Polyamines influence morphogenesis and caffeine biosynthesis in in vitro cultures of Coffea canephora P. ex Fr.

The influence of polyamines, polyamine
inhibitors and ethylene inhibitors were tested in Coffea
canephora for in vitro morphogenetic response and caffeine
biosynthesis. Coffea canephora produced nonembryogenic
and embryogenic calli. Somatic embryos
were produced only from the embryogenic callus. Endogenous
polyamine pools were estimated in these tissues.
Somatic embryos were subjected to secondary embryogenesis
under the influence of putrescine, silver nitrate and
specific inhibitors of polyamine biosynthesis. Estimation of
endogenous total polyamines revealed that embryogenic
callus contained 11-fold more spermine and 3.3-fold higher
spermidine when compared to non-embryogenic callus.
Incorporation of polyamines resulted in 58% explant
response for embryogenesis when compared to control with
42% response. Incorporation of silver nitrate resulted in
65% response for embryogenesis. Incorporation of polyamine
biosynthetic pathway inhibitors DFMO and DFMA
resulted in 83% reduction in embryogenic response with
concomitant increase in caffeine levels by two-fold as
compared to control. These results have clearly demonstrated
that polyamines play a crucial role in
embryogenesis and caffeine biosynthesis.