Akansha Jain

Rhizosphere competent microbial consortium mediates rapid changes in phenolic profiles in chickpea during Sclerotium rolfsii infection.

The present study was carried out with the aim of evaluating the effectiveness and potentiality of three compatible rhizosphere microbes, viz., fluorescent Pseudomonas aeruginosa (PHU094), Trichoderma harzianum (THU0816) and Mesorhizobium sp. (RL091), in promoting plant growth and mobilizing phenolic acid biosynthesis in chickpea under challenge of Sclerotium rolfsii. The microbes were applied as seed coating in different combinations in two experimental sets and the pathogen was inoculated after 25 days of sowing in one set. Results revealed that microbe application led to higher growth in chickpea particularly in the triple microbe combination compared to their individual treatments and control. Similarly, pathogen challenged plants accumulated higher amount of phenolic compounds both at the site of attack of the pathogen i.e. collar region as well as leaves compared to unchallenged plants. All the bioagents were found to trigger the level of phenolic compounds at collar region in varying degrees as compared to the healthy control (A). However, the most effective treatment was D7 (combined application of PHU094, THU0816 and RL091 with pathogen challenge) among all the treatments. Shikimic acid was maximally induced amongst all the phenolic compounds. In leaves also, the most effective treatment was D7 where shikimic acid, t-chlorogenic acid, ferulic acid, myricetin, quercetin and syringic acid were produced in higher amounts as compared to treatment B where the plants were challenged only with the pathogen.

Solid waste management of temple floral offerings by vermicomposting using Eisenia fetida

Recycling of temple waste (TW) mainly comprising of floral offerings was done through vermitechnology using Eisenia fetida and its impact on seed germination and plant growth parameters was studied by comparing with kitchen waste (KW) and farmyard waste (FYW) vermicompost (VC). The worm biomass was found to be maximum in TW VC compared to KW and FYW VCs at both 40 and 120days old VCs. Physico-chemical analysis of worm-worked substrates showed better results in TW VC especially in terms of electrical conductivity, C/N, C/P and TK. 10% TW VC-water extract (VCE) showed stimulatory effect on germination percentage of chickpea seeds while KW and FYW VCE proved effective at higher concentration. Variation in growth parameters was also observed with change in the VC-soil ratio and TW VC showed enhanced shoot length, root length, number of secondary roots and total biomass at 12.5% VC compared to KW and FYW VC.

Modulation of nutritional and antioxidant potential of seeds and pericarp of pea pods treated with microbial consortium

Microbial populations have diverse roles within rhizosphere where interactions among distinct microorganisms along with the host may lead to mutualistic associations. The present study aimed to investigate the nutritional and antioxidant qualities of seeds and pericarp of pea raised from seeds treated with beneficial microbes namely Bacillus subtilis BHHU100, Trichoderma harzianum TNHU27 and Pseudomonas aeruginosa PJHU15 either singly and/or in consortia. A significant increase in total phenolic, flavonoid, ascorbic acid and protein contents, free radical scavenging activity, hydroxyl radical scavenging activity, iron chelation and reducing power were observed in the seeds and pericarp of pods treated with a consortium of microbes in comparison to control pods. Also, the differential accumulation of phenolic compounds, namely, shikimic acid, gallic acid, tannic acid, syringic acid, p-coumaric acid, quercetin and kaempferol, was observed from the HPLC chromatogram of the seed extracts of different treatments. We especially emphasized on dietary importance of the pod pericarp, other than seeds, along with their modulation by microbial consortium. The study also highlights the role of beneficial microbes in improving nutritional value by providing protection against oxidative stress.

Biological management of Sclerotinia sclerotiorum in pea using plant growth promoting microbial consortium.

The beneficial plant‐microbe interactions play crucial roles in protection against large number of plant pathogens causing disease. The present study aims to investigate the growth promoting traits induced by beneficial microbes namely Pseudomonas aeruginosa PJHU15, Trichoderma harzianum TNHU27, and Bacillus subtilis BHHU100 treated singly and in combinations under greenhouse and field conditions to control Sclerotinia sclerotiorum. Plants treated with three microbe consortium enhanced plant growth maximally both in the presence and absence of the pathogen. Increase in plant length, total biomass, number of leaves, nodules and secondary roots, total chlorophyll and carotenoid content, and yield were recorded in plants treated with microbial consortia. Also, a decrease in plant mortality was observed in plants treated with microbial consortia in comparison to untreated control plants challenged with S. sclerotiorum. Furthermore, the decrease in disease of all the treatments can be associated with differential improvement of growth induced in pea.

Biocontrol agents-mediated suppression of oxalic acid induced cell death during Sclerotinia sclerotiorum-pea interaction.

Oxalic acid (OA) is an important pathogenic factor during early Sclerotinia sclerotiorum‐host interaction and might work by reducing hydrogen peroxide production (H2O2). In the present investigation, oxalic acid‐induced cell death in pea was studied. Pea plants treated with biocontrol agents (BCAs) viz., Pseudomonas aeruginosa PJHU15, Bacillus subtilis BHHU100, and Trichoderma harzianum TNHU27 either singly and/or in consortium acted on S. sclerotiorum indirectly by enabling plants to inhibit the OA‐mediated suppression of oxidative burst via induction of H2O2. Our results showed that BCA treated plants upon treatment with culture filtrate of the pathogen, conferred the resistance via. significantly decreasing relative cell death of pea against S. sclerotiorum compared to control plants without BCA treatment but treated with the culture filtrate of the pathogen. The results obtained from the present study indicate that the microbes especially in consortia play significant role in protection against S. sclerotiorum by modulating oxidative burst and partially enhancing tolerance by increasing the H2O2 generation, which is otherwise suppressed by OA produced by the pathogen.

Biotic Stress Management in Agricultural Crops Using Microbial Consortium

Microbial populations have functional roles within communities where interactions among distinct microorganisms will permit their survival. Therefore, it is suggested to device mixed inoculants that may interact synergistically, with different or complementary mode of action, so that increased disease resistance is provided and under certain stresses we can assume that atleast one is functional. The mechanisms responsible for this biocontrol activity include competition for nutrients, niche exclusion, induced systemic resistance (ISR), and the production of anti-microbial metabolites. Therefore, seeing the success stories of mixed inoculants (combination of microorganisms that interact synergistically) over single bioinoculant, consortiums are being currently devised for crop management. The extreme complexity of interactions occurring is highlighted, and some potential areas and shortcomings required to overcome for future researches in this area are discussed briefly.

Comparative proteomic analysis in pea treated with microbial consortia of beneficial microbes reveals changes in the protein network to enhance resistance against Sclerotinia sclerotiorum

Microbial consortia may provide protection against pathogenic ingress via enhancing plant defense responses. Pseudomonas aeruginosa PJHU15, Trichoderma harzianum TNHU27 and Bacillus subtilis BHHU100 were used either singly or in consortia in the pea rhizosphere to observe proteome level changes upon Sclerotinia sclerotiorum challenge. Thirty proteins were found to increase or decrease differentially in 2-DE gels of pea leaves, out of which 25 were identified by MALDI-TOF MS or MS/MS. These proteins were classified into several functional categories including photosynthesis, respiration, phenylpropanoid metabolism, protein synthesis, stress regulation, carbohydrate and nitrogen metabolism and disease/defense-related processes. The respective homologue of each protein identified was trapped in Pisum sativum and a phylogenetic tree was constructed to check the ancestry. The proteomic view of the defense response to S. sclerotiorum in pea, in the presence of beneficial microbes, highlights the enhanced protection that can be provided by these microbes in challenged plants.

Natural Antioxidants and Their Role in Cancer Prevention

We often credit antioxidants because of their ability to protect cells from the oxidative/electrophilic damage that makes them turn cancerous. A number of antioxidants have shown to inhibit the induction of cancer by a wide variety of chemical carcinogens and/or radiation at many target sites in mice, rats, and hamsters. Epidemiological studies suggest that a diet rich in plant products containing natural antioxidants may be a deterrent to carcinogenicity. Many antioxidants were tested to determine if they would inhibit tumor initiation, promotion, and/or progression. Use of a number of important antioxidants can be helpful in the treatment of cancer, either as sole agents or as adjuncts to standard radiation and chemotherapy protocols. Our knowledge of antioxidants in a cancer setting is still at its infancy stage. In order to understand antioxidants and their role in cancer prevention, we must know what exactly antioxidants are and how they help our bodies. The interactions between antioxidant and cancer prevention cannot be decided solely on the basis of presumed mechanism of action when used concurrently. Numerous natural antioxidants appear to have beneficial health effects. There is sufficient evidence to recommend consuming food sources rich in antioxidants but still much scientific research needs to be carried out before we can begin to make dietary recommendations. This chapter summarizes the current knowledge on the occurrence, types and antioxidative properties of natural antioxidants, underlying the necessity of further research.