Suppression Subtractive Hybridization (SSH)-Based Method for Estimating Cd-Induced Differences in Gene Expression at Cultivar Level and Identification of Genes Induced by Cd in Two Water Spinach Cultivars

• Published in: Journal of agricultural and food chemistry Vol. 57; no. 19; pp. 8950 - 8962
• Main Authors: Huang, Baifei, Xin, Junliang, Yang, Zhongyi, Zhou, Yihui, Yuan, Jiangang, Gong, Yulian
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 14.10.2009
• Subjects: amino acids; Biological and medical sciences; cadmium; Cadmium - analysis; Cadmium - pharmacology; Chemical Aspects of Food Safety; DNA libraries; DNA, Plant - analysis; Fish and seafood industries; Food Contamination; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression - drug effects; gene expression regulation; Gene Library; genes; Genotype; green leafy vegetables; heavy metals; heritability; hyperaccumulators; Ipomoea - chemistry; Ipomoea - genetics; Ipomoea aquatica; leaves; molecular sequence data; nucleic acid hybridization; Nucleic Acid Hybridization - methods; nucleotide sequences; Plant Roots - chemistry; Plant Shoots - chemistry; proteasome endopeptidase complex; quantitative genetics; Reverse Transcriptase Polymerase Chain Reaction; Species Specificity; suppression subtractive hybridization; transport proteins; uptake mechanisms; water spinach (Ipomoea aquatica Forsk.); Cadmium; differential gene expression; cultivar; suppression subtractive hybridization; Bass; Water; Edible fish; Vegetables; Suppression; Identification; Method; Gene expression; Heavy metal; Gene; water splnach (Ipomoea aquatica Forsk.); Spinach; Cultivar
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf900813p

The abilities to accumulate cadmium (Cd) are different among cultivars (cv.) in many species. The characteristic of Cd concentration among cultivars is heritable and is probably controlled by genes, but rather limited information about the relevant genes in vegetable crops has been published. In the present study, a suppression subtractive hybridization (SSH) approach was used to identify genes induced by Cd in two water spinach (an important vegetable in southern China) cultivars that differ in Cd accumulation in their edible parts. The two cultivars were cv. Qiangkunqinggu (QK), a low Cd accumulative cultivar and cv. Taiwan 308 (TW), a high Cd accumulative cultivar. In the construction of QK and TW libraries, the plants without Cd treatment were taken as drivers and the plants exposed to 6 mg L−1 Cd for 24 h as testers. Four hundred clones were sequenced, and 164 nonrepeated sequences (112 from the QK library and 52 from the TW library) were assigned to being functional genes or proteins. A tremendous difference in Cd-induced gene expressions between the two libraries was observed. In the QK library, genes implicated in disease/defense comprised one of the largest sets (20.6%), whereas the proportion was only 8.8% in the TW library. An MT3 gene (Q5), a wound inductive gene (Q22), an antioxidation relevant gene (Q34), a lectin gene (Q45), an f-box family protein gene (Q319), a 20S proteasome subunit gene (T17), a multidrug resistance associated protein gene (T156), and a cationic amino acid transporter gene (T218) were selected to compare semiquantitatively their expression between cv. QK and cv. TW using the RT-PCR method, and obvious differences were detected. The relationships between the identified differences in the expressions of the genes and the Cd accumulation of the two cultivars were discussed, and it was concluded that the SSH approach is useful for finding the difference in expression of Cd-induced gene even at the cultivar level and is applicable in the investigation of the mechanisms of low Cd accumulation.