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Expression of SofLAC, a new laccase in sugarcane, restores lignin content but not S:G ratio of Arabidopsis lac17 mutant

Texto completo
Cesarino, Igor [1, 2, 3] ; Araujo, Pedro [2] ; Sampaio Mayer, Juliana Lischka [2] ; Vicentini, Renato [4] ; Berthet, Serge [5] ; Demedts, Brecht [1, 3] ; Vanholme, Bartel [1, 3] ; Boerjan, Wout [3, 1] ; Mazzafera, Paulo [2]
Número total de Autores: 9
Afiliação do(s) autor(es):
[1] Univ Ghent, Dept Plant Biotechnol & Bioinformat, B-9052 Ghent - Belgium
[2] Univ Estadual Campinas, Inst Biol, Dept Biol Vegetal, BR-13083970 Campinas, SP - Brazil
[3] Univ Ghent VIB, Dept Plant Syst Biol, B-9052 Ghent - Belgium
[4] Univ Estadual Campinas, Ctr Biol Mol & Engn Genet, Lab Bioinformat & Biol Sistemas, BR-13083875 Campinas, SP - Brazil
[5] Univ Grenoble 1, CNRS, CEA, INRA, Lab Physiol Cellulaire Vegetale, iRTSV, UMR CEA 516, Grenoble - France
Número total de Afiliações: 5
Tipo de documento: Artigo Científico
Fonte: Journal of Experimental Botany; v. 64, n. 6, p. 1769-1781, APR 2013.
Citações Web of Science: 25

Lignin is a complex phenolic heteropolymer deposited in the secondarily thickened walls of specialized plant cells to provide strength for plants to stand upright and hydrophobicity to conducting cells for long-distance water transport. Although essential for plant growth and development, lignin is the major plant cell-wall component responsible for biomass recalcitrance to industrial processing. Peroxidases and laccases are generally thought to be responsible for lignin polymerization, but, given their broad substrate specificities and large gene families, specific isoforms involved in lignification are difficult to identify. This study used a combination of co-expression analysis, tissue/cell-type-specific expression analysis, and genetic complementation to correlate a sugarcane laccase gene, SofLAC, to the lignification process. A co-expression network constructed from 37 cDNA libraries showed that SofLAC was coordinately expressed with several phenylpropanoid biosynthesis genes. Tissue-specific expression analysis by quantitative RT-PCR showed that SofLAC was expressed preferentially in young internodes and that expression levels decrease with stem maturity. Cell-type-specific expression analysis by in situ hybridization demonstrated the localization of SofLAC mRNA in lignifying cell types, mainly in inner and outer portions of sclerenchymatic bundle sheaths. To investigate whether SofLAC is able to oxidize monolignols during lignification, the Arabidopsis lac17 mutant, which has reduced lignin levels, was complemented by expressing SofLAC under the control of the Arabidopsis AtLAC17 promoter. The expression of SofLAC restored the lignin content but not the lignin composition in complemented lac17 mutant lines. Taken together, these results suggest that SofLAC participates in lignification in sugarcane. (AU)

Processo FAPESP: 08/58035-6 - Control of lignin biosynthesis in sugar cane: many gaps still to be filled
Beneficiário:Paulo Mazzafera
Linha de fomento: Auxílio à Pesquisa - Programa BIOEN - Temático