RT Journal Article
SR Electronic
T1 Heterotrimeric G-proteins in unfolded protein response mediate plant growth-defense tradeoffs upstream of steroid and immune signaling
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 438135
DO 10.1101/438135
A1 Jimi C. Miller
A1 Stacey A. Lawrence
A1 Teresa Ceserani
A1 Caroline L. Beakes
A1 Nicole K. Clay
YR 2018
UL http://biorxiv.org/content/early/2018/10/08/438135.abstract
AB Plants prioritize growth over defense to gain a competitive advantage for limited resources, but change priorities to successfully fight infection and herbivory. Despite the importance of growth-defense tradeoffs in optimizing plant productivity in natural and agricultural populations, the molecular mechanisms that link growth and immunity remain unclear. Here, we demonstrate that growth-defense tradeoffs between pathways activated by BRI1, a steroid receptor, and FLS2, an innate immune receptor, are uncoupled in an Arabidopsis mutant (agg1 agg2) lacking two redundant heterotrimeric G-protein gamma subunits that form stable heterodimers with the Gβ subunit AGB1 to control one arm of the unfolded protein response (UPR) independently of ER stress. Growth inhibition from induced immunity in wild-type plants is likely caused by AGB1-AGG1/2 dimers interacting with nascent BRI1 and FLS2 proteins on the endoplasmic reticulum (ER) membrane and repressing an UPR response that is hardwired to promote BRI1 protein biogenesis and FLS2 protein degradation via autophagy. The ability to unlock and fine-tune growth-defense tradeoffs through UPR signaling provides a novel strategy to increase the natural defenses of crops while maintaining optimal plant productivity.Author ContributionsC.B. contributed to characterization of agg1 agg2/XVE:FLS2 lines. T.C. contributed to Endo H digestion. S.A.L. generated agb1/35S:YFP-AGB1 lines, and contributed to qPCR of ire1a/b, Endo H digestion and MAPK activation of agg1 agg2 atg7/3 N.K.C. generated XVE:BRI1-RFP construct and agg1 agg2/XVE:FLS2 lines, and contributed to Co-IPs and pathogen assays. J.C.M. generated all other constructs, and contributed to characterization of agg1 agg2/XVE:FLS2 lines, Co-IPs and all other experiments. J.C.M. and N.K.C. interpreted the results and N.K.C. wrote the paper.