Molecular characterization and expression of four cDNAs encoding sucrose synthase from green bamboo Bambusa oldhamii.
Bamboo is distinguished by its rapid growth. To investigate sucrose metabolism in this plant, we cloned the cDNAs encoding sucrose synthase (SuS) from Bambusa oldhamii and investigated their expression in growing shoots and leaves. Four cDNA clones, BoSus1, BoSus2, BoSus3 and BoSus4, were isolated by screening a cDNA library from etiolated bamboo shoots. Recombinant BoSuS proteins were produced in Escherichia coli and purified by immobilized metal affinity chromatography and ultrafiltration. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine the abundance of the transcript of each gene. BoSus1 and BoSus3 may be duplicate or homeologous genes, the sequences of which show high identity. Similarly, BoSus2 shows high identity with BoSus4. Kinetic analysis showed that the two BoSuS isoforms of each type had similar michaelis constant (Km) values for sucrose, but different values for UDP. The four genes were expressed in various bamboo organs but were differentially regulated. The increase in the abundance of their mRNA paralleled the growth rate of the bamboo. The results suggest that, in bamboo, SuS is encoded by at least four genes, each with a specific role in providing substrates for the polysaccharide biosynthesis and/or energy production necessary to support the rapid growth of this species.
Institute of Microbiology and Biochemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
Wen-Bin
WB
Chiu
Chiou-Hong
CH
Lin
Chun-Ju
CJ
Chang
Meng-Hsun
MH
Hsieh
Ai-Yu
AY
Wang
D000595:Amino Acid Sequence; D031723:Bambusa / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D015139:Blotting, Southern; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D017343:Genes, Plant; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018520:Plant Shoots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D013395:Sucrose / Q000378:metabolism
D018076:DNA, Complementary; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D013395:Sucrose; D005964:Glucosyltransferases; C022699:sucrose synthase