Isoprene research - 60 years later, the biology is still enigmatic

Isoprene emission is a major component of biosphere-atmosphere interactions. It is the single largest source of non-methane hydrocarbon in the atmosphere. The first report of isoprene emission from plants was published in 1957 by Professor Guivi Sanadze. While humans have smelled the monoterpene hydrocarbons made by coniferous trees since their earliest migrations, only in 1957 did the world became aware that other trees make a type of hydrocarbon in even greater amounts but one to which the human nose is much less sensitive. For this 60th anniversary of the first report of isoprene emission from leaves, we trace the discovery and development of the research field, highlighting some of the most seminal observations and theoretical interpretations. This is not an exhaustive review, and many important papers are not cited, but we hope it will be of general interest to read how research in this field developed, how new observations forced us to reevaluate our theories about the significance of isoprene biosynthesis to plant physiology and adaptation and how scientific serendipity can sometimes drive a topic forward.