Skip to main content
. 2013 Apr 12;162(2):537–552. doi: 10.1104/pp.112.213546

Figure 8.

Figure 8.

Bias toward meristematic expression in S. lycopersicum (S. lyco.) relative to S. pennellii (S. penn.). A, Distance clusters 3 and 6, which are enriched for GO terms associated with meristematic tissues, were examined with respect to the displacement of orthologous genes between different SOM clusters. The orthologs assigned to S. pennellii SOM clusters (black arcs) and the corresponding S. lycopersicum SOM clusters (orange arcs) are indicated by arrows (S. pennellii → S. lycopersicum direction). Note that unlike Figure 4, genes belonging to the same cluster are indicated. There is a trend for S. lycopersicum orthologs to become displaced to clusters with high expression in meristematic tissues. For example, in distance cluster 3, S. lycopersicum orthologs tend to occupy SOM cluster 5, with high seedling expression. In distance cluster 6, S. lycopersicum orthologs become displaced toward SOM cluster 1, with high vegetative apex expression. B, The displacement of distance cluster genes toward meristematic SOM clusters in S. lycopersicum is reflected in their expression profiles. Distance cluster 3 genes show much higher expression in the seedling (and somewhat in the vegetative meristem) in S. lycopersicum relative to S. pennellii. Distance cluster 6 genes show much higher vegetative apex expression (and somewhat higher in the inflorescence) in S. lycopersicum relative to S. pennellii. Both clusters show higher expression in the stem (a differentiated structure) in S. pennellii relative to S. lycopersicum. Inf., Inflorescence; Lf., leaf; Rt., root; Sd., seedling; St., stem; Veg., vegetative apex. C, The higher expression of genes in the meristematic tissues of S. lycopersicum is consistent with species differences relative to S. pennellii. The vegetative meristem of S. lycopersicum is much larger than that of S. pennellii, with more cells. Furthermore, the differentiated primordia of S. pennellii are larger, with more vacuolated cells, relative to the primordia of a similar stage in S. lycopersicum, indicating premature differentiation relative to S. lycopersicum. [See online article for color version of this figure.]