title: Salicylic acid is a modulator of catalase isozymes in chickpea plants infected with Fusarium oxysporum f. sp. ciceri.
abstract: The relationship between salicylic acid level catalases isoforms chickpea cv. ICCV-10 infected with Fusarium oxysporum f. sp. ciceri was investigated. Pathogen-treated chickpea plants showed high levels of SA compared with the control. Two isoforms of catalases in shoot extract (CAT-IS and CAT-IIS) and single isoform in root extract (CAT-R) were detected in chickpea. CAT-IS and CAT-R activities were inhibited in respective extracts treated with pathogen whereas, CAT-IIS activity was not inhibited. These isoforms were purified and their kinetic properties studied in the presence or absence of SA. The molecular mass determined by SDS-PAGE of CAT-IS, CAT-IIS and CAT-R was found to be 97, 40 and 66 kDa respectively. Kinetic studies indicated that Km and V(max) of CAT-IS were 0.2 mM and 300 U/mg, 0.53 mM and 180 U/mg for CAT-IIS and 0.25 mM and 280 U/mg for CAT-R, respectively. CAT-IS and CAT-R were found to be more sensitive to SA and 50% of their activities were inhibited at 6 and 4 μM respectively, whereas CAT-IIS was insensitive to SA up to 100 μM. Quenching of the intrinsic tryptophan fluorescence of purified catalases were used to quantitate SA binding; the estimated K(d) value for CAT-IS, CAT-IIS and CAT-R found to be 2.3 μM, 3.1 mM and 2.8 μM respectively. SA is a modulator of catalase isozymes activity, supports its role in establishment of SAR in chickpea plants infected with the pathogen.
authors.affiliation: Department of Biochemistry, Gulbarga University, Gulbarga 585106, Karnataka, India.
authors.forename: S
authors.initials: S
authors.lastname: Gayatridevi
authors.forename: S K
authors.initials: SK
authors.lastname: Jayalakshmi
authors.forename: K
authors.initials: K
authors.lastname: Sreeramulu
mesh_terms: D000595:Amino Acid Sequence; D000640:Amitrole / Q000494:pharmacology; D002374:Catalase / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D029863:Cicer / Q000201:enzymology* / Q000382:microbiology*; D005670:Fusarium / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D010084:Oxidation-Reduction; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000201:enzymology / Q000382:microbiology; D018520:Plant Shoots / Q000201:enzymology / Q000382:microbiology; D011485:Protein Binding; D020156:Salicylic Acid / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D007527:Isoenzymes; D002374:Catalase; D020156:Salicylic Acid; D000640:Amitrole