Isolation of lipoxygenase and antifungal compounds associated with resistance to crown rust

1987 Fiscal Year Final Research Report Summary

• Project/Area Number: 61560056
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 植物保護
• Research Institution: Tottori University (1988); Kagawa University (1986-1987)
• Principal Investigator: YAMAMOTO Hiroyuki Facuty of Agriculture, Kagawa University, Prof., 農学部, 教授 (70035997)
• Project Period (FY): 1986 – 1988
• Keywords: Crown rust / Resistance / Lipoxygenase(LOX) / 抗菌性物質

Research Abstract

1. Lipoxygenase
Total lipoxygenase (LOX) activity were extensively increased in leaves of cv Shokan 1 responding with resistance to race 226 of Puccinia coronata avenae. Specific anionic LOX isozyme (LOX-1) was found by gel electrophoresis in the extract of infected leaves. LOX-1 was purified by DEAE-Sepharose CL-6B and CM-Sepharose CL-6B column chromatography form 50-80% ammonium sulfate fraction. The purified enzyme revealed isoelectric point pH 5.1 and reacted equally well with oleic acid, linoleic acid, linolenic acid and arachidonic acid. The enzyme was inactivated to about 40 % of the initial activity by heating at 60 ゜C for 15 min. At 70゜C, LOX was completely inactivated. The enzyme was storongly inhibited byf SHAM. Specific precipitation band on the gel plat was detected between the antiserum from LOX and the antigene of purified LOX.
2. Antifungal compound
Antifugal compound other than avenalumin was detected in the neutral ethl ether extract of leaves responding with resistance. An antifugal compound corresponding to major compound from the infeted leaves was detected in the reaction mixture of linoleic acid and extract of healthy oat leaves with partially purified LOx.
Participation of LOX-1 synthesis was also suggested for the resistance expression in incompatible cultiva-race combinations.