Abstract
Camptotheca acuminata is a Chinese tree that produces the
anti-cancer monoterpenoid indole alkaloid camptothecin (CPT).
3-Hydroxy-3-methylglutaryl coenzyme A synthase (HMGS) catalyzes the
condensation of acetyl CoA and acetoacetyl CoA to form
3-hydroxy-3-methylglutaryl-CoA as an early step in the CPT biosynthetic
pathway. A full-length cDNA encoding HMGS (designated as CaHMGS, GenBank accession no. EU677841) was successfully isolated from young leaves of C. acuminata by rapid amplification of cDNA ends (RACE). The full-length cDNA of CaHMGS
was 1801 bp long and contained a 1413-bp open reading frame encoding a
polypeptide of 471 amino acids. Comparative and bioinformatic analyses
revealed that CaHMGS showed extensive homology with HMGSs from other plant species. Southern hybridization analysis showed that there were at least two HMGS gene members in the C. acuminata
genome. CPT content was found to be much higher in cotyledons and
hypocotyls as compared to roots. RT-PCR analysis revealed strong
expression in hypocotyls and cotyledons, but no expression in roots,
indicating good correlation between CaHMGS expression and CPT content in the tested tissues. The expression of CaHMGS could be regulated by exogenous elicitors, including salicylic acid and methyl jasmonate, suggesting that CaHMGS was elicitor-responsive. This work is a first step to acquire a better understanding on the role of HMGS in CPT biosynthesis.
Original language | English |
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Pages (from-to) | 131-138 |
Number of pages | 8 |
Journal | Russian Journal of Plant Physiology |
Volume | 60 |
Issue number | 1 |
Early online date | 28 Dec 2012 |
DOIs | |
Publication status | Published - Jan 2013 |
Scopus Subject Areas
- Plant Science
User-Defined Keywords
- CaHMGS
- Camptotheca acuminata
- cDNA cloning
- elicitor
- expression analysis