zur Suche springenzur Navigation springenzum Inhalt springen

Publikationen - Molekulare Signalverarbeitung

Sortieren nach: Erscheinungsjahr Typ der Publikation

Zeige Ergebnisse 1 bis 2 von 2.

Publikation

Ziegler, J.; Schmidt, S.; Strehmel, N.; Scheel, D.; Abel, S.; Arabidopsis Transporter ABCG37/PDR9 contributes primarily highly oxygenated Coumarins to Root Exudation Sci. Rep. 7, 3704, (2017) DOI: 10.1038/s41598-017-03250-6

The chemical composition of root exudates strongly impacts the interactions of plants with microorganisms in the rhizosphere and the efficiency of nutrient acquisition. Exudation of metabolites is in part mediated by ATP-binding cassette (ABC) transporters. In order to assess the contribution of individual ABC transporters to root exudation, we performed an LC-MS based non-targeted metabolite profiling of semi-polar metabolites accumulating in root exudates of Arabidopsis thaliana plants and mutants deficient in the expression of ABCG36 (PDR8/PEN3), ABCG37 (PDR9) or both transporters. Comparison of the metabolite profiles indicated distinct roles for each ABC transporter in root exudation. Thymidine exudation could be attributed to ABCG36 function, whereas coumarin exudation was strongly reduced only in ABCG37 deficient plants. However, coumarin exudation was compromised in abcg37 mutants only with respect to certain metabolites of this substance class. The specificity of ABCG37 for individual coumarins was further verified by a targeted LC-MS based coumarin profiling method. The response to iron deficiency, which is known to strongly induce coumarin exudation, was also investigated. In either treatment, the distribution of individual coumarins between roots and exudates in the investigated genotypes suggested the involvement of ABCG37 in the exudation specifically of highly oxygenated rather than monohydroxylated coumarins.
Publikation

Flores, R.; Navarro, B.; Gago, S.; De la Peña, M.; Chrysanthemum Chlorotic Mottle Viroid: a System for Reverse Genetics in the Family Avsunviroidae (Hammerhead Viroids) Plant Viruses 1, 27-32, (2007)

Viroids are small single-stranded circular RNAs able to infect plants. Chrysanthemum chlorotic mottle was one of the first viroid diseases reported, but identification and characterization of the causing RNA was delayed by its low accumulation in vivo. Chrysanthemum chlorotic mottle viroid (CChMVd) (398-401 nt) adopts a branched conformation instead of the rod-like secondary structure characteristic of most viroids. The natural sequence variability and the effects of artificial mutants support that the branched conformation is physiologically relevant and additionally stabilized by a kissing-loop interaction critical for RNA in vitro folding and in vivo viability. CChMVd shares structural similarities with peach latent mosaic viroid, with which forms the genus Pelamoviroid within the family Avsunviroidae. CChMVd adopts hammerhead structures that catalyze self-cleavage of the oligomeric strands of both polarities resulting from replication through a symmetric rolling-circle mechanism. The two CChMVd hammerheads display peculiarities: the plus has an extra A close to the central conserved core, and the minus an unsually long helix II. There are non-symptomatic strains (CChMVd-NS) that protect against challenge inoculation with severe strains (CChMVd-S). Introduction by site-directed mutagenesis of one of the CChMVd-NS specific mutations (UUUC?GAAA) is sufficient to change the symptomatic phenotype into non-symptomatic without altering the viroid titer. This pathogenicity determinant maps at a tetraloop of the CChMVd branched conformation. Co-inoculations with typical CChMVd-S and -NS variants showed that the infected plants remain symptomless only when the latter was in more than a 100-fold excess, indicating the higher fitness of the S variant. RNA silencing could mediate the observed cross-protection.
IPB Mainnav Search