A hidden world of fungi abounds inside healthy leaves, and scientists are beginning to learn what it's doing there. A research team reports that in tree leaves, these fungi, called endophytes, can limit damage from attacking disease agents.
In tests on chocolate trees in Panama, leaves colonized with endophytes that don't cause disease coped better with a vicious pathogen than fungusfree leaves did, report A. Elizabeth Arnold of Duke University in Durham, N.C., and her colleagues. "Here's a major role for broad-leaved-tree [endophytes] that's never been noticed," she says.
The endophytes in grasses fight pathogens, explains Keith Clay of Indiana University in Bloomington. He welcomes the similar result in these trees as "pretty dramatic." He adds, "I'm sure it's going