Rezwana Assad | University of Kashmir, Srinagar, J&K, India (original) (raw)

Papers by Rezwana Assad

Scientific Reports, Aug 3, 2022

Over the past few decades, many countries have attempted to carry out forest landscape restoratio... more Over the past few decades, many countries have attempted to carry out forest landscape restoration over millions of hectares of degraded land. Such efforts, however, have met with limited success because of several factors, including a lack of adequate emphasis on ectomycorrhization of the nursery seedlings. A similar scenario is seen in the Kashmir Himalaya, where the natural regeneration of degraded forests is poor despite ample restoration efforts by forest managers. To overcome this challenge, we identified two promising ectomycorrhizal species, namely Clitocybe nuda and Cortinarius distans, for their use in ectomycorrhization of seedlings of three common conifers, namely Abies pindrow, Cedrus deodara, and Picea smithiana. Laboratory studies were carried out to investigate the requirements for optimum mycelial growth of these ectomycorrhizal fungi. Best ECM mycelial growth was obtained in the basic MMN medium containing glucose as the source of carbon and nitrogen in ammonium form. C. distans showed higher growth than C. nuda across all the treatments and also proved significantly more effective in enhancing the survival and growth of the conifer host plant seedlings. The present study resulted in standardizing the requirements for mass inoculum production of the two mycobionts which could help in successful forest restoration programmes. Degradation of forest ecosystems due to detrimental anthropogenic activities poses a severe threat to biodiversity, impeding forest regeneration and impairing invaluable ecosystem services 1,2. Maintenance and restoration of structural organization and functional integrity of forest ecosystems is critical global precedence 2-4. The practice currently adopted for the restoration purpose is planting of conifer seedlings in the degraded forest ecosystems 5,6. However, it has been reported that the survival of these planted seedlings in the disturbed and degraded forest lands is very low 7 and hence it constrains the success of such restoration projects. Moreover, experiences worldwide reveal that degraded land restoration projects achieve little success or eventually fail altogether 8. Hence, understanding the underlying causes and accordingly devising appropriate restoration strategies is crucial. In doing so, one of the often-overlooked reasons for these restoration failures is the inadequate mycorrhization of the nursery seedlings. Ectomycorrhizal fungi (ECM) are a 'keystone' element of a functional community and one of the most effective biological tools for forest restoration projects 9. Successful reforestation and restoration depends on the early capture of site resources by tree seedlings which, in turn, assure space, a continuing resource supply and vigour to resist pests, pathogens and climate stress 10,11. Ectomycorrhizal fungi, in this context, are the key to optimal establishment and performance of forest tree species both under nursery and outplanted conditions 12-15. Hence use of ECM fungi in ectomycorrhization of conifer seedlings is of critical importance in ensuring that the planted seedlings survive, grow and establish under normal as well as stressful conditions. ECM fungi persist only for a short duration after disturbance. Generally, they fail to survive in the soil for prolonged periods without being associated with the roots of a living host 16 , except for some disturbance-resistant suilloid fungi like Rhizopogon and Suillus species which become dominant after disturbance 17. The post-disturbance natural recovery of ECM symbionts is a sluggish progression and generally takes decades to return to its original position 18. Consequently, highly disturbed forests lack requisite ectomycorrhizal association on plant root systems, which is one of the main reasons for high seedling mortality, poor regeneration, or even complete regeneration failure in such areas 19,20. A potential eco-friendly approach to overcome this regeneration failure is

Amaranthus, a cosmopolitan genus including endangered species, restricted endemics and widespread... more Amaranthus, a cosmopolitan genus including endangered species, restricted endemics and widespread weeds, is often difficult to characterize taxonomically and thus has generally been considered by systematists as a Bdifficult^genus. Species in this genus have high genetic variability, with diversity in growth form, plant height, number of inflorescences, seed colour, protein content, seed yield, resistance to pests and diseases, and adaptation to soil type, pH, climate, rainfall and day-length. The combination of various anatomical characteristics of Amaranthus, such as Kranz anatomy, well developed root system, stomatal conductance, and maintenance of leaf area, results in increased efficiency of using CO 2 under a wide range of temperatures, and higher light intensity and moisture stress environments which enables this plant to adapt under diverse geographic and environmental conditions. Buried seeds of Amaranthus constitute an important part of the soil seed bank and position, distribution and dormancy type of these seeds in the soil play an important role in their germination and subsequent emergence, which is further influenced by factors like temperature, soil moisture, and light availability. The current review highlights the positive as well as negative role of the various species of genus Amaranthus. Many species of the genus are medicinally important and bear antiallergic, anticancer, antihypertensive and antioxidant properties, thus being used in the treatment of several aliments. Amaranthus being a rich source of fatty acids, proteins, micronutrients, vitamins and squalene, are used as cereals, dye plants, forages, medicinal plants, ornamentals, and as vegetables. However some of the Amaranthus species are noxious weeds which are known to compete with many economic crops in different parts of the world and cause great yield losses. Thus, further research is warranted to strike a balance between the beneficial and harmful species of this Pseudocereal. Moreover, understanding the weedy behaviour of these plants would provide valuable information for improving our mechanistic models of crop-weed competition and weed population dynamics.

Abies pindrow (Royle ex D.Don) Royle (Himalayan pindrow fir) is an imperative conifer native to K... more Abies pindrow (Royle ex D.Don) Royle (Himalayan pindrow fir) is an imperative conifer native to Kashmir Himalaya, where its mono-dominant forests provide vital ecosystem services, besides being dwelling to endangered flora and fauna. However, in the past few decades, these forests have relentlessly undergone unprecedented deforestation and degradation, and consequently, biodiversity and biotic interactions are jeopardized in these ecosystems. Ectomycorrhizal (ECM) fungi of this fir species may prove helpful in the successful restoration of structural organization and functional integrity of these degraded fir forests. Consequently, the present study was undertaken to explore and document the root-associated ectomycorrhizal symbionts of Himalayan pindrow fir through ectomycorrhizal root tip surveys for morphotyping together with Next Generation Sequencing (Illumina MiSeq) of ITS region of fungal nuclear ribosomal DNA. Fine ECM infected root tips were grouped into fourteen distinct morphotypes based on the morphological attributes, with the monopodial pyramidal type being the most abundant morphotype. The molecular characterization revealed high fungal diversity associated with the roots of Himalayan pindrow fir. A total of 2,51,158 reads were obtained, representing 136 OTUs, of which 62 have confirmed ectomycorrhizal status. In addition, fir roots were found to host a large suite of diverse fungal taxa, including saprotrophs, parasites, and pathogens. FUNGuild assigned 9 prominent guilds to the fungi associated with the fir roots, and ectomycorrhizal fungi represented the largest guild. OTUs belonging to division Basidiomycota were more abundant than those belonging to Ascomycota. Inocybe, Russula, Otidea, Sebacina, Chalara, Tomentella, Cenococcum and Wilcoxina were the abundant ECM forming genera. The results of this study can serve as baseline information for future research and pave the way for experimental evaluation of these ectomycorrhizal mutualists for their prospective use in ectomycorrhization and ECM-mediated forest restoration.

Tropical Ecology, 2021

Several alien plant species have been introduced into Kashmir Himalaya from different regions of ... more Several alien plant species have been introduced into Kashmir Himalaya from different regions of the world and subsequently some of these have been able to colonize and become invasive. Why only some species among the alien species pool establish as strong invaders represents a fundamental question for invasion ecologists. Trait comparisons of invasive with less/non-invasive congeners help in understanding the role of various trait differences in invasion success. In this study, we investigated the differences in various phenological, physiological and morphological traits in three alien plant congeners (Amaranthus blitum Linn., A. caudatus Linn. and A. spinosus Linn.) which differ in their invasion status, and attempted to relate the trait differences to their differential invasion potential in Kashmir Himalaya. The results revealed that the more aggressive behavior of A. caudatus in contrast to other two congeneric species is more likely explained by its early and longer germinati...

Frontiers in Plant Science

The theory of coevolution suggests that herbivores play an important role in the diversification ... more The theory of coevolution suggests that herbivores play an important role in the diversification and composition of plant communities. A prevalent idea holds that grasses and grazing animals participated in an evolutionary "arms race" as grassland ecosystems started spreading across the continents. In this race, besides other things, silicification in the form of phytoliths occurred in the grasses, and the graminivorous herbivores responded through specialized mandibles to feed on plants rich in phytoliths. It is important to understand whether these mandibles equip the herbivores in different environments or the grasses can augment their defense by channelizing their energy in high resource milieu. Here we used rescuegrass (Bromus catharticus; Family: Poaceae), an alien species of South America, to understand the mechanism of resistance offered by this species against a local insect herbivore (Oxya grandis; Family: Acrididae), graminivorous grasshopper, in different silicon-rich environments. We used different concentrations of silicon and observed the types of phytoliths formed after Si amendments and studied the effect of phytoliths on mandible wear of the grasshopper. Silicon concentrations increased ca. 12 fold in the highest supplementation treatments. The results reveal that higher foliar silica concentration in Si-rich plants did not result in changing the morphology of the phytoliths; still the leaf tissue consumption was lower in higher Si treatments, perhaps due to mandibular wear of the grasshoppers. The study opens a new dimension of investigating the role of Si amendments in reducing herbivory.

Springer, 2020

Ectomycorrhizal (ECM) fungi play a crucial role in nutrient mobilization and cycling, particularl... more Ectomycorrhizal (ECM) fungi play a crucial role in nutrient mobilization and cycling, particularly in temperate forests dominated by coniferous species. The belowground ectomycorrhizal Wood Wide Web interconnects innumerable host plants and serves as a sustainable continuum for plant and soil health in forest ecosystems. Conifers, particularly conifer roots harbouring ectomycorrhizal fungi, are rich in phenolics and other secondary metabolites, which interfere and hamper their DNA extraction and inhibit all downstream processes like amplification and sequencing. The present study was projected for presenting the standardized molecular methodology for characterization of ectomycorrhizal fungi from conifer roots, starting from extraction of high-quality DNA and its PCR amplification, followed by DNA purification and loading, to final sequencing, all things reflected in a chronological manner. This chapter highlights the role of root-associated ectomycorrhizal fungi as biofertilizers in forest ecosystems and efficient molecular methods specially optimized for characterization of ectomycorrhizal fungi associated with conifers.

Himalayan forests are dwelling to intriguing plants that are imperative resources of pharmacologi... more Himalayan forests are dwelling to intriguing plants that are imperative resources of pharmacologically active products and possess diverse therapeutic effects. Scores of such plants have been harnessed since centuries for therapeutic and pharmacological demeanor, ensnared universal attention, and are being effectively commercialized across the globe. The present chapter provides an overview of morphological characteristics, distribution, phytochemical composition, and potential pharmacological applications of Abies pindrow (Royle ex D. Don) Royle (Himalayan pindrow fir). Himalayan pindrow fir possesses therapeutic effects including analgesic, antiasthmatic, anticataract, antidiabetic, antihypertensive, antiinflammatory, antimicrobial, antioxidant, antitumor, antitussive, antiulcerogenic, anxiolytic activity, and neuroprotective activities, accredited to its valuable phytoconstituents like carbohydrates, fatty acids, fatty alcohols, flavonoids, glycosides, hydrocarbons, lignans, phen...

Seedling ectomycorrhization is central to conifer forest restoration: a case study from Kashmir Himalaya, 2022

The ecological health hazards posed by unsystematic use of chemical pesticides, pesticide effluen... more The ecological health hazards posed by unsystematic use of chemical pesticides, pesticide effluence, and recuperation of pesticide polluted ecosystems have affianced global deliberations of ecologists, environmentalists, conservationists and environmental policy-makers. Nowadays, endeavours pertaining to application of intriguing ectomycorrhizal association for on-site pesticide remediation are acquiring huge consideration from global scientific community. These ectomycorrhizal (ECM) fungi represent a functional group of enormous importance, that interconnects plants through below-ground colossal hyphal networks and serve as potential indicators of changes in environmental quality. Owing to their specialized lifestyle and mycorrhizoremediation potential, ECM fungi remediate pesticides through enzymatic conversion of noxious pesticides into innocuous residues. As an innovative emerging discipline, ectomycorrhizal biotechnology engrosses application of subsist ECM fungal strains or their prominent fungal enzymes, via contemporary biotechnological approaches, for sustainable remediation and recuperation of gravely disturbed environs. This technology has persuasive potential to arise as an effectual substitute of conventional remediation systems. Present chapter provides an overview of ectomycorrhizal ecology, mycorrhizoremediation of pesticides, fungal enzymes entailed in remediation, role of ectomycorrhizal biotechnology in pesticide remediation, and plant-pollutant-mycorrhiza interactions with reference to climate change.

Heavy metal pollution has deleterious impacts on environment and public health, owing to their to... more Heavy metal pollution has deleterious impacts on environment and public health, owing to their toxicity and persistence, which is a huge apprehension for ecologists and environmentalists globally. Restoration of heavy metal contaminated environs can be achieved through reinstallation of efficient microbial community via soil health improvement, and successful revegetation. Hitherto, inoculation of plants with apposite ectomycorrhizal (ECM) fungi, either alone or in consortia, is the most eco-friendly approach for reclamation of polluted environs. ECM fungi possess adaptive tolerance to heavy metals and have been found to grow in heavy metal contaminated soils. These fungi augment the survival rate and early growth performance of associated host plants, which consecutively facilitate restoration of contaminated sites through acceleration of phyto/mycoremediation processes. Both host plant and associated ECM fungi possess different strategies of heavy metal remediation, which either act independently or operate together in symbiosis. The present chapter presents an overview of heavy metals, their influence on living systems, heavy metal remediation through ectomycorrhizal symbiosis, mechanism involved in remediation of heavy metals through ectomycorrhizal symbiosis, and future research directions.

Freshwater Pollution and Aquatic Ecosystems

Aquatic pollution is one of the grim ecological threats that the world faces, with the maintenanc... more Aquatic pollution is one of the grim ecological threats that the world faces, with the maintenance of appropriate water quality being a major challenge nowadays. Pollution of aquatic ecosystems has adverse impacts on the environment, public health, and economy. In view of that, there is an imperative obligation to safeguard the health of our aquatic ecosystems, and restoration of polluted aquatic environs has attracted worldwide attention. This review provides an overview of different types of aquatic pollutants, their consequences, and mitigation of these pollutants through mycoremediation. Emphasis is laid on different fungal species with their role in mycoremediation of chemical, suspended matter, microbiological, nutrient, groundwater, and oxygen depleting aquatic pollutants into environmentally less detrimental products via diverse mechanisms. Fungi execute a key function in environment cleanup through remediation of aquatic pollutants owing to their diverse metabolic capability comprising well-known fungal enzymes viz., catalases (CAT), cellulases, chitinases, cytochrome P450 monooxygenases, laccases, ligninase, lignocellulases, pectinases, peroxidases, oxidases, and xylanases. Further, this chapter provides comprehensive information about the mycoremediation potential of vast fungal diversity and can serve as a baseline for the selection and use of fungi either independently or in a consortium for forthcoming mycoremediation projects of aquatic ecosystems.

The accumulation and prevalence of pesticide residues in soil and aquatic ecosystems creates enor... more The accumulation and prevalence of pesticide residues in soil and aquatic ecosystems creates enormous ecological problems. Nowadays, besides some traditional means of monitoring pesticides residues, several novel and innovative technologies are being applied. Several developed regions have established pesticide risk assessment models which are of great significance for environmental sustainability. Environmental impact assessment of pesticides influences characterization of previously permitted pesticides, approval of new pesticides, and establishment of remediation goals along with maintenance of environmental quality. Pesticide management strategies encompass assorted pest as well as pesticide management strategies. Novel pesticide management tools and techniques with greater reliability are being developed for improved safety and mitigation of adverse pesticide impacts. Pesticide pollution instigated varied global governmental and non-governmental organizations to frame environmental regulations for management and mitigation of pesticide pollution. This chapter provides an overview of global environmental regulations framed for management of pesticides for global environmental safety, human welfare, and sustainable development.

Pesticides usage has gradually augmented and evolved ever since their initial application in the ... more Pesticides usage has gradually augmented and evolved ever since their initial application in the middle of the 20th century. Currently, usage of pesticides is an indispensable tool for escalating the crop yield as well as protection of economically important crops. Conversely, these pesticides are a major cause of pollution in aquatic and soil ecosystems and most of the pesticides belong to groups that are generally persistent and toxic. Persistent pesticide residues that accumulate and magnify over time, have adverse impacts on environmental and human health. Subsequently, systematic surveillance and management of pesticide utilization is crucial. Conventional methods aimed to eradicate pesticide residues are inefficient and presently bioremediation of these pollutants is a theme of attention with reference to ecological cleaning. This chapter gives an overview of potential "microbioremediation" strategies and use of potential microalgal-bacterial-fungal consortia for recuperation of pesticide polluted freshwater and soil environments. Information about potential microbial consortia that can be availed for remediation of range of pesticides can serve as baseline data for formulation of various remediation strategies and pesticide management projects.

Globally, in the process of agricultural development, the initial use of pesticides was an indisp... more Globally, in the process of agricultural development, the initial use of pesticides was an indispensable tool that improved food security by protecting economically important crops. Nevertheless, incessant and indiscriminate utilization of pesticides due to modern agricultural and healthcare practices contaminated the environment and has become a serious ecological and public health hazard due to their persistent nature, multifaceted toxicity, and recalcitrance, long-range environment transport potential, bioaccumulation, and biomagnification knack. To combat pesticide pollution in agricultural and non-agricultural settings, diverse techniques categorized as physical, chemical, physicochemical, biochemical, and biological remediation techniques have been employed worldwide either independently or in the alliance. Selection of effective remediation technique through proper screening method is crucial for restoration of pesticide-polluted environs. This chapter appraises global ecological and health hazards of pesticides, global scenario of pesticide production and usage, selection of remediation technique through screening approaches, global scenario of pesticide remediation techniques, indicators of sustainable remediation, and economics of global remediation sector. This chapter particularly summarizes the current global scenario of all the existing and emerging pesticide remediation techniques used to combat the menace of pesticide pollution hitherto. Moreover, this chapter focuses on knowledge gaps and future research directions for developing novel strategies for minimizing pesticide-related ecological problems.

Artemisia amygdalina, a critically endangered aromatic plant species, which is endemic to subalpi... more Artemisia amygdalina, a critically endangered aromatic plant species, which is endemic to subalpine habitats of North Western Himalayas, serves as a rich repository of pharmacologically active constituents. Despite being medicinally imperative, this Artemisia species has acquired diminutive attention and is presently limited to miniature populations in Kashmir Himalayan region. Therapeutically active phytoconstituents of this plant species encompass alkaloids, cardiac glycosides, phenolics, steroids, tannins, terpenes, and other essential oils, with 1,8-cineole, 3-carene, artemisinin, artesunate, camphene, ludartin, p-cymene, santonin, α-cadinol, α-pinene, and β-pinene being the characteristic compounds isolated so far. Several therapeutic activities ascribed to these essential bioactive compounds extracted from this species include analgesic, antibacterial, anticancerous, anticonvulsant, antidepressant, antidiabetic, antifungal, antihelminthic, antiinflammatory, antimalarial, antio...