| | EU 2× vs EU 4× | Relative Expression | EU 4× vs US 4× |
|---|
Gene | t | p-value | EU 2× | EU 4× | US 4× | t | p-value |
|---|
Actin | 0.84 | 0.411 | 0.80a | 1.00a | 0.69a | 1.41 | 0.174 |
COX | 0.96 | 0.348 | 1.25a | 1.00a | 0.86a | 0.63 | 0.538 |
UBQ | 0.84 | 0.413 | 1.24a | 1.00a | 1.07a | 0.26 | 0.795 |
PAL 1 | 1.20 | 0.245 | 0.71ab | 1.00b |
0.42
a
|
3.06
|
0.006
|
PAL 2a |
4.91
|
<0.001
|
0.37
a
| 1.00b |
0.39
a
|
4.00
|
<0.001
|
PAL 2b |
8.19
|
<0.001
|
0.21
b
| 1.00c |
0.06
a
|
8.19
|
<0.001
|
Chitinase | 0.47 | 0.644 | 0.89ab | 1.00b |
0.59
a
|
2.14
|
0.045
|
Glucanase | 0.90 | 0.373 | 0.72ab | 1.00b |
0.41
a
|
2.42
|
0.025
|
TE |
2.41
|
0.025
|
0.50
a
| 1.00b |
0.42
a
|
3.06
|
0.006
|
RAD | 1.55 | 0.136 | 0.61a | 1.00a | 0.57a | 1.78 | 0.090 |
- For each sample, total RNA (ng/ul) was estimated using the appropriate standard curve for each gene of interest and normalized using the geometric mean of the three standards: actin, cytochrome c oxidase (COX) and ubiquitin (UBQ), as suggested in Vandersompele et al. 2002 [61]. Genes of interest included three isoforms of PAL (phenylalanine ammonia lyase) 1, 2a, 2b, involved in secondary metabolism; chitinase and glucanase, involved in defense response; and a transposable element (TE) and DNA repair/recombination gene (RAD), potentially involved in rapid evolution. Geo-cytotypes are 2× EU, native Eurasian diploid populations; 4× EU, native Eurasian tetraploid populations; 4× US, invasive North American tetraploids. Significant differences in gene expression (log cDNA) were determined for geo-cytotypes of interest (EU 2× versus EU 4× and EU 4× versus US 4×) using pair-wise comparisons of LSmeans. LSmeans were back-transformed and expression values are shown relative to native Eurasian tetraploid populations (4× EU). Fisher's LSD and absolute t values are reported for each pair-wise comparison.
