In a previous study by our lab, ion transport proteins such as potassium channels and voltage-gated anion channels were not detected in the soybean pulvinus due to the difficulty of separating plasma membrane proteins using the trichloroacetic acid/acetone extraction methods.
The objective of this study was to compare pulvinus protein levels expressed during the light to that in darkness to identify areas of differential expression.
0 g of pulvinus tissue was ground into a powder using a mortar and pestle with liquid nitrogen, then extracted with a 10% TCA/0.
It was found that lateral and terminal gels were not significantly different from one another and so the lateral dark-harvested pulvinus gel was used as the control condition.
In this study we have undertaken 2-D PAGE and LC-MS/MS analysis for protein characterization of soybean pulvinus expressed under dark and light conditions under a controlled environment.
Figure 1: Comparative protein expression levels of light and dark harvested pulvinus.
complementary mechanisms that occur in similar cells differing only in their location within the pulvinus has yet to be offered.
The development of the proton motive force across theplasma membrane energizes the transport of K+ andCl-; the increasing pH gradient across adaxial plasma membranes between light and dark periods could correlate to a greater energy requirement in that motor region that could be detected at the translational level even with whole pulvinus samples.
Surprisingly, none of the proteins we detected as differentially expressed in the soybean pulvinus were directly involved in processes of ion transport and the development of a proton gradient.
Pulvinus Proteins More Highly Expressed in theLight Include Stress Response Proteins
Many of the proteins that were identified in the pulvinus proteome were categorized as stress response proteins (data not shown).
The increased expression in light-harvested pulvinus was greater for ascorbate peroxidase than superoxide dismutase (2.