title: TAA1-regulated local auxin biosynthesis in the root-apex transition zone mediates the aluminum-induced inhibition of root growth in Arabidopsis.
abstract: The transition zone (TZ) of the root apex is the perception site of Al toxicity. Here, we show that exposure of Arabidopsis thaliana roots to Al induces a localized enhancement of auxin signaling in the root-apex TZ that is dependent on TAA1, which encodes a Trp aminotransferase and regulates auxin biosynthesis. TAA1 is specifically upregulated in the root-apex TZ in response to Al treatment, thus mediating local auxin biosynthesis and inhibition of root growth. The TAA1-regulated local auxin biosynthesis in the root-apex TZ in response to Al stress is dependent on ethylene, as revealed by manipulating ethylene homeostasis via the precursor of ethylene biosynthesis 1-aminocyclopropane-1-carboxylic acid, the inhibitor of ethylene biosynthesis aminoethoxyvinylglycine, or mutant analysis. In response to Al stress, ethylene signaling locally upregulates TAA1 expression and thus auxin responses in the TZ and results in auxin-regulated root growth inhibition through a number of auxin response factors (ARFs). In particular, ARF10 and ARF16 are important in the regulation of cell wall modification-related genes. Our study suggests a mechanism underlying how environmental cues affect root growth plasticity through influencing local auxin biosynthesis and signaling.
authors: Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Science, Shandong University, Jinan 250100, People's Republic of China.
authors: Zhong-Bao
authors: ZB
authors: Yang
authors: Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Science, Shandong University, Jinan 250100, People's Republic of China.
authors: Xiaoyu
authors: X
authors: Geng
authors: Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Science, Shandong University, Jinan 250100, People's Republic of China.
authors: Chunmei
authors: C
authors: He
authors: Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Science, Shandong University, Jinan 250100, People's Republic of China.
authors: Feng
authors: F
authors: Zhang
authors: Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Science, Shandong University, Jinan 250100, People's Republic of China.
authors: Rong
authors: R
authors: Wang
authors: Institute of Plant Nutrition, Leibniz Universität Hannover, 30419 Hannover, Germany.
authors: Walter J
authors: WJ
authors: Horst
authors: Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, College of Life Science, Shandong University, Jinan 250100, People's Republic of China dingzhaojun@sdu.edu.cn.
authors: Zhaojun
authors: Z
authors: Ding
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D000598:Amino Acids, Cyclic / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D002473:Cell Wall / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D007210:Indoleacetic Acids / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D051279:Tryptophan Transaminase / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C505216:ARF10 protein, Arabidopsis; C505217:ARF16 protein, Arabidopsis; D000598:Amino Acids, Cyclic; D029681:Arabidopsis Proteins; D005030:Ethylenes; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D014157:Transcription Factors; C023863:1-aminocyclopropane-1-carboxylic acid; C036216:ethylene; D000535:Aluminum; D051279:Tryptophan Transaminase