DNA microarray revealed and RNAi plants confirmed key genes conferring low Cd accumulation in barley grains.
BACKGROUND
Understanding the mechanism of low Cd accumulation in crops is crucial for sustainable safe food production in Cd-contaminated soils.


RESULTS
Confocal microscopy, atomic absorption spectrometry, gas exchange and chlorophyll fluorescence analyses revealed a distinct difference in Cd accumulation and tolerance between the two contrasting barley genotypes: W6nk2 (a low-grain-Cd-accumulating and Cd-sensitive genotype) and Zhenong8 (a high-grain-Cd-accumulating and tolerant genotype). A DNA microarray analysis detected large-scale changes of gene expression in response to Cd stress with a substantial difference between the two genotypes. Cd stress led to higher expression of genes involved in transport, carbohydrate metabolism and signal transduction in the low-grain-Cd-accumulating genotype. Novel transporter genes such as zinc transporter genes were identified as being associated with low Cd accumulation. Quantitative RT-PCR confirmed our microarray data. Furthermore, suppression of the zinc transporter genes HvZIP3 and HvZIP8 by RNAi silencing showed increased Cd accumulation and reduced Zn and Mn concentrations in barley grains. Thus, HvZIP3 and HvZIP8 could be candidate genes related to low-grain-Cd-accumulation.


CONCLUSIONS
Novel transporter genes such as HvZIP3 and HvZIP8 were identified as being associated with low-grain-Cd-accumulation. In addition to advancing academic knowledge, our findings may also result in potential economic benefits for molecular breeding of low Cd accumulating barley and other crops.
Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, PR China. sunhongyan-8@163.com.
Hongyan
H
Sun
Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, PR China. Z.Chen@uws.edu.au.
Zhong-Hua
ZH
Chen
Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, PR China. chenfei1224@163.com.
Fei
F
Chen
Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, PR China. xielupeng@zju.edu.cn.
Lupeng
L
Xie
Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, PR China. zhanggp@zju.edu.cn.
Guoping
G
Zhang
Department of Molecular Biology and Genetics, Aarhus University, Slagelse, Denmark. eva.vincze@agrsci.dk.
Eva
E
Vincze
Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou, 310058, PR China. wufeibo@zju.edu.cn.|Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China. wufeibo@zju.edu.cn.
Feibo
F
Wu
D001692:Biological Transport / Q000187:drug effects / Q000235:genetics; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005838:Genotype; D001467:Hordeum / Q000187:drug effects / Q000235:genetics*; D008345:Manganese / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics; D034622:RNA Interference / Q000187:drug effects; D060888:Real-Time Polymerase Chain Reaction; D012639:Seeds / Q000187:drug effects / Q000235:genetics* / Q000648:ultrastructure; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D015032:Zinc / Q000378:metabolism
D026901:Membrane Transport Proteins; D010940:Plant Proteins; D002104:Cadmium; D008345:Manganese; D015032:Zinc