Among plants there are tons of things - for example the identification and cloning of most of the plant hormone receptors (ethylene, brassinosteroids, cytokinins, auxin, abscisic acid) and the auxin polar transporters (PINs). Plant peptide hormones. The downstream pathways for hormone perception (as AUX/IAAs, etc.) Floral organ identity genes as in the ABC model of flower development. NBS-LRR plant pathogen response genes (I think). Cloning of blue light receptors, UV receptors, elucidation of the phytochrome pathways. The mechanisms of flowering time perception, and circadian clocks. There must be lots more - it would be interesting to see the list you get. Take a look at http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2010.04176.x/full For across kingdoms it is a lot harder, as much of what Arabidopsis has been used for is to show how plants do things that animals also do, but differently. I think there are some aspects of miRNAs and histone modifications first found in Arabidopsis, but you should check with an expert.