Jp. Wubben et al., DIFFERENTIAL INDUCTION OF CHITINASE AND 1,3-BETA-GLUCANASE GENE-EXPRESSION IN TOMATO BY CLADOSPORIUM-FULVUM AND ITS RACE-SPECIFIC ELICITORS, Physiological and molecular plant pathology, 48(2), 1996, pp. 105-116
Accumulation of pathogenesis-related proteins is an important feature
of plant defence responses upon infection by pathogens. In the interac
tion between Cladosporium fulvum and tomato, resistance against the fu
ngus correlates with early induction of transcription of genes encodin
g apoplastic chitinase and 1,3-beta-glucanase and the accumulation of
these proteins in inoculated tomato leaves. For vacuolar, basic isofor
ms of chitinase and 1,3-beta-glucanase, however, early gene transcript
accumulation was observed in both incompatible and compatible interac
tions. Here we report on the tissue-specific expression of genes encod
ing these hydrolytic enzymes as studied by means of in situ hybridizat
ion. Only temporal differences in gene transcript accumulation were ob
served for each isoform studied. Expression of the acidic chitinase ge
ne was observed primarily near leaf vascular tissue. Expression of the
basic chitinase and the basic and acidic 1,3-beta-glucanase genes was
less confined to particular tissues. No preferential accumulation of
gene transcripts in tissue near penetrating hyphae was observed in com
patible or incompatible interactions. Injection of purified race-speci
fic elicitors, AVR4 and AVR9, in tomato genotypes Cf4 and Cf9, respect
ively, induced primarily differential expression of acidic chitinase a
nd acidic 1,3-beta-glucanase. The induction, observed most abundantly
in resistant genotypes, correlates well with the difference in gene ex
pression previously observed in time course experiments of compatible
and C. fulvum-tomato interactions. (C) 1996 Academic Press Limited