Transcript profiling reveals that cysteine protease inhibitors are up-regulated in tuber sprouts after extended darkness

GRANDELLIS CAROLINA; GIAMMARIA VERÓNICA; FANTINO, ELISA; CERRUDO IGNACIO; BACHMANN SANDRA D; SANTIN FRANCO; RITA M. ULLOA

FUNCTIONAL & INTEGRATIVE GENOMICS

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2016

1438-793X

Funct Integr Genomics. 2016 Apr 13. [Epub ahead of print]Transcript profiling reveals that cysteine protease inhibitors are up-regulated in tuber sprouts after extended darkness.Grandellis C1,2, Giammaria V1, Fantino E1, Cerrudo I1,3,4,5, Bachmann S1, Santin F1, Ulloa RM6,7.AbstractPotato (Solanum tuberosum L.) tubers are an excellent staple food due to its high nutritional value. When the tuber reaches physiological competence, sprouting proceeds accompanied by changes at mRNA and protein levels. Potato tubers become a source of carbon and energy until sprouts are capable of independent growth. Transcript profiling of sprouts grown under continuous light or dark conditions was performed using the TIGR 10K EST Solanaceae microarray. The profiles analyzed show a core of highly expressed transcripts that are associated to the reactivation of growth. Under light conditions, the photosynthetic machinery was fully activated; the highest up-regulation was observed for the Rubisco activase (RCA), the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and the Photosystem II 22 kDa protein (CP22) genes, among others. On the other hand, sprouts exposed to continuous darkness elongate longer, and after extended darkness, synthesis of chloroplast components was repressed, the expression of proteases was reduced while genes encoding cysteine protease inhibitors (CPIs) and metallocarboxypeptidase inhibitors (MPIs) were strongly induced. Northern blot and RT-PCR analysis confirmed that MPI levels correlated with the length of the dark period; however, CPI expression was strong only after longer periods of darkness, suggesting a feedback loop (regulation mechanism) in response to dark-induced senescence. Prevention of cysteine protease activity in etiolated sprouts exposed to extended darkness could delay senescence until they emerge to light.KEYWORDS:Light/dark conditions; Protease inhibitors; Solanum tuberosum; TIGR 10K microarrays; Tuber sproutingPMID: 27075731 [PubMed - as supplied by publisher]