Microbial Diversity in North Western Himalayan Agroecosystems: Functions and Applications

Jaggi, Vandana; Brindhaa, N. T.; Sahgal, Manvika

doi:10.1007/978-981-15-1902-4_8

Cited by 7 publications

(10 citation statements)

References 72 publications

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“…Amongst the 22 isolates, AS19, followed by AS21, showed strong antifungal activity against all the tested fungi in the in vitro antagonism tests, using microbial-cell culture as well as culture filtrate. The zone of inhibition around tested plant pathogens by AS19 and AS21 may be linked to their ability to produce secondary metabolites such as phenazine, ammonia, and hydrolytic enzymes 42 , 78 . Based on 16S rDNA analysis, the results revealed that AS19 belongs to Pseudomonas aeruginosa and AS21 belongs to P. indoloxidans Pseudomonas spp.…”

Section: Discussionmentioning

confidence: 99%

“…Plates were incubated at 28 ± 2 °C for 5 days until the mycelium growth reached to the edge of the control plate. Percent mycelial inhibition was calculated according to Jaggi et al 42 .…”

Section: Methodsmentioning

confidence: 99%

“…Plates were incubated at 28 ± 2 °C for 5–7 days and examined for mycelial growth inhibition (%). Growth inhibition was calculated according to Jaggi 42 .…”

Section: Methodsmentioning

confidence: 99%

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Antagonistic potential and biological control mechanisms of Pseudomonas strains against banded leaf and sheath blight disease of maize

Sahgal,

Saini,

Jaggi

et al. 2024

Sci Rep

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Rhizoctonia solani, the causal agent of banded leaf and sheath blight (BL&SB), poses a significant threat to maize and various crops globally. The increasing concerns surrounding the environmental and health impacts of chemical fungicides have encouraged intensified concern in the development of biological control agents (BCAs) as eco-friendly alternatives. In this study, we explored the potential of 22 rhizobacteria strains (AS1–AS22) isolates, recovered from the grasslands of the Pithoragarh region in the Central Himalayas, as effective BCAs against BL&SB disease. Among these strains, two Pseudomonas isolates, AS19 and AS21, exhibited pronounced inhibition of fungal mycelium growth in vitro, with respective inhibition rates of 57.04% and 54.15% in cell cultures and 66.56% and 65.60% in cell-free culture filtrates. Additionally, both strains demonstrated effective suppression of sclerotium growth. The strains AS19 and AS21 were identified as Pseudomonas sp. by 16S rDNA phylogeny and deposited under accession numbers NAIMCC-B-02303 and NAIMCC-B-02304, respectively. Further investigations revealed the mechanisms of action of AS19 and AS21, demonstrating their ability to induce systemic resistance (ISR) and exhibit broad-spectrum antifungal activity against Alternaria triticina, Bipolaris sorokiniana, Rhizoctonia maydis, and Fusarium oxysporum f. sp. lentis. Pot trials demonstrated significant reductions in BL&SB disease incidence (DI) following foliar applications of AS19 and AS21, with reductions ranging from 25 to 38.33% compared to control treatments. Scanning electron microscopy revealed substantial degradation of fungal mycelium by the strains, accompanied by the production of hydrolytic enzymes. These findings suggest the potential of Pseudomonas strains AS19 and AS21 as promising BCAs against BL&SB and other fungal pathogens. However, further field trials are warranted to validate their efficacy under natural conditions and elucidate the specific bacterial metabolites responsible for inducing systemic resistance. This study contributes to the advancement of sustainable disease management strategies and emphasizes the potential of Pseudomonas strains AS19 and AS21 in combating BL&SB and other fungal diseases affecting agricultural crops.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Antagonistic potential and biological control mechanisms of Pseudomonas strains against banded leaf and sheath blight disease of maize

Sahgal,

Saini,

Jaggi

et al. 2024

Sci Rep

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“…Meanwhile, their relative abundance, especially in free-living psychrophiles, increases with elevation ( Siles and Margesin, 2016 ; Rui et al, 2022 ). PGPBs natives to alpine systems are essential nowadays due to their ability to cope with low temperatures and to promote plant growth through different mechanisms under cold conditions and poor nutrient soils ( Chaturvedi and Shivaji, 2006 ; Jaggi et al, 2020 ; Farooq et al, 2022 ). These constraint conditions for plants can be alleviated by PGPBs through the activity of enzymes and phytohormones that favor plant nutrient uptake and stress resistance ( Haselwandter et al, 1983 ; Widawati and Suliasih, 2006 ; Joshi et al, 2014 ; Yarzábal, 2014 ; Kadioglu et al, 2018 ; Pandey and Yarzábal, 2019 ; Fan et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Relieving your stress: PGPB associated with Andean xerophytic plants are most abundant and active on the most extreme slopes

Aguilera-Torres

Riveros²,

Morales³

et al. 2023

Front. Microbiol.

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IntroductionPlants interact with plant growth-promoting bacteria (PGPB), especially under stress condition in natural and agricultural systems. Although a potentially beneficial microbiome has been found associated to plants from alpine systems, this plant- PGPB interaction has been scarcely studied. Nevados de Chillán Complex hold one of the southernmost xerophytic formations in Chile. Plant species living there have to cope with drought and extreme temperatures during the growing season period, microclimatic conditions that become harsher on equatorial than polar slopes, and where the interaction with PGPB could be key for plant survival. Our goal was to study the abundance and activity of different PGPB associated to two abundant plant species of Andean xerophytic formations on contrasting slopes.MethodsTwenty individuals of Berberis empetrifolia and Azorella prolifera shrubs were selected growing on a north and south slope nearby Las Fumarolas, at 2,050 m elevation. On each slope, microclimate based on temperature and moisture conditions were monitored throughout the growing period (oct. – apr.). Chemical properties of the soil under plant species canopies were also characterized. Bacterial abundance was measured as Log CFU g−1 from soil samples collected from each individual and slope. Then, the most abundant bacterial colonies were selected, and different hormonal (indoleacetic acid) and enzymatic (nitrogenase, phosphatase, ACC-deaminase) mechanisms that promote plant growth were assessed and measured.Results and DiscussionExtreme temperatures were observed in the north facing slope, recording the hottest days (41 vs. 36°C) and coldest nights (−9.9 vs. 6.6°C). Moreover, air and soil moisture were lower on north than on south slope, especially late in the growing season. We found that bacterial abundance was higher in soils on north than on south slope but only under B. empetrifolia canopy. Moreover, the activity of plant growth-promoting mechanisms varied between slopes, being on average higher on north than on south slope, but with plant species-dependent trends. Our work showed how the environmental heterogeneity at microscale in alpine systems (slope and plant species identity) underlies variations in the abundance and plant growth promoting activity of the microorganisms present under the plant canopy of the Andean xerophytic formations and highlight the importance of PGPB from harsh systems as biotechnological tools for restoration.

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“…The particular region comprises pristine habitats for the exploration of microorganisms capable of a multitude of functioning. The plant waste-of diversified nature-is continuously recycled in these forests by native microbial strains producing a thick layer of organic matter, which represents an excellent opportunity for the presence of efficient lytic organisms [22], potentially better than the already reported ones in the literature. A pristine environment of the Pangi-Chamba Himalayan (PCH) region was sampled for bioresource exploration and for bacterial diversity investigation to degrade cellulose.…”

Section: Introductionmentioning

confidence: 99%

Proficient Lignocellulolytic Novel Bacterial Isolates from Diversified Galiyat Forests of Lower Himalaya

Awan

Iqbal

Rashid

et al. 2023

Forests

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Lignocellulosic biomass needs attention as an alternative energy source to overcome the adverse impacts of fossil fuels. Diversified Galiyat forests of Lower Himalaya may represent the potential source of lignocellulose degrading microbiota, particularly the lytic bacteria. Therefore, soil and wood samples were collected from different sites of Nathiagali and Thandiani of Galiyat forests. The soil samples collected were clayey, with a pH between 6.7 and 7.0, and with an organic matter of 2.8%–2.9% in Nathiagali and 2.1%–2.2% in Thandiani. The soils were enriched with more diversified cultivable bacteria (9 Log CFU/g) than the respective wood samples (7.4–8.6 Log CFU/g). Out of 90 bacteria, 22 isolates were efficient for cellulose degradation, 14 for xylanase activity, and 10 for laccase production. Cluster analysis showed that lignocellulolytic bacteria were grouped based on the sample medium (soil–wood) rather than the sampling site (Thandiani–Nathiagali). Efficient bacteria were also sequenced, and we found that cellulase production was prevalent in Pseudomonas spp. while laccase activity was diverse among taxonomically varied bacteria. Moreover, Stenotrophomonas sp. TS2B1 performed the best for corncob xylose degradation. Overall, the results suggest that Galiyat forests represent diverse lignocellulolytic microbial populations which should be further evaluated for applications in lignocellulosic waste management and for potential consequent fuel production.

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Microbial Diversity in North Western Himalayan Agroecosystems: Functions and Applications

Cited by 7 publications

References 72 publications

Antagonistic potential and biological control mechanisms of Pseudomonas strains against banded leaf and sheath blight disease of maize

Antagonistic potential and biological control mechanisms of Pseudomonas strains against banded leaf and sheath blight disease of maize

Relieving your stress: PGPB associated with Andean xerophytic plants are most abundant and active on the most extreme slopes

Proficient Lignocellulolytic Novel Bacterial Isolates from Diversified Galiyat Forests of Lower Himalaya

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