Arabidopsis Hypocotyl Adventitious Root Formation Is Suppressed by ABA Signaling

[EN] Roots are composed of different root types and, in the dicotyledonous Arabidopsis, typically consist of a primary root that branches into lateral roots. Adventitious roots emerge from non-root tissue and are formed upon wounding or other types of abiotic stress. Here, we investigated adventitious root (AR) formation in Arabidopsis hypocotyls under conditions of altered abscisic acid (ABA) signaling. Exogenously applied ABA suppressed AR formation at 0.25 mu M or higher doses. AR formation was less sensitive to the synthetic ABA analog pyrabactin (PB). However, PB was a more potent inhibitor at concentrations above 1 mu M, suggesting that it was more selective in triggering a root inhibition response. Analysis of a series of phosphonamide and phosphonate pyrabactin analogs suggested that adventitious root formation and lateral root branching are differentially regulated by ABA signaling. ABA biosynthesis and signaling mutants affirmed a general inhibitory role of ABA and point to PYL1 and PYL2 as candidate ABA receptors that regulate AR inhibition.This research was supported by the Research Foundation Flanders (FWO Vlaanderen, T.H.). IV was supported by the Agency for Innovation by Science and Technology in Flanders (VLAIO) and a fellowship from Ghent University (BOF). Y.Z. was provided with a China Scholarship Council (CSC) grant (No. 201806300036). This work was supported by FWO Vlaanderen (FWO), project numbers 1S48517N and G094619N. Work in the P.L.R. lab was supported by grant BIO2017-82503-R (MICINN).Zeng, Y.; Verstraeten, I.; Trinh, HK.; Heugebaert, T.; Stevens, CV.; García-Maquilón, I.; Rodríguez Egea, PL.... (2021). Arabidopsis Hypocotyl Adventitious Root Formation Is Suppressed by ABA Signaling. Genes. 12(8):1-11. https://doi.org/10.3390/genes1208114111112