Apoplastic Proteins

1135 Words3 Pages

The apoplast is the outer segment of the plant cell membrane. The apoplast has a variety of functions during plant physiological and development stage. It acts as a barricade and also a connection between the atmosphere and the protoplast. The apoplast is the main location, where plants express proteins. These proteins each of them have various roles that have physiological importance in the apoplast and overall fundamental impact in plant cell function. The primary objective of this paper is to establish the principle functions of apoplastic proteins in higher plants which include slowing ice formation and increasing survival at freezing temperatures, cell expansion, and their response to defense against pathogens.

Firstly, apoplastic proteins are important in slowing ice formation and increasing survival at freezing temperatures. Experiments were conducted where apoplastic proteins were extracted from cold acclimated (adapted to a new environment) winter rye leaves and compared to cold acclimated winter rye leaves where the apoplastic proteins were not extracted. Each test subject was subjected to freezing temperatures. What they found was that the cold acclimated winter rye with the apoplastic proteins were not injured by ice formation, in contrast the extracted apoplastic protein plant had succumb to injury and began to break down, when exposed at all freezing temperatures. Moreover, the injuries were directly proportional to the amount of ion leakage, the greater the injury the more ion loss. Table 1 shows the ion leakage of leaf samples under freezing temperatures. The ion leakage was most significant for extracted apoplastic protein winter rye plants (circle) and had very little change for the winter rye with apoplas...

... middle of paper ...

...shitani Kazuhiko.A Proteomic Approach to Apoplastic Proteins Involved in Cell Wall Regeneration in Protoplasts of Arabidopsis Suspension-cultured Cells. Plant Cell Physiol. 46(6): 843–857 (2005)

8 Joosten H. A. J. Matthieu and De Wit J. G. M.Pierre. Identification of Several Pathogenesis-Related Proteins in Tomato Leaves Inoculated with Cladosporium fulvum (syn.Fulvia fulva) as 1,3-fl-Glucanases and Chitinases. Plant Physiol. (1989) 89: 945-951.

7 Il SO, Ae RP, Min SB, Sun JK, Young SK, Ji EL, Na YK, Sumin L, Hyeonsook C, Ohkmae KP.Secretome analysis reveals an Arabidopsis lipase involved in defense against Alternaria brassicicola. Plant Cell 2005; 17:2832-47.

2 Boudart Georges et al. Cell wall proteins in apoplastic fluids of Arabidopsis thaliana rosettes: identification by mass spectrometry and bioinformatics. Proteomics 5, 1: 212-221 (2005)

Open Document