Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
Geu-Flores, F.; Møldrup, M. E.; Böttcher, C.; Olsen, C. E.; Scheel, D.; Halkier, B. A.;Cytosolic γ-Glutamyl Peptidases Process Glutathione Conjugates in the Biosynthesis of Glucosinolates and Camalexin in ArabidopsisPlant Cell232456-2469(2011)DOI: 10.1105/tpc.111.083998
The defense-related plant metabolites known as glucosinolates play important roles in agriculture, ecology, and human health. Despite an advanced biochemical understanding of the glucosinolate pathway, the source of the reduced sulfur atom in the core glucosinolate structure remains unknown. Recent evidence has pointed toward GSH, which would require further involvement of a GSH conjugate processing enzyme. In this article, we show that an Arabidopsis thaliana mutant impaired in the production of the γ-glutamyl peptidases GGP1 and GGP3 has altered glucosinolate levels and accumulates up to 10 related GSH conjugates. We also show that the double mutant is impaired in the production of camalexin and accumulates high amounts of the camalexin intermediate GS-IAN upon induction. In addition, we demonstrate that the cellular and subcellular localization of GGP1 and GGP3 matches that of known glucosinolate and camalexin enzymes. Finally, we show that the purified recombinant GGPs can metabolize at least nine of the 10 glucosinolate-related GSH conjugates as well as GS-IAN. Our results demonstrate that GSH is the sulfur donor in the biosynthesis of glucosinolates and establish an in vivo function for the only known cytosolic plant γ-glutamyl peptidases, namely, the processing of GSH conjugates in the glucosinolate and camalexin pathways.
Publikation
Helber, N.; Wippel, K.; Sauer, N.; Schaarschmidt, S.; Hause, B.; Requena, N.;A Versatile Monosaccharide Transporter That Operates in the Arbuscular Mycorrhizal Fungus Glomus sp Is Crucial for the Symbiotic Relationship with PlantsPlant Cell233812-3823(2011)DOI: 10.1105/tpc.111.089813
For more than 400 million years, plants have maintained a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi. This evolutionary success can be traced to the role of these fungi in providing plants with mineral nutrients, particularly phosphate. In return, photosynthates are given to the fungus, which support its obligate biotrophic lifestyle. Although the mechanisms involved in phosphate transfer have been extensively studied, less is known about the reciprocal transfer of carbon. Here, we present the high-affinity Monosaccharide Transporter2 (MST2) from Glomus sp with a broad substrate spectrum that functions at several symbiotic root locations. Plant cell wall sugars can efficiently outcompete the Glc uptake capacity of MST2, suggesting they can serve as alternative carbon sources. MST2 expression closely correlates with that of the mycorrhiza-specific PhosphateTransporter4 (PT4). Furthermore, reduction of MST2 expression using host-induced gene silencing resulted in impaired mycorrhiza formation, malformed arbuscules, and reduced PT4 expression. These findings highlight the symbiotic role of MST2 and support the hypothesis that the exchange of carbon for phosphate is tightly linked. Unexpectedly, we found that the external mycelium of AM fungi is able to take up sugars in a proton-dependent manner. These results imply that the sugar uptake system operating in this symbiosis is more complex than previously anticipated.