DIFFERENTIAL EXPRESSION OF CHITINASE AND BETA-1,3-GLUCANASE GENES IN VARIOUS TISSUES OF POTATO PLANTS

We have analyzed the tissue-specific expression of chitinase, beta-1,3 -glucanase and, for comparison, phenylalanine ammonia-lyase genes in h ealthy, unstressed potato (Solanum tuberosum) plants by using RNA-RNA hybridization and immunostaining techniques to localize the respective mRNAs and proteins in situ. Preparations of leaf, newer, shoot tip, n ode and axillary bud revealed that chitinase exhibited a distinctive a nd characteristic expression pattern in being confined to the epiderma l cell layer, while beta-1,3-glucanase and phenylalanine ammonia-lyase were present to varying extents in most tissues of these organs. Thes e distinctive patterns of expression suggest fundamentally different r oles for the two glucanohydrolases in the metabolism of unstressed pla nts.