Project description:Recent advances have defined some of the components of photoperiodic signalling that lead to tuberisation in potato including orthologues of FLOWERING LOCUS T (StSP6A) and CYCLING DOF FACTOR (StCDF1). The aim of the current study is to investigate the molecular basis of permissive tuber initiation under long days in Solanum tuberosum Neo-Tuberosum by comparative analysis with an obligate short day Solanum tuberosum ssp. Andigena accession. We show that the Neo-Tuberosum accession, but not the Andigena, contains alleles that encode StCDF1 proteins modified in the C-terminal region, likely to evade long day inhibition of StSP6A expression. We also identify an allele of StSP6A from the Neo-Tuberosum accession, absent in the Andigena, which is expressed under long days. Other leaf transcripts and metabolites that show different abundances in tuberising and non-tuberising samples were identified adding detail to tuberisation-associated processes. Overall, the data presented in this study highlight the subtle interplay between components of the clock-CONSTANS-StSP6A axis which collectively may interact to fine-tune the timing of tuberisation.
Project description:Summary StSP6A is a protein with sequence homology to the Arabidopsis FLOWERING LOCUS T (FT). FT is a main component of the long range flowering promoting signal or florigen that induces photoperiodic flowering under long days (LDs). In potato, short days (SDs) promote tuber induction, and wild subspecies like Solanum tuberosum ssp andigena (wild type line 7540) are strictly dependent on SDs to tuberize. StSP6A transcription is induced in leaves and stolons at early stages upon transfer to SD inductive conditions, priotr to visible solon swelling. Transgenic andigena lines over-expressing the StSP6A gene under the control of the 35S promoter are able to tuberize under LD non-inductive conditions, whereas silencing of this gene by means of an specific RNAi construct are strongly delayed in tuber induction in SD inductive conditions. This data indicate that StSP6A plays a central role in the control of tuber induction.
Project description:Summary StSP6A is a protein with sequence homology to the Arabidopsis FLOWERING LOCUS T (FT). FT is a main component of the long range flowering promoting signal or florigen that induces photoperiodic flowering under long days (LDs). In potato, short days (SDs) promote tuber induction, and wild subspecies like Solanum tuberosum ssp andigena (wild type line 7540) are strictly dependent on SDs to tuberize. StSP6A transcription is induced in leaves and stolons at early stages upon transfer to SD inductive conditions, priotr to visible solon swelling. Transgenic andigena lines over-expressing the StSP6A gene under the control of the 35S promoter are able to tuberize under LD non-inductive conditions, whereas silencing of this gene by means of an specific RNAi construct are strongly delayed in tuber induction in SD inductive conditions. This data indicate that StSP6A plays a central role in the control of tuber induction. For each sample of the two comparisons (35S-StSP6A versus Wild Type and StSP6A-RNAi versus Wild Type) two biological replicates were prepared. In the case of 35S-StSP6A and StSP6A-RNAi each replicate was composed by a pool of several transgenic lines.
Project description:Two independent Solanum tuberosum ssp. Andigena ADG StCEN RNAi and two ADG StCEN 35S overexpressing OE transgenic lines and a wild type WT control were grown under standard glasshouse conditions for 6 weeks prior to being moved to controlled growth cabinet conditions. Plants were grown under 4 different daylengths (8,10,12 and 16 hr) at 20 °C day and 14 °C night temperatures. ADG StCEN RNAi lines showed signs of early tuberization phenotype compared with the WT control after 23 days in the cabinets. Non-swelling stolons were harvested at this timepoint. ADG StCEN 35S OE lines demonstrated a delayed tuberization phenotype compared with the WT control. Non-swelling stolons were harvested after 38 days in the controlled cabinet conditions.
Project description:Purpose: observe the difference between potato (Solanum tuberosum ssp. andigena) WT and BRC1b RNAi axillary buds in response to the transition from long-day to short-day conditions. The time course includes four time points: Long days, after 2 days in short days, 1 week in short days and 2 weeks in short days. Methods: stem were flash-frozen in N2(l) one hour after dawn and the axillary buds were dissected in the cold room. The four axillary buds bellow the third visible node counting from the apex (those most likely to produce tubers in RNAi line) were collected. RNA was extracted with FavorPrep™ Plant Total RNA Mini Kit from FAVORGEN. DNA was degraded in the column with RNase-free DNase I (Roche). Three biological replicates were used and each replicate is a pool of axillary buds from 4 plants.
Project description:For expression profiling analyses of early stages of tuber induction, plants of Solanum tuberosum ssp andigena (7540) were used. This wild subspecies is strictly dependent on photoperiod for tuberisation, such that short days (SD) inductive conditions are required in order to trigger tuber induction in the stolons. Andigena plants were grown in the greenhouse under LD non-inductive conditions until a 10-leaf stage. They were subsequently transferred to inductive SD conditions (8 h light/16 h dark), and sampled at 0, 2, 4, 6 and 8 days after transfer to SDs. Tuber swelling was visible approximately 6-8 days after transfer to inductive conditions. The apical region of the stolons (2 cm) was collected one hour before the beginning of the light period.
Project description:Seed of 4 lines of S. tuberosum var andigena were sown and, after transplanting, grown in 3 gal nursery containers in a greenhouse with natural daylight. The seeds were sown in July and the drought stress experiment began in September. Drought stress was administered by withholding water and monitored by measuring the rate of photosynthesis (PS; LiCor 6400). We found that loss of photosynthetic capability (ie a PS rate of 0-2 mM CO2/m2/sec) correlated with a severe drought stress. Control plants were watered normally and maintained a PS rate of 18-20 mM CO2/m2/sec. After drought stress, the treated plants were re-watered and PS measurements taken again. After the first cycles of stress, control and treated plants were harvested and roots, tubers and shoots were stored at –80°C for RNA extractions. The drought experiment was then repeated for the remaining plants such that they were exposed to a second cycle of stress. For each line of S. andigena, there were 2 control and 2 treated plants per cycle of stress. RNA was extracted following the acid phenol protocol of TIGR. Keywords: Direct comparison, loop design