Synthesis of Deoxyradicinin, an Inhibitor of Xylella fastidiosa and Liberibacter crescens, a Culturable Surrogate
for Candidatus Liberibacter
asiaticus
posted on 2020-06-08, 18:16authored byConnor
A. Brandenburg, Claudia A. Castro, Alex A. Blacutt, Elizabeth A. Costa, Kyler C. Brinton, Diana W. Corral, Christopher L. Drozd, M. Caroline Roper, Philippe E. Rolshausen, Katherine N. Maloney, Jonathan W. Lockner
Pierce’s disease of grapevine
and citrus huanglongbing are
caused by the bacterial pathogens Xylella fastidiosa and Candidatus Liberibacter asiaticus (CLas), respectively. Both pathogens reside within the plant
vascular system, occluding water and nutrient transport, leading to
a decrease in productivity and fruit marketability and ultimately
death of their hosts. Field observations of apparently healthy plants
in disease-affected vineyards and groves led to the hypothesis that
natural products from endophytes may inhibit these bacterial pathogens.
Previously, we showed that the natural product radicinin from Cochliobolus sp. inhibits X. fastidiosa. Herein we describe a chemical synthesis of deoxyradicinin and establish
it as an inhibitor of both X. fastidiosa and Liberibacter crescens, a culturable surrogate for CLas. The key to this three-step route is a zinc-mediated
enolate C-acylation, which allows for direct introduction
of the propenyl side chain without extraneous redox manipulations.