Crop breeding during the Green Revolution re-sulted in high yields largely due to the creation of plants with semi-dwarf architectures that could tolerate high-density planting. Although semi-dwarf varieties have been developed in rice, wheat and maize, none was reported in soybean (Glycine max), and few genes controlling plant architecture have been characterized in soybean. Here, we demonstrate that the auxin efflux transporter PIN-FORMED1 (GmPIN1), which determines polar auxin transport, regulates the leaf petiole angle in soy-bean. CRISPR-Cas9-induced Gmpin1abc and Gmpin1bc multiple mutants displayed a compact architecture with a smaller petiole angle than wild-type plants. GmPIN1 transcripts and auxin were distributed asymmetrically in the petiole base, with high levels of GmPIN1a/c transcript and auxin in the lower cells, which resulted in asymmetric cell expansion. By contrast, the (iso)flavonoid content was greater in the upper petiole cells than in the lower cells. Our results suggest that (iso)flavonoids inhibit GmPIN1a/c expression to regulate the pe-tiole angle. Overall, our study demonstrates that a signal cascade that integrates (iso)flavonoid bio-synthesis, GmPIN1a/c expression, auxin accumu-lation, and cell expansion in an asymmetric manner creates a desirable petiole curvature in soybean. This study provides a genetic resource for im-proving soybean plant architecture.

Zhongqin Zhang;Le Gao;Meiyu Ke;Zhen Gao;Tianli Tu;Laimei Huang;Jiaomei Chen;Yuefeng Guan;Xi Huang;Xu Chen

Key Laboratory of Ministry of Education for Genetics,Breeding and Multiple Utilization of Crops,College of Agriculture,Fujian Agriculture and Forestry University,Fuzhou 350002,China;Haixia Institute of Science and Technology,Horticultural Plant Biology and Metabolomics Center,Fujian Agriculture and Forestry University,Fuzhou 350002,China;Department of Horticulture,Beijing Vocational College of Agriculture,Beijing 102442,China;College of Life Science,Fujian Agriculture and Forestry University,Fuzhou 350002,China;State Key Laboratory of Cellular Stress Biology,School of Life Sciences,Xiamen University,Xiamen 361102,China

植物学报（英文版）

[1]Zhongqin Zhang;Le Gao;Meiyu Ke;Zhen Gao;Tianli Tu;Laimei Huang;Jiaomei Chen;Yuefeng Guan;Xi Huang;Xu Chen-.GmPIN1-mediated auxin asymmetry regulates leaf petiole angle and plant architecture in soybean)[J].植物学报（英文版）,2022(07):1325-1338

GmPIN1,FORMED1,Gmpin1abc,Gmpin1bc,GmPIN1a,tiole

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