Moving towards chemical-free agriculture, 37 kb at a time.

Domestic crop plants are modern marvels of extensive breeding; however, many of their natural defenses against pests and pathogens have been lost. Wild relatives still harbor disease resistance genes, but transferring these large sequences into complex, polyploid plant genomes calls for advanced genomic engineering technologies. Recently, government researchers in Australia, successfully transferred a 37kb resistance stack into the genome of a domesticated wheat species such that it is pro-tected against the rapidly evolving wheat leaf rust pathogen Puccinia graminis f. sp. tritici ( Pgt ) without losing any agronomic features. 1 Plant diseases caused by pathogenic fungi can devastate crop yield and pose a threat to food security. 2,3 About 30% of our most important crops are lost every year to fungal diseases. 3 Over decades, agricultural crops have been bred towards maxi-mum productivity under high fungicide treatment, meanwhile breeding out the plants’ own defense genes. 3 The genetic ar-mory still intact in wild crop relatives (so-called R genes) could provide an effective means towards a chemical-free disease control. 4 Introducing those genes into domestic crops is a multi-factorial challenge yet underappreciated by much of the synthetic biology community.