Browsing by Author "Lal, M."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Characterization of glycolipid biosurfactant from Pseudomonas aeruginosa PA 1 and its efficacy against Phytophtora infestans
    (Triveni Enterprises, 2019-07) Tomar, S.; Lal, M.; Khan, M.A.; Singh, B.P.; Sharma, S.
    Aim: The aim of the present study was to identify biosurfactant produced by Pseudomonas aeruginosa and to determine the effectiveness of biosurfactants (rhamnolipid) against P. infestans causing late blight of potato. Methodology: Pseudomonas aeruginosa strains were isolated from soil samples and the potential strain PA 1, selected because of its antagonistic ability, was used to optimize anti-metabolite production and its characterization using HPLC-Mass spectrometry. Rhamnolipid based formulation was developed and its efficacy was tested against late blight disease. Results: The results revealed that four rhamnolipids congeners were identified, among them three were mono-rhamno-di-lipidic congeners and one was di-rhamno-di-lipdic congeners, abundantly present in the crude biosurfactant obtained from P. aeruginosa PA1. The mass spectra of mono-rhamno-di-lipidic Rha-C12-C14 peak value (m/z 584), Rha-C12.1-C10.CH3 peak value (m/z 545), Rha-C12-C-12-CH3 peak value (m/z 575) and di-rhamno-di-lipidic. Rha-Rha-C10-C10 peak value (m/z 651) were also detected. Rhamnolipid-based formulation was developed and evaluated at different concentration ranging from 0.012 and 0.3% in detached leaf test. Significant reduction in lesion area was recorded at 0.2% concentration (lesion area 0.06 cm2 as against 9.8 cm2 on 5th day of inoculation). Interpretation: Microbial produced rhamnolipid based formulation at 0.2% concentration was found effective against late blight of potato in detached leaf test. Further, it could be used in field study as green chemical which would help in replacing application of chemicals in agriculture.
  • No Thumbnail Available
    Item
    Morpho-genetic variability of Rhizoctonia solani population causing sheath blight disease in rice (Oryza sativa L.)
    (Triveni Enterprises, 2023-01) Chaudhary, S.; Sagar, S.; Lal, M.; Tomar, A.; Kumar, J.; Kumar, V.; Kumar, M.
    Aim: The present study aims to investigate the morpho-pathological and molecular variability among the R. solani isolates from different geographical regions of India. Methodology: R. solani isolates were collected from sheath blight infected rice plants from diverse regions of Western Uttar Pradesh and Uttarakhand. Morphological variability among the isolates was studied in-vitro on PDA medium. The anastomosis grouping was determined by hyphal fusion reactions paired with tester strain and confirmed by AG-specific-PCR assay. Pathogenicity assay was conducted in-vivo on four rice varieties using artificial inoculation method under greenhouse conditions. Evolutionary relationship among the isolates was determined using rDNA-ITS-PCR with ITS1 & ITS4 primers. Further, genetic variability among the isolates was assessed using ISSR primers. Results: A total of 21 isolates of R. solani were recovered and based on morphological and sclerotial features, significant variation was observed among the isolates. All the isolates belonged to AG1-IA group which was confirmed by AG-specific PCR assay. Based on pathogenicity, eight isolates were found highly virulent, eight were moderately virulent and six were less virulent. ISSR markers showed high level of polymorphism and grouped all isolates into three major clusters showing partial correlation with geographical origin of the isolates. Sequence variations in ITS region were observed in the form of insertions or deletions of the nucleotide when rDNA-ITS sequences were compared that led to the interspecies diversity and diversity was observed in clad-specific manner. The phylogenetic tree separated the isolates into ten distinct clades showing high level of genetic diversity. Interpretation: The results of the present study may be helpful for the phylogenetic classification of complex R. solani species and provide information on the genetic divergence and occurrence of pathogenic races. This information will be helpful for the development of effective disease management strategies based on the molecular breeding and other approaches.