Abstract
Suspension-cultured cells of azuki bean cannot grow in media containing mannose.However, callus cells of the plant can grow on media containing mannose, possibly by converting it to sucrose. To confirm this pathway, we analyzed selected enzymatic activities and contents of the neutral and acidic sugars in the cells. We found an activity of enzyme (PMI) converting mannose-6-phosphate to fructose-6-phosphate but it was low in both the cells, grown either in the presence of mannose or sucrose. Both cells contained high levels of sucrose. Analysis of the acid sugar fractions using DEAE-Sephadex column revealed that higher levels of sugar phosphates and UDP-sugars are present in cells cultured with mannose than with sucrose. Unknown sugar phosphates also contained in the former mannose-cultured cells. We conclude that some pathway via UDP-mannose or other sugar nucleotides, beside PMI activities, might be involved in sucrose biosynthesis from mannose in azuki bean callus cells.
