Peroxidase activity and induced lignification in rusted flax interactions varying in their degree of incompatibility

摘要

A histological comparison of theL9,K,P,P1,P2,and P3genotypes in flax revealed differences in their expression of incompatibility.KandP1were only moderately incompatible, whereasP,P2, andP3were highly incompatible, restricting fungal development completely by the 4th day after inoculation. Host cell necrosis was delayed until day 3 inP3and day 2 inP2; it was present at day 1 inP. Peroxidase, using guaiacol as a proton donor, was detected inPafter 2 days, inKat 5 days, and inL9after 7 days. Soluble peroxidase activity increased in the rustedPgenotype from day 3 and from day 7 inK. Gel electrophoresis of infectedPrevealed a new peroxidase isozyme at 6 days after inoculation. Three new protein bands were also detected at this stage. In 3- and 4-day-old rustedP, peroxidase was detected in the host cell walls of tissue surrounding necrotic infection sites. It was not located in the host cell walls of the compatibleL9genotype at this stage. Lignin was detected histochemically inPafter 2 days, inKafter 5 days, and inL9after 9 days. The Wiesner, Maiile, and KMnO4tests gave equivalent results. Suberin was detected inP,K, andL9at the same time that lignin became observable.