title: Ethylene-induced transcriptional and hormonal responses at the onset of sugarcane ripening.
abstract: The effects of ethephon as a sugarcane ripener are attributed to ethylene. However, the role of this phytohormone at the molecular level is unknown. We performed a transcriptome analysis combined with the evaluation of sucrose metabolism and hormone profiling of sugarcane plants sprayed with ethephon or aminoethoxyvinylglycine (AVG), an ethylene inhibitor, at the onset of ripening. The differential response between ethephon and AVG on sucrose level and sucrose synthase activity in internodes indicates ethylene as a potential regulator of sink strength. The correlation between hormone levels and transcriptional changes suggests ethylene as a trigger of multiple hormone signal cascades, with approximately 18% of differentially expressed genes involved in hormone biosynthesis, metabolism, signalling, and response. A defence response elicited in leaves favoured salicylic acid over the ethylene/jasmonic acid pathway, while the upper internode was prone to respond to ethylene with strong stimuli on ethylene biosynthesis and signalling genes. Besides, ethylene acted synergistically with abscisic acid, another ripening factor, and antagonistically with gibberellin and auxin. We identified potential ethylene target genes and characterized the hormonal status during ripening, providing insights into the action of ethylene at the site of sucrose accumulation. A molecular model of ethylene interplay with other hormones is proposed.
authors.affiliation: Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, 13083-862, Campinas, Brasil.
authors.forename: Camila P
authors.initials: CP
authors.lastname: Cunha
authors.affiliation: Centro de Ecofisiologia e Biofísica, Instituto Agronômico de Campinas, 13001-970, Campinas, Brasil.
authors.forename: Guilherme G
authors.initials: GG
authors.lastname: Roberto
authors.affiliation: Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, 13083-862, Campinas, Brasil.
authors.forename: Renato
authors.initials: R
authors.lastname: Vicentini
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, Brasil.
authors.forename: Carolina G
authors.initials: CG
authors.lastname: Lembke
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, Brasil.
authors.forename: Glaucia M
authors.initials: GM
authors.lastname: Souza
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, 13083-862, Campinas, Brasil.
authors.forename: Rafael V
authors.initials: RV
authors.lastname: Ribeiro
authors.affiliation: Centro de Ecofisiologia e Biofísica, Instituto Agronômico de Campinas, 13001-970, Campinas, Brasil.
authors.forename: Eduardo C
authors.initials: EC
authors.lastname: Machado
authors.affiliation: Centro de Ecofisiologia e Biofísica, Instituto Agronômico de Campinas, 13001-970, Campinas, Brasil.
authors.forename: Ana M M A
authors.initials: AM
authors.lastname: Lagôa
authors.affiliation: Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, 13083-862, Campinas, Brasil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Menossi
mesh_terms: D005030:Ethylenes / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D063245:Plant Development / Q000187:drug effects*; D010937:Plant Growth Regulators / Q000378:metabolism*; D031786:Saccharum / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D013395:Sucrose; C036216:ethylene