Dataset Information

Reprogramming of gene expression during compression wood formation in pine: coordinated modulation of S-adenosylmethionine, lignin and lignan related genes.

ABSTRACT: BACKGROUND: Transcript profiling of differentiating secondary xylem has allowed us to draw a general picture of the genes involved in wood formation. However, our knowledge is still limited about the regulatory mechanisms that coordinate and modulate the different pathways providing substrates during xylogenesis. The development of compression wood in conifers constitutes an exceptional model for these studies. Although differential expression of a few genes in differentiating compression wood compared to normal or opposite wood has been reported, the broad range of features that distinguish this reaction wood suggest that the expression of a larger set of genes would be modified. RESULTS: By combining the construction of different cDNA libraries with microarray analyses we have identified a total of 496 genes in maritime pine (Pinus pinaster, Ait.) that change in expression during differentiation of compression wood (331 up-regulated and 165 down-regulated compared to opposite wood). Samples from different provenances collected in different years and geographic locations were integrated into the analyses to mitigate the effects of multiple sources of variability. This strategy allowed us to define a group of genes that are consistently associated with compression wood formation. Correlating with the deposition of a thicker secondary cell wall that characterizes compression wood development, the expression of a number of genes involved in synthesis of cellulose, hemicellulose, lignin and lignans was up-regulated. Further analysis of a set of these genes involved in S-adenosylmethionine metabolism, ammonium recycling, and lignin and lignans biosynthesis showed changes in expression levels in parallel to the levels of lignin accumulation in cells undergoing xylogenesis in vivo and in vitro. CONCLUSIONS: The comparative transcriptomic analysis reported here have revealed a broad spectrum of coordinated transcriptional modulation of genes involved in biosynthesis of different cell wall polymers associated with within-tree variations in pine wood structure and composition. In particular, we demonstrate the coordinated modulation at transcriptional level of a gene set involved in S-adenosylmethionine synthesis and ammonium assimilation with increased demand for coniferyl alcohol for lignin and lignan synthesis, enabling a better understanding of the metabolic requirements in cells undergoing lignification.

SUBMITTER: Villalobos DP

PROVIDER: S-EPMC3406974 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Reprogramming of gene expression during compression wood formation in pine: coordinated modulation of S-adenosylmethionine, lignin and lignan related genes.

Villalobos David P DP Díaz-Moreno Sara M SM Said El-Sayed S el-SS Cañas Rafael A RA Osuna Daniel D Van Kerckhoven Sonia H E SH Bautista Rocío R Claros Manuel Gonzalo MG Cánovas Francisco M FM Cantón Francisco R FR

BMC plant biology 20120629

<h4>Background</h4>Transcript profiling of differentiating secondary xylem has allowed us to draw a general picture of the genes involved in wood formation. However, our knowledge is still limited about the regulatory mechanisms that coordinate and modulate the different pathways providing substrates during xylogenesis. The development of compression wood in conifers constitutes an exceptional model for these studies. Although differential expression of a few genes in differentiating compression ...[more]

PMID: 22747794

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Project description:Pine wilt disease is a dangerous pine disease globally. We used Masson pine (Pinus massoniana) clones, selected through traditional breeding and testing for 20 years, to study the molecular mechanism of their high resistance to pine wood nematodes (PWN,Bursaphelenchus xylophilus). Nine strains of seedlings of genetically stable Masson pine screened from different families with high resistance to PWN were used. The same number of sensitive clones were used as susceptible controls. Total proteins were extracted for tandem mass tag (TMT) quantitative proteomic analysis. The key proteins were verified by parallel reaction monitoring (PRM). A threshold of upregulation greater than 1.3-fold or downregulation greater than 0.3-fold was considered significant in highly resistant strains versus sensitive strains. A total of 3491 proteins were identified from the seedling tissues, among which 2783 proteins contained quantitative information. A total of 42 proteins were upregulated and 96 proteins were downregulated in the resistant strains. Functional enrichment analysis found significant differences in the proteins with pectin esterase activity or peroxidase activity. The proteins participating in salicylic acid metabolism, antioxidant stress reaction, polysaccharide degradation, glucose acid ester sheath lipid biosynthesis, and the sugar glycosaminoglycan degradation pathway were also changed significantly. The PRM results showed that pectin acetyl esterase, carbonic anhydrase, peroxidase, and chitinase were significantly downregulated, while aspartic protease was significantly upregulated, which was consistent with the proteomic data. These results suggest that Masson pine can degrade nematode-related proteins by increasing protease to inhibit their infestation, and can enhance the resistance of Masson pine to PWN by downregulating carbon metabolism to limit the carbon available to PWN or for involvement in cell wall components or tissue softening. Most of the downregulated proteins are supposed to act as an alternative mechanism for latter enhancement after pathogen attacks. The highly resistant Masson pine, very likely, harbors multiple pathways, both passive and active, to defend against PWN infestation.

Project description:BackgroundRecently, pine wood nematode (PWN, Bursaphelenchus xylophilus) has been found in the extreme cold area of northeast China. The third-stage dispersal juvenile (DJ3) of PWN, which is a long-lived stress-resistant stage, plays an important role in the process of PWN spreading to low-temperature areas, as this stage can survive under unfavorable conditions.ResultsWeighted correlation network analysis (WGCNA) was used to analyze the expression patterns of 15,889 genes included in 21 RNA-Seq results of PWN at DJ3 and the other 6 different stages, and a total of 12 coexpression modules were obtained. Among them, the magenta module has the highest correlation with DJ3, which included a total of 652 genes. KEGG enrichment analysis showed that most of the genes in the magenta module were involved in metabolic processes, which were related to autophagy and longevity regulation. These pathways included starch and sucrose metabolism, which contains trehalose metabolism. To explore the function of trehalose in DJ3 formation and survival under - 20 °C, a trehalose-6-phosphate synthase encoding gene (Bx-tps), a trehalose-6-phosphate phosphatase encoding gene (Bx-tpp) and 7 trehalase encoding genes (Bx-tres) were identified and investigated. The expression of these 9 genes was related to the formation of DJ3. A treatment under - 20 °C induced the accumulation of trehalose. The survival rate of DJ3 at -20 °C reduced after silencing of any of these trehalose metabolism genes. Further analysis suggested that two trehalose synthesis genes were highly correlated with DJ3 and might be involved in autophagy by regulating with energy conversion related genes.ConclusionsThe above results indicated that trehalose metabolism promotes DJ3 formation and helps DJ3 survive at -20 °C. Although trehalose accumulation is favorable for DJ3 to cope with low-temperature stress, multiple trehalose metabolism genes need to work together. There may be a multi-path regulated physiological process involving trehalose synthesis genes under low-temperature stress resistance. This physiological process may regulate the formation and maintenance of DJ3 through autophagy and energy conversion.

Dataset Information

Reprogramming of gene expression during compression wood formation in pine: coordinated modulation of S-adenosylmethionine, lignin and lignan related genes.

Publications

Reprogramming of gene expression during compression wood formation in pine: coordinated modulation of S-adenosylmethionine, lignin and lignan related genes.

Similar Datasets

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