Integrated analysis of gene expression from carbon metabolism, proteome and metabolome, reveals altered primary metabolism in Eucalyptus grandis bark, in response to seasonal variation

Abstract

BackgroundSeasonal variation is presumed to play an important role in the regulation of tree growth, especially for Eucalyptus grandis, a fast-growing tree. This variation may induce changes in the whole tree at transcriptional, protein and metabolite levels. Bark represents an important group of tissues that protect trees from desiccation and pathogen attack, and it has been identified as potential feedstock for lignocellulosic derived biofuels. Despite the growing interest, little is known about the molecular mechanisms that regulates bark metabolism, particularly in tropical countries.ResultsIn this study we report the changes observed in the primary metabolism of E. grandis bark during two contrasting seasons in Brazil, summer (wet) and winter (dry), through the combination of transcripts (RT-qPCR), proteome (2-DE gels) and metabolome (GC-MS) analysis, in an integrated manner. Twenty-four genes, involved in carbon metabolism, were analyzed in the two seasons. Eleven were up-regulated in summer, three were up-regulated in winter and ten did not show statistical differences in the expression pattern. The proteomic analysis using 2-DE gels showed 77 proteins expressing differences in abundance, with 38 spots up-regulated in summer and 37 in winter. Different metabolites significantly accumulated during winter.ConclusionsThis study revealed a metabolic reconfiguration in the primary metabolism of E. grandis bark, triggered by seasonal variation. Transcripts and protein data suggests that during winter carbohydrate formation seems to be favored by tree metabolism. Glucose, fructose and sucrose accumulated at significant levels during the winter.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0839-8) contains supplementary material, which is available to authorized users.

Seasonal Alterations in Organic Phosphorus Metabolism Drive the Phosphorus Economy of Annual Growth in F. sylvatica Trees on P-Impoverished Soil

“…This indicates restricted loading of P metabolites into the xylem sap. Mobilization of nutrients from storage pools of the stem and its transport to developing buds in spring was described for several tree species and may be the consequence of temperature restricted nutrient uptake from the soil (Geßler et al, 1998 ; Rennenberg et al, 2010 ; Budzinski et al, 2016 ). Degradation of bark storage proteins (BSP) during spring to release AAs for its allocation to developing buds via the xylem sap is a well-known feature of deciduous trees (Schneider et al, 1996 ; Nahm et al, 2006 ; Rennenberg et al, 2010 ) and was also evident in beech trees of the present study (Figure 3 ).…”

Impact of Seasonal and Temperature-Dependent Variation in Root Defense Metabolites on Herbivore Preference in Taraxacum officinale

“…Seasonal fluctuations in plant defenses co-occur with many other phenotypic alterations that may affect plant attractiveness and resistance to herbivores. Concentrations of plant primary metabolites, including amino acids and sugars, for instance, vary substantially during growing season (Budzinski et al 2016;Riipi et al 2002) and are important determinants of plant quality for herbivores (Behmer 2009;Erb et al 2013). Moreover, seasonal changes in water supply can alter physiological characteristics such as turgor pressure (Mitchell et al 2008;Simpson et al 2012) and water content (Claussen 2005;Fernàndez-Martínez et al 2013) and, thereby, influence plant palatability (Huberty and Denno 2004).…”

Experimental Design and Sample Preparation in Forest Tree Metabolomics

“…In addition to the direct economic benefits provided by tree species, i.e., timber and non-timber products, gaming and tourism, forests have an immensurable ecological value, being the major determinants for water, oxygen, carbon, and energy balance and can be seen as a major opportunity to mitigate climate change effects [12], i.e., continued drought, increased soil and water salinization and acidification, and intensification of extreme temperatures [13]. In forest tree metabolomics research, most biological questions are indeed related to the responses towards the acclimation and adaptation to a permanently changing environment [14][15][16][17][18][19][20][21][22][23][24][25][26] as well as to the identification of potentially active components in tree species of pharmacological, agricultural, environmental, or industrial importance [27][28][29][30][31][32][33].…”

“…Despite the low number of publications in forest tree metabolomics, when compared to other omics studies [66], GC-TOF-MS has been the method of choice for the primary metabolite profiling of forest tree responses to abiotic and biotic stresses [24,25,58,[67][68][69] as well as other plant growth-related processes [17,26,[70][71][72][73][74][75][76][77]. In these forest tree metabolomics studies, as for plant metabolomics in general, primary metabolites for GC-TOF-MS analysis are commonly extracted using the well-established chloroform:methanol:water extraction protocol, with minor optimization variations across studies (e.g., time of extraction, temperature, solvent ratio, or addition order), and further derivatized with N-methyl-N-(trimethylsilyl)trifloracetamide (MSTFA), containing a mixture of fatty acid methyl esters (FAMEs) with different chain length as time standards (i.e., standard for retention time calibration) [2,34,50,63].…”