Ribonucleases in the seedlings of pearl millet and their involvement in resistance against downy mildew disease

Shivakumar, P. D. and Vasanthi, N. S. and Shetty, H. S. and Smedegaard-Petersen, V. (2000) Ribonucleases in the seedlings of pearl millet and their involvement in resistance against downy mildew disease. European Journal of Plant Pathology, 106 (9). pp. 825-836. ISSN 0929-1873

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Official URL: http://doi.org/10.1023/A:1008775806087

Abstract

Tissue homogenates of pearl millet seedlings (cultivars HB 3, 843 B, ICMP 451 and IP 18292), with varying degree of resistance to downy mildew disease were tested for ribonuclease (RNase enzyme activity and the profile of major RNase isozymes by substrate based gel assay. Polyacrylamide gel electrophoresis (PAGE) of the four pearl millet homogenates revealed 15-20 isozymes, varying in size from 6.5 to 121.0 kDa. Most of the RNases were highly active between pH 6 and 8 with maximum activity at pH 7. Tissue specific expression of RNase was observed with more activity in the root, i.e., 38.84, 59.61, 39.90 and 49.23 units in KB 3, 843 B, ICMP 451 and IP 18292, respectively than in shoot 11.54, 9.95, 9.46 and 9.49 units in HE 3, 843 B, ICMP 451 and IP 18292, respectively. Effect of metal ions on the RNase profile indicates Zn++ at 2, 20 and 200 muM concentrations to be inhibitory. Ca++ and Mg++ at 1 mM concentration enhanced the enzyme activity while at 10 mM inhibition of enzyme activity was observed. Inoculation with the downy mildew pathogen Sclerospora graminicola reduced RNase activity by 4-13% in compatible interactions while in incompatible combinations, the enzyme activity increased by 10-27%. The significance of RNase in pearl millet-downy mildew interaction and its involvement of in systemic acquired resistance of pearl millet against the downy mildew pathogen are discussed.

Item Type: Article
Uncontrolled Keywords: ELISA; RNase isozymes; Sclerospora graminicola; systemic acquired resistance
Subjects: B Life Science > Biotechnology
Divisions: Department of > Biotechnology
Depositing User: Shrirekha N
Date Deposited: 19 Sep 2019 06:21
Last Modified: 19 Sep 2019 06:21
URI: http://eprints.uni-mysore.ac.in/id/eprint/8269

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