Effect of greenhouse conditions on the leaf apoplastic proteome of Coffea arabica plants.
This work describes the coffee leaf apoplastic proteome and its modulation by the greenhouse conditions. The apoplastic fluid (APF) was obtained by leaf vacuum infiltration, and the recovered proteins were separated by 2-DE and subsequently identified by matrix assisted laser desorption/ionization time of flight-mass spectrometry, followed by homology search in EST coffee databases. Prediction tools revealed that the majority of the 195 identified proteins are involved in cell wall metabolism and in stress/defense responses. Although most of the proteins follow the classical secretory mechanism, a low percentage of them seem to result from unconventional secretion (leaderless secreted proteins). Principal components analysis revealed that the APF samples formed two distinct groups, with the temperature amplitude mostly contributing for this separation (higher or lower than 10°C, respectively). Sixty one polypeptide spots allowed defining these two groups and 28 proteins were identified, belonging to carbohydrate metabolism, cell wall modification and proteolysis. Interestingly stress/defense proteins appeared as more abundant in Group I which is associated with a higher temperature amplitude. It seems that the proteins in the coffee leaf APF might be implicated in structural modifications in the extracellular space that are crucial for plant development/adaptation to the conditions of the prevailing environment.


CONCLUSIONS
This is the first detailed proteomic study of the coffee leaf apoplastic fluid (APF) and of its modulation by the greenhouse conditions. The comprehensive overview of the most abundant proteins present in the extra-cellular compartment is particularly important for the understanding of coffee responses to abiotic/biotic stress. This article is part of a Special Issue entitled: Environmental and structural proteomics.
Centro de Investigação das Ferrugens do Cafeeiro/Biotrop/Instituto de Investigação Científica Tropical, Quinta do Marquês, 2784-505 Oeiras, Portugal. Electronic address: leonorguima@gmail.com.
Leonor
L
Guerra-Guimarães
Centro de Investigação das Ferrugens do Cafeeiro/Biotrop/Instituto de Investigação Científica Tropical, Quinta do Marquês, 2784-505 Oeiras, Portugal.
Ana
A
Vieira
Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa (UNL), Apt 127, 2781-901 Oeiras, Portugal; Instituto de Biologia Experimental e Tecnológica, EAN, 2781-901 Oeiras, Portugal.
Inês
I
Chaves
Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa (UNL), Apt 127, 2781-901 Oeiras, Portugal; DCV - Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Carla
C
Pinheiro
Departamento de Química e Física/CCA/Universidade Federal do Espirito Santo (UFES), 29500-000 Alegre, ES, Brazil.
Vagner
V
Queiroz
Centre de Recherche Public-Gabriel Lippmann, Rue du Brill 41, L-4422 Belvaux, Luxembourg.
Jenny
J
Renaut
Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa (UNL), Apt 127, 2781-901 Oeiras, Portugal.
Cândido P
CP
Ricardo
D040503:Coffea / Q000378:metabolism*; D003198:Computer Simulation; D004777:Environment; D017752:Greenhouse Effect / Q000706:statistics & numerical data*; D008954:Models, Biological; D015233:Models, Statistical; D035261:Plant Components, Aerial / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism*
D010940:Plant Proteins; D020543:Proteome
2-DE; Apoplastic proteome; Blast2GO; Coffee; Leaf secretome; MALDI TOF/TOF-MS