Fungal Endophytes to Combat Biotic and Abiotic Stresses for Climate-Smart and Sustainable Agriculture

The agricultural sustainability concept considers higher food production combating biotic and abiotic stresses, socio-economic well-being, and environmental conservation. On the contrary, global warming-led climatic changes have appalling consequences on agriculture, generating shifting rainfall patterns, high temperature, CO2, drought, etc., prompting abiotic stress conditions for plants. Such stresses abandon the plants to thrive, demoting food productivity and ultimately hampering food security. Though environmental issues are natural and cannot be regulated, plants can still be enabled to endure these abnormal abiotic conditions, reinforcing the stress resilience in an eco-friendly fashion by incorporating fungal endophytes. Endophytic fungi are a group of subtle, non-pathogenic microorganisms establishing a mutualistic association with diverse plant species. Their varied association with the host plant under dynamic environments boosts the endogenic tolerance mechanism of the host plant against various stresses via overall modulations of local and systemic mechanisms accompanied by higher antioxidants secretion, ample enough to scavenge Reactive Oxygen Species (ROS) hence, coping over-expression of defensive redox regulatory system of host plant as an aversion to stressed condition. They are also reported to ameliorate plants toward biotic stress mitigation and elevate phytohormone levels forging them worthy enough to be used as biocontrol agents and as biofertilizers against various pathogens, promoting crop improvement and soil improvement, respectively. This review summarizes the present-day conception of the endophytic fungi, their diversity in various crops, and the molecular mechanism behind abiotic and biotic resistance prompting climate-resilient aided sustainable agriculture.Peer reviewe

Antimicrobial and Antioxidant activities of Arnebia benthamii (Wall ex. G. Don Johnston) - A Critically Endangered Medicinal plant of Kashmir

Plants used in traditional medicines contain a vast array of substances that can be used to treat chronic and infectious diseases and the present study was carried out with the same intentto appraisethe possible medicinal value of Arnebia benthamii L. (Wall. ex G. Don) Johnston [Syn Macrotomia benthamii (Wall.) DC.] a threatened medicinal plant of Kashmir valley by examining its phyto-chemical constituents and evaluating the antimicrobial and antioxidant activity. Preliminary phytochemical screening was carried out to detect the presence of phyto-chemicals that add to the medicinal value of the plant. The antimicrobial assay was carried out by Disc diffusion and Micro-broth dilution methods. The crude plant extracts (both root as well as aerial parts) exhibited significant antimicrobial activity on majority of test organisms tested. The highest occurrence of secondary metabolites was of alkaloids and phenolic substances. The tannins and saponins were absent in all plant extracts. The total phenolic content that was quantitatively estimated showed highest presence in methanol extracts of the aerial parts. The antibacterial results revealed that methanol extracts of aerial parts were found to exhibit significant antibacterial activities against all tested bacterial strains except Staphylococcus aureus which was found resistant. The highest inhibition zone diameter (30mm) was recorded for Pseudomonas aeruginosa and Escherichia coli with respect to control i.e. Gentamycin (16 and21mm) followed by Salmonella typhimurium (28 mm). Chloroform extract also showed good inhibitory activity against all the tested bacterial strains likeE. coli (22mm) followed by Klebsella pnuemonie (20 mm) and P. aeruginosa (17mm). The aqueous extract didn’t show any inhibitory activity against the tested bacterial strains. The root extracts were separately tested for antibacterial activity against pathogenic strains and it was apparent from the results that they were less active than aerial part extracts. Among the strains tested, S. aureus was found susceptible to chloroform, ethyl acetate and methanol root extracts with an average inhibition zone diameter (10 mm) with respect to control and rest of extracts showed no activity against it. The Shigella flexneri was found susceptible to all the root extracts and the highest inhibition zone diameter was recorded for methanol (20mm) followed by ethanol (15 mm)against the control (Erythromicin 30 mm). Among all the strains, E. coli was highly susceptible towards the methanol root extracts followed by chloroform and ethyl acetate extract while the rest of the extracts did not exhibit any inhibitory activity. Most of the root extracts exhibit highest antibacterial activity against S. typhimurium compared to aerial parts. The screening served a s an indicator f or the selection of bacterial strains that displayed antibacterial activity for further testing to determine the MIC’s of plant extracts. Four bacterial strains S. fle xnerii, K. pneumonia, E. coli and P. aeruginosa were found viable for testing with the specific plant extracts. S. flexnerii was found highly susceptible towards methanol aerial part extract with MIC and MBC value of 200μg/ml and 750 μg/ml respectively as compared to reference (Erythromycin75 and 100 μg/ml) followed by methanol root extract { MIC 300 μg/ml and500 MBC μg/ml}. Methanol aerial part extract exhibited the MIC value 500 μg/ml and MBC 750 μg/ml against K. pneumonia. However the root extracts showed co mparatively higher value of MIC against the tested organism ranging f rom400-500μg/ml with respect to positive control (MIC-150 μg/ml).The MIC value for E . coli ranged between 150 to 500 μg/ml towards aerial part extracts w ith lowest MIC observed for methanol aerial part extract with respect to Erythromycin (175 μg/ml), and for root extract MIC value ranged between 225 -425 μg/ml. P. aeruginosa was found to be most susceptible towards all aerial part extracts with MIC value ranged between 75 μg/ml and 425 μg/ml and MBC value from 100 to750 μg/ml. All the fungal strains except Candida parapsilosis were more or less inhibited b y both aerial and root part extracts of the plant. The aqueous extract of both root as well as aerial parts did not show any antifungal activity. Asperigillus flavus was found to be highly susceptible to butanol aerial part extract with inhibition zone diameter (25mm) followed by ethyl acetate extract(22 mm) and chlorof orm extract (14 mm) compared to the control (Nystatin 35mm) used. The methanol aerial part extract showed highest inhibitory activity against Asperigill us versicolor with inhibition zone diameter (22 mm) and Acremonium spp (25 mm). The petroleum ether, ethyl acetate and chloroform extracts of aerial part did not exhibit any inhibitory activity against Candida spp . Only methanol extract followed by ethanol and butanol extract exhibited antif ungal activity against Candida spp. Among the Candida spp, the highest inhibition zone diameter (14 mm) of methanol extract was seen against C. albicans whereas C. parapsalosis was found completely resistant against the all aerial part extra cts. The ethanol and aqueous root extracts didn’t exhibit any inhibitory activity against any tested fungal strains. Meanwhile the ethyl acetate extract sho wed highest inhibition zone diameter(33mm) against C. albicans f ollowed by Acremonium spp (18mm).The methanol root extract showed good inhibitory activity with an average inhibition zone diameter (12mm) against A. versicolor, C. albicans and C. kruesie with respect to reference used. The four in-vitro tests i.e. DPPH radical scavenging action, riboflavin photo- oxidation method, hydroxyl scavenging and the lipid peroxidation assay for antioxidant activity were used. Together all the methods provide a better assessment of antioxidant properties and results revealed that inhibitory activity was concentration dependent. Free radical scavenging potential of aerial and root part extracts at different concentrations was tested by the DPPH method. Highest inhibition of 86% and 94% was recorded for both methanol extracts of aerial as well as root parts with respect to reference (Ascorbic acid 90%) at the higher concentration (300 μg/ml) followed by ethyl acetate (60%) and chloroform extract (63 %) of aerial parts. The superoxide radical scavenging activity of aerial parts was observed in the following order butanol extract (85%) >ethyl acetate (79%)> methanol extract (70%) however Petroleum ether, ethanol and aqueous extracts didn't exhibit any scavenging activity. The root extracts were also effective in scavenging the superoxide radicals and the order of scavenging was as butanol (91%)> methanol (88%)>aqueous (79%) extracts. As far as the protective effect of deoxyribose was concerned, the highest inhibition of radicals was observed for methanol extract of root part and aerial part (~85% inhibition). The ethanol extracts of both parts were found to be ineffective. The overall inhibition of FeSO4 induced lipid peroxidation was high in presence of positive control (ascorbic acid 95.78±1.0%) compared to the plant extracts of A. benthamii. However, the ethyl acetate extract of aerial parts (95 %) showed almost the same activity as compared to the reference antioxidant. The ethyl acetate (87%) of root parts also exhibited significant inhibitory activity followed by ethanol extracts (78%)

Role of Salicylic Acid in Combating Heat Stress in Plants : Insights into Modulation of Vital Processes

Peer reviewe

Radical scavenging potential and DNA damage protection of wild edible mushrooms of Kashmir Himalaya

The edible mushrooms Verpa bohemica and Morchella esculenta are locally used for dietary and antioxidant in tribal areas of Kashmir Himalaya. In the present study, sequences of solvents on the basis of their polarity were used for the extraction from selected mushrooms. The comprehensive antioxidant activity of all edible mushroom extracts was evaluated by seven different methods. V. bohemica exhibited significant inhibitory activity of radicals among all the mushrooms while Morchella extracts protected the DNA damage from OH· radicals. This study provides us the substantiation for the use of these mushrooms as antioxidants besides being already eaten as food

Cloning and Expression of the Organophosphate Pesticide-Degrading α-β Hydrolase Gene in Plasmid pMK-07 to Confer Cross-Resistance to Antibiotics

Pesticide residual persistence in agriculture soil selectively increases the pesticide-degrading population and transfers the pesticide-degrading gene to other populations, leading to cross-resistance to a wide range of antibiotics. The enzymes that degrade pesticides can also catabolize the antibiotics by inducing changes in the gene or protein structure through induced mutations. The present work focuses on the pesticide-degrading bacteria isolated from an agricultural field that develop cross-resistance to antibiotics. This cross-resistance is developed through catabolic gene clusters present in an extrachromosomal plasmid. A larger plasmid (236.7 Kbp) isolated from Bacillus sp. was sequenced by next-generation sequencing, and important features such as α-β hydrolase, DNA topoisomerase, DNA polymerase III subunit beta, reverse transcriptase, plasmid replication rep X, recombination U, transposase, and S-formylglutathione hydrolase were found in this plasmid. Among these, the α-β hydrolase enzyme is known for the degradation of organophosphate pesticides. The cloning and expression of the α-β hydrolase gene imply nonspecific cleavage of antibiotics through a cross-resistance phenomenon in the host. The docking of α-β hydrolase with a spectrum of antibiotics showed a high G-score against chloramphenicol (−3.793), streptomycin (−2.865), cefotaxime (−5.885), ampicillin (−4.316), and tetracycline (−3.972). This study concludes that continuous exposure to pesticide residues may lead to the emergence of multidrug-resistant strains among the wild microbial flora

Manipulation of Plant Growth Regulators on Phytochemical Constituents and DNA Protection Potential of the Medicinal Plant Arnebia benthamii

Arnebia benthamii of the family Boraginaceae is a critically endangered nonendemic plant of the Kashmir Himalayas and is used to treat a number of human diseases. The current study was based on developing an in vitro micropropagation protocol vis-à-vis induction of various secondary metabolites under in vitro conditions for the possible biological activity. A tissue culture protocol was developed for A. benthamii for the first time in the Himalayan region using varied combinations and proper media formulations, including various adjuvants: Murashige and Skoog (MS) media, growth hormones, sugars, agar, and so forth. The influence of different media combinations was estimated, and the MS + thidiazuron (TDZ) + indole 3-acetic acid (IAA) combination favors a higher regeneration potential. The higher amounts of chemical constituents were also recorded on the same treatment. The in vitro plant samples also showed a noteworthy effect of scavenging of hydroxyl radicals vis-à-vis protection from oxidative DNA damage. The in vitro raised plants are good candidates for the development of antioxidant molecules