M. Marte et P. Montalbini, Histological observations on Uromyces phaseoli and Puccinia recondita infection in allopurinol-treated susceptible plants, J PHYTOPATH, 147(3), 1999, pp. 163-168
Citations number
18
Categorie Soggetti
Plant Sciences
Journal title
JOURNAL OF PHYTOPATHOLOGY-PHYTOPATHOLOGISCHE ZEITSCHRIFT
The development of rust after administering allopurinol, a specific inhibit
or of xanthine oxidoreductase, via roots was studied at the histological le
vel in leaves of susceptible 'Pinto 111' bean plants inoculated with Uromyc
es phaseoli and 'Thatcher', 'Mentana' and 'Leopardo' wheat plants challenge
d with Puccinia recondita. A marked reduction and delay in fungal growth wa
s observed in allopurinol-treated plants starting between 24 h and 48 h pos
t-inoculation, i.e, after differentiation of the first haustoria (onset of
the biotrophic plant-parasite relationship). Infection hyphae often grew tw
isted and convoluted in treated hosts, sometimes producing small, irregular
ly shaped colonies. Differentiation of subepidermal stromata in fungal colo
nies was delayed and restricted by the treatment and uredospore yield sever
ely reduced. Allopurinol administration also tended to increase the proport
ion of haustoria which became embedded in thick translucent sheaths during
the late stages of infection. These results support the view that plant xan
thine oxidoreductase activity is necessary for biotrophic development of ru
st fungi and suggest that the inhibition of this enzyme, which impairs the
pathogen metabolism may favour some natural host responses to attack such a
s haustorial sheath formation.