteria on PDA. These isolates were screened for production of hydrolytic enzymes activities and they showed positive for production of pectinase, protease and cellulase under in vitro conditions. These isolates amplified chitinase and β-1, 3-glucanase-related genes at 402 and 750 bp, respectively. In addition, bacterial strains reduced the mycelium weight of F. udum with the range of 58.42 − 86.84% during co-inoculation in PDB. However, B. amyloliquefaciens had the highest percentage of biomass reduction, up to 86.84%. Bacterial treatments are considered beneficial and nature-friendly. The results propose that the eight potential strains and their hydrolytic enzymatic properties made them promise to manage wilt disease of pigeonpea. © The Author(s) under exclusive licence to Società Italiana di Patologia Vegetale (S.I.Pa.V.) 2024.
Impact of climate change on soil carbon exchange, ecosystem dynamics, and plant-microbe interactions
(Elsevier, 2019) Mohd Aamir; Krishna Kumar Rai; Manish Kumar Dubey; Andleeb Zehra; Yashoda Nandan Tripathi; Kumari Divyanshu; Swarnmala Samal; R.S. Upadhyay
In the present scenario, global climate change is a serious concern with respect to global food production. Adverse environmental conditions including high temperature, drought, salinity, and precipitation resulting from the changing climate in different regions increase the risk of dramatic losses in agricultural production. The altered species distribution resulting from the changed climatic scenario has affected the functional interactions and integrations existing between species. The differential origin, evolution, and dispersal abilities of organisms determine their susceptibility and response mechanisms under the changed environment and functions on multiple levels. Soil microbiota (including rhizospheric and endophytic microorganisms) play an indispensable role in the mitigation of climate change and induced abiotic stresses, and also promote plant growth and development through a plethora of mechanisms that work at multiple levels, including regulation of nutrient transformation, allowing for coexistence among neighboring and controlling plant populations. The functional aspects and ecological dynamics of natural ecosystems are highly dependent on plant functional traits and their interactions with organisms occupied at a multitrophic level. The changed climatic conditions influence the environmental variables and therefore alter the multifunctional responses or interaction mechanisms existing between the plants and microbes. Furthermore, the mutual interactions between plants and soil microbes have substantial consequences in regulating the community compositions and ecosystem functions. This chapter discusses the effect of climate change on ecosystem mechanics and dynamics, and how microorganisms play crucial roles in regulating the functional dynamics of ecosystem properties. In recent years, rapid industrialization and increased anthropogenic activities have resulted in rapid and continuous changes in climatic conditions, causing significant changes in agricultural productivity. In this context, there is an urgent need to understand, define, and interpret the plant-microbe interactions in terms of their efficient use and indigenous mechanisms against abiotic stresses without compromising the sustainability of the ecosystem. © 2019 Elsevier Inc. All rights reserved.
Insight into an Effective Development of Biocontrol Agent Formulation for Commercial Production
(Springer Science+Business Media, 2025) Swarnmala Samal; Rahul Kumar; Divya Gunsola; Apaarna; Debasis Mitra; Madhu Thapliyal; Subhankar Mondal; Bahman Khoshru; Magdalena M. Knezevic; R. D. Dodiya
Sustainable agriculture relies heavily on effective biocontrol agents (BCAs), which provide a greener substitute for conventional pesticides. The key elements in the creation and formulation of BCAs for commercial production were examined in this study. Important factors to consider include the choice of strong microbial strains or natural enemies, growth condition optimization, formulation techniques to improve stability and efficacy, and regulatory needs for commercial viability. The analysis of case studies and latest developments in BCA formulation technologies aims to emphasize the effective strategies and obstacles encountered while transitioning from lab prototypes to large-scale manufacturing. This study offers a thorough framework for developing BCA formulations for sustainable agricultural practices by combining knowledge from microbiology, agriculture, and biotechnology. © 2025 The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Isolation, identification, carbon utilization profile and control of Pythium graminicola, the causal agent of chilli damping-off
(Blackwell Publishing Ltd, 2020) Manish Kumar Dubey; Andleeb Zehra; Mohd. Aamir; Mukesh Yadav; Swarnmala Samal; Ram Sanmukh Upadhyay
Postemergence damping-off of chilli caused by Pythium spp. is a common and serious problem in large chilli growing areas of India under the moist conditions that generally prevails during the sowing period. Therefore, in order to better understand this disease, an isolate belonging to the genus Pythium (Pythiales) was isolated from the infected chilli (Capsicum annuum L.) plant root parts collected from the fields of Chandauli district, Uttar Pradesh, India. Based on the congruence of cultural, morphological, cardinal growth rate and the sequence data analysis, the isolate was identified as Pythium graminicola. The molecular phylogenetic analysis based on ITS-rDNA sequences clustered the isolate with representative sequences for P. graminicola from GenBank in the Pythium clade. The isolate carbon utilization profiles were characterized using Biolog FF MicroPlate method. The results revealed that the isolate used a wide range of carbon sources, mainly carbohydrates, but also amino acids, suggesting the use of metabolic routes that include glycolysis/gluconeogenesis. Moreover, an in vitro colony growth inhibition assay was performed to determine the influence of chemical (fungicides) and biological (bacteria and fungi) antagonists over the pathogen using the poison plate and dual culture method, respectively. Overall, the results revealed that the presence of aggressive broad range biocontrol agents can be used as an effective environmentally friendly approach for management and control of damping-off in production systems. The antagonist can serve as a bio-efficient and eco-friendly alternative to synthetic fungicides for the development of an effective integrated pest management (IPM) system and obtaining higher yields. © 2019 Blackwell Verlag GmbH
Microbial endophytes as probiotics for the plant health: an overview
(Elsevier, 2022) Shalini Rai; Manoj Kumar Solanki; Anjali Chandrol Solanki; Swarnmala Samal
Probiotics act as biostimulants and are applied to crop microbiome to improve growth, development, alleviation of abiotic stress, fitness, and enhanced immune responses. Endophytic microbes and derived substances are extensively formulated as probiotics that are introduced to elicit a positive change in plant fitness. Endophytes-based bioformulation has been predominantly effective in agronomic crops because of their biocontrol activity against phytopathogen. This chapter elaborately focused on the recent prospectus of endophytic microbes as probiotics that modulate numerous mechanisms that participate during the probiotic–plant interactions. The colonization and induction of positive traits include acquiring nutrients, secretion of secondary metabolites, siderophores, and phytohormone production, stimulating resistance responses in crops, and developing defense mechanisms in response to abiotic and biotic stresses. Presently, the search for novel endophytic with multifarious functions received great attention due to its application in the rhizosphere and seed engineering that modulate structure, composition, diversity, and beneficial traits of crops. The recent development of endophytic microbes encourages its application in agricultural sectors to improve crop production. © 2023 Elsevier Inc. All rights reserved.
Unraveling the involvement of WRKY TFs in regulating plant disease defense signaling
(Springer Science and Business Media Deutschland GmbH, 2024) Baisista Saha; Jagatjeet Nayak; Richa Srivastava; Swarnmala Samal; Deepak Kumar; Jeky Chanwala; Nrisingha Dey; Mrunmay Kumar Giri
Main conclusion: This review article explores the intricate role, regulation, and signaling mechanisms of WRKY TFs in response to biotic stress, particularly emphasizing their pivotal role in the trophism of plant-pathogen interactions. Abstract: Transcription factors (TFs) play a vital role in governing both plant defense and development by controlling the expression of various downstream target genes. Early studies have shown the differential expression of certain WRKY transcription factors by microbial infections. Several transcriptome-wide studies later demonstrated that diverse sets of WRKYs are significantly activated in the early stages of viral, bacterial, and fungal infections. Furthermore, functional investigations indicated that overexpression or silencing of certain WRKY genes in plants can drastically alter disease symptoms as well as pathogen multiplication rates. Hence the new aspects of pathogen-triggered WRKY TFs mediated regulation of plant defense can be explored. The already recognized roles of WRKYs include transcriptional regulation of defense-related genes, modulation of hormonal signaling, and participation in signal transduction pathways. Some WRKYs have been shown to directly bind to pathogen effectors, acting as decoys or resistance proteins. Notably, the signaling molecules like salicylic acid, jasmonic acid, and ethylene which are associated with plant defense significantly increase the expression of several WRKYs. Moreover, induction of WRKY genes or heightened WRKY activities is also observed during ISR triggered by the beneficial microbes which protect the plants from subsequent pathogen infection. To understand the contribution of WRKY TFs towards disease resistance and their exact metabolic functions in infected plants, further studies are required. This review article explores the intrinsic transcriptional regulation, signaling mechanisms, and hormonal crosstalk governed by WRKY TFs in plant disease defense response, particularly emphasizing their specific role against different biotrophic, hemibiotrophic, and necrotrophic pathogen infections. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.