The first two papers in this weeks Arabidopsis Research Roundup investigate different aspects of the plants response to temperature fluctuations. Firstly Lars Ostergaard (JIC) looks at the influence of temperature in the control of fruit dehiscence whilst Phil Wigge (SLCU) investigates crosstalk between chloroplast and nuclear signaling.
The third paper from Ian Henderson (University of Cambridge) studies the genetic elements that control rates of meiotic recombination. The next paper from the University of Leeds looks at the potential of using MET1 in the induction of novel epi-alleles whilst the penultimate paper includes the GARNet PI Jim Murray (Cardiff University) as a co-author and defines the role of CYCD7;1 in guard cell formation.
The final paper focusses on an enzyme involved in chlorophyll biosynthesis and includes Guy Hanke (QMUL) as a co-author.
Li XR, Deb J, Kumar SV, Østergaard L (2018) Temperature Modulates Tissue-Specification Program to Control Fruit Dehiscence in Brassicaceae. Molecular Plant doi: 10.1016/j.molp.2018.01.003 Open Access
Lars Ostergaard (John Innes Centre) is the corresponding author that continues his groups work on the function of the INDEHISCENT protein, on this occasion looking at its involvement in the link between temperature and fruit dehiscence. They show that fruit valve margin development is accelerated at higher temperatures, facilitated by the activity of IND. This activity is associated with the changes in the induction dynamics of the known thermosensory histone H2A.Z and demonstrate a molecular framework for the response to changing temperature during fruit ripening.
Dickinson PJ, Kumar M, Martinho C, Yoo SJ, Lan H, Artavanis G, Charoensawan V, Schöttler MA, Bock R, Jaeger KE, Wigge PA (2018) Chloroplast Signaling Gates Thermotolerance in Arabidopsis. Cell Rep. doi: 10.1016/j.celrep.2018.01.054 Open Access
Phil Wigge (SLCU) is the corresponding author on this study of the link between light-induced chloroplast signaling and thermotolerance. A forward genetic screen allowed the authors to identify two genes that demonstrated a key role for chloroplast signaling in controlling the activity of heat shock factors (HSFs), which enable the plant to cope with temperature variations. Subsequently they show that altering the binding activities of the HSFA1a protein can mimic heat shock response independent of any changes in temperature.
Serra H, Lambing C, Griffin CH, Topp SD, Nageswaran DC, Underwood CJ, Ziolkowski PA, Séguéla-Arnaud M, Fernandes JB,, Mercier R, Henderson IR (2018) Massive crossover elevation via combination of HEI10 and recq4a recq4b during Arabidopsis meiosis. PNAS doi: 10.1073/pnas.1713071115
Ian Henderson (University of Cambridge) is the corresponding author on this collaboration with French colleagues in a study that investigates the factors that control recombination frequency in meiosis. During normal meiotic recombination the majority of double stranded breaks will not form crossovers (over 90%) so to increase this frequency they altered the active dosage of genetic elements that are either pro-crossover or anti-crossover control. This strategy results in a massive increase in crossovers and provides a genetic framework for increasing recombination, a strategy that can be critically important for increasing variation during crop breeding.
Brocklehurst S, Watson M, Carr IM, Out S, Heidmann I, Meyer P (2018) Induction of epigenetic variation in Arabidopsis by over-expression of DNA METHYLTRANSFERASE1 (MET1). PLoS One. doi: 10.1371/journal.pone.0192170 Open Access
This study from the University of Leeds is led by Peter Meyer and investigates how overexpression of the METHYLTRANSFERASE1 (MET1) gene might generate novel epi-alleles that result in altered gene expression. This strategy indeed generated novel epi-alleles that increased expression at loci encoding TEs, non-coding RNAs and protein coding genes. Importantly any altered expression can be transmitted to the next generation, independent of the presence of a MET1 expressing transgene. However the long term stability of these epi-alleles differs in an loci-specific manner.
Weimer AK, Matos JL, Sharma N, Patell F, Murray JAH, Dewitte W, Bergmann DC (2018) Lineage and stage-specific expressed CYCD7;1 coordinates the single symmetric division that creates stomatal guard cells. Development. doi: 10.1242/dev.160671
GARNet PI Jim Murray and Walter DeWitte (Cardiff University) are co-authors on this US-led study that adds complexity to our understanding of the molecular players that control guard cell specification. The authors show that the D-type cyclin CYCD7;1 is expressed during a short time window prior to the symmetry division that forms two guard cells. This activity is controlled by cell-type specific transcription factors acting in the appropriate time period.
Herbst J, Girke A, Hajirezaei MR, Hanke G, Grimm B (2018) Potential Roles of YCF54 and Ferredoxin-NADPH Reductase for Magnesium Protoporphyrin Monomethylester Cyclase. Plant J. doi: 10.1111/tpj.13869
Guy Hanke (QMUL) is a co-author on this German-led study that investigates an enzyme reactions that occur during chlorophyll biosynthesis. Specifically they showed that plants lacking the LCAA/YCF54 subunit of the enzyme MgProto monomethylester (MgProtoME) cyclase causes accumulation of MgProtoME and destabilization of the entire cyclase enzyme. This disrupts chlorophyll synthesis and negatively effects photosynthetic activity.