Richa Raghuwanshi

Towards the Soil Sustainability and Potassium-Solubilizing Microorganisms

Potassium (K) is needed in adequate quantities for a crop to achieve its maximum yield. The function of potassium in plant growth has not been clearly defined but it is associated with movement of water, nutrients and carbohydrates in plant tissue. When potassium is not adequate, the plants will have poor root development and will grow slowly, and their seeds will become small and have lower yields. About 5 million tonnes of potassic fertilizer requirement would be fulfilled through imports because India does not have commercial-grade sources of potash reserve. India is totally dependent on the import of potassic fertilizers. On the other hand, India has the largest reserve for low potassium-containing minerals. The depletion of potassium in soil has been started, and in future this will aggravate. In most of the soils, about 90–98 % of total K exists in relatively unavailable minerals such as feldspar, orthoclase and the micas (muscovite, biotite, phlogopite, etc.). These minerals are very resistant to decomposition and probably supply relatively smaller quantity of potassium to growing crops. Potassium in soil is present in four forms: water-soluble (solution K), exchangeable, non-exchangeable and structural or mineral forms. The fixed form of K minerals is solubilized by K solubilizers, and then acquisition or accumulation of potassium by crop plants certainly will be enhanced. For evergreen agriculture, production can only be fulfilled when the environment, its caretakers and surrounding communities are healthy, for this application of KSMs holds a key approach for K availability in soils. KSB increased K availability in soils and increased mineral nutrient specially K uptake by plant.

Trichoderma species mediated differential tolerance against biotic stress of phytopathogens in Cicer arietinum L.

Trichoderma spp. have been reported to aid in imparting biotic as well as abiotic tolerance to plants. However, there are only few reports unfolding the differential ability of separate species of Trichoderma genera generally exploited for their biocontrol potential in this framework. A study was undertaken to evaluate the biocontrol potential of different Trichoderma species namely T. harzianum, T. asperellum, T. koningiopsis, T. longibrachiatum, and T. aureoviride as identified in the group of indigenous isolates from the agricultural soils of Eastern Uttar Pradesh, India. Their biocontrol potential against three major soilborne phytopathogens, i.e., Sclerotium rolfsii, Sclerotinia sclerotiorum, and Colletotrichum capsici was confirmed by dual culture plate technique. Efficient mycoparasitic ability was further assessed in all the isolates in relation to chitinase, β‐1,3 glucanase, pectinase, lipase, amylase, and cellulase production while equally consistent results were obtained for their probable phosphate solubilization and indole acetic acid (IAA) production abilities. The selected isolates were further subjected to test their ability to promote plant growth, to reduce disease incidence and to tolerate biotic stress in terms of lignification pattern against S. rolfsii in chickpea plants. Among the identified Trichoderma species, excellent results were observed for T. harzianum and T. koningiopsis indicating better biocontrol potential of these species in the group and thus exhibiting perspective for their commercial exploitation.

Molecular, phenotypic and pathogenic variability in Colletotrichum isolates of subtropical region in north-eastern India, causing fruit rot of chillies

To study the genetic variability and population structure of Colletotrichum species found to be associated with anthracnose of chilli in the north‐eastern region of India.

Chilli Anthracnose: The Epidemiology and Management

Indian cuisine is renowned and celebrated throughout the world for its spicy treat to the tongue. The flavor and aroma of the food generated due to the use of spices creates an indelible experience. Among the commonly utilized spices to stimulate the taste buds in Indian food, whole or powdered chilli constitutes an inevitable position. Besides being a vital ingredient of of Indian food, chilli occupy an important position as an economic commodity, a major share in Indian economy. Chilli also has uncountable benefits to human health. Fresh green chilli fruits contain more Vitamin C than found in citrus fruits, while red chilli fruits have more Vitamin A content than as found in carrots. The active component of the spice, Capsaicin possesses the antioxidant, anti-mutagenic, anti-carcinogenic and immunosuppressive activities having ability to inhibit bacterial growth and platelet aggregation. Though introduced by the Portuguese in the Seventeenth century, India has been one of the major producers and exporters of this crop. During 2010–2011, India was the leading exporter and producer of chilli in the world, but recently due to a decline in chilli production, it stands at third position in terms of its production. The decline in chilli production has been attributed to the diseases linked with crop like anthracnose or fruit rot causing the major share of crop loss. The disease causes severe damage to both mature fruits in the field as well as during their storage under favorable conditions, which amplifies the loss in yield and overall production of the crop. This review gives an account of the loss in production and yield procured in chili cultivation due to anthracnose disease in Indian sub-continent, with emphasis given to the sustainable management strategies against the conventionally recommended control for the disease. Also, the review highlights the various pathogenic species of Colletotrichum spp, the causal agent of the disease, associated with the host crop in the country. The information in the review will prove of immense importance for the groups targeting the problem, for giving a collective information on various aspects of the epidemiology and management of the disease.

Microbial Diversity and Biotechnology in Food Security

The roles of microbes in agriculture, industry and environment have been the point of interest since long time for their potential exploitation. Although only a fraction of microbial diversity was accessed by microbiologists earlier for harnessing them owing to limited techniques available. The molecular techniques have opened new vistas to access the wide field of the unexplored microbes and their exploitation for useful genes and novel metabolites. Sincere efforts have been made in biotechnology using microbes leading to improve our life with respect to agriculture and people health. This comprehensive volume covers different aspects of microbial biotechnology and its management in sustainable agriculture for food security and improved human health. The book comprises four sections: Endophytes and Mycorrhizae, Microbial Diversity and Plant Protection, Microbial Functions and Biotechnology, and Microbes and the Environment, which contain 53 chapters. The book examines the aspects on endophytes and mycorrhizae, bioactive compounds, growth promoting microorganisms, disease management with emphasis on biocontrol, genetics of disease resistance, microbial enzymes, advances in potential of microbes and their industrial as well as pharmaceutical applications. In addition, the use of botanicals, and the etiology and management of medicinal and aromatic plants in the post harvest management have been reviewed in greater depth for the benefit of teaching and research community. The biotechnological developments using microbe potential have enabled us combat the environment and human health problems worldwide in ecofriendly manner. We are sure that this volume will be highly useful to all those concerned with fungi, bacteria, viruses and their biology, including environmental and public health officers and professionals in the field of interest. The volume is an exhaustive coverage of almost all the aspects of microbial biology and biotechnology

Perspectives of Rhizobacteria with ACC Deaminase Activity in Plant Growth Under Abiotic Stress

The abiotic and biotic stresses in the environment trigger the synthesis of ethylene, a gaseous plant hormone that leads to many physiological changes in plants that inhibit plant growth and development. Plant growth inhibition that accrues from the stress can be overcome to a large extent by lowering the amount of ethylene that is synthesized in response to stress by the application of ACC deaminase-producing bacteria. The plant growth-promoting bacteria also give other multifacet benefits as they promote plant growth through enhancing nutrient uptake and hormone production and acting as a biocontrol agent. The enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase present in bacterium cleaves ACC, the precursor of ethylene, and thereby lowers the ethylene level and facilitates plant growth. Plants respond similarly to ACC deaminase regardless of whether the enzyme is expressed in the roots of transgenic plants or as part of a root-associated bacterium. The role of growth-promoting bacteria is encouraging in this area. Thus overcoming stress responses in plants through ACC deaminase-producing bacteria has come up as an effective tool, when the agricultural practices worldwide are seeking a sustainable approach to the issues of food security under the changing climatic conditions. The present review discusses the role of ACC deaminase-producing bacteria in ameliorating the various abiotic stress responses in plants induced by ethylene.

Microfungi in Biofuel and Bioenergy Research

During the last two decades, there has been increasing interest in biodiesel as an alternative biofuel. Oleaginous fungi can represent a sustainable alternative to plant oil for the production of biodiesel and they can accumulate intracellular lipids up to 70 % under stress condition. Oleaginous fungi have given a new turn to fuel generation, as their lipids are rich in Tri-acyl glyceraldehydes (TAG) and specific polyunsaturated fatty acids (PUFA). With the increase in population, fuel production will be highly expensive and therefore a promising alternative is to look at microbial oil technology. This chapter focuses on the important fungi and enzymes involved in biofuel production and recent technologies for lipid extraction, which provide a platform for a viable and successful development in an industrial production process.

Linking Mycorrhizal Technology with Medicinal Plant Secondary Metabolites

Mycorrhizae are symbiotic associations formed between the roots of most plant species and fungi. Symbiosis is characterized by bidirectional movement of nutrients where carbon flows to the fungus from the plant and inorganic nutrients move to the plant, thereby providing a critical linkage between the plant, root and soil. Symbiosis of arbuscular mycorrhizal fungi (AMF) with higher plants results in growth promotion and accumulation of secondary metabolites like alkaloids, flavonoids and terpenoids, which have pharmacological characteristics. A detailed study revealed that mutualistic symbiosis has great applications in cultivation of medicinal/endangered plants for obtaining a high level of bioactive compounds. Recent work suggest that mycorrhization not only has a positive effect on various plant growth parameters but also enhances the essential oil concentrations, alkaloids, flavanoids and other secondary metabolites in a number of plants from different plant families. Endangered plant species like Plantago atrata, Pulsatilla slavica (IUCN Red list) and Senecio umbrosus have wide possibilities in improving their ex-situ conservation and enhancement of metabolic content through mycorrhizal technology. Mycorrhizal technology may be used in the enhancement of plant’s secondary metabolites efficacious as antioxidant, antibacterial, antifungal content and also in conservation of endangered plant species.

Carnivorous Plants: The molecular biology behind the wonder plants

Nature has a plethora of fascinations with its microbial diversity to its unusual live forms. One of the many fascinations that have caught the interest of both scientists as well as common man are the insect eating plants. Against the conventionally prevailing norm of autotrophy among plants, this group has been successful in setting ripples in the scientific world. This article gives brief information regarding the habitat and nutrition of the group along with its evolutionary history describing the diversity that persists. The role of molecular biology in solving many unsolved mysteries concerning the mechanisms involved in the probable adaptation of carnivory by the group has been elucidated. The only species endemic to India, Nepenthes khasiana, has been described with its conservation and cultivation strategies employed. Owing to their different mode of nutrition, appearance and habitat, these can be referred to as the “Non-Veggies” of plant kingdom!!