Antioxidant activities and reactive oxygen species in flag leaves of Fusarium-inoculated wheat genotypes Szeged

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Antioxidant activities and reactive oxygen
species in flag leaves of Fusarium-inoculated
wheat genotypes Szeged Timisoara axis for the
safe food and feedSZETISA1HURO/0901/147/2.2.2
Two countries, one goal, joint success!
Reporting period 01.06. 2011 30.09. 2011

• Ágnes Gallé
• Department of Plant Biology
• University of Szeged

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www.huro-cbc.eu www.hungary-romania-cbc.eu
2nd Progress Report Meeting Szeged, 22-23
September, 2011
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Fusarium head blight (FHB) is an important
disease of wheat and has worldwide distribution,
which results in yield loss and mycotoxin
contamination of grain when the disease is caused
by a mycotoxin-producing Fusarium
species. Fusarium graminearum and F. culmorum
are the Fusarium species that most commonly cause
FHB of wheat and both can produce trichothecene
mycotoxins, predominantly deoxynivalenol (DON,
also known as vomitoxin), zearalenone, nivalenol,
dideoxynivalenol, 3-acetyldeoxynivalenol
Fusarium culmorum
Fusarium graminearum
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Vomitoxin, also known as deoxynivalenol (DON), is
a type B trichothecene, an epoxy-sesquiterpeoid.
When compared to other trichothecene mycotoxins
which can form in grains and forages, vomitoxin
is relatively mild. Vomitoxin belongs to a
class of mycotoxins which are strong protein
inhibitors. Inhibition of protein synthesis
following exposure to vomitoxin causes the brain
to increase its uptake of the amino acid
tryptophan and, in turn, its synthesis of
serotonin. Increased levels of serotonin are
believed to be responsible for the anorexic
effects of DON and other tricothecenes.
Irritation of the gastrointestinal tract may
also play a role in reducing feed intake.
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Zearalenone is also a trichothecene mycotoxin,
and has estrogen effect, and can cause inflame in
the uterus in swine.
Nivalenol was shown to inhibit protein synthesis
in rabbit reticulocytes in vitro, with an ID50 of
2.5 mg/ml, probably by impairment of the
ribosomal function. Nivalenol inhibited the
synthesis of nucleic acids in vitro (Ueno and
Fukushima, 1968). This response appeared at doses
much higher than the inhibition of protein
synthesis. The mechanism of nucleic acid
inhibition is not known.
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Plant material
GK Mini Manó/Nobeokabozu genetic mapping
population (Prof. Mesterházy Ákos )
Nobeokabozu FHB resistant line A recombinant
line from China WSY, Wangshubai/Sumai3/Yangangf
anzhou
GK Mini Manó Arthur 71 / Sava // Rusalka / NS
171.2 /3/ F 30.74
Resistant line to e.g. leaf rust
inoculation
anthesis
SAMPLING
Dough stage
Premilk stage
Milk stage
Before inoculation sampling (ROS and total
antioxidant capacity)
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Enzymatic antioxidants
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Peroxidases (POX EC 1.11.1.7) are
oxido-reductive enzymes that participate in the
wall-building processes such as oxidation of
phenols, suberization, and lignification of host
plant cells during the defense reaction against
pathogenic agents. Accumulation of lignin and
phenolic compounds have been correlated with
disease resistance in a number of plantpathogen
interactions. These include wheat, tomato and
rice. Enhanced POX activity has been correlated
with resistance in rice, wheat, barley and
sugarcane following the inoculation with
phytopathogens. POX activity was rather delayed
or remained unchanged during the compatible
interaction in susceptible plants. .
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Peroxidase specific activity in heads of wheat
cultivars. C, non-inoculated control I,
inoculated plants. (F. graminearum)
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Some protein families (examples) which were
induced during Fusarium infection Zhou et al
2005

• Proteins with an antioxidant function
  superoxide dismutase, dehydroascorbate reductase,
  and glutathione S-transferases (GSTs)
• Expression of proteins with highest similarity
  to dehydroascorbate reductase and TaGSTF5 (a
  glutathione S-transferase) differed following FHB
  infection in susceptible and resistant cultivars.

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FUSARIUM CULMORUM
Parameter 561 474 501 483 488
POD
SOD
KAT
GR
GST
Total ROS
Total antioxidant capacity
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FUSARIUM GRAMINEARUM
Parameter 561 474 501 483 488
POD
SOD
KAT
GR
GST
Total ROS
Total antioxidant capacity
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!
!
CONTROL
Parameter 561 474 501 483 488
POD
SOD
KAT
GR
GST
Total ROS
Total antioxidant capacity
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Conclusions The Fusarium inoculation on the ear
influenced the hole antioxidant system in the
flag leaves of wheat in dough stage! There were
differences between the resistant and the
sensitive cultivars in POD activity
inductions. BUT according our measurements
differences were detecable in control
circumstances. And the amount of ROS,
antioxidant capacity and the GST activity
correlated with the resistance.
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Thank you for your attention!