Protein Mobilization from Potato Tubers during Long-Term Storage and Daughter Tuber Formation

Abstract

AbstractThe role of protease inhibitors in modulating changes in protein content of potato (Solanum tuberosum L.) tubers was investigated using a mother/daughter tuber model system. Changes in patatin, potato multicystatin (PMC), proteases, serine (Ser) protease inhibitors, and their gene expression were temporally coordinated over a 22-mo storage interval in genotypes with short (cv. Ranger Russet) and long (cv. Russet Burbank) dormancy. Daughter tubers were initiated on Ranger Russet tubers at ∼15 mo. PMC (Cys protease inhibitor) declined linearly (∼4.2-fold) in Ranger Russet mother tubers from 4 to 15 mo and then maintained low levels through 22 mo. Conversely, protease activity was low and constant from 4 to 15 mo before increasing 7.4-fold through 22 mo. This increase coincided with the most rapid decline (54%) in patatin and the formation of daughter tubers. The proteases induced during aging of mother tubers were inhibited by PMC. Ser protease inhibitors were maintained in mother tubers throughout ...