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Eucalyptustranscriptome analysis revealed molecular chaperones highly expressed in xylem
© Gonçalves et al; licensee BioMed Central Ltd. 2011
- Published: 13 September 2011
- Lignin Content
- Molecular Chaperone
- Wood Quality
- Wood Formation
Plant development is very plastic, being coupled to environmental cues. As sessile organisms, plants must be able to respond rapidly to environmental stresses such as changes in temperature and salinity, heavy metals and water deficit. Efficient stress response systems are prerequisites for plant survival and productivity .
Molecular chaperones (or Heat Shock Proteins – HSP) compose a ubiquitous class of proteins involved in cellular protein quality control (PQC) and homeostasis. They play a critical role in folding and degradation of polypeptides, and therefore, in maintenance and modulation of cellular pathways, which are dependent of function (correct folding) and availability (stability and degradation) of involved proteins, under normal and stress conditions .
Genetics and proteomics studies of wood formation have highlighted some chaperones up-regulated in xylem of Eucalyptus, Pinus and Populus species, stating that they may play an important role in cell wall formation and xylem development [3, 4].
Different species of Eucalyptus are known for their superior performance in growth, wood quality and resistance to different types of stress . Such characteristics are probably driven by distinct gene expression coordination in xylogenesis. Eucalyptus grandis is one of the most planted species in the world due to its rapid growth, wide adaptability and wood quality. Eucalyptus globulus wood has higher S/G ratio which provides high yields in cellulose extraction .
Lignin extraction consumes large quantities of chemicals and energy, and many efforts have been made to improve this process by modifying lignin content or composition in trees, in order to reduce lignin content or make it easier to extract. Results have been achieved by supplementation and genetic modification [7, 8].
This study aims to identify chaperones possibly involved in wood formation and quality of wood for pulp and paper industries.
The RNA-Seq reads were produced from two xylem libraries for comparison between species (Eucalyptus globulus andE. grandis), and from two libraries for evaluating flavonoids supplementation (E. urograndis supplemented with naringenin and narigenin-chalcone).
Reads were aligned against the assembled unigenes using SOAP2 aligner  configured to allow up two mismatches, discard sequences with “N”s and return all optimal alignments. To perform the differential expression analysis between libraries, a normalization and statistics pipeline were applied using DEG-seq software  (confidence rate: 99%; cut-off: 0.01). RNA-Seq libraries and Gbrowse are available at http://bioinfo03.ibi.unicamp.br/eucalyptus/.
SmHsp family is active in a wide range of environmental stresses, including heat, cold, drought, salinity and oxidative stress . Gion et al  noted smHsp accumulation in wood forming tissues, and suggested a role in extending the cell wall thickening phase during xylogenesis.
Hsp70 family acts in protein refolding, translocation, and facilitating the degradation of unstable proteins, directing them to lysosomes or proteasomes .
Hsp90 family has a select group of substrate proteins as polymerases and kinases . InA. thaliana some kinases are required for optimal cell elongation, which is important for plant growth and vascular system formation .
We have successfully identified chaperones with higher expression on E. globulus xylem and in E. urograndis flavonoids-supplemented plants, which provide evidences to link xylogenesis and chaperone expression. Those findings are crucial on helping to elucidate the role of chaperones on plant development, stress response and wood formation.
- Neumann D, Nover L, Partier R, Scharf KD: Heat shock and other stress response systems of plants. Biol. Zbl. 1989, 108: 1-156.Google Scholar
- Tiroli-Cepeda AO, Ramos CHI: An Overview of the Role of Molecular Chaperones in Protein Homeostasis. Protein Pept. Lett. 2011, 18 (2): 101-9. 10.2174/092986611794475093.View ArticlePubMedGoogle Scholar
- Le Provost G, Paiva J, Pot D, Brach J, Plomion C: Seasonal variation in transcript accumulation in wood forming tissues of maritime pine (Pinus pinaster Ait.) with emphasis on a cell wall Glycine Rich Protein. Planta. 2003, 217: 820-830. 10.1007/s00425-003-1051-2.View ArticlePubMedGoogle Scholar
- Gion JM, Lalanne C, Le Provost G, Ferry-Dumazet H, Paiva J, Chaumeil P, Frigerio JM, Brach J, Barré A, de Daruvar A, Claverol S, Bonneu M, Sommerer N, Negroni L, Plomion C: The proteome of maritime pine wood forming tissue. Proteomics. 2005, 5: 3731-3751. 10.1002/pmic.200401197.View ArticlePubMedGoogle Scholar
- Grattapaglia D, Kirst M: Eucalyptus applied genomics: from gene sequences to breeding tools. New Phytol. 2008, 179: 911-929. 10.1111/j.1469-8137.2008.02503.x.View ArticlePubMedGoogle Scholar
- Silva JC: Eucalipto: a madeira do futuro. Revista da Madeira. 2001, Curitiba, 59: 114-Google Scholar
- Baucher M, Halpin C, Petit-Conil M, Boerjan W: Lignin: genetic engineering and impact on pulping. Crit Rev Biochem Mol Biol. 2003, 38: 305-350. 10.1080/10409230391036757.View ArticlePubMedGoogle Scholar
- Chen W, Yun M, Deng F, Yogo Y: The rates of maize growth and lignin biosynthesis change after root-applied chalcone. Weed Biology and Management. 2005, 5: 118-122. 10.1111/j.1445-6664.2005.00165.x.View ArticleGoogle Scholar
- Li R, Yu C, Li Y, Lam TW, Yiu SM, Kristiansen K, Wang J: SOAP2: an improved ultrafast tool for short read alignment. Bioinformatics. 2009, 25 (15): 1966-1967. 10.1093/bioinformatics/btp336.View ArticlePubMedGoogle Scholar
- Wang L, Feng Z, Wang X, Wang X, Zhang X: DEGseq: an R package for identifying differentially expressed genes from RNA-seq data. Bioinformatics. 2010, 26 (1): 136-138. 10.1093/bioinformatics/btp612.View ArticlePubMedGoogle Scholar
- Vierling E: The roles of heat shock proteins in plants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 1991, 42: 579-620. 10.1146/annurev.pp.42.060191.003051.View ArticleGoogle Scholar
- Hartl FU: Molecular chaperones in cellular protein folding. Nature. 1996, 381: 571-580. 10.1038/381571a0.View ArticlePubMedGoogle Scholar
- Gava LM, Ramos CHI: Human 90kDa heat shock protein Hsp90 as a target for cancer therapeutics. 2009, 3: 10-21.Google Scholar
- Guo H, Li L, Ye H, Yu X, Algreen A, Yin Y: Three related receptor-like kinases are required for optimal cell elongation in Arabidopsis thaliana. PNAS. 2009, 106 (18): 7648-7653. 10.1073/pnas.0812346106.PubMed CentralView ArticlePubMedGoogle Scholar
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