Identification and characterization of genes differentially expressed during arbuscular mycorrhiza development in sugarcane

Author(s)

Soraya Gabriela Kiriachek

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2008-11-18

Examining board members

Marcio Rodrigues Lambais; Welington Luiz de Araujo; Arnoldo Rocha Façanha; Gonçalo Amarante Guimarães Pereira; Lazaro Eustaquio Pereira Peres

• Advisor: Marcio Rodrigues Lambais

Abstract

Arbuscular mycorrhizae (AM) are mutualistic symbiotic associations between fungi of the order Glomales and most of the terrestrial plants. The molecular mechanisms regulating AM development and efficiency are not well understood so that agricultural large scale application is so difficult. Although so many approaches are being used to the identification of differentially expressed genes in AMs, large scale analysis it must contributed to the knowledge of symbiosis molecular biology. The aim of this work was identify genes induced or suppressed in sugarcane roots colonized for G. clarum in low and high phosphorus (P) conditions, during symbiosis development. Using suppressive subtractive hybridization (SSH) was possible to detect 74 genes with differential significant expression in 12 weeks mycorrhized roots. In other hand a total of 386 genes were spotted into nylon membranes and differential expression was evaluated with probes of cDNA of 4 and 12 weeks. Macroarray hybridization shows increase of genes transcripts involved in jasmonate metabolism (COI1) and ethylene metabolism (ET) 4 weeks after inoculation, and in salycilic acid 12 weeks after inoculation. Twelve genes differentially expressed in mycorrhizal presences were choosen to analyse the expression with qRT-PCR in 4, 6, 8, 10 and 12 weeks after inoculation. A cistein protease (protein metabolism); a remorin (cellular dynamic), dehydroascorbate reductase, hidroxiproline rich protein (estress response); two proteins associated to senescence; a horcolin (unknown function); COI1 (jasmonate metabolism); catalase, germin, glutathione (oxidative estress); chitinase (defence response) were tested. The results showed that genes relationated with oxidative stress are activated in early stages of MAs development, and, in late stages these phytohormones metabolism related genes are suppressed. Patterns expression of genes involved in MAs development it must contributed to elucidate the genetics mechanisms controlling the symbiosis and it must facilitate large scale use of FMAs. (AU)