Download Influence of post-anthesis drought stress on

Korana Surdonja, Dipl.-Biol.
[email protected]
Independent Research group: Abiotic Stress Genomics (until 2016)
Supervisor: Dr. Markus Kuhlmann
Ph.D. Student since October 2012
Influence of post-anthesis drought stress on barley germination and seedling growth
Germination is a complex process where the imbibed mature
seed must quickly shift from a maturation state to a
germination driven program of development. From the
economical point of view this process is of importance because
it is part of the first step in the malting process of barley and
defines the quality of the malt. During the germination process
the plant embryo uses the resources from the endsperm and
prepares for seedling growth. The antagonism between the
phytohormones gibberelin (GA) and abscisic acid (ABA) is an
important factor controlling the transition from embryogenesis
to germination in the seed. The ability of the seed to germinate
depends on its physiological state. One major factor
contributing to this state is determined by stored mRNAs that
are translated upon imbibition and are germination essential.
The stored transcripts are accumulated both in embryo and
endosperm during seed development, most of them are ABA
responsive, and their accumulation is affected under
challenging environmental conditions, such as drought.
In my work, transgenic lines with overexpressed AtNCED6 by embryo and endosperm specific
promoters and lines with RNAi suppressed 8’-OH-ABA in embryo are used to investigate their
different germination behavior and seedling establishment. The results show that post-anthesis
drought stressed seeds have an enhanced germination rate during early stages of germination which
correlates with lower ABA levels found in the seedlings. The observed faster germination caused by
drought stress brings negative impact on several malting quality parameters. Microarray approach is
used to elucidate the role of germination essential transcripts and how is their regulation and
accumulation changing under influence of different ABA levels produced in different seed tissues and
their role during malting process.