Effect of maize root exudates on indole-3-acetic acid production by rice endophytic bacteria under influence of L-tryptophan [version 1; referees: 2 approved]

Background: It is assumed that plant growth regulators produced by beneficial bacterial species could also influence plant growth. IAA is a major plant growth regulator responsible for stimulation of plant growth. There are several microorganisms which are naturally responsible for L- tryptophan metabolism. Methods: In total, 56 indigenous morphologically distinct isolates from rice roots were selected and subsequently characterized with biochemical tests, 16S rRNA sequencing and plant growth promoting activities. Pseudomonas fluorescens RE1 (GenBank: MF102882.1) and RE17 (GenBank: MF103672.1) endophytes resulted in better PGP activity against the other 54 isolates. Both endophytes were tested to screen indole-3-acetic acid production ability in pure culture conditions with L-tryptophan at 0, 50, 100, 200 and 500µg/ml concentrations. Results: P. fluorescens RE1 was recorded efficient for indole production in comparison to P. fluorescens RE17 at various L-tryptophan concentrations. P. fluorescens RE1 was shown to produce between 0.8 µg/ml and 11.5µg/ml of indole at various tryptophan concentrations, while RE17 produced between 1.2µg/ml and 10.2µg/ml. At 200 and 500µg/ml tryptophan concentration, P. fluorescens RE17 produced 7.4pmol/ml and 9.3pmol/ml IAA, respectively.  Conclusions: Inoculation of maize seed with P. fluorescens RE1 and RE17 showed a significantly higher level of IAA production in comparison to non-inoculated seeds. Current study outcomes proved that plant growth regulators produced by Pseudomonas species could also play a critical role in plant growth promotion

Status of ginger diseases in Himachal Pradesh.

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Recent developments in Neem (Azadirachta indica – A. Juss) derived antimicrobial constituents for control of human and plant diseases – a review

Neem has immense biocontrol potential against a large number of pathogens causing various diseases in human beings and plants. The plant has maximum useful value in its leaves, bark, flowers and fruits than any other tree species. These values include antiallergic, antidermatic, antifeedent, antifungal and anti-inflammatory properties. Due to the vast activities of neem, it has become extremely valuable in making our ecosystem a green treasure. Neem leaves have been demonstrated to exhibit immuno-modulatory, anti-inflammatory, antiulcer, antimalarial properties. Neem tree plant parts contain a promising pest control substance which has found effective use against economically important agricultural pests. Neem plant products are easy to process by village level industries on the micro scale level and use by resource poor farmers in crop protection resulting thereby in income generation. This plant also has antioxidant properties and free radical scavenging potential in its different extracted solvents. The present review highlights the properties of neem against the pathogens of living organisms for environmental protection

Recent developments in Neem (Azadirachta indica – A. Juss) derived antimicrobial constituents for control of human and plant diseases – a review

Neem has immense biocontrol potential against a large number of pathogens causing various diseases in human beings and plants. The plant has maximum useful value in its leaves, bark, flowers and fruits than any other tree species. These values include antiallergic, antidermatic, antifeedent, antifungal and anti-inflammatory properties. Due to the vast activities of neem, it has become extremely valuable in making our ecosystem a green treasure. Neem leaves have been demonstrated to exhibit immuno-modulatory, anti-inflammatory, antiulcer, antimalarial properties. Neem tree plant parts contain a promising pest control substance which has found effective use against economically important agricultural pests. Neem plant products are easy to process by village level industries on the micro scale level and use by resource poor farmers in crop protection resulting thereby in income generation. This plant also has antioxidant properties and free radical scavenging potential in its different extracted solvents. The present review highlights the properties of neem against the pathogens of living organisms for environmental protection

Selection of a compatible biocontrol strain mixture based on co-cultivation to control rhizome rot of ginger

Rhizobacteria and Trichoderma spp. that were antagonistic against Fusarium oxysporum f.sp. zingiberi and Pythium splendens inciting rhizome rot disease of ginger were identified. In vitro assays identified positive interactions for growth, antifungal and chitinase gene expression between antagonistic TEPF-Sungal (Burkholderia cepacia) and S2BC-1 (Bacillus subtilis) with S17TH (Trichoderma harzianum), and vice versa. In comparison with the other strains and strain mixtures, one strain mixture, TEPFSungal þ S17TH, recorded a maximum rhizome production of 84% efficiency with less incidences of yellows and rhizome rot at an 84.2 and 79.7% reduction over the pathogen control, respectively, in a polyhouse with a challenge inoculation with the pathogens. Inoculation of the mixture of biocontrol agents was associated with an increase in known defence gene products such as chitinase etc., so we speculate that these are involved in the mechanism of disease suppression. In field experiments, the strain mixture reduced yellows and rhizome rot to 45.9 and 49.3% over the untreated control, respectively, which is comparatively better than that produced with fungicide (44.3 and 45.3%, respectively). The treatment also produced an increased rhizome yield with an average increase of 60.0% relative to the contro