1021-4437/02/4902- $27.00 © 2002
Russian Journal of Plant Physiology, Vol. 49, No. 2, 2002, pp. 221–224. Translated from Fiziologiya Rastenii, Vol. 49, No. 2, 2002, pp. 248–252.
Original Russian Text Copyright © 2002 by Maksimov, Ganiev, Khairullin.
Many researchers determined the phytohormone
content in plants during pathogenesis. These studies
showed that the phytohormone content in infected
plants depended on the pattern of fungus development.
However, the detailed investigations were devoted only
to characterizing the phytohormone balance in plants
infected by pathogens, which cause diseases of only
leaves, stems, or roots (local fungal development) [1–
6]. In contrast, at the initial stages of plant pathogene-
sis, bunt develops diffusively . Thus, it was estab-
ﬁrst invades virtually all seed-
ling tissues, but further development of the fungus pro-
ceeds in a stem zone situated near the apical meristem .
However, the data on phytohormone content in the patho-
gen-infected wheat are very scarce , and the balance of
phytohormones at the initial stages of pathogenesis was
not investigated at all. There is also no evidence on the
changes in the phytohormone content in the pathogen-
resistant wheat species, which, at tillering and during the
development of the third leaf, are capable of destroying
the mycelium of a pathogenic fungus [10, 11].
In this regard, the objective of this work was to
investigate the changes in the IAA, ABA, and cytokinin
content in the tissues of wheat genotypes differing in
their phytopathogen resistance after infecting them
MATERIALS AND METHODS
Seeds of common wheat (
Zhnitsa, a bunt-susceptible genotype) and
Zhuk. (k-58666 by the VIR catalogue, a
resistant genotype) were used. Seeds were sterilized
using 70% ethanol for 3–5 min and then using 3%
hydrogen peroxide for 10 min, washed with sterile
redistilled water, and germinated in a sand–soil (1 : 1,
w/w) mixture previously sterilized in an autoclave for
1.5 h at 115
C and 0.15 kPa.
A portion of the seeds was infected according to
Krivchenko  by fungal spores reproduced on the
greenhouse-grown wheat plants, cv. Zhnitsa. Trays
with infected seeds were kept for three days at 10–12
in darkness and then germinated at room temperature
with a 16-h photoperiod and an illuminance of 16 klx.
For determining endogenous phytohormones, 10–
15 seedlings were ﬁxed on the same days. The length of
200 seedlings was estimated on the third, sixth, and
ninth days of germination. The determination of phyto-
hormones was performed using the method of indirect
competitive immunoenzyme analysis . Uninfected
seedlings served as a control.
On the sixth and ninth days of the experiment, the
pathogen of bunt stimulated the growth of the suscepti-
ble seedlings (Table 1). In contrast, throughout the
entire experiment, the infected seedlings of resistant
wheat were characterized by a decreased growth as
compared to the control ones.
Wheat seed infection with phytopathogen
teliospores resulted in a substantial increase in the IAA
content in the susceptible wheat seedlings (Table 2).
Changes in the Levels of IAA, ABA, and Cytokinins in Wheat
Seedlings Infected with
I. V. Maksimov, R. M. Ganiev, and R. M. Khairullin
Institute of Biochemistry and Genetics, Ufa Research Center, Russian Academy of Sciences,
pr. Oktyabrya 69, Ufa, 450054 Russia;
Received January 9, 2001
—The seedling growth and the content of endogenous phytohormones in wheat seedlings were esti-
mated 3, 6, and 9 days after infection with the bunt pathogen (
) (DC.)TUL. The infection of a
L. and a resistant species
Zhuk. resulted, respec-
tively, in an increase and a decrease in the seedling growth and the IAA content as compared to the control. The
cytokinin content increased in both species, and the increase in
was more rapid. The pathogen-
induced increase in auxin content is suggested to enhance fungal invasion of plants. In the susceptible species,
a high ABA concentration was retained for a longer period of time and could act as a factor of virulence. At the
same time, in the resistant species, an increase in ABA content was transient and seems to trigger plant defense
Key words: Triticum aestivum - Triticum timopheevii - Tilletia caries - IAA - ABA - cytokinins - pathogenesis