Probably yes but maybe not. I think that you should make an experiment to confirm it in the related species.

This is a very interesting question .

In Mendelian genetics there are two types of genetic interaction:

a) Genetic interaction without epistasis, in which limiting the example to two loci, the classical segregation ratio of a dihybrid is 9:3:3:1, but new phenotypes appear. The typical example is in the shape of the comb of the hens. In this case, we need to cross two breeds within the same specie, to observe the interaction. If we do not cross the breeds, we can not observe that interaction, simply because the genotypic state required, may not be present ( each breed does not have all the required alleles) .

Now consider a species of birds, say for example canaries, you'll never see that interaction because they do not have the anatomical structure (comb).

b ) Interaction of genes with epistasis. The classic example in these cases is that the typical ratio of segregation of 9:3:3:1 of a dihybrid changes to 9:6:1, for only looking at the example of epistasis with cumulative effects in pigs of the Duroc breed. Even within the same species you will not see this interaction, simply because they do not have the alleles necessary for the expression of this interaction. I we look at the case of the wild pig, we would see the same. (they do not have the genotypic combinations, required for the phenotypic expression).

Without being a specialist in molecular genetics, I will give my modest contribution to this question. Genetic interaction exist whenever for the final expression of a phenotype, there exist several steps, involving enzymes, encoded by genes. Consider for example, the Krebs cycle, (present in all species), the final phenotypic expression is Energy + water+ other products. This energetic pathway, requires sequential steps, where a step depends on the previous (otherwise it would block in the metabolic pathway ), in this case we conclude that the answer is certainly yes, and therefore that, the interaction in other species exists. Finally, consider the genetic homology between the human and the chimpanzee from the viewpoint of the genome.

I hope this help.

The story is as follows：the interaction of two genes exists in arabidopsis, while I cloned the homologous genes in Brassica napus, the interaction disappeared

Could you better define what do you mean as "interaction" between your genes?

Yeast Two-Hybrid System was used to study the interaction, the interaction in arabidopsis actually exists, while in the case of Brassica napus, it disappeard.