Non-dispersive phloem-protein bodies (NPBs) of Populus trichocarpa consist of a SEOR protein and do not respond to cell wounding and Ca 2+

PeerJ

article

Daniel L. Mullendore¹  Timothy Ross-Elliott²  Yan Liu¹  Hanjo H. Hellmann¹  Eric H. Roalson¹  Winfried S. Peters¹  Michael Knoblauch¹ 

[1] School of Biological Sciences, Washington State University;Biology Department, University of North Carolina at Chapel Hill

关键词: Populus trichocarpa;    P-protein;    Sieve element;    Non-dispersive P-protein body;    Phloem transport;    SEOR protein;   

DOI  :  10.7717/peerj.4665

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Differentiating sieve elements in the phloem of angiosperms produce abundant phloem-specific proteins before their protein synthesis machinery is degraded. These P-proteins initially form dense bodies, which disperse into individual filaments when the sieve element matures. In some cases, however, the dense protein agglomerations remain intact and are visible in functional sieve tubes as non-dispersive P-protein bodies, or NPBs. Species exhibiting NPBs are distributed across the entire angiosperm clade. We found that NPBs in the model tree, Populus trichocarpa, resemble the protein bodies described from other species of the order Malpighiales as they all consist of coaligned tubular fibrils bundled in hexagonal symmetry. NPBs of all Malpighiales tested proved unresponsive to sieve tube wounding and Ca2+. The P. trichocarpa NPBs consisted of a protein encoded by a gene that in the genome database of this species had been annotated as a homolog of SEOR1 (sieve element occlusion-related 1) in Arabidopsis. Sequencing of the gene in our plants corroborated this interpretation, and we named the gene PtSEOR1. Previously characterized SEOR proteins form irregular masses of P-protein slime in functional sieve tubes. We conclude that a subgroup of these proteins is involved in the formation of NPBs at least in the Malpighiales, and that these protein bodies have no role in rapid wound responses of the sieve tube network.

【 授权许可】

CC BY