Differentially expressed genes in potato sprouts in light/dark conditions detected by microarrays

GRANDELLIS C; GIAMMARIA V; BACHMANN S; CERRUDO I; ULLOA RM

Villa Carlos Paz / Córdoba / Argentina

Congreso; XLIV Reunión Anual - Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

SAIB

Differentially expressed genes in potato sprouts in light/dark conditions detected by microarrays Grandellis C, GiammariaV, Bachmann S, Cerrudo I, Ulloa RM. grandellis@dna.uba,ar INGEBI, Vuelta de Obligado 2490 2do piso, Capital Tuber sprouting initiates after a period of dormancy under favorable conditions. In order to analyze genes expressed upon sprouting in different light conditions, tubers were grown for 10 days under continuous light (10L) or for 10 or 35 days under complete darkness (10D, 35D). Total RNA was obtained from sprouts, labeled with Cy3 or Cy5 and hybridized to potato microarrays produced by TIGR.  A group of genes related to photosynthesis, carbon metabolism and light perception was enhanced (>5 fold induction) in 10L (light induced genes) while in 35 days etiolated sprouts different proteinase inhibitors (PIs): Kunitz-type PIs, protease inhibitor/seed storage/lipid transfer protein (LTP), Metallocarboxypeptidase inhibitor IIa (MCPI2) were drastically induced (13-fold). These results were confirmed by RT-PCR. PIs play a potent defensive role against predators and pathogens and interfere with physiological processes such as germination and maturation. PIs may regulate cell proteolysis by inhibition of endogenous proteases and thus control protein turnover and metabolism. Diverse functions have been proposed for PIs, ranging from regulators of endogenous proteinases to storage proteins. In chick pea, PIs could be involved in xylem vessel formation and a cell wall PI in the elongation process. We suggest that in potato, PIs might be involved in regulating the elongation of etiolated sprouts.