Table 3.
Correlation between relative gene expression and SGA levels in potato tubers subjected to two SGA-inducing treatments.
| Gene | Slope (mg SGA qpcr expr−1 ) |
t-test |
|---|---|---|
| Positive correlation vs. SGA | ||
| TAMiso2 | 141 | p < 0.0001 |
| DWF1-L | 137 | p < 0.0001 |
| HMGR1 | 134 | p < 0.0001 |
| SGT3 | 88 | p < 0.0001 |
| SMO1-L | 79 | p < 0.0001 |
| SGT2 | 99 | p < 0.01 |
| SGT1 | 68 | p < 0.01 |
| Negative correlation vs. SGA | ||
| SMT1 | −101 | p < 0.05 |
| SMO1 | −256 | p < 0.05 |
|
No correlation vs. SGA
DWF1 |
n.s. a | |
Expression of ten genes with a role in sterol/SGA synthesis was monitored by QPCR in tubers from five potato cultivars that had been subjected to a wounding (24 h) or a light exposure (48 h) treatment either at tuber harvest or after 6 months of tuber storage under dark and cold conditions. Tuber SGA levels were quantified by LC-MS in the same experiments, either after 48 h (wounding) or 8 days (light). The experiment was performed for 2 cultivation years, giving in total 56 data pairs for each gene. A correlation between gene expression and SGA level was analyzed by linear regression of untransformed data, and a t-test of the slope difference from zero.
Slopes with p-values >0.05 were considered as being not significantly different from zero (n.s.).