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Publikationen - Molekulare Signalverarbeitung

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Publikation

Costa, C. T.; Strieder, M. L.; Abel, S.; Delatorre, C. A.; Phosphorus and nitrogen interaction: loss of QC identity in response to P or N limitation is antecipated in pdr23 mutant Braz. J. Plant Physiol. 23, 219-229, (2011) DOI: 10.1590/S1677-04202011000300006

Changes in root architecture are an important adaptive strategy used by plants in response to limited nutrient availability to increase the odds of acquiring them. The quiescent center (QC) plays an important role by altering the meristem activity causing differentiation and therefore, inducing a determinate growth program. The arabidopsis mutant pdr23 presents primary short root in the presence of nitrate and is inefficient in the use of nucleic acids as a source of phosphorus. In this study the effect of the pdr23 mutation on the QC maintenance under low phosphorus (P) and/or nitrogen is evaluated. QC identity is maintained in wild-type in the absence of nitrate and/or phosphate if nucleic acids can be used as an alternative source of these nutrients, but not in pdr23. The mutant is not able to use nucleic acids efficiently for substitute Pi, determinate growth is observed, similar to wild-type in the total absence of P. In the absence of N pdr23 loses the expression of QC identity marker earlier than wild-type, indicating that not only the response to P is altered, but also to N. The data suggest that the mutation affects a gene involved either in the crosstalk between these nutrients or in a pathway shared by both nutrients limitation response. Moreover loss of QC identity is also observed in wild-type in the absence of N at longer limitation. Less drastic symptoms are observed in lateral roots of both genotypes.
Publikation

Asquini, E.; Gerdol, M.; Gasperini, D.; Igic, B.; Graziosi, G.; Pallavicini, A.; S-RNase-like Sequences in Styles of Coffea (Rubiaceae). Evidence for S-RNase Based Gametophytic Self-Incompatibility? Trop. Plant Biol. 4, 237-249, (2011) DOI: 10.1007/s12042-011-9085-2

Although RNase-based self-incompatibility (SI) is suspected to operate in a wide group of plant families, it has been characterized as the molecular genetic basis of SI in only three distantly related families, Solanaceae, Plantaginaceae, and Rosaceae, all described over a decade ago. Previous studies found that gametophytic SI, controlled by a multi-allelic S-locus, operates in the coffee family (Rubiaceae). The molecular genetic basis of this mechanism remains unknown, despite the immense importance of coffee as an agricultural commodity. Here, we isolated ten sequences with features of T2-S-type RNases from two Coffea species. While three of the sequences were identified in both species and clearly do not appear to be S-locus products, our data suggest that six sequences may be S-alleles in the self-incompatible C. canephora, and one may be a relict in the self-compatible C. arabica. We demonstrate that these sequences show style-specific expression, display polymorphism in C. canephora, and cluster with S-locus products in a phylogenetic analysis that includes other plant families with RNase-based SI. Although our results are not definitive, in part because the available plant materials were limited and data patterns relatively complex, our results strongly hint that RNase-based SI mechanism operates in the Rubiaceae family.
Publikation

Abel, S.; Phosphate sensing in root development Curr. Opin. Plant Biol. 14, 303-309, (2011) DOI: 10.1016/j.pbi.2011.04.007

Phosphate (Pi) and its anhydrides constitute major nodes in metabolism. Thus, plant performance depends directly on Pi nutrition. Inadequate Pi availability in the rhizosphere is a common challenge to plants, which activate metabolic and developmental responses to maximize Pi usage and acquisition. The sensory mechanisms that monitor environmental Pi and transmit the nutritional signal to adjust root development have increasingly come into focus. Recent transcriptomic analyses and genetic approaches have highlighted complex antagonistic interactions between external Pi and Fe bioavailability and have implicated the stem cell niche as a target of Pi sensing to regulate root meristem activity.
Publikation

Kopycki, J.; Schmidt, J.; Abel, S.; Grubb, C. D.; Chemoenzymatic synthesis of diverse thiohydroximates from glucosinolate-utilizing enzymes from Helix pomatia and Caldicellulosiruptor saccharolyticus Biotechnol. Lett. 33, 1039-1046, (2011) DOI: 10.1007/s10529-011-0530-y

Thiohydroximates comprise a diverse class of compounds important in both biological and industrial chemistry. Their syntheses are generally limited to simple alkyl and aryl compounds with few stereocenters and a narrow range of functional groups. We hypothesized that sequential action of two recombinant enzymes, a sulfatase from Helix pomatia and a β-O-glucosidase from Caldicellulosiruptor saccharolyticus, on glucosinolates would allow synthesis of thiohydroximates from a structurally broad array of abundant precursors. We report successful synthesis of thiohydroximates of varied chemical classes, including from homochiral compounds of demonstrated biological activity. The chemoenzymatic synthetic route reported here should allow access to many, if not all, of the thiohydroximate core structures of the ~200 known naturally occurring glucosinolates. The enrichment of this group for compounds with possible pharmacological potential is discussed.
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