Aj. Pereira et al., Differential esterase expression in leaves of Manihot esculenta Crantz infected with Xanthomonas axonopodis pv. manihotis, BIOCHEM GEN, 39(9-10), 2001, pp. 289-296
The polyacrylamide gel electrophoresis system (PAGE) and inhibition tests f
or biochemical characterization of alpha- and beta -esterases were used to
obtain a functional classification of esterases in plants and to show a dif
ferential expression of esterases as markers of pathogenesis in cassava pla
nts (Manihot esculenta Crantz). The characterization of alpha- and beta -es
terases from leaves of M. esculenta by the PAGE system was possible using a
n extraction solution containing two phenol-complexing agents (PVP-40 and s
odium metabisulfite), three antioxidant agents (EDTA, beta -mercaptoethanol
, and DTT), and one quinone reducer (ascorbic acid). Fourteen esterase isoz
ymes were detected in young unexpanded leaves of M. esculenta cultivars. Th
e inhibition pattern of alpha- and beta -esterases of M. esculenta showed t
hat Est-9 is an arylesterase, and in the unexpended leaves of the M. escule
nta plants infected with Xanthomonas axonopodis pu manihotis, the Est-7 bet
a -esterase showed the characteristic staining of an alpha/beta -esterase.
This differential expression of Est-7 isozyme in young unexpanded leaves of
cassava plants can be used as a marker of pathogenesis after infection wit
h X. axonopodis pu manihotis.