Proteins associated with cork formation in Quercus suber L. stem tissues

详细信息    查看全文

• 作者：Câ ; ndido P.P. Ricardo^a ; ^b ; ^{ricardo@itqb.unl.pt"" rel=""nofollow} ; Isabel Martins^a ; ¹ ; Rita Francisco^a ; ¹ ; Kjell Sergeant^c ; ¹ ; Carla Pinheiro^a ; Alexandre Campos^a ; Jenny Renaut^c ; Pedro Fevereiro^a ; ^d
• 关键词：Cork ; Phellem formation ; Suberisation ; Proteomics ; Quercus suber stem
• 刊名：Journal of Proteomics
• 出版年：2011
• 出版时间：12 August 2011
• 年：2011
• 卷：74
• 期：8
• 页码：1266-1278
• 全文大小：968 K

文摘

Cork (phellem) formation in Quercus suber stem was studied by proteomic analysis of young shoots of increasing age (Y0, Y1 and Y4) and recently-formed phellem (Y8Ph) and xylem (Y8X) from an 8-year-old branch. In this study 99 proteins were identified, 45 excised from Y8X and 54 from Y8Ph. These ones, specifically associated with phellem, are of “carbohydrate metabolism” (28 % ), “defence” (22 % ), “protein folding, stability and degradation” (19 % ), “regulation/signalling” (11 % ), “secondary metabolism” (9 % ), “energy metabolism” (6 % ), and “membrane transport” (2 % ).

The identification in phellem of galactosidases, xylosidases, apiose/xylose synthase, laccases and diphenol oxidases suggests intense cell wall reorganization, possibly with participation of hemicellulose/pectin biosynthesis and phenol oxidation. The identification of proteasome subunits, heat shock proteins, cyclophylin, subtilisin-like proteases, 14-3-3 proteins, Rab2 protein and enzymes interacting with nucleosides/nucleic acids gives additional evidence for cellular reorganization, involving cellular secretion, protein turnover regulation and active control processes.

The high involvement in phellem of defence proteins (thioredoxin-dependent peroxidase, glutathione-S-transferase, SGT1 protein, cystatin, and chitinases) suggests a strong need for cell protection from the intense stressful events occurring in active phellem, namely, desiccation, pests/disease protection, detoxification and cell death. Identically, highly enhanced defence functions were previously reported for potato periderm formation.