Capitate glandular trichomes in Aldama discolor (Heliantheae - Asteraceae): morphology, metabolite profile and sesquiterpene biosynthesis

Autor(es)

Bombo, A. B. ^[1] ; Appezzato-da-Gloria, B. ^[1] ; Aschenbrenner, A. -K. ^[2] ; Spring, O. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Luiz de Queiroz Coll Agr, Dept Biol Sci, Av Padua Dias 11, BR-13418900 Piracicaba - Brazil

^[2] Univ Hohenheim, Inst Bot, Stuttgart - Germany

• Tipo de documento: Artigo Científico
• Fonte: Plant Biology; v. 18, n. 3, p. 455-462, MAY 2016.
• Citações Web of Science: 3

Resumo

The capitate glandular trichome is the most common type described in Asteraceae species. It is known for its ability to produce various plant metabolites of ecological and economic importance, among which sesquiterpene lactones are predominant. In this paper, we applied microscopy, phytochemical and molecular genetics techniques to characterise the capitate glandular trichome in Aldama discolor, a native Brazilian species of Asteraceae, with pharmacological potential. It was found that formation of trichomes on leaf primordia of germinating seeds starts between 24h and 48h after radicle growth indicates germination. The start of metabolic activity of trichomes was indicated by separation of the cuticle from the cell wall of secretory cells at the trichome tip after 72h. This coincided with the accumulation of budlein A, the major sesquiterpene lactone of A.discolor capitate glandular trichomes, in extracts of leaf primordia after 96h. In the same timeframe of 72-96h post-germination, gene expression studies showed up-regulation of the putative germacrene A synthase (pGAS2) and putative germacrene A oxidase (pGAO) of A.discolor in the transcriptome of these samples, indicating the start of sesquiterpene lactone biosynthesis. Sequencing of the two genes revealed high similarity to HaGAS and HaGAO from sunflower, which shows that key steps of this pathway are highly conserved. The processes of trichome differentiation, metabolic activity and genetic regulation in A.discolor and in sunflower appear to be typical for other species of the subtribe Helianthinae. (AU)

• Processo FAPESP: 10/51454-3 - Estudos morfoanatômicos, metabolômicos e moleculares como subsídios à sistemática de espécies de Asteraceae e acesso ao seu potencial farmacológico
• Beneficiário: Beatriz Appezzato da Glória
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/06851-5 - Tricomas glandulares em espécies de Aldama la Llave (Heliantheae - Asteraceae): aspectos estruturais e do desenvolvimento
• Beneficiário: Aline Bertolosi Bombo
• Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Doutorado