ACC levels in pear fruit during development and ripening.

<p>Closed and open circles indicate 2010 and 2011 samples. Error bars indicate the standard deviations of three replicates.</p

Amounts of representative metabolites of each group.

<p>Panels A to F correspond to groups A to F as presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131408#pone.0131408.g003" target="_blank">Fig 3</a>. Closed and open circles indicate 2010 and 2011 samples. Error bars indicate standard deviations of three replicates.</p

Changes in amounts of sugars, starch, and citrate.

<p>Closed and open circles indicate 2010 and 2011 samples. Error bars indicate standard deviations of three replicates.</p

Metabolic Profiling of Developing Pear Fruits Reveals Dynamic Variation in Primary and Secondary Metabolites, Including Plant Hormones

<div><p>Metabolites in the fruits of edible plants include sweet sugars, visually appealing pigments, various products with human nutritional value, and biologically active plant hormones. Although quantities of these metabolites vary during fruit development and ripening because of cell division and enlargement, there are few reports describing the actual dynamics of these changes. Therefore, we applied multiple metabolomic techniques to identify the changes in metabolite levels during the development and ripening of pear fruits (<i>Pyrus communis</i> L. ‘La France’). We quantified and classified over 250 metabolites into six groups depending on their specific patterns of variation during development and ripening. Approximately half the total number of metabolites, including histidine and malate, accumulated transiently around the blooming period, during which cells are actively dividing, and then decreased either rapidly or slowly. Furthermore, the amounts of sulfur-containing amino acids also increased in pear fruits around 3–4 months after the blooming period, when fruit cells are enlarging, but virtually disappeared from ripened fruits. Some metabolites, including the plant hormone abscisic acid, accumulated particularly in the receptacle prior to blooming and/or fruit ripening. Our results show several patterns of variation in metabolite levels in developing and ripening pear fruits, and provide fundamental metabolomic data that is useful for understanding pear fruit physiology and enhancing the nutritional traits of new cultivars.</p></div

Changes in amounts of sugars, starch, and citrate.

<p>Closed and open circles indicate 2010 and 2011 samples. Error bars indicate standard deviations of three replicates.</p

Principal component analysis (PCA) of metabolome data.

<p>(a) Data obtained from pear fruits after blooming in 2010 (open circles) and 2011 (closed circles). The horizontal and vertical axes represent principal component 1 (PC1, contribution ratio 45.7%) and 2 (PC2, 18.1%), respectively. (b) Data for pear fruits from 2MAB onward during the same 2 years. The horizontal and vertical axes represent PC1 (33.9%) and PC2 (14.9%), respectively.</p

Time-course changes in amounts of plant hormones in developing and ripening pear fruits.

<p>Closed and open circles indicate 2010 and 2011 samples. Abbreviations: SA, salicylic acid; JA, jasmonic acid; JA-Ile, jasmonic acid Ile conjugate; ABA, abscisic acid; GA1, gibberellin A1; GA4, gibberellin A4; IAA, indole acetic acid; BL, brassinolide; CS, castasterone; tZ, <i>trans</i>-zeatin; DHZ, dihydrozeatin; iP, isopentenyladenine; tZR, <i>trans</i>-zeatin riboside; DHZR, dihydrozeatin riboside; iPR, isopentenyladenine riboside.</p

Hierarchical cluster analysis (HCA) of metabolome data of pear fruits from 2WBB to 1MAH in 2011.

<p>Yellow and blue colors represent higher and lower amounts of metabolites, respectively. Details of HCA are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131408#pone.0131408.s001" target="_blank">S1 Fig</a> Depending on the variation patterns of metabolite amounts, detected metabolites were classified into 6 groups, A to F. The enlarged figures show HCA results of four representative metabolites in each group. The detailed changes in the amounts of the underlined metabolites in the enlarged graphs are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131408#pone.0131408.g004" target="_blank">Fig 4</a>.</p

Fresh weight of pear fruits during development and ripening.

<p>Sampling times were at 2 weeks before blooming (2WBB), 1 week before blooming (1WBB), the time of blooming (B), 2 weeks after blooming (2WAB), 1 month after blooming (1MAB), 2 months after blooming (2MAB), 3 months after blooming (3MAB), 4 months after blooming (4MAB), the time of harvesting (H), and 1 month after harvesting (1MAH). The values from 2WBB to 1MAB are shown in the inset. Error bars indicate standard deviations of three replicates.</p

Protein and sulfur-containing amino acid levels in pear fruits.

<p>(A) Amounts of free and protein-derived Met and Cys in pear fruits at 3MAB, 4MAB, H, and 1MAH. Closed and open circles and triangles represent free and protein-derived Met and Cys, respectively. (B) Total protein amounts in pear fruits at the same sampling times as (A). Error bars indicate standard deviations of three replicates.</p