Screening and Identification of Novel Genes Involved in
Biosynthesis of Ginsenoside in Panax ginseng Plant
LUO Zhi-Yong*, LU Qiu-Heng, LIU
Shui-Ping, CHEN Xiang-Hui, LUO Jian-Qing, TAN Li-Jun, HU Wei-Xin*
( Molecular
Biology Research Centre, Xiangya Medical College, Central South University,
Changsha 410078, China )
Abstract The
root of Panax ginseng plant undergoes a specific developmental process to
become a biosynthesis and accumulation organ for ginsenosides. To identify and
analyze genes involved in the biosynthesis of ginsenoside, suppression
subtractive hybridization (SSH) between mRNAs of 4- and 1-year-old root tissues
was performed, and a subtracted cDNA library specific to 4-year-old roots was
constructed. Forty cDNA clones selected randomly from the subtracted cDNA
library were sequenced. Sequence information of all clones was evaluated by
Nucleotide Blast analysis in GenBank/DDBJ/EMBL. The results showed that six
subtracted cDNA clones represented the novel genes (ESTs), because no sequence
homology with any known sequences was found in the database. Expression in 4-year-old
P. ginseng root tissues was verified by reverse Northern dot hybridization for
the six clones. These six novel genes were named GBR1, GBR2, GBR3, GBR4, GBR5,
and GBR6, and their Accession numbers of GenBank are AF485334, AF485335,
AF485336, AF485337, AF485332, and AF485333, respectively. Finally, Northern
blot analysis and semi-quantitative reverse transcription polymerase chain
reaction (RT-PCR) confirmed that these six novel genes were differentially
expressed in the defined development stage of P. ginseng plant roots. It is
possible that their overexpression may play an important role in the
ginsenoside biosynthesis. In addition, most of transcripts of all genes could
also be detected in other P. ginseng plant tissues such as stem, leaf and seed.
Our results provided a basis for obtaining the full-length cDNA sequences of
such six novel genes, and for identifying their function involved in the
biosynthesis of ginsenoside.
Key words Panax ginseng plant; ginsenoside biosynthesis; gene screening;
suppression subtractive hybridization
*Corresponding
author: Tel, 86-731-4805449; Fax, 86-731-4481180;
e-mail, [email protected] or
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