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Chitinases and glucanases in the process of somatic embryogenesis of Pinus
nigra Arn. and hybrid firs
Lenka Fráterová, Terézia Salaj, Ildikó Matušíková, Ján Salaj
Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademická 2, P. O. Box
39A, 950 07 Nitra, Slovak Republic
In our work, 17 embryogenic cell lines of Pinus nigra Arn. and 7 embryogenic cell lines of
hybrid firs (Abies alba x A. cephalonica and A. alba x A. numidica) with different
embryogenic potential were used with the aim to study the role of chitinases and glucanases in
somatic embryogenesis. The embryogenic potential of cell lines was characterised on the
basis of structural observations and maturation capacity of somatic embryos. For biochemical
analyses suspension cultures were prepared.
The chitinolytic activity of the extracellular protein fractions was analysed in cultivation
media of embryogenic lines of P. nigra (11 embryogenic lines with high embryogenic
potential, 6 with low embryogenic potential) and hybrid firs embryogenic lines (6 high, 1 low
embryogenic potential). In case of P. nigra the presence or absence of chitinase isoforms does
not correlate significantly with the high or low embryogenic potential. In case of firs two
chitinase isoforms were absent in the embryogenic line with low embryogenic capacity
(AC79), whereas the same two isoforms are present in all other tested lines. This might
indicate a correlation between chitinase isoforms and the high or low embryogenic potential
of tested lines.
Glucanase activity was detected from cultivation media of 12 lines of P. nigra and of 6
hybrid fir lines with high embryogenic potential. SDS-PAGE analysis of these lines showed
the presence of six glucanase isoforms in cultivation media, having different abundance in
different embryogenic lines - glucanase isoform with a molecular weight of ~ 33.8 kDa was
present in all examined embryogenic lines. In the cell line AN72, apart from the mentioned
glucanase isoform, we detected another glucanase isoform with a molecular weight of ~ 41.2
kDa.
Analyses of profiles of extracellular chitinases and glucanases in cultivation media of
embryogenic tissues suggest that these profiles are results of the heterogenity of cell cultures
and that the probability of a direct correlation between the presence or absence of particular
chitinase or glucanase isoforms and embryogenic potential is low. However, the isoenzyme
profiles of these enzymes, together with the ratio of accumulation/activity can be important
components of the embryogenic process.
Acknowledgment: The financial support from the Slovak Grant Agency VEGA, proj. no.
2/0144/11, is highly appreciated.
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