Auxin and auxin-mediated signaling pathways are known to regulate lateral root development. Although exocytic vesicle trafficking plays an important role in recycling the PIN-FORMED (PIN) auxin efflux carriers and in polar auxin transport during lateral root formation, the mechanistic details of these processes are not well understood. Here, we demonstrate that BYPASS1-LIKE (B1L) regulates lateral root ini-tiation via exocytic vesicular trafficking-mediated PIN recycling in Arabidopsis thaliana. b1l mu-tants contained significantly more lateral roots than the wild type, primarily due to increased lateral root primordium initiation. Furthermore, the auxin signal was stronger in stage I lateral root primordia of b1l than in those of the wild type. Treatment with exogenous auxin and an auxin transport inhibitor indicated that the lateral root phenotype of b1l could be attributed to higher auxin levels and that B1L regulates auxin efflux. Indeed, compared to the wild type, C-terminally green fluorescent protein-tagged PIN1 and PIN3 accumulated at higher levels in b1l lateral root primordia. B1L interacted with the exocyst, and b1l showed defective PIN exocytosis. These observations indicate that B1L interacts with the exocyst to regulate PIN-mediated polar auxin transport and lateral root initiation in Arabidopsis.

Gang Yang;Bi-Xia Chen;Tao Chen;Jia-Hui Chen;Xiang-Yu Lin;Xiu-Le Yue;Li-Zhe An;Hua Zhang

Key Laboratory of Cell Activities and Stress Adaptations,Ministry of Education,School of Life Sciences,Lanzhou University,Lanzhou 730000,China;College of Life Science and Technology,Gansu Agricultural University,Lanzhou 730070,China;School of Forestry,Beijing Forestry University,Beijing 100083,China

植物学报（英文版）

[1]Gang Yang;Bi-Xia Chen;Tao Chen;Jia-Hui Chen;Xiang-Yu Lin;Xiu-Le Yue;Li-Zhe An;Hua Zhang-.BYPASS1-LIKE regulates lateral root initiation via exocytic vesicular trafficking-mediated PIN recycling in Arabidopsis)[J].植物学报（英文版）,2022(05):965-978

BYPASS1,exocytic,FORMED,B1L,b1l,primordium,exocyst

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