TY - INPR ID - 2425 TI - Inhibition of jasmonate-mediated plant defences by the fungal metabolite higginsianin B JO - bioRxiv PY - 2019 SP - AU - Dallery, J.-F. AU - Zimmer, M. AU - Halder, V. AU - Suliman, M. AU - Pigné, S. AU - Le Goff, G. AU - Gianniou, D. D. AU - Trougakos, I. P. AU - Ouazzani, J. AU - Gasperini, D. AU - O’Connell, R. J. VL - UR - https://dx.doi.org/10.1101/651562 DO - 10.1101/651562 AB - Infection of Arabidopsis thaliana by the ascomycete fungus Colletotrichum higginsianum is characterised by an early symptomless biotrophic phase followed by a destructive necrotrophic phase. The fungal genome contains 77 secondary metabolism-related biosynthetic gene clusters (BGCs), and their expression during the infection process is tightly regulated. Deleting CclA, a chromatin regulator involved in repression of some BGCs through H3K4 trimethylation, allowed overproduction of 3 families of terpenoids and isolation of 12 different molecules. These natural products were tested in combination with methyl jasmonate (MeJA), an elicitor of jasmonate responses, for their capacity to alter defence gene induction in Arabidopsis. Higginsianin B inhibited MeJA-triggered expression of the defence reporter VSP1p:GUS, suggesting it may block bioactive JA-Ile synthesis or signalling in planta. Using the JA-Ile sensor Jas9-VENUS, we found that higginsianin B, but not three other structurally-related molecules, suppressed JA-Ile signalling by preventing degradation of JAZ proteins, the repressors of JA responses. Higginsianin B likely blocks the 26S proteasome-dependent degradation of JAZ proteins because it inhibited chymotrypsin- and caspase-like protease activities. The inhibition of target degradation by higginsianin B also extended to auxin signalling, as higginsianin B treatment reduced IAA-dependent expression of DR5p:GUS. Overall, our data indicate that specific fungal secondary metabolites can act similarly to protein effectors to subvert plant immune and developmental responses. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2325 TI - Shoot-to-root translocation of the jasmonate precursor 12-oxo-phytodienoic acid (OPDA) coordinates plant growth responses following tissue damage JO - bioRxiv PY - 2019 SP - AU - Schulze, A. AU - Zimmer, M. AU - Mielke, S. AU - Stellmach, H. AU - Melnyk, C. W. AU - Hause, B. AU - Gasperini, D. VL - UR - https://doi.org/10.1101/517193 DO - 10.1101/517193 AB - Multicellular organisms rely upon the movement of signaling molecules across cells, tissues and organs to communicate among distal sites. In plants, herbivorous insects, necrotrophic pathogens and mechanical wounding stimulate the activation of the jasmonate (JA) pathway, which in turn triggers the transcriptional changes necessary to protect plants against those challenges, often at the expense of growth. Although previous evidence indicated that JA species can translocate from damaged into distal sites, the identity of the mobile compound(s), the tissues through which they translocate and the consequences of their relocation remain unknown. Here, we demonstrated that endogenous JA species generated after shoot injury translocate to unharmed roots via the phloem vascular tissue in Arabidopsis thaliana. By wounding wild-type shoots of chimeric plants and by quantifying the relocating compounds from their JA-deficient roots, we uncovered that the JA-Ile precursor 12-oxo-phytodienoic acid (OPDA) is a mobile JA species. Our data also showed that OPDA is a primary mobile compound relocating to roots where, upon conversion to the bioactive hormone, it induces JA-mediated gene expression and root growth inhibition. Collectively, our findings reveal the existence of long-distance transport of endogenous OPDA which serves as a communication molecule to coordinate shoot-to-root responses, and highlight the importance of a controlled distribution of JA species among organs during plant stress acclimation. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - INPR ID - 2441 TI - Interplay between Plant Cell Walls and Jasmonate Production JO - Plant Cell Physiol PY - 2019 SP - AU - Mielke, S. AU - Gasperini, D. VL - UR - https://dx.doi.org/10.1093/pcp/pcz119 DO - 10.1093/pcp/pcz119 AB - Plant cell walls are sophisticated carbohydrate-rich structures representing the immediate contact surface with the extracellular environment, often serving as the first barrier against biotic and abiotic stresses. Notably, a variety of perturbations in plant cell walls result in upregulated jasmonate (JA) production, a phytohormone with essential roles in defense and growth responses. Hence, cell wall-derived signals can initiate intracellular JA-mediated responses and the elucidation of the underlying signaling pathways could provide novel insights into cell wall maintenance and remodeling, as well as advance our understanding on how is JA biosynthesis initiated. This Mini Review will describe current knowledge about cell wall-derived damage signals and their effects on JA biosynthesis, as well as provide future perspectives. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2427 TI - Wound-Induced Shoot-to-Root Relocation of JA-Ile Precursors Coordinates Arabidopsis Growth JO - Mol Plant PY - 2019 SP - 1383-1394 AU - Schulze, A. AU - Zimmer, M. AU - Mielke, S. AU - Stellmach, H. AU - Melnyk, C. W. AU - Hause, B. AU - Gasperini, D. VL - 12 UR - https://dx.doi.org/10.1016/j.molp.2019.05.013 DO - 10.1016/j.molp.2019.05.013 AB - Multicellular organisms rely on the movement of signaling molecules across cells, tissues, and organs to communicate among distal sites. In plants, localized leaf damage activates jasmonic acid (JA)-dependent transcriptional reprogramming in both harmed and unharmed tissues. Although it has been indicated that JA species can translocate from damaged into distal sites, the identity of the mobile compound(s), the tissues through which they translocate, and the effect of their relocation remain unknown. Here, we found that following shoot wounding, the relocation of endogenous jasmonates through the phloem is essential to initiate JA signaling and stunt growth in unharmed roots of Arabidopsis thaliana. By employing grafting experiments and hormone profiling, we uncovered that the hormone precursor cis-12-oxo-phytodienoic acid (OPDA) and its derivatives, but not the bioactive JA-Ile conjugate, translocate from wounded shoots into undamaged roots. Upon root relocation, the mobile precursors cooperatively regulated JA responses through their conversion into JA-Ile and JA signaling activation. Collectively, our findings demonstrate the existence of long-distance translocation of endogenous OPDA and its derivatives, which serve as mobile molecules to coordinate shoot-to-root responses, and highlight the importance of a controlled redistribution of hormone precursors among organs during plant stress acclimation. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 1961 TI - Cotyledon Wounding of Arabidopsis Seedlings. JO - Bio-protocol PY - 2016 SP - e1712 AU - Gasperini, D. AU - Acosta, I. F. and Farmer, E. E. VL - 6 (2) UR - http://www.bio-protocol.org/e1712 DO - 10.21769/BioProtoc.1712 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2019 TI - Agronomic assessment of the wheat semi-dwarfing gene Rht8 in contrasting nitrogen treatments and water regimes JO - Field Crop Res PY - 2016 SP - 150-160 AU - Kowalski, A. M. AU - Gooding, M. AU - Ferrante, A. AU - Slafer, G. A. AU - Orford, S. AU - Gasperini, D. AU - Griffiths, S. VL - 191 UR - http://www.sciencedirect.com/science/article/pii/S0378429016300521 DO - 10.1016/j.fcr.2016.02.026 AB - Reduced height 8 (Rht8) is the main alternative to the GA-insensitive Rht alleles in hot and dry environments where it reduces plant height without yield penalty. The potential of Rht8 in northern-European wheat breeding remains unclear, since the close linkage with the photoperiod-insensitive allele Ppd-D1a is unfavourable in the relatively cool summers. In the present study, two near-isogenic lines (NILs) contrasting for the Rht8/tall allele from Mara in a UK-adapted and photoperiod-sensitive wheat variety were evaluated in trials with varying nitrogen fertiliser (N) treatments and water regimes across sites in the UK and Spain.The Rht8 introgression was associated with a robust height reduction of 11% regardless of N treatment and water regime and the Rht8 NIL was more resistant to root-lodging at agronomically-relevant N levels than the tall NIL. In the UK with reduced solar radiation over the growing season than the site in Spain, the Rht8 NIL showed a 10% yield penalty at standard agronomic N levels due to concomitant reduction in grain number and spike number whereas grain weight and harvest index were not significantly different to the tall NIL. The yield penalty associated with the Rht8 introgression was overcome at low N and in irrigated conditions in the UK, and in the high-temperature site in Spain. Decreased spike length and constant spikelet number in the Rht8 NIL resulted in spike compaction of 15%, independent of N and water regime. The genetic interval of Rht8 overlaps with the compactum gene on 2DS, raising the possibility of the same causative gene. Further genetic dissection of these loci is required.Abbreviations ANOVA, analysis of variance; Y, yield; HI, harvest index; GN, grain number (m−2); SS, spikelet number (spike−1); SN, spike number (m−2); HD, heading date; AN, anthesis; 12L, length of the second internode from the top; 13L, length of the third internode from the top; PAR, photosynthetically active radiation; R: FR, red: far-red light reflectance ratio; RCBD, randomised complete block design A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1963 TI - Multilayered Organization of Jasmonate Signalling in the Regulation of Root Growth JO - PLoS Genet. PY - 2015 SP - e1005300 AU - Gasperini, D. AU - Chételat, A. AU - Acosta, I.F. AU - Goossens, J. AU - Pauwels, L. AU - Goossens, A. AU - Dreos, R. AU - Alonso, E. AU - Farmer, E.E. VL - 11 (6) UR - DO - 10.1371/journal.pgen.1005300 AB - Physical damage can strongly affect plant growth, reducing the biomass of developing organs situated at a distance from wounds. These effects, previously studied in leaves, require the activation of jasmonate (JA) signalling. Using a novel assay involving repetitive cotyledon wounding in Arabidopsis seedlings, we uncovered a function of JA in suppressing cell division and elongation in roots. Regulatory JA signalling components were then manipulated to delineate their relative impacts on root growth. The new transcription factor mutant myc2-322B was isolated. In vitro transcription assays and whole-plant approaches revealed that myc2-322B is a dosage-dependent gain-of-function mutant that can amplify JA growth responses. Moreover, myc2-322B displayed extreme hypersensitivity to JA that totally suppressed root elongation. The mutation weakly reduced root growth in undamaged plants but, when the upstream negative regulator NINJA was genetically removed, myc2-322B powerfully repressed root growth through its effects on cell division and cell elongation. Furthermore, in a JA-deficient mutant background, ninja1 myc2-322B still repressed root elongation, indicating that it is possible to generate JA-responses in the absence of JA. We show that NINJA forms a broadly expressed regulatory layer that is required to inhibit JA signalling in the apex of roots grown under basal conditions. By contrast, MYC2, MYC3 and MYC4 displayed cell layer-specific localisations and MYC3 and MYC4 were expressed in mutually exclusive regions. In nature, growing roots are likely subjected to constant mechanical stress during soil penetration that could lead to JA production and subsequent detrimental effects on growth. Our data reveal how distinct negative regulatory layers, including both NINJA-dependent and -independent mechanisms, restrain JA responses to allow normal root growth. Mechanistic insights from this work underline the importance of mapping JA signalling components to specific cell types in order to understand and potentially engineer the growth reduction that follows physical damage. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1962 TI - Axial and Radial Oxylipin Transport. JO - Plant Physiol. PY - 2015 SP - 2244-2254 AU - Gasperini, D. AU - Chauvin, A. AU - Acosta, I.F. AU - Kurenda, A. AU - Stolz, S. AU - Chétalat, A. AU - Wolfender J.-L. AU - Farmer, E.E. VL - 169 UR - DO - 10.1104/pp.15.01104 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1964 TI - The squeeze cell hypothesis for the activation of jasmonate synthesis in response to wounding JO - New Phytol. PY - 2014 SP - 282-288 AU - Farmer, E.E. AU - Gasperini, D. AU - Acosta, I.F. VL - 204 UR - DO - 10.1111/nph.12897 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1965 TI - Role of NINJA in root jasmonate signaling JO - PNAS PY - 2013 SP - 15473-15478 AU - Acosta, I.F. AU - Gasperini, D. AU - Chételat, A. AU - Stolz, S. AU - Santuari, L. AU - Farmer, E.E. VL - 110 (38) UR - DO - 10.1073/pnas.1307910110 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1966 TI - Genetic and physiological analysis of Rht8 in bread wheat: an alternative source of semi-dwarfism with a reduced sensitivity to brassinosteroids JO - J Exp Bot PY - 2012 SP - 4419-4436 AU - Gasperini, D. AU - Greenland, A. AU - Hedden, P. AU - Dreos, R. AU - Harwood, W. AU - Griffiths, S. VL - 63 UR - https://dx.doi.org/10.1093/jxb/ers138 DO - 10.1093/jxb/ers138 AB - Over the next decade, wheat grain production must increase to meet the demand of a fast growing human population. One strategy to meet this challenge is to raise wheat productivity by optimizing plant stature. The Reduced height 8 (Rht8) semi-dwarfing gene is one of the few, together with the Green Revolution genes, to reduce stature of wheat (Triticum aestivum L.), and improve lodging resistance, without compromising grain yield. Rht8 is widely used in dry environments such as Mediterranean countries where it increases plant adaptability. With recent climate change, its use could become increasingly important even in more northern latitudes. In the present study, the characterization of Rht8 was furthered. Morphological analyses show that the semi-dwarf phenotype of Rht8 lines is due to shorter internodal segments along the wheat culm, achieved through reduced cell elongation. Physiological experiments show that the reduced cell elongation is not due to defective gibberellin biosynthesis or signalling, but possibly to a reduced sensitivity to brassinosteroids. Using a fine-resolution mapping approach and screening 3104 F2 individuals of a newly developed mapping population, the Rht8 genetic interval was reduced from 20.5 cM to 1.29 cM. Comparative genomics with model genomes confined the Rht8 syntenic intervals to 3.3 Mb of the short arm of rice chromosome 4, and to 2 Mb of Brachypodium distachyon chromosome 5. The very high resolution potential of the plant material generated is crucial for the eventual cloning of Rht8. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1967 TI - S-RNase-like Sequences in Styles of Coffea (Rubiaceae). Evidence for S-RNase Based Gametophytic Self-Incompatibility? JO - Tropical Plant Biol. PY - 2011 SP - 237-249 AU - Asquini, E. AU - Gerdol, M. AU - Gasperini, D. AU - Igic, B. AU - Graziosi, G. AU - Pallavicini A. VL - 4 UR - DO - 10.1007/s12042-011-9085-2 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1960 TI - Differential responses of Coffea arabica L. leaves and roots to chemically induced systemic acquired resistance JO - Genome PY - 2006 SP - 1594-1605 AU - De Nardi, B. AU - Dreos, R. AU - Del Terra, L. AU - Martellossi, C. AU - Asquini, E. AU - Tornincasa, P. AU - Gasperini, D. AU - Pacchioni, B. AU - Rathinavelu, R. AU - Pallavicini, A. AU - Graziosi, G. VL - 49 UR - DO - 10.1139/g06-125 AB - A2 - C1 - Molecular Signal Processing ER -