OpenPlant PI Anne Osbourne recently published work in collaboration with colleagues from the John Innes Centre, Shanghai, the Czech Republic and Aberystwyth describing the structure and organisation of the avenacin antimicrobial gene cluster in oats, and their subsequent work reconstituting this antimicrobial pathway in the tobacco plant.

Subtelomeric assembly of a multi-gene pathway for antimicrobial defense compounds in cereals

Li Y, Leveau A, Zhao Q, Feng Q, Lu H, Miao J, Xue Z, Martin AC, Wegel E, Wang J, Orme A, Rey MD, Karafiátová M, Vrána J, Steuernagel B, Joynson R, Owen C, Reed J, Louveau T, Stephenson MJ, Zhang L, Huang X, Huang T, Fan D, Zhou C, Tian Q, Li W, Lu Y, Chen J, Zhao Y, Lu Y, Zhu C, Liu Z, Polturak G, Casson R, Hill L, Moore G, Melton R, Hall N, Wulff BBH, Doležel J, Langdon T, Han B, Osbourn A.

Nat Commun. 7;12(1):2563

https://doi.org/10.1038/s41467-021-22920-8

ABSTRACT

Non-random gene organization in eukaryotes plays a significant role in genome evolution. Here, we investigate the origin of a biosynthetic gene cluster for production of defence compounds in oat—the avenacin cluster. We elucidate the structure and organisation of this 12-gene cluster, characterise the last two missing pathway steps, and reconstitute the entire pathway in tobacco by transient expression. We show that the cluster has formed de novo since the divergence of oats in a subtelomeric region of the genome that lacks homology with other grasses, and that gene order is approximately colinear with the biosynthetic pathway. We speculate that the positioning of the late pathway genes furthest away from the telomere may mitigate against a ‘self-poisoning’ scenario in which toxic intermediates accumulate as a result of telomeric gene deletions. Our investigations reveal a striking example of adaptive evolution underpinned by remarkable genome plasticity.