DIFFERENTIAL INDUCTION AND ACCUMULATION OF BETA-1,3-GLUCANASE AND CHITINASE ISOFORMS IN THE INTERCELLULAR SPACE AND LEAF TISSUES OF PEPPER BY XANTHOMONAS-CAMPESTRIS PV VESICATORIA INFECTION
Yk. Lee et Bk. Hwang, DIFFERENTIAL INDUCTION AND ACCUMULATION OF BETA-1,3-GLUCANASE AND CHITINASE ISOFORMS IN THE INTERCELLULAR SPACE AND LEAF TISSUES OF PEPPER BY XANTHOMONAS-CAMPESTRIS PV VESICATORIA INFECTION, Journal of phytopathology, 144(2), 1996, pp. 79-87
The virulent strain Ds 1 of Xanthomonas campestris pv. vesicatoria mul
tiplied in pepper (cv. Hanbyul) leaves better than did the avirulent s
train 81-23, which formed localized necrosis at the onset of pathogene
sis. Infection of pepper leaves by X. campestris pv. vesicatoria induc
ed the synthesis and accumulation of beta-1,3-glucanase and chitinase
in the intercellular space and leaf tissue of pepper plants. In the un
inoculated controls. the two hydrolases remained at a very low level.
High levels of the two enzymes were found in an incompatible interacti
on of pepper leaves with X. campestris pv. vesicatoria. In particular,
chitinase activity in the intercellular washing fluids (IWF) was high
er in the incompatible than in the compatible interactions. The direct
detection of acidic beta-1,3-glucanases on 10% native PAGE gels revea
led only two isoform bands (Ga 1 and Ga 2). Isoelectric focusing ident
ified two acidic beta-1,3-glucanase isoforms with pI 5.0 and 5.2, and
four basic isoforms with pI 7.1, 7.4, 7.9, and 8.8 in the IWF and extr
acts of infected leaf tissues. Some of the isoforms disappeared during
pathogenesis and the others appeared during symptom expression. The a
cidic chitinase isoforms (Ca 1: Ca 2, and Ca 3) were located primarily
in the intercellular spaces. Synthesis of high levels of the acidic i
soform Ca 3 in infected pepper leaves was seen. Several basis chitinas
e isoforms accumulated only in diseased leaf tissue, and especially mo
re in the incompatible than the compatible interaction. By using isoel
ectric focusing, the three acidic and seven basic chitinase isoforms i
n the IWF and leaf extracts were detected on chitin overlay gels.