Septoria and Stagonospora Diseases of Cereals - CIMMYT ...

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Session 1 — S. Hamza, M. Medini, T. Sassi, S. Abdennour, M. Rouassi, A.B. Salah, M. Cherif, R. Strange, and M. Harrabi
Figure 2. cont.
conversion of one variant to the
other by genetic exchange of
virulence genes may occur through
sexual reproduction.
Diagnosis of S. tritici
and S. nodorum
In order to investigate the
specificity of S. tritici and S.
nodorum specific primers
determined by Beck and Ligon
(1995), we examined whether they
produce PCR products from other
fungal pathogens of wheat, such as
Fusarium graminearum, Ustilago
maydis, and Puccinia graminis. The
S. tritici specific primers JB446 and
ITS1, and S. nodorum specific
primers JB433 and JB434 did
produce PCR products only
from those pathogens (Figure
3) revealing that these
primers can be used to
diagnose S. tritici and S.
nodorum isolates collected
from Tunisia.
Amounts ranging from 2
µg to 2 pg of S. nodorum were
tested by PCR amplification with
their respective specific primers
(JB433, JB434) to determine the
DNA threshold that can be
detected. PCR amplification with
550 bp
JB446 and ITS1 JB433 and JB434
Labda HindIII
Healthy wheat
Septoria tritici
Stagonospora nodorum
Fusarium graminearum
Puccinia graminis
Ustilago maydis
Lambda HindIII
Healty wheat
Septoria tritici
Stagonospora nodorum
Fusarium graminearum
Puccinia graminis
Ustilago maydis
Lambda HindIII
Figure 3. Ethidium bromide stained agarose gel of
polymerase chain reaction amplification product
using Septoria tritici specific primers (JB446 and
ITS1) and Stagonospora nodorum specific primers
(JB433 and JB434) with healthy wheat DNA and
fungal DNA of wheat pathogen.
Lambda DNA HindIII
2 µg
200 ng
20 ng
2 ng
200 pg
20 pg
2 pg
Lambda DNA HindIII
Figure 4. Ethidium bromide stained agarose gel of
polymerase chain reaction products from
amplification of 0.2 pg to 2 µg of genomic DNA of
Stagonospora nodorum DNA using S. nodorum
specific primers JB433 and JB434.
JB433 and JB434 was able to detect
2 pg of S. nodorum DNA (Figure 4),
which is almost the same amount
detected by Beck and Ligon (1995).