Expression pattern of four storage xyloglucan mobilization-related genes during seedling development of the rain forest tree Hymenaea courbaril L.

Autor(es)

Brandao, A. D. ^{[1, 2]} ; Del Bem, L. E. V. ^{[1, 3]} ; Vincentz, M. ^{[1, 3]} ; Buckeridge, M. S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Ctr Biol Mol & Engn Genet, Campinas, SP - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Dept Bot, BR-05508 Sao Paulo - Brazil

^[3] Univ Estadual Campinas, Inst Biol, Dept Genet & Evolucao, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Experimental Botany; v. 60, n. 4, p. 1191-1206, MAR 2009.
• Citações Web of Science: 8

Resumo

During seedling establishment, cotyledons of the rain forest tree Hymenaea courbaril mobilize storage cell wall xyloglucan to sustain growth. The polysaccharide is degraded and its products are transported to growing sink tissues. Auxin from the shoot controls the level of xyloglucan hydrolytic enzymes. It is not yet known how important the expression of these genes is for the control of storage xyloglucan degradation. In this work, partial cDNAs of the genes xyloglucan transglycosylase hydrolase (HcXTH1) and beta-galactosidase (HcBGAL1), both related to xyloglucan degradation, and two other genes related to sucrose metabolism {[}alkaline invertase (HcAlkIN1) and sucrose synthase (HcSUS1)], were isolated. The partial sequences were characterized by comparison with sequences available in the literature, and phylogenetic trees were assembled. Gene expression was evaluated at intervals of 6 h during 24 h in cotyledons, hypocotyl, roots, and leaves, using 45-d-old plantlets. HcXTH1 and HcBGAL1 were correlated to xyloglucan degradation and responded to auxin and light, being down-regulated when transport of auxin was prevented by N-1-naphthylphthalamic acid (NPA) and stimulated by constant light. Genes related to sucrose metabolism, HcAlkIN1 and HcSUS1, responded to inhibition of auxin transport in consonance with storage mobilization in the cotyledons. A model is proposed suggesting that auxin and light are involved in the control of the expression of genes related to storage xyloglucan mobilization in seedlings of H. courbaril. It is concluded that gene expression plays a role in the control of the intercommunication system of the source-sink relationship during seeding growth, favouring its establishment in the shaded environment of the rain forest understorey. (AU)

• Processo FAPESP: 04/10159-8 - Controle da expressão gênica do metabolismo de carboidratos pela auxina durante a mobilização de reservas e o desenvolvimento de plântulas de jatobá (Hymenaea courbaril var. Stilbocarpa)
• Beneficiário: Aline Dias Brandão
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 07/59708-1 - Respostas fisiológicas e bioquímicas de três espécies de leguminosas tropicais às mudanças climáticas
• Beneficiário: Marcos Silveira Buckeridge
• Modalidade de apoio: Auxílio à Pesquisa - Regular