ABSTRACT
Milicia regia and M . excelsa are inva.lua.iDle plant
species in Ghana for their durable timber. Their
numbers are however dwindling. Efforts by the forestry
department to establish plantations have been
unsuccessful due primarily to attack by Phytolyma
species, resulting in gall formation.
Phenols and phenolic oxidases appear to be important in
the defence mechanisms of some plants as well as in
wound healing and regulation of growth in these plants.
Thus, they may be natural resistance factors of the
Phytolyma-induced gall disease of Milicia species.
The activities of phenolic oxidases, [polyphenol oxidase
(PPO) and peroxidase (PRO)] and the phenolic content in
galls and leaves of Milicia species differing in
susceptibility to Phytolyma attack were determined.
Polyphenol oxidase and peroxidase were also extracted
and partially purified from acetone powders prepared
from the galls and leaves.
The activity of polyphenol oxidase was found to be
higher in the leaves of the resistant plants than in the
x
tolerant and susceptible plants. Galls of the seedlings
also showed higher activity of the enzyme than in the
normal leaves. Similar trends were also observed for
the activity of peroxidase in the samples but the
differences in activity were insignificant. Phenol and
o-dihydroxyphenol contents of galls of seedlings were
slightly lower than in the normal leaves. The resistant
plants also showed slightly higher phenol content than
the tolerant and susceptible plants. The susceptible
plants on the other hand appeared to contain slightly
higher o-dihydroxyphenol than the resistant plants.
Peroxidase and polyphenol oxidase were extracted and
partially purified from acetone powders prepared from
galls and leaves of the samples. The peroxidase and
polyphenol oxidase from the galls were purified 10 and
14-fold, respectively, using gel filtration followed by
ion-exchange chromatography. The peroxidase and
polyphenol oxidase from the leaves were also purified 37
and 17-fold, respectively, using ion-exchange
chromatography followed by gel filtration. The
activities of the two enzymes could not be separated as
they co-eluted in the same fractions. The purified
enzymes from both sources did not oxidize monophenols
and had an estimated molecular weight of 34 kDa.
DORLEKU, W (2021). PHENOLIC OXIDASES IN GALL DISEASE OF MILICIA SPECIES. Afribary. Retrieved from https://tracking.afribary.com/works/phenolic-oxidases-in-gall-disease-of-milicia-species
DORLEKU, WINFRED-PECK "PHENOLIC OXIDASES IN GALL DISEASE OF MILICIA SPECIES" Afribary. Afribary, 01 Apr. 2021, https://tracking.afribary.com/works/phenolic-oxidases-in-gall-disease-of-milicia-species. Accessed 09 Nov. 2024.
DORLEKU, WINFRED-PECK . "PHENOLIC OXIDASES IN GALL DISEASE OF MILICIA SPECIES". Afribary, Afribary, 01 Apr. 2021. Web. 09 Nov. 2024. < https://tracking.afribary.com/works/phenolic-oxidases-in-gall-disease-of-milicia-species >.
DORLEKU, WINFRED-PECK . "PHENOLIC OXIDASES IN GALL DISEASE OF MILICIA SPECIES" Afribary (2021). Accessed November 09, 2024. https://tracking.afribary.com/works/phenolic-oxidases-in-gall-disease-of-milicia-species