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Abstract

 

This article in CS

  1. Vol. 34 No. 4, p. 1070-1073
     
    Received: Sept 22, 1993


    * Corresponding author(s):
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doi:10.2135/cropsci1994.0011183X003400040043x

Determination of Chitinase Activity in Tall Fescue by Near Infrared Reflectance Spectroscopy

  1. C. A. Roberts ,
  2. S. M. Marek,
  3. Wang Lei and
  4. A. L. Karr
  1. D ep. of Biochemistry, Kansas State Univ., Manhattan, KS, 66506
    D ep. of Plant Pathology, Univ. of Missouri, Columbia, MO 65211

Abstract

Abstract

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.

Contribution from the Univ. of Missouri Agric. Exp. Stn., Columbia.

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Copyright © 1994. Crop Science Society of America, Inc.Copyright © 1994 by the Crop Science Society of America, Inc.