here - First Legume Society Conference (LSC1)

Book of Abstracts First Legume Society Conference 2013: A Legume Odyssey Novi Sad, Serbia, 9-11 May 2013
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Effect of endogenous signals on regulation mechanism of synthesis and accumulation of
flavonoids in yellow lupine infected by Fusarium oxysporum and its impact on the
cytoskeleton of plant cells
Iwona Morkunas 1 , Magda Formela 1 , Jolanta Floryszak-Wieczorek 1 , Łukasz Marczak 2 , Dorota
NaroŜna 3 , Witold Nowak 4 , Sławomir Borek 5 , Maciej Stobiecki 2
1 Department of Plant Physiology, Poznań University of Life Sciences, Poznań, Poland
2 Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
3 Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
4 Laboratory of Molecular Biology Techniques, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
5 Department of Plant Physiology, Adam Mickiewicz University, Poznań, Poland
Flavonoids are an important group of secondary plant metabolites with many and diverse key
functions in plants. They are known as agents of defense against pathogens, with antimicrobial
and antioxidant functions. Recently, they have also been shown to function as intracellular signal
molecules. The first aim of the study was to examine cross-talk interactions of sucrose and
infection caused by Fusarium oxysporum f.sp. lupini on expression of phenylpropanoid pathway
genes and precisely the flavonoid biosynthesis pathway. Additionally, the accumulation and
cytochemical localization of end products, i.e. flavonoids, were analyzed in embryo axes cells of
Lupinus luteus L. cv. Juno. Moreover, it was checked whether the accumulation of flavonoids,
especially genistein affects on the changes in the cytoskeleton of cells. The second aim of the
study was to examine cross-talk of exogenous nitric oxide (NO) and sucrose in the mechanisms
of synthesis and accumulation of isoflavonoids in yellow lupine embryo axes. It was verified
whether the dialogue of these molecules can modulate defence response of axes to infection and
development of the pathogenic fungus F. oxysporum. The experimental protocol used in this study
was based on a model system: embryo axes from germinating yellow lupine seeds inoculated with
Fusarium oxysporum f.sp. lupini and cultured in vitro on a medium with or without sucrose,
analyzed to 96 h after inoculation. The obtained results show that sucrose as signal molecule
stimulated phenylpropanoid metabolism. Sucrose strongly stimulated the expression of the
flavonoid biosynthetic genes, i.e. phenylalanine ammonialyase (PAL), chalcone synthase (CHS),
chalcone isomerase (CHI) and isoflavone synthase (IFS). The sensing of carbohydrate levels and
the response to fungal pathogens may be interrelated at some level. In the early phase of
infection the flavonoid biosynthesis pathway is considerably enhanced in yellow lupine embryo
axes as a strong signal amplification effect of sucrose and the pathogenic fungus F. oxysporum.
Moreover the strong accumulation of isoflavonoids in inoculated F. oxysporum embryo axes of
yellow lupine pretreated with a nitric oxide donor with a high level of sucrose is a result of
amplification of the signal coming from sucrose, the nitric oxide donor and the pathogenic
fungus. Sucrose and nitric oxide act as signal molecules, which correlated with up-regulation of
genes engaged in isoflavonoids production.
Acknowledgments
This study was supported by the Polish Committee for Scientific Research (KBN, grant no. N N303 414437)
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