Proteins differentially-accumulated and identified by MALDI-TOF-TOF MS in <i>Populus</i> × <i>canadensis</i> Moench seeds under controlled aging treatment at 30°C and 75% relative humidity for 0, 45 and 90 d.

<p>Only protein spots that changed in abundance at least 1.5-fold (<i>P</i> < 0.05) of three replicates are included. Some fold changes are between –1.5 and +1.5, because there is a change of at least 1.5-fold in one of the other treatments. The positions of the spots are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132509#pone.0132509.g002" target="_blank">Fig 2</a>. Exp. protein mass, experimental protein mass; Theo. protein mass, theoretical protein mass. 0, 45 and 90 d, seeds controlled deteriorated at 30°C and 75% relative humidity for 0, 45 and 90 d, respectively; A, appeared; D, disappeared; NA, undetected in both treatments. +, increased;–, decreased. * Blasted from other species.</p

Germination time course (A), response to temperature (B), relative ion leakage (C) and respiration rate (D) of poplar seeds with different vigor.

<p>A and B, seeds aged at 30°C and 75% relative humidity for different times were incubated in darkness at 10°C for the indicated time (A) or at 10–40°C for 168 h (B). A radicle protrusion of 1 mm was used as the criterion for completion of germination. C and D, after aging for the indicated time, relative ion leakage and respiration rate of seeds were immediately measured as described in Materials and methods. All values are means ± SD of three replicates of 50 or 100 seeds each. Bars with different lower case letters are significantly different among seeds aged for different times (<i>P</i> = 0.05).</p

The reference gel (seeds aged for 0 d) for the total protein extract from poplar seeds aged for 0, 45 and 90 d.

<p>A total of 600 μg of proteins was extracted from poplar seeds, separated by 2-D gel as described in Materials and methods, and visualized with CBB. The protein spots accumulated differentially in different treatments are numbered and highlighted by circles and arrows. Their identities and properties are described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132509#pone.0132509.t001" target="_blank">Table 1</a>.</p

Functional classification and distribution of the 65 proteins differentially changed and identified in poplar seeds aged for 0, 45 and 90 d.

<p>These proteins were categorized into 7 functional groups and 19 sub-functional groups according to Bevan et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132509#pone.0132509.ref041" target="_blank">41</a>] and Schiltz et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132509#pone.0132509.ref080" target="_blank">80</a>].</p

Proteomic Comparison between Maturation Drying and Prematurely Imposed Drying of <i>Zea mays</i> Seeds Reveals a Potential Role of Maturation Drying in Preparing Proteins for Seed Germination, Seedling Vigor, and Pathogen Resistance

We have studied the role(s) of maturation drying in the acquisition of germinability, seedling vigor and pathogen resistance by comparing the proteome changes in maize embryo and endosperm during mature and prematurely imposed drying. Prematurely imposed dried seeds at 40 days after pollination (DAP) germinated almost as well as mature seeds (at 65 DAP), but their seedling growth was slower and they were seriously infected by fungi. A total of 80 and 114 proteins were identified to change at least two-fold (<i>p</i> < 0.05) in abundance during maturation drying in embryo and endosperm, respectively. Fewer proteins (48 and 59 in embryo and endosperm, respectively) changed in abundance during prematurely imposed drying. A number of proteins, 33 and 38 in embryo and endosperm, respectively, changed similarly in abundance during both maturation and prematurely imposed drying. Storage proteins were abundant in this group and may contribute to the acquisition of seed germinability. However, a relatively large number of proteins changed in the embryo (47 spots) and endosperm (76 spots) specifically during maturation drying. Among these proteins, storage proteins in the embryo and defense proteins in the endosperm may be particularly important for seedling vigor and resistance to fungal infection, respectively