Induction of H(2)O(2) synthesis by beta-glucan elicitors in soybean is independent of cytosolic calcium transients.
Soybean cell suspension cultures have been used to investigate the role of the elevation of the cytosolic Ca(2+) concentration in beta-glucan elicitors-induced defence responses, such as H(2)O(2) and phytoalexin production. The intracellular Ca(2+) concentration was monitored in transgenic cells expressing the Ca(2+)-sensing aequorin. Two lines of evidence showed that a transient increase of the cytosolic Ca(2+) concentration is not necessarily involved in the induction of H(2)O(2) generation: (i) a Bradyrhizobium japonicum cyclic beta-glucan induced the H(2)O(2) burst without increasing the cytosolic Ca(2+) concentration; (ii) two ion channel blockers (anthracene-9-carboxylate, A9C; 5-nitro-2-(3-phenylpropylamino)-benzoate, NPPB) could not prevent a Phytophthora soja beta-glucan elicitor-induced H(2)O(2) synthesis but did prevent a cytosolic Ca(2+) concentration increase. Moreover, A9C and NPPB inhibited P. sojae beta-glucan-elicited defence-related gene inductions as well as the inducible accumulation of phytoalexins, suggesting that the P. sojae beta-glucan-induced transient cytosolic Ca(2+) increase is not necessary for the elicitation of H(2)O(2) production but is very likely required for phytoalexin synthesis.
Mithöfer
A
A
Botanisches Institut, Munich, Germany. amithoef@botanik.biologie.uni-muenchen.de
Fliegmann
J
J
Daxberger
A
A
Ebel
C
C
Neuhaus-Url
G
G
Bhagwat
A A
AA
Keister
D L
DL
Ebel
J
J
D000331:Aequorin / Q000378:metabolism; D001578:Benzopyrans / Q000032:analysis; D015152:Blotting, Northern; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D005936:Glucans / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D015640:Ion Channel Gating / Q000187:drug effects; D009579:Nitrobenzoates / Q000494:pharmacology; D010936:Plant Extracts / Q000032:analysis; D036343:Pterocarpans; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000494:pharmacology; D012717:Sesquiterpenes; D030262:Soybean Proteins / Q000378:metabolism*; D013025:Glycine max / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D013729:Terpenes; D000094162:Phytoalexins
D001578:Benzopyrans; D005936:Glucans; D009579:Nitrobenzoates; D010936:Plant Extracts; D036343:Pterocarpans; D012333:RNA, Messenger; D018749:RNA, Plant; D017382:Reactive Oxygen Species; D012717:Sesquiterpenes; D030262:Soybean Proteins; D013729:Terpenes; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D000331:Aequorin; C017343:glyceollin; D006861:Hydrogen Peroxide; D002118:Calcium; D000094162:Phytoalexins