Ethylene-binding activity, gene expression levels, and receptor system output for ethylene receptor family members from Arabidopsis and tomato.
Ethylene signaling in plants is mediated by a family of ethylene receptors related to bacterial two-component regulators. Expression in yeast of ethylene-binding domains from the five receptor isoforms from Arabidopsis thaliana and five-receptor isoforms from tomato confirmed that all members of the family are capable of high-affinity ethylene-binding activity. All receptor isoforms displayed a similar level of ethylene binding on a per unit protein basis, while members of both subfamily I and subfamily II from Arabidopsis showed similar slow-release kinetics for ethylene. Quantification of receptor-isoform mRNA levels in receptor-deficient Arabidopsis lines indicated a direct correlation between total message level and total ethylene-binding activity in planta. Increased expression of remaining receptor isoforms in receptor-deficient lines tended to compensate for missing receptors at the level of mRNA expression and ethylene-binding activity, but not at the level of receptor signaling, consistent with specialized roles for family members in receptor signal output.
O'Malley
Ronan C
RC
Department of Botany, University of Wisconsin, 430 Lincoln Drive, Madison, WI 53706, USA.
Rodriguez
Fernando I
FI
Esch
Jeffrey J
JJ
Binder
Brad M
BM
O'Donnell
Philip
P
Klee
Harry J
HJ
Bleecker
Anthony B
AB
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007700:Kinetics; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism*
D029681:Arabidopsis Proteins; D005030:Ethylenes; D010940:Plant Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; C036216:ethylene