The Genome and Transcriptomes of Wild and Laboratory strains of Nicotiana benthamiana.

Nicotiana benthamiana is widely used as a model plant for functional genomics, synthetic metabolic engineering, RNA interference and plant-microbe interaction research.  The transcriptomes of five wild strains, collected from across the spectrum of the species’ natural distribution in Australia, and one popular GFP-expressing line, 16C, have been assembled and mapped onto the laboratory (LAB) strain genome to provide details and insights about the variability of the species and the cause of the LAB strain’s unusual properties. LAB, and an accession from South Australia, have a 72nt insertion in a critical defence gene (Rdr1). This not only renders these plants hyper-susceptible to virus infection, more amenable to transient transgene expression and virus induced gene silencing (VIGS), but also confers increased early vigour and seed size. This insertion event occurred about 750,000 years ago and appears to give the plants a selective advantage in the harsh conditions of Central Australia where the disease pressure is very low but a speedy lifecycle, with high water-use efficiency, is important.  An interactive website (www.benthgenome.com) has been set up to facilitate examination of the laboratory and wild strain genomes and transcriptomes, their gene expression patterns and their microRNA regulation.