Functional Characterization of the Rice UDP-glucose 4-epimerase 1, OsUGE1: A Potential Role in Cell Wall Carbohydrate Partitioning during Limiting Nitrogen Conditions

被引：33

作者：

Guevara, David R. ^{[2
]}

El-Kereamy, Ashraf ^{[2
]}

Yaish, Mahmoud W. ^{[1
]}

Yong Mei-Bi ^{[2
]}

Rothstein, Steven J. ^{[2
]}

机构：

[1] Sultan Qaboos Univ, Coll Sci, Dept Biol, Muscat, Oman

[2] Univ Guelph, Dept Mol & Cellular Biol, Guelph, ON N1G 2W1, Canada

来源：

PLOS ONE | 2014年 / 9卷 / 05期

基金：

加拿大自然科学与工程研究理事会;

关键词：

GENE-EXPRESSION; SUCROSE SYNTHASE; PHOSPHOMANNOSE-ISOMERASE; GALACTOSE; 4-EPIMERASE; CELLULOSE SYNTHESIS; SELECTABLE MARKER; CARBON; PHOTOSYNTHESIS; LIMITATION; PLANTS;

D O I：

10.1371/journal.pone.0096158

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Plants grown under inadequate mineralized nitrogen (N) levels undergo N and carbon (C) metabolic re-programming which leads to significant changes in both soluble and insoluble carbohydrate profiles. However, relatively little information is available on the genetic factors controlling carbohydrate partitioning during adaptation to N-limitation conditions in plants. A gene encoding a uridine-diphospho-(UDP)-glucose 4-epimerase (OsUGE-1) from rice (Oryza sativa) was found to be N-responsive. We developed transgenic rice plants to constitutively over-express the OsUGE-1 gene (OsUGE1-OX1-2). The transgenic rice lines were similar in size to wild-type plants at the vegetative stage and at maturity regardless of the N-level tested. However, OsUGE1-OX lines maintained 18-24% more sucrose and 12-22% less cellulose in shoots compared to wildtype when subjected to sub-optimal N-levels. Interestingly, OsUGE1-OX lines maintained proportionally more galactose and glucose in the hemicellulosic polysaccharide profile of plants compared to wild-type plants when grown under low N. The altered cell wall C-partitioning during N-limitation in the OsUGE1-OX lines appears to be mediated by OsUGE1 via the repression of the cellulose synthesis associated genes, OsSus1, OsCesA4, 7, and 9. This relationship may implicate a novel control point for the deposition of UDP-glucose to the complex polysaccharide profiles of rice cell walls. However, a direct relationship between OsUGE1 and cell wall C-partitioning during N-limitation requires further investigation.

引用

页数：10