Indigenous entomopathogenic nematode as biocontrol agents for insect pest management in hilly regions

The present investigation mainly emphasized on the development and use of entomopathogenic nematodes (EPNs) as a bio-insecticide. The success in controlling insect pests in the soil environments increased the production and use of the adapted indigenous EPNs species for insect management in the fields. EPNs as biocontrol agents were capable for high virulence, easy for application, safe for non-target animals and eco-friendly in nature. These nematodes have ubiquitous nature. These occur in low population in their natural habitat which was mass multiplied in the laboratory. In the present investigation, 5 concentrations (30IJs, 60IJs, 90IJs, 120IJs and 150IJs) of Heterorhabditis bacteriophora strain S15 were applied against the 3rd and 4th instar larvae of four major agricultural insect pests, namely Helicoverpa armigera, Spodoptera litura, Agrotis segetum and Mythimna separata under laboratory conditions at different time exposure (24, 48, 72 and 96 hr). It was observed that the 3rd and 4th larval instars of all 4 insects (H. armigera, S. litura, A. segetum and M. separata) were highly susceptible for the pathogenesis caused by H. bacteriophora Sirmaur isolates. Amongst all insects, both the larval instars of M. separata are highly susceptible for EPNs infection with highest 96% and 98% mortality in highest dose @150IJs. In 3rd instar larvae of other insects such as H. armigera, S. litura and A. segetum larval mortality ranges from 84%, 92% and 94% respectively. Among 4th instar larvae of H. armigera, S. litura and A. segetum the pathogenicity varies from 88%, 94% and 96% respectively. The recorded median lethal concentration (LC50) in 3rd instar larvae of H. armigera, S. litura, A. segetum and M. separata varies from 36.15, 30.05, 30.97 and 23.8. Similarly in 4th instar larvae of H. armigera, S. litura, A. segetum and M. separata, LC50 ranged from 31.41, 28.64, 26.92 and 20.64 respectively. Statistically significant variations were observed in the data recorded on the mortality, in all the treatments. EPNs are the best weapon to overcome insect resistance problems and must be employed to manage insect population

Soil and phytomicrobiomes for plant growth and soil fertility

Soil is the basic requirement for agriculture crop production and simultaneously the microbial activity is important to improve soil health for healthy crop growth because microbial communities play an important role in building a complex link between plants and soil. Microbiomes from plants, soil and extreme environments are naturally gifted with amazing capabilities which play significant roles in the maintenance of global nutrient balance and ecosystem functions. The microbiomes from diverse niches have in fact emerged as potential tools for improving the plant growth and productivity by diverse mechanisms include solubilization of nutrients, nitrogen fixation, hormonal stimulation as well as biotic and abiotic stress tolerance. Further, these microbiomes have an immense potential to maintain soil health and fertility. Thus, dependent on their mode of action and effects, these microbiomes can be used as biofertilizers, biopesticides, plant strengtheners, and phytostimulators which will play a major role in improving productivity and achieving sustainability in an eco-friendly, economical and cost effective manner

Plant growth promotion of barley (Hordeum vulgare L.) by potassium solubilizing bacteria with multifarious plant growth promoting attributes

Potassium (K) is the foremost macronutrients for growth of plant, soil health and fertility. The huge application of NPK chemical fertilizers negatively impacts the economy and is a threat to environmental sustainability. The rapid depletion of K mineral in soil is due to the application of agrochemicals agricultural fields for the production of crops in India. In present investigation, K-solubilizing microbes (KSM) were isolated and enumerated from cereal crops growing in Sirmour Himachal Pradesh. A total 125 bacteria were isolated and screened for K- solubilization on Aleksandrov agar plates and found that 31 bacterial strains exhibited K-solubilization. These 31 K-solubilizing strains of bacteria were additionally screened for other plant growth promoting (PGP) potential including solubilization of minerals, production of siderophores, ammonia, hydrogen cyanide and indole acetic acids. The performance of an efficient K-solubilizer was evaluated for plant growth promoting ability in pot assay under in vitro conditions. The strain EU-LWNA-25 positively influenced shoot length, fresh weight, carotenoids and total sugar content than the full dose, half dose and control. The strain enhancing physiological and growth parameters was identified by BLASTn analysis as Pseudomonas gessardii EU-LWNA-25. K-solubilizing plant growth promoting bacteria could be suitable bioinoculants for Rabi seasonal crops and overcomes the challenges of sustainable agriculture in K-deficient soil

Plant Growth Promoting Microbes as Biofertilizers: Promising solutions for sustainable agriculture under climate change associated abiotic stresses

Abiotic stresses are major constraints for plant growth, crop yield and global food security. Plant physiological, biochemical and molecular processes are highly affected under unfavorable environmental conditions, resulting in substantial losses to crop productivity and requiring an immediate response. Abiotic stress resistant plant growth-promoting rhizobacteria (PGPR) are a profitable and sustainable solution because of their efficiency in plant growth regulation, crop yield improvement and abiotic stress alleviation. They help plants to cope with growth inhibitory effects of abiotic stresses through several mechanisms, mainly phytohormones and osmolyte production, improvement of nutrient acquisition, enhancement of antioxidant system. Plant-PGPR interactions are vital for sustainable agriculture and industrial purposes, because they are based on biological processes and replace conventional agricultural practices. PGPR may play a key role as an ecological engineer to solve environmental stress problems. The use of microbes is a feasible and potential technology to help meeting the future global food needs with reduced impact on soil and environmental quality. Present review deals about the abiotic stresses (drought and salinity) affecting plant growth and highlights the impact of PGPR on restoration of plant growth under the stressful conditions with the goal of developing an eco-friendly and cost-effective strategy for agricultural sustainability

Edible Mushrooms: A Comprehensive Review on Bioactive Compounds with Health Benefits and Processing Aspects

Mushrooms are well-known functional foods due to the presence of a huge quantity of nutraceutical components. These are well recognized for their nutritional importance such as high protein, low fat, and low energy contents. These are rich in minerals such as iron, phosphorus, as well as in vitamins like riboflavin, thiamine, ergosterol, niacin, and ascorbic acid. They also contain bioactive constituents like secondary metabolites (terpenoids, acids, alkaloids, sesquiterpenes, polyphenolic compounds, lactones, sterols, nucleotide analogues, vitamins, and metal chelating agents) and polysaccharides chiefly β-glucans and glycoproteins. Due to the occurrence of biologically active substances, mushrooms can serve as hepatoprotective, immune-potentiating, anti-cancer, anti-viral, and hypocholesterolemic agents. They have great potential to prevent cardiovascular diseases due to their low fat and high fiber contents, as well as being foremost sources of natural antioxidants useful in reducing oxidative damages. However, mushrooms remained underutilized, despite their wide nutritional and bioactive potential. Novel green techniques are being explored for the extraction of bioactive components from edible mushrooms. The current review is intended to deliberate the nutraceutical potential of mushrooms, therapeutic properties, bioactive compounds, health benefits, and processing aspects of edible mushrooms for maintenance, and promotion of a healthy lifestyle.info:eu-repo/semantics/publishedVersio

Hot springs of Indian Himalayas: potential sources of microbial diversity and thermostable hydrolytic enzymes

Microbial communities in hot springs at high elevations have been extensively studied worldwide. In this sense, the Indian Himalaya regions is valuable ecosystems for providing both the extreme ‘cold’ and ‘hot’ sites for exploring microbial diversity. In the present study, a total of 140 thermophilic bacteria were isolated from 12 samples collected from Manikaran and Yumthang hot springs of Indian Himalayas. The bacterial isolates were studied for phylogenetic profiling, growth properties at varying conditions and potential sources of extracellular thermostable hydrolytic enzymes such as protease, amylase, xylanase and cellulase. Based on production of extracellular hydrolases, 51 isolates from Manikaran (28) and Yumthang thermal springs (23) were selected and identified using 16S rRNA gene sequencing which included 37 distinct species of 14 different genera namely Anoxybacillus, Bacillus, Brevibacillus, Brevundimonas, Burkholderia, Geobacillus, Paenibacillus, Planococcus, Pseudomonas, Rhodanobacter, Thermoactinomyces, Thermobacillus, Thermonema and Thiobacillus. Out of 51 hydrolase producing bacteria, 24 isolates showed stability at wide range of temperature and pH treatments. In present investigation, three thermotolerant bacteria namely, Thermobacillus sp NBM6, Paenibacillus ehimensis NBM24 and Paenibacillus popilliae NBM68 were found to produced cellulase-free xylanase. These potential extracellular thermostable hydrolytic enzymes producing thermophilic bacteria have a great commercial prospect in various industrial, medical and agriculture applications

The Plant Growth-Promoting Potential of Halotolerant Bacteria Is Not Phylogenetically Determined: Evidence from Two Bacillus megaterium Strains Isolated from Saline Soils Used to Grow Wheat

1) Background: Increasing salinity, further potentiated by climate change and soil degra- dation, will jeopardize food security even more. Therefore, there is an urgent need for sustainable agricultural practices capable of maintaining high crop yields despite adverse conditions. Here, we tested if wheat, a salt-sensitive crop, could be a good reservoir for halotolerant bacteria with plant growth-promoting (PGP) capabilities. (2) Methods: We used two agricultural soils from Algeria, which differ in salinity but are both used to grow wheat. Soil halotolerant bacterial strains were isolated and screened for 12 PGP traits related to phytohormone production, improved nitrogen and phosphorus availability, nutrient cycling, and plant defence. The four ‘most promising’ halotolerant PGPB strains were tested hydroponically on wheat by measuring their effect on germination, sur- vival, and biomass along a salinity gradient. (3) Results: Two halotolerant bacterial strains with PGP traits were isolated from the non-saline soil and were identified as Bacillus subtilis and Pseudomonas fluorescens, and another two halotolerant bacterial strains with PGP traits were isolated from the saline soil and identified as B. megaterium. When grown under 250 mM of NaCl, only the inoculated wheat seedlings survived. The halotolerant bacterial strain that displayed all 12 PGP traits and promoted seed germination and plant growth the most was one of the B. megaterium strains isolated from the saline soil. Although they both belonged to the B. megaterium clade and displayed a remarkable halotolerance, the two bacterial strains isolated from the saline soil differed in two PGP traits and had different effects on plant performance, which clearly shows that PGP potential is not phylogenetically determined. (4) Conclusions: Our data highlight that salt-sensitive plants and non-saline soils can be reservoirs for halotolerant microbes with the potential to become effective and sustainable strategies to improve plant tolerance to salinity. However, these strains need to be tested under field conditions and with more crops before being considered biofertilizer candidates.info:eu-repo/semantics/publishedVersio

Mitigation of low temperature stress and plant growth promotion in barley (Hordeum vulgare L.) by inoculation of psychrotrophic P-solubilizing Serratia nematodiphila EU-PW75

Agriculture is one of the exposed sectors to abiotic stress conditions. There are diverse abiotic stress in which low temperature is an important abiotic stress limiting plant growth and development. The low temperature (0–20 °C) adaptive microbial communities are of particular interest because of their adaptability to prevailing conditions. Phosphorus is an important growth nutrient for the plants. Low temperature and phosphorus limitations act as the stress factors for the plants. Psychrotrophic microbiomes with P-solubilizing ability are gaining attention because of their amazing role in enhancing the availability of P and growth under low temperatures. In the present study, different crops with their rhizospheric soil from Poonch region of Jammu and Kashmir were collected for isolation of potential plant growth promoting psychrotrophic bacteria. A total of 65 isolates were obtained on different growth media. Among 65 isolates, 29 exhibited P-solubilizing capability. On basis of P-solubilizing ability and multiple PGP attributes, bacterial strain EU-PW75 was identified on basis of 16S rRNA gene sequencing as Serratia nematodiphila. The strain EU-PW75 was used for plant growth promotion of barley under conditions of low temperature where it efficiently improved the growth and physiological parameters of barley. The low temperature adaptive microbes with PGP activities could be useful for cold stress alleviation and plant growth promotion of crops growing under the low temperature

Bioprospecting of plant growth promoting psychrotrophic Bacilli from the cold desert of north western Indian Himalayas

142-150<span style="font-size:11.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-GB">The plant growth promoting psychrotrophic<span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-in;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-in;="" mso-bidi-language:hi"="" lang="EN-GB">Bacilli were investigated from different sites in north<span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">western Indian Himalayas. A total of 247 morphotypes were obtained from different soil and water samples and were grouped into 43 clusters based on 16S rDNA-RFLP analysis with three restriction endonucleases. Sequencing of representative isolates has revealed that these 43 Bacilli belonged to different species of 11 genera viz.<span style="mso-bidi-font-style: italic">, Desemzia, Exiguobacterium,<i style="mso-bidi-font-style: normal"> Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus,<i style="mso-bidi-font-style: normal"> Pontibacillus, Sinobaca, Sporosarcina,<i style="mso-bidi-font-style: normal"> Staphylococcus and Virgibacillus. With an aim to develop microbial inoculants that can perform efficiently at low temperatures, all representative isolates were screened for different plant growth promoting traits at low temperatures (5-15<span style="font-size:11.0pt; font-family:Symbol;mso-ascii-font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-hansi-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi;mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">°C). Among the strains, variations were observed for production (%) of indole-3-acetic acid (20), ammonia (19), siderophores (11), gibberellic acid (4) and hydrogen cyanide (2); <span style="font-size: 11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">solubilisation (%) of zinc (14), phosphate (13) and potassium (7); 1-aminocyclopropane-1-carboxylate deaminase activity (6%) and biocontrol activity (4%) against <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi;mso-bidi-font-weight:bold"="" lang="EN-GB">Rhizoctonia solani and Macrophomina phaseolina. Among all the strains, <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">Bacillus licheniformis,<i style="mso-bidi-font-style: normal"> Bacillus muralis, Desemzia incerta, <span style="mso-bidi-font-weight: bold;mso-bidi-font-style:italic">Paenibacillus tylopili and Sporosarcina globispora were found to be potent candidates to be developed as inoculants as they exhibited multiple PGP traits at low temperature.</span

Understanding the plant-microbe interactions in environments exposed to abiotic stresses: An overview

Abiotic stress poses a severe danger to agriculture since it negatively impacts cellular homeostasis and eventually stunts plant growth and development. Abiotic stressors like drought and excessive heat are expected to occur more frequently in the future due to climate change, which would reduce the yields of important crops like maize, wheat, and rice which may jeopardize the food security of human populations. The plant microbiomes are a varied and taxonomically organized microbial community that is connected to plants. By supplying nutrients and water to plants, and regulating their physiology and metabolism, plant microbiota frequently helps plants develop and tolerate abiotic stresses, which can boost crop yield under abiotic stresses. In this present study, with emphasis on temperature, salt, and drought stress, we describe current findings on how abiotic stresses impact the plants, microbiomes, microbe-microbe interactions, and plant-microbe interactions as the way microor ganisms affect the metabolism and physiology of the plant. We also explore crucial measures that must be taken in applying plant microbiomes in agriculture practices faced with abiotic stresses