期刊
PLANT PHYSIOLOGY
卷 158, 期 1, 页码 465-475出版社
OXFORD UNIV PRESS INC
DOI: 10.1104/pp.111.189779
关键词
-
资金
- U.S. Department of Energy, Office of Science and Office of Basic Energy Sciences [DE-SC0001090]
- National Science Foundation [RCN0090281, DBI 0421683]
The main load-bearing network in the primary cell wall of most land plants is commonly depicted as a scaffold of cellulose microfibrils tethered by xyloglucans. However, a xyloglucan-deficient mutant (xylosyltransferase1/xylosyltransferase2 [xxt1/xxt2]) was recently developed that was smaller than the wild type but otherwise nearly normal in its development, casting doubt on xyloglucan's role in wall structure. To assess xyloglucan function in the Arabidopsis (Arabidopsis thaliana) wall, we compared the behavior of petiole cell walls from xxt1/xxt2 and wild-type plants using creep, stress relaxation, and stress/strain assays, in combination with reagents that cut or solubilize specific components of the wall matrix. Stress/strain assays showed xxt1/xxt2 walls to be more extensible than wild-type walls (supporting a reinforcing role for xyloglucan) but less extensible in creep and stress relaxation processes mediated by alpha-expansin. Fusicoccin-induced acid growth was likewise reduced in xxt1/xxt2 petioles. The results show that xyloglucan is important for wall loosening by alpha-expansin, and the smaller size of the xxt1/xxt2 mutant may stem from the reduced effectiveness of alpha-expansins in the absence of xyloglucan. Loosening agents that act on xylans and pectins elicited greater extension in creep assays of xxt1/xxt2 cell walls compared with wild-type walls, consistent with a larger mechanical role for these matrix polymers in the absence of xyloglucan. Our results illustrate the need for multiple biomechanical assays to evaluate wall properties and indicate that the common depiction of a cellulose-xyloglucan network as the major load-bearing structure is in need of revision.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据