Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transcription of two gene families, SAURs and GH3, in soybean has been shown to be specifically induced by the plant hormone auxin. The SAUR mRNAs have been shown to accumulate on the lower half and disappear from the upper half of soybean hypocotyls during gravitropic curvature. The SAUR and GH3 promoters have been fused to the beta-glucuronidase (GUS) reporter gene and shown to be specifically induced by auxins in transgenic tobacco plants. Histochemical staining and quantitative GUS assays indicate that these auxin inducible promoters are activated on the lower half of transgenic tobacco stems undergoing gravitropic curvature. The auxin transport inhibitors, TIBA and NPA, block both gravitropic curvature and the activation of the auxin responsive promoters in transgenic tobacco stems. The auxin responsive elements (AuxREs) within the SAUR and GH3 promoters have been identified, and these AuxREs are likely to be the elements that are responsible for the increased expression of the SAUR and GH3 genes during gravitropism.
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PMID:Auxin regulated gene expression and gravitropism in plants. 1153 49

The changes in root system architecture (RSA) triggered by phosphate (P) deprivation were studied in Arabidopsis (Arabidopsis thaliana) plants grown for 14 d on 1 mM or 3 microM P. Two different temporal phases were observed in the response of RSA to low P. First, lateral root (LR) development was promoted between days 7 and 11 after germination, but, after day 11, all root growth parameters were negatively affected, leading to a general reduction of primary root (PR) and LR lengths and of LR density. Low P availability had contrasting effects on various stages of LR development, with a marked inhibition of primordia initiation but a strong stimulation of activation of the initiated primordia. The involvement of auxin signaling in these morphological changes was investigated in wild-type plants treated with indole-3-acetic acid or 2,3,5-triiodobenzoic acid and in axr4-1, aux1-7, and eir1-1 mutants. Most effects of low P on RSA were dramatically modified in the mutants or hormone-treated wild-type plants. This shows that auxin plays a major role in the P starvation-induced changes of root development. From these data, we hypothesize that several aspects of the RSA response to low P are triggered by local modifications of auxin concentration. A model is proposed that postulates that P starvation results in (1) an overaccumulation of auxin in the apex of the PR and in young LRs, (2) an overaccumulation of auxin or a change in sensitivity to auxin in the lateral primordia, and (3) a decrease in auxin concentration in the lateral primordia initiation zone of the PR and in old laterals. Measurements of local changes in auxin concentrations induced by low P, either by direct quantification or by biosensor expression pattern (DR5::beta-glucuronidase reporter gene), are in line with these hypotheses. Furthermore, the observation that low P availability mimicked the action of auxin in promoting LR development in the alf3 mutant confirmed that P starvation stimulates primordia emergence through increased accumulation of auxin or change in sensitivity to auxin in the primordia. Both the strong effect of 2,3,5-triiodobenzoic acid and the phenotype of the auxin-transport mutants (aux1, eir1) suggest that low P availability modifies local auxin concentrations within the root system through changes in auxin transport rather than auxin synthesis.
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PMID:A role for auxin redistribution in the responses of the root system architecture to phosphate starvation in Arabidopsis. 1604 Jun 60