摘要
Gravity-induced root curvature involves the asymmetric distribution of the phytohormone auxin.This response depends on the concerted activities of the auxin transporters such as PIN-FORMED(PIN)proteins for auxin efflux and AUXIN RESISTANT 1(AUX1)for auxin influx.However,how the auxin gradient is established remains elusive.Here we identified a new mutant with a short root,strong auxin distribution in the lateral root cap and an impaired gravitropic response.The causal gene encoded an Arabidopsis homolog of the human unconventional prefoldin RPB5 interactor(URI).At URI interacted with prefoldin 2(PFD2)and PFD6,twoβ-type PFD members that modulate actin and tubulin patterning in roots.The auxin reporter DR5_(rev):GFP showed that asymmetric auxin redistribution after gravistimulation is disordered in aturi-1 root tips.Treatment with the endomembrane protein trafficking inhibitor brefeldin A indicated that recycling of the auxin transporter PIN2 is disrupted in aturi-1 roots as well as in pfd mutants.We propose that At URI cooperates with PFDs to recycle PIN2and modulate auxin distribution.
基金
supported by an initiation fund from the Shandong Agricultural University,the National Natural Science Foundation of China(31570291)
the Shandong“Foreign experts double hundred”Program(WST2017008)
the Natural Science Foundation of Shandong Province(ZR2021MC175)。
