There are some lists of useful Greek and Latin word roots here:
Examples:
- cyto- or -cyte comes from the Greek root that is used for cell.
- kinin is for hormones. It’s related to “kinetic” or movement.
Cytokinin (“cell-kinetic”) is related to plant growth.
Other examples with cyto- or -cyte:
- astro-cyte (star-cell, because it’s star shaped)
- oligo-dendro-cyte (few-tree-cell or few-branch-cell, because it has few branches)
A quick search for the etymology of tumefaciens leads to a Latin dictionary:
From tumeō (“I swell”) + faciō (“I do, make”).
Tume- is related to “tumor”, and it looks like tumefaciens causes (makes) tumors on some kinds of plants.
Some Romance languages have words that are similar to faciō (like faço in Portuguese or fais in French), which could be a mnemonic link. In English, you could also create a link with the sound of the word “face” and link the meaning of “make” through a mnemonic image of “make-up”.
Another idea is to imagine a face on crown gall and then picture a tumor on it: “tumor-face” (tumefaciens) on crown gall.