The photoreceptor phytochrome B (PHYB) and the homeodomain protein BEL5 are involved in the response of potato tuber induction to the photoperiod. However, whether they act in the same tuberization pathway is unknown. Here we show the effect of a microRNA, miR172, on this developmental event. miR172 levels are higher under tuber-inducing short days than under non-inductive long days and are upr...

The identification of FLOWERING LOCUS T (FT) and several FT homologs as phloem-mobile proteins that regulate flowering has sparked the search for additional homologs involved in the long-distance regulation of other developmental processes. Given that flowering and tuber induction share regulatory pathways, the quest for long-distance tuberization signals has been further stimulated. Several tu...

Tuberization in potato is known to be under complex biochemical control involving hormones. A number of studies have provided evidence for a critical role of GA in tuberization. There is also evidence that GA in plants can be modulated by a Ca/calmodulin pathway. The purpose of the present study was to determine the influence of supplemental Ca fertilization on tuber size and tuber number. Plan...

Using high pressure liquid chromatography, the cucumber cotyledon bioassay, and mass spectrometry a cytokinin isolated from Solanum tuberosum L. cv. Katahdin plant tissues has been identified as cis-zeatin riboside. Zeatin riboside (ZR) levels in plants grown under inducing conditions (28 C day and 13 C night with a 10-hour photoperiod) were significantly higher than those in plants grown under...

Under optimum environmental conditions, tuberization in potato (Solanum tuberosum) is activated by signals that either function in the leaf or arise in this organ and move down into stolon tips to induce tuber formation. Three major signals have been identified: CYCLING DOF FACTOR1 (StCDF1) for earliness and StBEL5 mRNA and SELF-PRUNING6A (StSP6A) protein as mobile signals originating in the le...

Ethylene inhibited the tuberization of etiolated potato (Solanum tuberosum L. var. Red La Soda) sprout sections cultured in vitro. Carbon dioxide did not overcome the C(2)H(4) inhibition but it was required for normal tuberization. Ethylene totally prevented root formation and development. It inhibited stolon elongation, and caused thickening and diageotropical growth of the stolon. In addition...

High concentrations of 2-chloroethylphosphonic acid inhibited tuberization on aged potato tubers (Solanum tuberosum) that had been predisposed to the little tuber disorder. As a result of this treatment sprouts developed which contained relatively high levels of endogenous gibberellins and which elongated normally. The endogenous cytokinin levels in the different treatments did not change appre...

Reactive oxygen species (ROS), especially hydrogen peroxide, H2O2, act as signaling molecules to widely mediate growth, development, and stress response of plants. In the present study, internal ROS accumulation, effects exogenous H2O2 treatment, expression key tuberization-related genes, effect knockout Solanum tuberosum self-pruning 6A (StSP6A) on H2O2-induced tuber formation were investigate...

The effects of plant hormones and sucrose (Suc) on potato (Solanum tuberosum L.) tuberization were studied using in vitro cultured single-node cuttings. Tuber-inducing (high Suc) and -noninducing (low Suc or high Suc plus gibberellin [GA]) media were tested. Tuberization frequencies, tuber widths, and stolon lengths were measured during successive stages of development. Endogenous GAs and absci...

Several recent publications reported different subcellular localization of the sucrose transporters belonging to the SUT4 subfamily. The physiological function of the SUT4 sucrose transporters requires clarification, because down-regulation of the members of the SUT4 clade had different effects in rice, poplar, and potato. Here, we provide new data for the localization and function of the Solan...