EFS12- Book of abstracts - Contact

SESSION 4: GENETICS OF HOSTS – PLANT RESISTANCE TO FUSARIUM,
VARIETY DEVELOPMENT
P101 - Functional characterization of a lipid transfer
protein associated with Qfhs.ifa-5A
G. Siegwart, J. J. Peter, W. Schweiger, H. Buerstmayr
BOKU - University of Natural Resources and Life Sciences, A-1180 Vienna - Department for
Biotechnology in Plant production, A-3430 Tulln
E-mail: gerald.siegwart@boku.ac.at
Fusarium head blight (FHB) is a substantial disease for wheat and other small
grain cereals. Resistance is generated by many QTL, all providing a distinct part
to the mutually produced quantitative resistance. Beneath these many QTL, two
of them are outstanding as they provide together about 40% of the total
resistance – these QTL are designated Fhb1 and Qfhs.ifa-5A. (Buerstmayr 2002,
Buerstmayr 2003). It is not known which or how many genes are responsible for
the effect of these QTL, but potential candidates could be used as target for virusinduced
gene silencing (VIGS) in order to transiently silence the gene and hence
experience differences in spread of the disease. A candidate gene that was
shown strongly associated with the major type I resistance QTL Qfhs.ifa-5A in
Affymetrix microarray as well as in RNA-seq encodes a Lipid transfer protein
(LTP). LTPs are small and abundant proteins involved in membrane biosynthesis,
lipid trafficking, cutin/suberin formation as well as in stress response and defense
against bacterial or fungal pathogens. (Kirubakaran, 2008)The candidate
emerged due to its high upregulation (150x), when comparing mock-inoculated
near-isogenic lines (NIL) that only differed in Qfhs.ifa-5A, suggesting constitutive
expression associated with the QTL. We mapped the LTP close to the centromere
on chromosome 5AL, proving that it only seems to be associated with Qfhs.ifa-5A,
but not the causal protein itself, as this is located on 5AS. Nevertheless there is a
strong connection between the LTP and the QTL, so we subjected it to our VIGSpipeline.
We transiently silenced the gene in a NIL only harboring Qfhs.ifa-5A,
which should facilitate comparison between silenced- and control plants. We
observed a faster spread of disease symptoms and earlier wilting, compared to
controls. Results of two independent biological replications using two different
silencing-constructs both times as well as qPCR validation will be presented.
Keywords: LTP, Virus induced gene silencing, Qfhs.ifa-5A, wheat
194