Folate shapes plant root architecture by affecting auxin distribution. (31st January 2023)

• Record Type: Journal Article
• Authors: Li, Ying; Luo, Jinying; Chen, Rong; Zhou, Yuhong; Yu, Huiyang; Chu, Zhuannan; Lu, Yongen; Gu, Xiaofeng; Wu, Shuang; Wang, Pengwei; Kuang, Hanhui; Ouyang, Bo
• Is Part Of: Plant journal. Volume 113:Number 5(2023)
• Page Start: 969
• Page End: 985
• Publication Date: 2023-01-31
• Subjects: folate -- auxin -- AtFolB2 -- root development -- PIN reporter; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.16093
• Languages: English
• ISSNs: 0960-7412

Abstract

SUMMARY: Folate (vitamin B9) is important for plant root development, but the mechanism is largely unknown. Here we characterized a root defective mutant, folb2, in Arabidopsis, which has severe developmental defects in the primary root. The root apical meristem of the folb2 mutant is impaired, and adventitious roots are frequently found at the root–hypocotyl junction. Positional cloning revealed that a 61‐bp deletion is present in the predicted junction region of the promoter and the 5′ untranslated region of AtFolB2, a gene encoding a dihydroneopterin aldolase that functions in folate biosynthesis. This mutation leads to a significant reduction in the transcript level of AtFolB2 . Liquid chromatography–mass spectrometry analysis showed that the contents of the selected folate compounds were decreased in folb2 . Arabidopsis AtFolB2 knockdown lines phenocopy the folb2 mutant. On the other hand, the application of exogenous 5‐formyltetrahydrofolic acid could rescue the root phenotype of folb2, indicating that the root phenotype is indeed related to the folate level. Further analysis revealed that folate could promote rootward auxin transport through auxin transporters and that folate may affect particular auxin/indole‐3‐acetic acid proteins and auxin response factors. Our findings provide new insights into the important role of folic acid in shaping root structure. Significance Statement: Various metabolites appear to be important for adventitious rooting. We demonstrate the importance of folates in adventitious root development at the shoot–root junction by studying a mutant ( folb2 ) with impaired AtFolB2 expression and decreased folate levels. AtFolB2 encodes a dihydroneopterin aldolase that is active in the folate biosynthesis pathway, and folate participates in adventitious rooting by promoting rootward auxin transport through auxin transporters.