Analysis of sprouting in potato plants

GIAMMARIA V; GRANDELLIS C; VILLASUSO AL; ULLOA RM

Mar del Plata

Congreso; XLIII reunion anual SAIB; 2007

SAIB

Growing and freshly harvested potato tubers do not sprout and are dormant, even when environmental conditions are favourable. Sprouting is initiated after a period of dormancy and hormones play an important role in this process: ABA and ethylene are required for the initiation and maintenance of dormancy, cytokinins (CK) are involved in its termination and gibberellins (GAs) are thought to regulate sprout growth after termination of dormancy. Tubers were C in MS-agar with: hormones (GAs, ABA, CK), sucrose or a°grown in the dark at 4 combination of hormones and sucrose. In addition, control and GA-treated tubers C. Early sprouting (10 days) was observed°were exposed to continuous light at 18 in light conditions but it was evident 1 month later in dark-grown tubers: GA-treated ones had numerous sprouts buts CCC, ABA or CK-treated tuber had only incipient sprouts confirming GA as a sprouting-promoting signal. Ca2+-dependent protein kinases (CDPKs) and lipid kinases could be involved in GA signalling. Up-regulation of StCDPK2 expression was observed in GA-treated tubers (light conditions) and in dark-incubated tubers treated with GAs and sucrose. In addition, lipid kinase activity and StCDPK2 expression increased in GA-treated (2-6h) potato plants. To understand how GAs affect sprouting we are making microarrays (TIGR, Potato Functional Genomics Expression profiling Project).