Plant grafting is a process whereby a piece of one plant is inserted into another and results in a change of the original plant. For example, grafting a piece of a lemon tree into a bitter orange tree will cause that tree to produce lemons instead of oranges for the rest of its life.
How does this work? I mean, at the genetic level. I guess the grafted plant is now a chimera of some sort but if so
How does the grafted DNA affect the host cells?
Are all of the host's cells affected?
If we were to sequence the grafted tree which genome would we find?
Is it perhaps that the host DNA is not affected at all and the effects come via a change in expression levels? If that is the case I would assume grafting will only work between very closely related species. Is that so?
Basically I know very little about plant genetics and physiology. I remember from my undergraduate days that plant genetics are just plain weird. Most, if not all, have various levels of polyploidy. Is that relevant?