DELLA, o gene da revolução verde: Caracterização e análise de sua função no acúmulo de sacarose e na regulação fonte-dreno em cana-de-açúcar

Author(s)

Rafael Garcia Tavares

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2017-04-18

Examining board members

Marcelo Menossi; Rafael Vasconcelos Ribeiro; Luciano Freschi; Luiz Gonzaga Esteves Vieira; Paulo Cezar De Lucca

• Advisor: Marcelo Menossi

Abstract

The source-sink regulation for the energy balance is vital for all plants. The molecular mechanisms that act in this developmental regulation must be connected to the abiotic and biotic stresses-related stimuli throughout the life cycle of plants, providing energy homeostasis. Plant hormones play a key role in the interaction between development and environmental stresses. For instance, the biosynthesis of the growth hormone gibberellin is blocked under abiotic stresses, allowing the plants adjust their development until optimum conditions. In sugarcane, the growth is strictly related to the sucrose accumulation in the internodes and the increase of biomass for bioenergy production. Besides, growth arrest is one of the first responses under abiotic stress, affecting cane and sugar yields. The DELLA gene, that mediates the hormonal arrest of development, is an interesting candidate in the study of the developmental process and source-sink in cane. In this thesis, we characterized the ScGAI gene that encodes a DELLA protein from sugarcane. ScGAI presents different expression levels in leaf tissue and along the stem. In leaf, ScGAI protein is conjugated to SUMO, a post-translational process known as SUMOylation, in a spatio-temporal manner to control leaf elongation. Transgenic sugarcane plants overexpressing the ScGAI gene (ScGAIOE) showed a retarded growth, a large number of tillers and an energy deficit. On the other hand, silenced plants for the ScGAI gene (HpScGAI) are higher with preserved diameter, increased number of internodes, earlier onset of the elongated internodes without compromised sucrose levels in comparison with wild-type plants. As demonstrated for DELLA proteins from Arabidopsis, the ScGAI protein also interacted with the ScPIF3/ScPIF4 proteins and the transcription factors ScEIN3/ScEIL1 for the controlling of growth in sugarcane. Our data demonstrated that ScGAI protein acts as a hub between growth and energy status in sugarcane (AU)

• FAPESP's process: 12/06877-9 - DELLA, the gene of green revolution. Caracterization and analysis of your function in sucrose accumulation and source-sink regulation in sugarcane
• Grantee: Rafael Garcia Tavares
• Support Opportunities: Scholarships in Brazil - Doctorate