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Determination of Chitinase Activity in Tall Fescue by Near Infrared Reflectance Spectroscopy
Author(s) -
Roberts C. A.,
Marek S. M.,
Lei Wang,
Karr A. L.
Publication year - 1994
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1994.0011183x003400040043x
Subject(s) - cultivar , biology , chitinase , festuca arundinacea , pasture , chitin , endophyte , poaceae , horticulture , botany , agronomy , biochemistry , enzyme , chitosan
New cultivars of pasture‐type tall fescue ( Festuca arundinacea Schreber) lack the fungal endophyte, Acremonium coenophialum Morgan‐Jones & W. Gams. Although Acremonium ‐free cultivars are less toxic to livestock than Acremonium ‐infected cultivars, they are less disease tolerant. Acremonium ‐free cultivars may be improved for disease tolerance using a biochemical marker such as chitinase, a defense hydrolase associated with disease resistance in many crops. The objective of this research was to measure chitinase activity in tall fescue seedlings by near infrared reflectance Spectroscopy (NIRS). Ninety‐nine seedling samples were freeze‐dried, ground, and analyzed for total and specific chitinase activity using tritiated chitin as a substrate. Near infrared spectra were recorded for each sample, and an NIRS equation was developed by regressing radiochemical data against spectral data; regression procedures included forward stepwise multiple regression and modified partial least squares (MPLS). In optimum equations, standard errors of calibration and validation were near or below 10% of the mean, similar to errors observed in routine chemical analysis of chitinase. The optimum equation used MPLS to predict specific activity, resulting in a coefficient of determination of 0.90 and a mean and standard error of 88.8 ± 7.2 disintegrations min −1 mg −1 protein. The NIRS‐chitinase procedure is accurate and efficient. Once a spectrophotometer is calibrated, the NIRS procedure is at least 10 tunes faster than chemical procedures, permitting analysis in 60 s per sample.