Publikation
Ibañez, C.; Poeschl, Y.; Peterson, T.; Bellstädt, J.; Denk, K.; Gogol-Döring, A.; Quint, M.; Delker, C. Ambient temperature and genotype differentially affect developmental and phenotypic plasticity in Arabidopsis thaliana BMC Plant Biol 17, 114, (2017) DOI: 10.1186/s12870-017-1068-5
BackgroundGlobal increase in ambient temperatures
constitute a significant challenge to wild and cultivated plant species.
Forward genetic analyses of individual temperature-responsive traits
have resulted in the identification of several signaling and response
components. However, a comprehensive knowledge about temperature
sensitivity of different developmental stages and the contribution of
natural variation is still scarce and fragmented at best.ResultsHere, we
systematically analyze thermomorphogenesis throughout a complete life
cycle in ten natural Arabidopsis thaliana accessions grown under long
day conditions in four different temperatures ranging from 16 to 28 °C.
We used Q10, GxE, phenotypic divergence and correlation analyses to
assess temperature sensitivity and genotype effects of more than 30
morphometric and developmental traits representing five phenotype
classes. We found that genotype and temperature differentially affected
plant growth and development with variing strengths. Furthermore,
overall correlations among phenotypic temperature responses was
relatively low which seems to be caused by differential capacities for
temperature adaptations of individual
accessions.ConclusionGenotype-specific temperature responses may be
attractive targets for future forward genetic approaches and
accession-specific thermomorphogenesis maps may aid the assessment of
functional relevance of known and novel regulatory components.
Publikation
Drost, H.-G.; Bellstädt, J.; Ó'Maoiléidigh, D. S.; Silva, A. T.; Gabel, A.; Weinholdt, C.; Ryan, P. T.; Dekkers, B. J. W.; Bentsink, L.; Hilhorst, H. W. M.; Ligterink, W.; Wellmer, F.; Grosse, I.; Quint, M. Post-embryonic Hourglass Patterns Mark Ontogenetic Transitions in Plant Development Mol Biol Evol 33, 1158-1163, (2016) DOI: 10.1093/molbev/msw039
The historic developmental hourglass concept depicts the convergence of animal embryos to a common form during the phylotypic period. Recently, it has been shown that a transcriptomic hourglass is associated with this morphological pattern, consistent with the idea of underlying selective constraints due to intense molecular interactions during body plan establishment. Although plants do not exhibit a morphological hourglass during embryogenesis, a transcriptomic hourglass has nevertheless been identified in the model plant Arabidopsis thaliana. Here, we investigated whether plant hourglass patterns are also found postembryonically. We found that the two main phase changes during the life cycle of Arabidopsis, from embryonic to vegetative and from vegetative to reproductive development, are associated with transcriptomic hourglass patterns. In contrast, flower development, a process dominated by organ formation, is not. This suggests that plant hourglass patterns are decoupled from organogenesis and body plan establishment. Instead, they may reflect general transitions through organizational checkpoints.
Publikation
Hoehenwarter, W.; Mönchgesang, S.; Neumann, S.; Majovsky, P.; Abel, S.; Müller, J. Comparative expression profiling reveals a role of the root apoplast in local phosphate response BMC Plant Biol 16 , 106, (2016) DOI: 10.1186/s12870-016-0790-8
BackgroundPlant adaptation to limited phosphate availability
comprises a wide range of responses to conserve and remobilize internal
phosphate sources and to enhance phosphate acquisition. Vigorous
restructuring of root system architecture provides a developmental
strategy for topsoil exploration and phosphate scavenging. Changes in
external phosphate availability are locally sensed at root tips and
adjust root growth by modulating cell expansion and cell division. The
functionally interacting Arabidopsis genes, LOW PHOSPHATE RESPONSE 1 and
2 (LPR1/LPR2) and PHOSPHATE DEFICIENCY RESPONSE 2 (PDR2), are key
components of root phosphate sensing. We recently demonstrated that the
LOW PHOSPHATE RESPONSE 1 - PHOSPHATE DEFICIENCY RESPONSE 2 (LPR1-PDR2)
module mediates apoplastic deposition of ferric iron (Fe3+) in the
growing root tip during phosphate limitation. Iron deposition coincides
with sites of reactive oxygen species generation and triggers cell wall
thickening and callose accumulation, which interfere with cell-to-cell
communication and inhibit root growth.ResultsWe took advantage of
the opposite phosphate-conditional root phenotype of the phosphate
deficiency response 2 mutant (hypersensitive) and low phosphate response
1 and 2 double mutant (insensitive) to investigate the phosphate
dependent regulation of gene and protein expression in roots using
genome-wide transcriptome and proteome analysis. We observed an
overrepresentation of genes and proteins that are involved in the
regulation of iron homeostasis, cell wall remodeling and reactive oxygen
species formation, and we highlight a number of candidate genes with a
potential function in root adaptation to limited phosphate availability.
Our experiments reveal that FERRIC REDUCTASE DEFECTIVE 3 mediated,
apoplastic iron redistribution, but not intracellular iron uptake and
iron storage, triggers phosphate-dependent root growth modulation. We
further highlight expressional changes of several cell wall-modifying
enzymes and provide evidence for adjustment of the pectin network at
sites of iron accumulation in the root.ConclusionOur study
reveals new aspects of the elaborate interplay between phosphate
starvation responses and changes in iron homeostasis. The results
emphasize the importance of apoplastic iron redistribution to mediate
phosphate-dependent root growth adjustment and suggest an important role
for citrate in phosphate-dependent apoplastic iron transport. We
further demonstrate that root growth modulation correlates with an
altered expression of cell wall modifying enzymes and changes in the
pectin network of the phosphate-deprived root tip, supporting the
hypothesis that pectins are involved in iron binding and/or phosphate
mobilization.
Publikation
Müller, J.; Toev, T.; Heisters, M.; Teller, J.; Moore, K. L.; Hause, G.; Dinesh, D. C.; Bürstenbinder, K.; Abel, S. Iron-Dependent Callose Deposition Adjusts Root Meristem Maintenance to Phosphate Availability Devel Cell 33, 216–230, (2015) DOI: 10.1016/j.devcel.2015.02.007
Plant root development is informed by numerous edaphic cues. Phosphate (Pi) availability impacts the root system architecture by adjusting meristem activity. However, the sensory mechanisms monitoring external Pi status are elusive. Two functionally interacting Arabidopsis genes, LPR1 (ferroxidase) and PDR2 (P5-type ATPase), are key players in root Pi sensing, which is modified by iron (Fe) availability. We show that the LPR1-PDR2 module facilitates, upon Pi limitation, cell-specific apoplastic Fe and callose deposition in the meristem and elongation zone of primary roots. Expression of cell-wall-targeted LPR1 determines the sites of Fe accumulation as well as callose production, which interferes with symplastic communication in the stem cell niche, as demonstrated by impaired SHORT-ROOT movement. Antagonistic interactions of Pi and Fe availability control primary root growth via meristem-specific callose formation, likely triggered by LPR1-dependent redox signaling. Our results link callose-regulated cell-to-cell signaling in root meristems to the perception of an abiotic cue
Publikation
Drost, H.-G.; Gabel, A.; Grosse, I.; Quint, M. Evidence for Active Maintenance of Phylotranscriptomic Hourglass Patterns in Animal and Plant Embryogenesis Mol Biol Evol 32, 1221-1231, (2015) DOI: 10.1093/molbev/msv012
The developmental hourglass model has been used to describe the morphological transitions of related species throughout embryogenesis. Recently, quantifiable approaches combining transcriptomic and evolutionary information provided novel evidence for the presence of a phylotranscriptomic hourglass pattern across kingdoms. As its biological function is unknown it remains speculative whether this pattern is functional or merely represents a nonfunctional evolutionary relic. The latter would seriously hamper future experimental approaches designed to test hypotheses regarding its function. Here, we address this question by generating transcriptome divergence index (TDI) profiles across embryogenesis of Danio rerio, Drosophila melanogaster, and Arabidopsis thaliana. To enable meaningful evaluation of the resulting patterns, we develop a statistical test that specifically assesses potential hourglass patterns. Based on this objective measure we find that two of these profiles follow a statistically significant hourglass pattern with the most conserved transcriptomes in the phylotypic periods. As the TDI considers only recent evolutionary signals, this indicates that the phylotranscriptomic hourglass pattern is not a rudiment but possibly actively maintained, implicating the existence of some linked biological function associated with embryogenesis in extant species.
Publikation
De Nardi, B.; Dreos, R.; Del Terra, L.; Martellossi, C.; Asquini, E.; Tornincasa, P.; Gasperini, D.; Pacchioni, B.; Rathinavelu, R.; Pallavicini, A.; Graziosi, G. Differential responses of Coffea arabica L. leaves and roots to chemically induced systemic acquired resistance Genome 49, 1594-1605, (2006) DOI: 10.1139/g06-125
Coffea arabica is susceptible to several pests
and diseases, some of which affect the leaves and roots. Systemic
acquired resistance (SAR) is the main defence mechanism activated in
plants in response to pathogen attack. Here, we report the effects of
benzo(1,2,3)thiadiazole-7-carbothioic acid-s-methyl ester (BTH), a SAR
chemical inducer, on the expression profile of C. arabica. Two cDNA
libraries were constructed from the mRNA isolated from leaves and
embryonic roots to create 1587 nonredundant expressed sequence tags
(ESTs). We developed a cDNA microarray containing 1506 ESTs from the
leaves and embryonic roots, and 48 NBS-LRR (nucleotide-binding site
leucine-rich repeat) gene fragments derived from 2 specific genomic
libraries. Competitive hybridization between untreated and BTH-treated
leaves resulted in 55 genes that were significantly overexpressed and 16
genes that were significantly underexpressed. In the roots, 37 and 42
genes were over and underexpressed, respectively. A general shift in
metabolism from housekeeping to defence occurred in the leaves and roots
after BTH treatment. We observed a systemic increase in
pathogenesis-related protein synthesis, in the oxidative burst, and in
the cell wall strengthening processes. Moreover, responses in the roots
and leaves varied significantly.