It was probably a range of plants and fungi seeking interaction with a species that could care for them and bring them to new places. Maybe wheat and yeast ganged up to control the apes? However the first plant humans propagated were fig trees, and apparently the first plant we grew in a gardening context was the bottle gourd (pot to ferment stuff in!) Maybe we find out one day which of those fuckers are responsible for us having credit scores and 9-5 now!!