Leaves of Lemna

A science fiction set in a post-apocalyptic post-photosynthetic future where people have accidentally released a deadly virus that infects plants and the world is slowly running out of food. Decades into this grim reality the status quo is disrupted and a two person team (yup, one man and one woman) is sent out to look for strategically useful information. They start with very different perspectives, encounter other communities and find something unexpected.