The expression of tgas118, encoding a defensin in Lycopersicon esculentum, is regulated by gibberellin.
A flower specific cDNA, tgas118, has been isolated after differential screening of a gib-1 anther cDNA library of Lycopersicon esculentum. The corresponding mRNA was present in all tissues analysed. Northern blot analysis revealed that in wild-type tomato the gene was predominantly expressed throughout flower development, while in the gibberellin (GA)-deficient mutant of tomato (gib-1) the abundance declined. Treatment of the mutant with GA resulted in an accumulation of the tgas118 mRNA within hours in leaf and bud tissues. In the leaf, GA1, GA3 and GA9 were effective in enhancing the expression while GA4 was not. In addition to GA, wounding and dehydration also increased the accumulation of tgas118 mRNA in leaf tissue. In situ hybridization showed that application of 50 ng GA3 bud(-1) induced a similar spatial expression of the tgas118 mRNA in gib-1 buds 24 h post treatment to that found in wild-type flower buds. The deduced TGAS118 protein displays up to 77% similarity with defensins and as its expression is up-regulated by stimuli such as wounding it is proposed that it may play a role in protection against pathogens.
van den Heuvel
K J
KJ
Department of Molecular Plant Physiology, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, Netherlands.
Hulzink
J M
JM
Barendse
G W
GW
Wullems
G J
GJ
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018744:DNA, Plant / Q000302:isolation & purification; D023082:Defensins / Q000235:genetics* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism / Q000494:pharmacology*; D018551:Solanum lycopersicum / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics*; D018514:Plant Structures / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000302:isolation & purification; D018749:RNA, Plant
D018076:DNA, Complementary; D018744:DNA, Plant; D023082:Defensins; D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C435832:tgas118, Lycopersicon esculentum