Disruption of Secondary Wall Cellulose Biosynthesis Alters Cadmium Translocation and Tolerance in Rice Plants

作     者：Xue-Qin Song Li-Feng Liu Yi-Jun Jiang Bao-Cai Zhang Ya-Ping Gao Xiang-Ling Liu Qing-Shan Lin Hong-Qing Ling Yi-Hua Zhou 

作者机构：State Key Laboratory of Plant Genomics Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing 100101 China Rice Research Institute Guangdong Academy of Agricultural Sciences Guangzhou 510640 China State Key Laboratory of Plant Cell and Chromosome Engineering Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing 100101 China 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2013年第6卷第3期

页      面：768-780页

核心收录：

学科分类：0710[理学-生物学] 0821[工学-纺织科学与工程] 07[理学] 08[工学] 09[农学] 071007[理学-遗传学] 082102[工学-纺织材料与纺织品设计] 0901[农学-作物学] 090102[农学-作物遗传育种] 

基　　金：This work was supported by grants from the Ministry of Agriculture of China for transgenic research (2011ZX08009- 003) the Ministry of Sciences and Technology of China (2012CB114501) and the National Natural Science Foundation of China (31125019).We thank Tai-Hua Zhang (Institute of Mechanics, Chinese Academy of Sciences, Beijing, China) for measurement of breaking force of rice plants, and Hong-Zhi Zhang (Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China) for elemental analysis. No conflict of interest declared 

主　　题：secondary cell wall cellulose synthesis vascular system cadmium accumulation tricheary elements rice. 

摘      要：Tricheary elements （TEs）, wrapped by secondary cell wall, play essential roles in water, mineral, and nutrient transduction. Cadmium （Cd） is a toxic heavy metal that is absorbed by roots and transported to shoot, leaves, and grains through vascular systems in plants. As rice is a major source of Cd intake, many efforts have been made to establish ＇low- Cd rice＇. However, no links have been found between cellulose biosynthesis and cadmium accumulation. We report here a rice brittle culm13 mutant, resulting from a novel missense mutation （G101K） in the N-terminus of cellulose synthase subunit 9 （CESA9）. Except for the abnormal mechanical strength, the mutant plants are morphologically indistinguishable from the wild-type plants. Transmission electron microscopy （TEM） and chemical analyses showed a slight reduction in secondary wall thickness and 22% decrease in cellulose content in bc13 plants. Moreover, this mutation unexpectedly confers the mutant plants Cd tolerance due to less Cd accumulation in leaves. Expression analysis of the genes required for Cd uptake and transport revealed complicated alterations after applying Cd to wild-type and bc13. The mutants were further found to have altered vascular structure. More importantly, Cd concentration in the xylem saps from the bc13 plants was significantly lower than that from the wild-type. Combining the analyses of CESA9 gene expression and Cd content retention in the cell-wall residues, we conclude that CESA9^G101K mutation alters cell-wall properties in the conducting tissues, which consequently affects Cd translocation efficiency that largely contributes to the low Cd accumulation in the mutant plants.