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)

Thioglucoside glucohydrolase 1 (TGG1) is one of two known functional myrosinase enzymes in Arabidopsis. The enzyme catalyzes the hydrolysis of glucosinolates into compounds that are toxic to various microbes and herbivores. Transgenic Arabidopsis plants carrying beta-glucuronidase and green fluorescent protein reporter genes fused to 0.5 or 2.5 kb of the TGG1 promoter region were used to study spatial promoter activity. Promoter activity was found to be highly specific and restricted to guard cells and distinct cells of the phloem. No promoter activity was detected in the root or seed. All guard cells show promoter activity. Positive phloem cells are distributed in a discontinuous pattern and occur more frequent in young tissues. Immunocytochemical localization of myrosinase in transverse and longitudinal sections of embedded material show that the TGG1 promoter activity reflects the position of the myrosinase enzyme. In the flower stalk, the myrosinase-containing phloem cells are located between phloem sieve elements and glucosinolate-rich S cells. Our results suggest a cellular separation of myrosinase enzyme and glucosinolate substrate, and that myrosinase is contained in distinct cells. We discuss the potential advantages of locating defense and communication systems to only a few specific cell types.
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PMID:Guard cell- and phloem idioblast-specific expression of thioglucoside glucohydrolase 1 (myrosinase) in Arabidopsis. 1195 Sep 67

Despite the fact that roots are the organs most subject to microbial interactions, very little is known about the response of roots to microbe-associated molecular patterns (MAMPs). By monitoring transcriptional activation of beta-glucuronidase reporters and MAMP-elicited callose deposition, we show that three MAMPs, the flagellar peptide Flg22, peptidoglycan, and chitin, trigger a strong tissue-specific response in Arabidopsis thaliana roots, either at the elongation zone for Flg22 and peptidoglycan or in the mature parts of the roots for chitin. Ethylene signaling, the 4-methoxy-indole-3-ylmethylglucosinolate biosynthetic pathway, and the PEN2 myrosinase, but not salicylic acid or jasmonic acid signaling, play major roles in this MAMP response. We also show that Flg22 induces the cytochrome P450 CYP71A12-dependent exudation of the phytoalexin camalexin by Arabidopsis roots. The phytotoxin coronatine, an Ile-jasmonic acid mimic produced by Pseudomonas syringae pathovars, suppresses MAMP-activated responses in the roots. This suppression requires the E3 ubiquitin ligase COI1 as well as the transcription factor JIN1/MYC2 but does not rely on salicylic acid-jasmonic acid antagonism. These experiments demonstrate the presence of highly orchestrated and tissue-specific MAMP responses in roots and potential pathogen-encoded mechanisms to block these MAMP-elicited signaling pathways.
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PMID:Innate immune responses activated in Arabidopsis roots by microbe-associated molecular patterns. 2034 32