Callus, shoot and hairy root formation in vitro as affected by the sensitivity to auxin and ethylene in tomato mutants.
We analyzed the impact of ethylene and auxin disturbances on callus, shoots and Agrobacterium rhizogenes-induced hairy root formation in tomato (Solanum lycopersicum L.). The auxin low-sensitivity dgt mutation showed little hairy root initiation, whereas the ethylene low-sensitivity Nr mutation did not differ from the control Micro-Tom cultivar. Micro-Tom and dgt hairy roots containing auxin sensitivity/biosynthesis rol and aux genes formed prominent callus onto media supplemented with cytokinin. Under the same conditions, Nr hairy roots did not form callus. Double mutants combining Rg1, a mutation conferring elevated shoot formation capacity, with either dgt or Nr produced explants that formed shoots with little callus proliferation. The presence of rol + aux genes in Rg1 hairy roots prevented shoot formation. Taken together, the results suggest that although ethylene does not affect hairy root induction, as auxin does, it may be necessary for auxin-induced callus formation in tomato. Moreover, excess auxin prevents shoot formation in Rg1.
Lima
Joni Esrom
JE
Centro de Energia Nuclear na Agricultura, USP, Av. Centenário, 303, Piracicaba, SP, 13400-970, Brazil.
Benedito
Vagner Augusto
VA
Figueira
Antonio
A
Peres
Lázaro Eustáquio Pereira
LE
D018744:DNA, Plant / Q000235:genetics; D005030:Ethylenes / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000494:pharmacology*; D018551:Solanum lycopersicum / Q000187:drug effects* / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D018517:Plant Roots / Q000187:drug effects*; D018520:Plant Shoots / Q000187:drug effects*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics; D014170:Transformation, Genetic
D018744:DNA, Plant; D005030:Ethylenes; D007210:Indoleacetic Acids; C036216:ethylene