F. Zhang et al., EFFECT OF AEROBIC PRIMING ON THE RESPONSE OF ECHINOCHLOA-CRUS-PAVONISTO ANAEROBIC STRESS - PROTEIN-SYNTHESIS AND PHOSPHORYLATION, Plant physiology, 105(4), 1994, pp. 1149-1157
Echinochloa species differ in their ability to germinate and grow in t
he absence of oxygen. Seeds of Echinochloa crus-pavonis (H.B.K.) Schul
t do not germinate under anoxia but remain viable for extended periods
(at least 30 d) when incubated in an anaerobic environment. E. crus-p
avonis can be induced to germinate and grow in an anaerobic environmen
t if the seeds are first subjected to a short (1-18 h) exposure to aer
obic conditions (aerobic priming). Changes in polypeptide patterns (co
nstitutive and de novo synthesized) and protein phosphorylation induce
d by aerobic priming were investigated. In the absence of aerobic prim
ing protein degradation was not evident under anaerobic conditions, al
though synthesis of a 20-kD polypeptide was induced. During aerobic pr
iming, however, synthesis of 37- and 55-kD polypeptides was induced an
d persisted upon return of the seeds to anoxia. Furthermore, phosphory
lation of two 18-kD polypeptides was observed only in those seeds that
were labeled with (PO4)-P-32 during the aerobic priming period. Subse
quent chasing in an anaerobic environment resulted in a decrease in ph
osphorylation of these polypeptides. Likewise, phosphorylation of the
18-kD polypeptides was not observed if the seeds were labeled in an an
aerobic atmosphere. These results suggest that the regulated induction
of the 20-, 37-, and 55-kD polypeptides may be important for anaerobi
c germination and growth of E. crus-pavonis and that the specific phos
phorylation of the 18-kD polypeptides may be a factor in regulating th
is induction.