Why some of the most dangerous potato diseases are successful

All but a few of the plants and animals we’re familiar with have one thing in common: they require oxygen in the atmosphere (or the water) to exist. We refer to these oxygen-dependent lifeforms as being “aerobic.” Less familiar are lifeforms that cannot grow in the presence of oxygen. Referred to as “anaerobic,” most of these organisms are bacteria, though a few rare, multi-cellular forms do exist. There is also a group of organisms that straddle the fence and are able to live in the presence or absence of oxygen, their metabolism converting to some form of fermentation under low oxygen conditions. We refer to these types as “facultative anaerobes.” So, what does this have to do with potatoes? Soft rot bacteria, arguably the most important potato pathogen known, are facultative anaerobes. Bacteria of the genera Pectobacterium (formerly Erwinia), and Dickeya (responsible for causing seed piece decay), blackleg, stem soft rot, as well as extensive storage losses, are members of this group. Like it or not, potato tubers are regularly subjected to anaerobic conditions in the field and in storage. In fact, the most frequent cause of soft rot seed decay and blackleg is probably soils that become waterlogged at the wrong time. Article by Phil Nolte, University of Idaho