Fungal Endophyte and Endohyphal Bacterium symbiosis increases IAA production

I found this very interesting journal claiming that a symbiosis between Fungal Endophytes (Lives on the surface of the leaves) and Endohyphal bacterium (Lives in symbiosis with the fungi on the surface of the leaves) results in an increased concentration of Indole-3-acetic acid, the natural hormone that stimulates plants to grow.
Let me know what knowledge you already have on the subject, thanks in advance.
Anyways here's the journal:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0073132