Fungi as Plant Pathogens

Plants are a vastly available source of food for the fungi, provided the fungi can breach the multilayered cell wall and counter the myriad intracellular defensive chemicals produced by the plant. The necrotrophic fungi secrete plant cell-wall degrading enzymes, causing much tissue destruction known as soft rots; however, these are a relatively unimportant pathogen of plants. The most destructive fungal pathogens infect the aerial parts, producing thousands of spores that are disseminated by wind or rain. Because of mutation, newer and more virulent races of fungal pathogens keep arising, requiring constant breeding of new varieties. The breeding of rust-resistant, high-yielding dwarf varieties of wheat by the American plant breeder Norman Borlaug led Mexico to become a net exporter of wheat by 1963. Norman Borlaug was awarded the 1970 Nobel Peace Prize for his contribution to peace through preventing hunger. Presently, a rust disease on soybean caused by Phakospora pachyrhizi ( https://www.stopsoybeanrust.com/mcbrazil.asp ) is of concern. This pathogen is spreading westward from its center of origin in China.