ISSN:
1573-8469
Keywords:
ELISA
;
RNase isozymes
;
Sclerospora graminicola
;
systemic acquired resistance
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
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 HB 3, 843 B, ICMP 451 and IP 18292, respectively than in shoot 11.54, 9.95, 9.46 and 9.49 units in HB 3, 843 B, ICMP 451 and IP 18292, respectively. Effect of metal ions on the RNase profile indicates Zn++ at 2, 20 and 200 μM 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008775806087
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