EFS12- Book of abstracts - Contact

SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
Insights into the Fusarium-wheat root pathosystem
uncover a hidden danger to wheat production
Q. Wang, A. Furch, S. Buxa, A. Römpp, D. R. Bhandari, W. Friedt, S.
Gottwald
Department of Plant Breeding, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26, 35392
Giessen, Germany
E-mail: sven.gottwald@agrar.uni-giessen.de
While the floral Fusarium disease FHB relies on successful spike colonization,
soil- but also seed-borne diseases rely on successful colonization of roots which
provide an excellent nutrient supply. Roots are the ʻplant hidden halfʼ and their
diseases are often unseen, misdiagnosed and challenge disease assessments.
We are investigating root rot (FRR) as a model for Fusarium-wheat root
interactions which still represent a knowledge gap regarding epidemiology,
pathogenesis, and the genetics of wheat resistance.
Our current investigations on a diverse set of wheats have demonstrated the high
capability of F. graminearum to infect and colonize wheat roots - followed by its
spread into distal plant tissue. Studies on the mode of FRR disease revealed a
four-phase colonization strategy similar to other Fusarium diseases. Unique
confocal microscopic analyses on F. graminearum root colonization exhibit a
devastating invasion of all cell types. Stems and leaves were preferentially
colonised via the vascular system. In addition, mass spectrometry imaging has
been established as new technology for the metabolic profiling of infested/noninfested
root, stem and leaf tissues. Finally, diminished water/nutrient supply,
intracellular hyphae growth and fungal toxins seem to be essential damaging
factors at seedling and adult stage. Hence, reduced seedling vigour, impaired
plant development and prematurity blight of side shoots/heads were identified as
major threats to yield.
Generally, inverse reactions to Fusarium infestation seem to be present between
root and spike. The major FHB resistances failed to protect wheat plants against
FRR, while a partial resistance to root colonization was found for FHB susceptible
genotypes. Accordingly, three well-known FHB/DON resistance genes were
Fusarium-induced associated with low FRR infestations, thereby revealing an
activity contrary to FHB treated spikes. Hence, current FHB resistant cultivars are
probably insufficient to prevent root colonization and to meet challenges
represented by present and future soil pathogen accumulations associated with
intensive agriculture.
Keywords: F. graminearum-wheat root interactions, root rot, pathogenesis,
histopathology
52