CHANGES IN LEVELS OF MESSENGER-RNAS FOR CELL WALL-RELATED ENZYMES IN GROWING COTTON FIBER CELLS

mRNAs for cell wall-related enzymes in developing cotton fiber cells w ere measured by reverse transcription-PCR analysis. Both endo-1,4-beta -glucanase and expansin mRNA levels were high during cell elongation b ut decreased when cell elongation ceased, and xyloglucan decreased. Th e endo-1,3-beta-glucanase mRNA level was very low in the elongating ce lls but increased gradually at the onset of secondary wall synthesis, accompanying the massive deposition of cellulose. Endoxyloglucan trans ferase and sucrose synthase mRNA levels were constant during all stage s of growth.