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Arabidopsis indole synthase, a homolog of tryptophan synthase alpha, is an enzyme involved in the Trp-independent indole-containing metabolite biosynthesis.
J Integr Plant Biol. 2008 Sep; 50(9):1070-7.JI

Abstract

The plant tryptophan (Trp) biosynthetic pathway produces many secondary metabolites with diverse functions. Indole-3-acetic acid (IAA), proposed as a derivative from Trp or its precursors, plays an essential role in plant growth and development. Although the Trp-dependant and Trp-independent IAA biosynthetic pathways have been proposed, the enzymes, reactions and regulatory mechanisms are largely unknown. In Arabidopsis, indole-3-glycerol phosphate (IGP) is suggested to serve as a branchpoint component in the Trp-independent IAA biosynthesis. To address whether other enzymes in addition to Trp synthase alpha (TSA1) catalyze IGP cleavage, we identified and characterized an indole synthase (INS) gene, a homolog of TSA1 in Arabidopsis. INS exhibits different subcellular localization from TSA1 owing to the lack of chloroplast transit peptide (cTP). In silico data show that the expression levels of INS and TSA1 in all examined organs are quite different. Histochemical staining of INS promoter-GUS transgenic lines indicates that INS is expressed in vascular tissue of cotyledons, hypocotyls, roots and rosette leaves as well as in flowers and siliques. INS is capable of complementing the Trp auxotrophy of Escherichia coliDeltatrpA strain, which is defective in Trp synthesis due to the deletion of TSA. This implies that INS catalyzes the conversion of IGP to indole and may be involved in the biosynthesis of Trp-independent IAA or other secondary metabolites in Arabidopsis.

Authors+Show Affiliations

State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18844775

Citation

Zhang, Rui, et al. "Arabidopsis Indole Synthase, a Homolog of Tryptophan Synthase Alpha, Is an Enzyme Involved in the Trp-independent Indole-containing Metabolite Biosynthesis." Journal of Integrative Plant Biology, vol. 50, no. 9, 2008, pp. 1070-7.
Zhang R, Wang B, Ouyang J, et al. Arabidopsis indole synthase, a homolog of tryptophan synthase alpha, is an enzyme involved in the Trp-independent indole-containing metabolite biosynthesis. J Integr Plant Biol. 2008;50(9):1070-7.
Zhang, R., Wang, B., Ouyang, J., Li, J., & Wang, Y. (2008). Arabidopsis indole synthase, a homolog of tryptophan synthase alpha, is an enzyme involved in the Trp-independent indole-containing metabolite biosynthesis. Journal of Integrative Plant Biology, 50(9), 1070-7. https://doi.org/10.1111/j.1744-7909.2008.00729.x
Zhang R, et al. Arabidopsis Indole Synthase, a Homolog of Tryptophan Synthase Alpha, Is an Enzyme Involved in the Trp-independent Indole-containing Metabolite Biosynthesis. J Integr Plant Biol. 2008;50(9):1070-7. PubMed PMID: 18844775.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Arabidopsis indole synthase, a homolog of tryptophan synthase alpha, is an enzyme involved in the Trp-independent indole-containing metabolite biosynthesis. AU - Zhang,Rui, AU - Wang,Bing, AU - Ouyang,Jian, AU - Li,Jiayang, AU - Wang,Yonghong, PY - 2008/10/11/pubmed PY - 2009/1/24/medline PY - 2008/10/11/entrez SP - 1070 EP - 7 JF - Journal of integrative plant biology JO - J Integr Plant Biol VL - 50 IS - 9 N2 - The plant tryptophan (Trp) biosynthetic pathway produces many secondary metabolites with diverse functions. Indole-3-acetic acid (IAA), proposed as a derivative from Trp or its precursors, plays an essential role in plant growth and development. Although the Trp-dependant and Trp-independent IAA biosynthetic pathways have been proposed, the enzymes, reactions and regulatory mechanisms are largely unknown. In Arabidopsis, indole-3-glycerol phosphate (IGP) is suggested to serve as a branchpoint component in the Trp-independent IAA biosynthesis. To address whether other enzymes in addition to Trp synthase alpha (TSA1) catalyze IGP cleavage, we identified and characterized an indole synthase (INS) gene, a homolog of TSA1 in Arabidopsis. INS exhibits different subcellular localization from TSA1 owing to the lack of chloroplast transit peptide (cTP). In silico data show that the expression levels of INS and TSA1 in all examined organs are quite different. Histochemical staining of INS promoter-GUS transgenic lines indicates that INS is expressed in vascular tissue of cotyledons, hypocotyls, roots and rosette leaves as well as in flowers and siliques. INS is capable of complementing the Trp auxotrophy of Escherichia coliDeltatrpA strain, which is defective in Trp synthesis due to the deletion of TSA. This implies that INS catalyzes the conversion of IGP to indole and may be involved in the biosynthesis of Trp-independent IAA or other secondary metabolites in Arabidopsis. SN - 1744-7909 UR - https://www.unboundmedicine.com/medline/citation/18844775/Arabidopsis_indole_synthase_a_homolog_of_tryptophan_synthase_alpha_is_an_enzyme_involved_in_the_Trp_independent_indole_containing_metabolite_biosynthesis_ DB - PRIME DP - Unbound Medicine ER -