Characterization and complementation of a Pichia stipitis mutant unable to grow on D-xylose or L-arabinose.
Pichia stipitis CBS 6054 will grow on D-xylose, D-arabinose, and L-arabinose. D-Xylose and L-arabinose are abundant in seed hulls of maize, and their utilization is important in processing grain residues. To elucidate the degradation pathway for L-arabinose, we obtained a mutant, FPL-MY30, that was unable to grow on D-xylose and L-arabinose but that could grow on D-arabinitol. Activity assays of oxidoreductase and pentulokinase enzymes involved in D-xylose, D-arabinose, and L-arabinose pathways indicated that FPL-MY30 is deficient in D-xylitol dehydrogenase (D-XDH), D- and L-arabinitol dehydrogenases, and D-ribitol dehydrogenase. Transforming FPL-MY30 with a gene for xylitol dehydrogenase (PsXYL2), which was cloned from CBS 6054 (GenBank AF127801), restored the D-XDH activity and the capacity for FPL-MY30 to grow on L-arabinose. This suggested that FPL-MY30 is critically deficient in XYL2 and that the D-xylose and L-arabinose metabolic pathways have xylitol as a common intermediate. The capacity for FPL-MY30 to grow on D-arabinitol could proceed through D-ribulose.
Shi
N Q
NQ
Department of Bacteriology, University of Wisconsin, Madison 53706, USA.
Prahl
K
K
Hendrick
J
J
Cruz
J
J
Lu
P
P
Cho
J Y
JY
Jones
S
S
Jeffries
T
T
D001089:Arabinose / Q000378:metabolism*; D050542:D-Xylulose Reductase; D005816:Genetic Complementation Test; D016296:Mutagenesis; D010843:Pichia / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D012639:Seeds; D013237:Stereoisomerism; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics / Q000378:metabolism; D014994:Xylose / Q000378:metabolism*; D003313:Zea mays
D014994:Xylose; D001089:Arabinose; D013401:Sugar Alcohol Dehydrogenases; C022529:ribitol 2-dehydrogenase; D050542:D-Xylulose Reductase