ISSN 10227954, Russian Journal of Genetics, 2011, Vol. 47, No. 7, pp. 879–883. © Pleiades Publishing, Inc., 2011.
(Ito and Kuribayashi) Drechs. ex
the causal agent of spot blotch (
), is a common foliar
pathogen of barley (
L.) worldwide, a
disease responsible for heavy crop losses [1, 2].
The infection process of
on leaves usually
occurs through natural wounding, stomata or with the
use of an appresoriumlike structure through the cell
wall [2, 3]. In susceptible plants the disease can result
more dead and collapsed tissue and further uncon
trolled spread leading to visible necrotic spots .
Development of stable forms of resistance to
depends upon identification of resistances effective
against the prevalent isolates in barley growing areas
[1–4]. However, even susceptible hosts are not fully
but express different degrees of
background resistance that is mainly achieved by pen
etration defense .
Few studies demonstrate differential gene expression
barley genotypes during the early phase of
infection, before any visible symptoms are apparent in
the tissues [6, 7]. However, still, little is known about the
genetic background and regulation of interaction mech
anisms. In addition, understanding the basis of suscepti
bility would greatly facilitate the development of new
control strategies and the identification of pathogen and
host factors required for disease progression .
One useful approach to the molecular analysis of
plantpathogen interactions is the determination of
changes in steady state mRNA levels occurring during
infection. Such amplified fragment length polymor
The article is published in the original.
phism (AFLP) display of complementary DNA (cDNA)
has been undertaken to reveal altered expression of any
gene that carries suitable restriction sites leads to an accu
rate way for understanding plant responses to pathogens
[9, 10]. The cDNAAFLP approach, once established, is
an efficient and economical method to display whole
transcript profiles of single tissues, particular develop
mental stages or other inducible characters . There
fore, the aim of the present research was to better under
stand the interaction between the fungal pathogen
and the barley susceptible genotype WI 2291,
via cDNAAFLP method.
The major Syrian pathotype
in the study was the most virulent of 40 isolates as
described by Arabi and Jawhar [4, 12, 13]. The fungus
was incubated on Petri dishes containing potato dex
trose agar (PDA, DIFCO, Detroit, MI, USA) for
8days at 20–22
C in the dark to allow mycelial growth.
After an extensive screening for over ten years in the
greenhouse and in the laboratory, the Australian cv.
WI2291 was proved to be the most susceptible geno
type to all
isolates available so far. Therefore, it was
selected for the cDNAAFLP analysis. Inoculation
tests of C41 isolate was performed using the method
described by Arabi and Jawhar .
Seeds were planted in plastic flats (
filled with sterilized peatmoss and placed in a growth
chamber at temperatures
22 ± 1
(night) with a daylength of 12 h and a relative humidity of
80–90%. Seedlings were irrigated by Knop nutrient solu
tion (1 g
; and 10 mg
per 1000 ml water).
Transcriptional Interactions During Barley Susceptible Genotype
M. I. E. Arabi, A. AlDaoude, A. Shoaib, and M. Jawhar
Department of Molecular Biology and Microbiology, AECS, Damascus 6091, Syria
Received November 12, 2010
—A systematic sequencing of expressed sequence tags (ESTs) was used to obtain a global picture of
the assembly of barley genes differentially expressed during the hypersensitive reaction of a susceptible geno
type in response to an incompatible
pathovar. To identify a large number of plant ESTs,
which are induced at different time points, an amplified fragment length polymorphism (AFLP) display of
(cDNA) was ulilized. Significant transcriptional changes in the host plant occurred
already 4 h post inoculation. Four hundred and fifty six ESTs have been generated, of which 17 (
regulated, 47% downregulated) have no previously described function. On one hand, the majority of EST
annotations showed protein synthesis, but genes related to signal transduction pathway were also identified.
This study provides novel global catalogue of gene regulations involved in
barley interaction not
currently represented in EST databases.