Georg Jander

Date & Time: September 9, 2024, at 4 pm

Location: BCH 101

Zoom: https://msu.zoom.us/j/91993518218?pwd=SzN0Umd0dElSblVSOGJEY2U0UzJJdz09
Meeting ID: 919 9351 8218
Passcode: 028299

Host: Aleksandra Skirycz

About the Speaker

Institution: Boyce Thompson Institute

Subject: Maize defense and growth regulation by COI F‐box proteins

Abstract: Recognition of jasmonate-isoleucine by COI F-box proteins is an essential component of defense signaling in many plant species. Whereas the better-studied Arabidopsis and tomato signaling pathways involve a single COI protein, the maize genome encodes six predicted COI proteins (COI1a, COI1b, COI1c, COI1d, COI2a, and COI2b). To investigate maize COI gene functions, we used transposon insertions to make single and multi-gene knockout lines. A maize coi2a coi2b knockout line has inviable pollen and phenotypes similar to those observed in Arabidopsis coi mutants. By contrast, a coi1a coi1b coi1c coi1d quadruple knockout line has shortened internodes that are characteristic of defects in gibberellic acid signaling. Consistent with this observation, the quadruple knockout accumulates DELLA (DWARF8 and/or DWARF9) proteins, which are negative regulators of the gibberellic acid signaling pathway. Coexpression of maize COI1 and DELLA genes in Nicotiana benthamiana showed that the COI1 proteins trigger proteasome-dependent DELLA degradation. Together, these results demonstrate divergent functions of the six maize COI proteins and suggest a role for COI1 proteins in regulating growth through DELLA degradation.