60º CONGRESSO BRASILEIRO DE GENÉTICA
26 a 29 de agosto de 2014 Casa Grande Hotel Resort • Guarujá • SP • Brasil
www.sbg.org.br - ISBN 978-85-89109-06-2
Molecular and structural characterization of the cell wall in
two genotypes of sugarcane with contrasting efficiencies of
association with diazotrofic bacteria
Forero, BH1; Grativol, C1; Carvalho, TLG1; Farinelli, L2; Ferreira, PCG1; Hemerly, AS1
Laboratório de Biologia Molecular de Plantas, Instituto de Bioquímica Médica Leopoldo de Meis, UFRJ, Rio de Janeiro,
RJ, Brasil; 2Fasteris SA, Switzerland
1
[email protected]
Keywords: Sugarcane, diazotrofic bacteria, cell wall, transcriptome, endophytes
Sugarcane is a plant of the group of grasses (Family Poaceae) that is highly cultivated in Brazil as an energy resource. Many
studies are being conducted characterizing sugarcane cell wall, since it is a main reserve of the polysaccharides essential for
the production of biodiesel. Sugarcane is associated with beneficial endophytic diazotrophic bacteria and our group has been
shown, that these microorganisms could influence metabolic pathways such as cell division and growth, synthesis of hormones
and defense compounds. Nevertheless, little is known on the formation and development of the cell wall in this grass correlated
with a role during the association with the diazotrofic bacteria. Our main goal in this study is to perform a molecular and
structural characterization of the cell wall in two genotypes of sugarcane with contrasting efficiencies of association with
diazotrofic bacteria: SP70 -1143 (high efficiency) and Chunee (low efficiency). A reference sugarcane transcriptome and four
differential transcriptomes of the two genotypes were generated with Illumina RNAseq. Databases of protein sequences related
to formation of the cell wall of Arabidopsis thaliana, Oryza sativa and Zea mays were used to identify potential orthologs in
the sugarcane transcriptome. The candidates were filtered and classified in libraries of differentially expressed transcripts in
two different growth conditions (naturally colonized and free of endophytic bacteria) and separated in shoot and root tissues.​​
The most representative pathways, according to the number of differentially expressed transcripts (DET), these were the
functional categories ‘formation and growth’, ‘formation of substrates’ and ‘secondary wall formation’. DET belonging to the
three functional categories were selected to be evaluated by qRT-PCR. The morphology and cell wall content of roots and
shoots of stalk plants and hydroponic plants of the two genotypes were analyzed in stained tissue sections and observed with
a confocal microscope. The results showed that the stalk root and stalk shoot of plants of genotype SP70 -1143 have a greater
number of pathways regulated compared to genotype Chunee. In contrast, in plants free of diazotrophic bacteria, roots of
the genotype Chunee have a larger number of pathways regulated. Altogether, the results suggest that the presence of bacteria
can change the morphology as well as the formation, synthesis and final content of cell wall compounds in the two genotypes
that associate with different efficiencies with the beneficial diazotrophic bacteria.
Funded by INCT, CNPq, FAPERJ and CAPES.
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