| Wheat Information Service Number 18-20 (1989) Polyphenol oxidase enzyme in isogenic lines of Wheat in relation to leaf rust resistance J .V. Narasimham and H.S. Chawla Plant Breeding Deptt., G.B. Pant Univ. Pantnagar-263145, India Introduction It has been observed that fungal infection results in changes of multiple forms and activity of enzymes in the host parasite complex. Enzymic studies have been conducted on various plant species after infection (Desai and Pillai 1974; De Witt and Bakker 1980; Kanugo and Chawla 1988) but limited studies have been made to characterise the healthy wheat genotypes (Narasimham and Chawla 1984). In view of this role of polyphenoloxidase which is one of the phenol oxidising enzymes involved in disease resistance (Batra and Kuhn 1975) was studied for its activity and isozymes in near isogenic lines of wheat with different leaf rust resistance, Lr genes in different genetic backgrounds. Materials and Methods Material consisted of nine near isogenic lines of wheat with different leaf rust resistance - Lr genes in different genetic back grounds (Thatcher - Tc; Prelude - Pr, Chinese spring - CS) and two susceptible cultivars which have been numbered as a to k. The lines with their accession numbers were : (a) RL 6028 - Lr1 (Pr), (b) RL 6002 - Lr3 (Tc), (c) RL 6029 - Lr3 (Pr), (d) RL 6007 - Lr3ka (Tc), (e) RK 6030 - Lr3ka (Pr), (f) RL 6024 - Lr3bg (Tc), (g) Acc 1003 - Lr9 (CS), (h) Acc 1407 - Lr9 (Tc), (i) Acc 1417 - Lr19 (Tc) and two susceptible Cvs (j) Sonalika and (k) WL 711. Seed material was grown in petri dishes in an incubator for different germination stages of 0, 24, 48, 72, 96 hrs and one week at a temp of 25C. 2g sample material of each was homogenised in 3 ml of cold 0.9% NaCl solution and centrifuged at 12,000g for 20 min at 0C. 0-diphenolase (PPO) activity was determined by the method of Haskins (1974). One unit of enzyme activity was the change in O.D. by 0.1 unit per minute. Benjamin and Montgomery (1973) procedure for staining the polyphenol oxidase bands was followed after polyacrylamide gel electrophoresis. |
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