The phosphate transporters LjPT4 and MtPT4 mediate early root responses to phosphate status in non mycorrhizal roots

Arbuscular mycorrhizal (AM) symbiosis improves host plant phosphorous (P) status and elicits the expression of AM-inducible phosphate transporters (PTs) in arbuscule-containing cells, where they control arbuscule morphogenesis and P release. We confirmed such functions for LjPT4 in mycorrhizal Lotus japonicus. Promoter-GUS experiments showed LjPT4 transcription not only in arbusculated cells but also in root tips, in the absence of the fungus: here LjPT4 transcription profile depended on the phosphate level. In addition, quantitative RT-PCR confirmed the expression of Lotus and Medicago truncatula PT4 in the tips of non-mycorrhizal roots. Starting from these observations, we hypothesized that AM-inducible PTs may have a regulatory role in plant development, irrespective of the fungal presence. Firstly, we focused on root development responses to different phosphate treatments in both plants demonstrating that phosphate starvation induced a higher number of lateral roots. By contrast, Lotus PT4i plants and Medicago mtpt4 mutants did not show any differential response to phosphate levels, suggesting that PT4 genes affect early root branching. Phosphate starvation-induced genes and a key auxin receptor, MtTIR1, showed an impaired expression in mtpt4 plants. We suggest PT4 genes as novel components of the P-sensing machinery at the root tip level, independently of AM fungi

Native soils with their microbiotas elicit a state of alert in tomato plants

Several studies have investigated soil microbial biodiversity, but understanding of the mechanisms underlying plant responses to soil microbiota remains in its infancy. Here, we focused on tomato (Solanum lycopersicum), testing the hypothesis that plants grown on native soils display different responses to soil microbiotas. Using transcriptomics, proteomics, and biochemistry, we describe the responses of two tomato genotypes (susceptible or resistant to Fusarium oxysporum f. sp. lycopersici) grown on an artificial growth substrate and two native soils (conducive and suppressive to Fusarium). Native soils affected tomato responses by modulating pathways involved in responses to oxidative stress, phenol biosynthesis, lignin deposition, and innate immunity, particularly in the suppressive soil. In tomato plants grown on steam‐disinfected soils, total phenols and lignin decreased significantly. The inoculation of a mycorrhizal fungus partly rescued this response locally and systemically. Plants inoculated with the fungal pathogen showed reduced disease symptoms in the resistant genotype in both soils, but the susceptible genotype was partially protected from the pathogen only when grown on the suppressive soil. The ‘state of alert’ detected in tomatoes reveals novel mechanisms operating in plants in native soils and the soil microbiota appears to be one of the drivers of these plant responses

Lotus japonicus NOOT-BOP-COCH-LIKE1 is essential for nodule, nectary, leaf and flower development

[EN] The NOOT-BOP-COCH-LIKE (NBCL) genes are orthologs of Arabidopsis thaliana BLADE-ON-PETIOLE1/2. The NBCLs are developmental regulators essential for plant shaping, mainly through the regulation of organ boundaries, the promotion of lateral organ differentiation and the acquisition of organ identity. In addition to their roles in leaf, stipule and flower development, NBCLs are required for maintaining the identity of indeterminate nitrogen-fixing nodules with persistent meristems in legumes. In legumes forming determinate nodules, without persistent meristem, the roles of NBCL genes are not known. We thus investigated the role of Lotus japonicus NOOT-BOP-COCH-LIKE1 (LjNBCL1) in determinate nodule identity and studied its functions in aerial organ development using LORE1 insertional mutants and RNA interference-mediated silencing approaches. In Lotus, LjNBCL1 is involved in leaf patterning and participates in the regulation of axillary outgrowth. Wild-type Lotus leaves are composed of five leaflets and possess a pair of nectaries at the leaf axil. Legumes such as pea and Medicago have a pair of stipules, rather than nectaries, at the base of their leaves. In Ljnbcl1, nectary development is abolished, demonstrating that nectaries and stipules share a common evolutionary origin. In addition, ectopic roots arising from nodule vascular meristems and reorganization of the nodule vascular bundle vessels were observed on Ljnbcl1 nodules. This demonstrates that NBCL functions are conserved in both indeterminate and determinate nodules through the maintenance of nodule vascular bundle identity. In contrast to its role in floral patterning described in other plants, LjNBCL1 appears essential for the development of both secondary inflorescence meristem and floral meristem.This work was supported by the CNRS and by the grants ANR-14-CE19-0003 (NOOT) from the Agence National de la Recherche (ANR) to PR. This work has benefited from the facilities and expertise of the Servicio de Microscopia Electronica Universitat Politecnica de Valencia (Spain, http://www.upv.es/entidades/SME/) and of the IMAGIF Cell Biology Unit of the Gif campus (France, www.imagif.cnrs.fr) which is supported by the Conseil General de l'Essonne. The authors thank Dr Mathias Brault from the Institute of Plant Sciences Paris-Saclay (France) for providing the pFRN: RNAi plasmid, A. rhizogenes ARqua1 strain and control GUS:RNAi construction, and Dr Simona Radutoiu from the University of Aarhus (Denmark), for providing the Na-Borate/TRIZOL RNA extraction protocol. We are grateful to Dr Cristina Ferrandiz from the Instituto de Biologia Molecular y Celular de Plantas (Spain) for help in interpreting the identity of the meristems in the SEM pictures and Professor Frederique Guinel from the University of Wilfrid Laurier (Canada) for help in interpreting the identity of L. japonicus nodule vascular tissues. We thank Dr Julie Hofer from the University of Auckland (New Zealand), for manuscript revision and English language polishing.Magne, K.; George, J.; Berbel Tornero, A.; Broquet, B.; Madueño Albi, F.; Andersen, S.; Ratet, P. (2018). Lotus japonicus NOOT-BOP-COCH-LIKE1 is essential for nodule, nectary, leaf and flower development. The Plant Journal. 94(5):880-894. https://doi.org/10.1111/tpj.13905S880894945Aida, M., & Tasaka, M. (2006). Genetic control of shoot organ boundaries. Current Opinion in Plant Biology, 9(1), 72-77. doi:10.1016/j.pbi.2005.11.011Aida, M., & Tasaka, M. (2006). Morphogenesis and Patterning at the Organ Boundaries in the Higher Plant Shoot Apex. Plant Molecular Biology, 60(6), 915-928. doi:10.1007/s11103-005-2760-7Aida, M., Ishida, T., Fukaki, H., Fujisawa, H., & Tasaka, M. (1997). Genes involved in organ separation in Arabidopsis: an analysis of the cup-shaped cotyledon mutant. The Plant Cell, 9(6), 841-857. doi:10.1105/tpc.9.6.841AKASAKA, Y. (1998). Morphological Alterations and Root Nodule Formation inAgrobacterium rhizogenes-mediated Transgenic Hairy Roots of Peanut (Arachis hypogaeaL.). Annals of Botany, 81(2), 355-362. doi:10.1006/anbo.1997.0566Benlloch, R., Berbel, A., Ali, L., Gohari, G., Millán, T., & Madueño, F. (2015). Genetic control of inflorescence architecture in legumes. Frontiers in Plant Science, 6. doi:10.3389/fpls.2015.00543Berbel, A., Ferrándiz, C., Hecht, V., Dalmais, M., Lund, O. S., Sussmilch, F. C., … Madueño, F. (2012). VEGETATIVE1 is essential for development of the compound inflorescence in pea. Nature Communications, 3(1). doi:10.1038/ncomms1801Blázquez, M. A., Ferrándiz, C., Madueño, F., & Parcy, F. (2006). How Floral Meristems are Built. Plant Molecular Biology, 60(6), 855-870. doi:10.1007/s11103-006-0013-zBrown, S. M., Oparka, K. J., Sprent, J. I., & Walsh, K. B. (1995). Symplastic transport in soybean root nodules. Soil Biology and Biochemistry, 27(4-5), 387-399. doi:10.1016/0038-0717(95)98609-rChen, Y., Chen, W., Li, X., Jiang, H., Wu, P., Xia, K., … Wu, G. (2013). Knockdown of LjIPT3 influences nodule development in Lotus japonicus. Plant and Cell Physiology, 55(1), 183-193. doi:10.1093/pcp/pct171Cho, E., & Zambryski, P. C. (2011). ORGAN BOUNDARY1defines a gene expressed at the junction between the shoot apical meristem and lateral organs. Proceedings of the National Academy of Sciences, 108(5), 2154-2159. doi:10.1073/pnas.1018542108Couzigou, J.-M., & Ratet, P. (2015). NOOT-Dependent Control of Nodule Identity: Nodule Homeosis and Merirostem Perturbation. Biological Nitrogen Fixation, 487-498. doi:10.1002/9781119053095.ch49Couzigou, J.-M., Zhukov, V., Mondy, S., Abu el Heba, G., Cosson, V., Ellis, T. H. N., … Ratet, P. (2012). NODULE ROOT and COCHLEATA Maintain Nodule Development and Are Legume Orthologs of Arabidopsis BLADE-ON-PETIOLE Genes. The Plant Cell, 24(11), 4498-4510. doi:10.1105/tpc.112.103747Couzigou, J.-M., Magne, K., Mondy, S., Cosson, V., Clements, J., & Ratet, P. (2015). The legume NOOT-BOP-COCH-LIKE genes are conserved regulators of abscission, a major agronomical trait in cultivated crops. New Phytologist, 209(1), 228-240. doi:10.1111/nph.13634Czechowski, T., Stitt, M., Altmann, T., Udvardi, M. K., & Scheible, W.-R. (2005). Genome-Wide Identification and Testing of Superior Reference Genes for Transcript Normalization in Arabidopsis. Plant Physiology, 139(1), 5-17. doi:10.1104/pp.105.063743Dong, Z., Zhao, Z., Liu, C., Luo, J., Yang, J., Huang, W., … Luo, D. (2005). Floral Patterning in Lotus japonicus. Plant Physiology, 137(4), 1272-1282. doi:10.1104/pp.104.054288Ehrhardt, D., Atkinson, E., & Long. (1992). Depolarization of alfalfa root hair membrane potential by Rhizobium meliloti Nod factors. Science, 256(5059), 998-1000. doi:10.1126/science.10744524Feng, X., Zhao, Z., Tian, Z., Xu, S., Luo, Y., Cai, Z., … Luo, D. (2006). Control of petal shape and floral zygomorphy in Lotus japonicus. Proceedings of the National Academy of Sciences, 103(13), 4970-4975. doi:10.1073/pnas.0600681103Ferguson, B. J., & Reid, J. B. (2005). Cochleata: Getting to the Root of Legume Nodules. Plant and Cell Physiology, 46(9), 1583-1589. doi:10.1093/pcp/pci171Ferraioli, S., Tatè, R., Rogato, A., Chiurazzi, M., & Patriarca, E. J. (2004). Development of Ectopic Roots from Abortive Nodule Primordia. Molecular Plant-Microbe Interactions®, 17(10), 1043-1050. doi:10.1094/mpmi.2004.17.10.1043Franssen, H. J., Xiao, T. T., Kulikova, O., Wan, X., Bisseling, T., Scheres, B., & Heidstra, R. (2015). Root developmental programs shape the Medicago truncatula nodule meristem. Development, 142(17), 2941-2950. doi:10.1242/dev.120774Gonzalez-Rizzo, S., Crespi, M., & Frugier, F. (2006). The Medicago truncatula CRE1 Cytokinin Receptor Regulates Lateral Root Development and Early Symbiotic Interaction with Sinorhizobium meliloti. The Plant Cell, 18(10), 2680-2693. doi:10.1105/tpc.106.043778Gourion, B., Sulser, S., Frunzke, J., Francez-Charlot, A., Stiefel, P., Pessi, G., … Fischer, H.-M. (2009). The PhyR-σEcfGsignalling cascade is involved in stress response and symbiotic efficiency inBradyrhizobium japonicum. Molecular Microbiology, 73(2), 291-305. doi:10.1111/j.1365-2958.2009.06769.xGourlay, C. W., Hofer, J. M. I., & Ellis, T. H. N. (2000). Pea Compound Leaf Architecture Is Regulated by Interactions among the Genes UNIFOLIATA, COCHLEATA, AFILA, and TENDRIL-LESS. The Plant Cell, 12(8), 1279-1294. doi:10.1105/tpc.12.8.1279Guether, M., Balestrini, R., Hannah, M., He, J., Udvardi, M. K., & Bonfante, P. (2009). Genome-wide reprogramming of regulatory networks, transport, cell wall and membrane biogenesis during arbuscular mycorrhizal symbiosis in Lotus japonicus. New Phytologist, 182(1), 200-212. doi:10.1111/j.1469-8137.2008.02725.xGuinel, F. C. (2009). Getting around the legume nodule: I. The structure of the peripheral zone in four nodule types. Botany, 87(12), 1117-1138. doi:10.1139/b09-074Ha, C. M. (2003). The BLADE-ON-PETIOLE 1 gene controls leaf pattern formation through the modulation of meristematic activity in Arabidopsis. Development, 130(1), 161-172. doi:10.1242/dev.00196Ha, C. M., Jun, J. H., Nam, H. G., & Fletcher, J. C. (2004). BLADE-ON-PETIOLE1 Encodes a BTB/POZ Domain Protein Required for Leaf Morphogenesis in Arabidopsis thaliana. Plant and Cell Physiology, 45(10), 1361-1370. doi:10.1093/pcp/pch201Ha, C. M., Jun, J. H., Nam, H. G., & Fletcher, J. C. (2007). BLADE-ON-PETIOLE1 and 2 Control Arabidopsis Lateral Organ Fate through Regulation of LOB Domain and Adaxial-Abaxial Polarity Genes. The Plant Cell, 19(6), 1809-1825. doi:10.1105/tpc.107.051938Handberg, K., & Stougaard, J. (1992). Lotus japonicus, an autogamous, diploid legume species for classical and molecular genetics. The Plant Journal, 2(4), 487-496. doi:10.1111/j.1365-313x.1992.00487.xHepworth, S. R., & Pautot, V. A. (2015). Beyond the Divide: Boundaries for Patterning and Stem Cell Regulation in Plants. Frontiers in Plant Science, 6. doi:10.3389/fpls.2015.01052Hepworth, S. R., Zhang, Y., McKim, S., Li, X., & Haughn, G. W. (2005). BLADE-ON-PETIOLE–Dependent Signaling Controls Leaf and Floral Patterning in Arabidopsis. The Plant Cell, 17(5), 1434-1448. doi:10.1105/tpc.104.030536Hepworth, S. R., Klenz, J. E., & Haughn, G. W. (2005). UFO in the Arabidopsis inflorescence apex is required for floral-meristem identity and bract suppression. Planta, 223(4), 769-778. doi:10.1007/s00425-005-0138-3Hibara, K., Karim, M. R., Takada, S., Taoka, K., Furutani, M., Aida, M., & Tasaka, M. (2006). Arabidopsis CUP-SHAPED COTYLEDON3 Regulates Postembryonic Shoot Meristem and Organ Boundary Formation. The Plant Cell, 18(11), 2946-2957. doi:10.1105/tpc.106.045716Høgslund, N., Radutoiu, S., Krusell, L., Voroshilova, V., Hannah, M. A., Goffard, N., … Stougaard, J. (2009). Dissection of Symbiosis and Organ Development by Integrated Transcriptome Analysis of Lotus japonicus Mutant and Wild-Type Plants. PLoS ONE, 4(8), e6556. doi:10.1371/journal.pone.0006556JARVIS, B. D. W., PANKHURST, C. E., & PATEL, J. J. (1982). Rhizobium loti, a New Species of Legume Root Nodule Bacteria. International Journal of Systematic Bacteriology, 32(3), 378-380. doi:10.1099/00207713-32-3-378Karim, M. R., Hirota, A., Kwiatkowska, D., Tasaka, M., & Aida, M. (2009). A Role for Arabidopsis PUCHI in Floral Meristem Identity and Bract Suppression. The Plant Cell, 21(5), 1360-1372. doi:10.1105/tpc.109.067025Khan, M., Xu, M., Murmu, J., Tabb, P., Liu, Y., Storey, K., … Hepworth, S. R. (2011). Antagonistic Interaction of BLADE-ON-PETIOLE1 and 2 with BREVIPEDICELLUS and PENNYWISE Regulates Arabidopsis Inflorescence Architecture. Plant Physiology, 158(2), 946-960. doi:10.1104/pp.111.188573Koch, B., & Evans, H. J. (1966). Reduction of Acetylene to Ethylene by Soybean Root Nodules. Plant Physiology, 41(10), 1748-1750. doi:10.1104/pp.41.10.1748Krall, L., Wiedemann, U., Unsin, G., Weiss, S., Domke, N., & Baron, C. (2002). Detergent extraction identifies different VirB protein subassemblies of the type IV secretion machinery in the membranes of Agrobacterium tumefaciens. Proceedings of the National Academy of Sciences, 99(17), 11405-11410. doi:10.1073/pnas.172390699Kumagai, H., & Kouchi, H. (2003). Gene Silencing by Expression of Hairpin RNA in Lotus japonicus Roots and Root Nodules. Molecular Plant-Microbe Interactions®, 16(8), 663-668. doi:10.1094/mpmi.2003.16.8.663Levin, J. Z., & Meyerowitz, E. M. (1995). UFO: an Arabidopsis gene involved in both floral meristem and floral organ development. The Plant Cell, 7(5), 529-548. doi:10.1105/tpc.7.5.529Long, J., & Barton, M. K. (2000). Initiation of Axillary and Floral Meristems in Arabidopsis. Developmental Biology, 218(2), 341-353. doi:10.1006/dbio.1999.9572Małolepszy, A., Mun, T., Sandal, N., Gupta, V., Dubin, M., Urbański, D., … Andersen, S. U. (2016). The LORE 1 insertion mutant resource. The Plant Journal, 88(2), 306-317. doi:10.1111/tpj.13243McKim, S. M., Stenvik, G.-E., Butenko, M. A., Kristiansen, W., Cho, S. K., Hepworth, S. R., … Haughn, G. W. (2008). The BLADE-ON-PETIOLE genes are essential for abscission zone formation in Arabidopsis. Development, 135(8), 1537-1546. doi:10.1242/dev.012807Mun, T., Bachmann, A., Gupta, V., Stougaard, J., & Andersen, S. U. (2016). Lotus Base: An integrated information portal for the model legume Lotus japonicus. Scientific Reports, 6(1). doi:10.1038/srep39447Norberg, M. (2005). The BLADE ON PETIOLE genes act redundantly to control the growth and development of lateral organs. Development, 132(9), 2203-2213. doi:10.1242/dev.01815Okamoto, S., Yoro, E., Suzaki, T., & Kawaguchi, M. (2013). Hairy Root Transformation in Lotus japonicus. BIO-PROTOCOL, 3(12). doi:10.21769/bioprotoc.795Oldroyd, G. E. D. (2013). Speak, friend, and enter: signalling systems that promote beneficial symbiotic associations in plants. Nature Reviews Microbiology, 11(4), 252-263. doi:10.1038/nrmicro2990Oldroyd, G. E. D., & Downie, J. A. (2008). Coordinating Nodule Morphogenesis with Rhizobial Infection in Legumes. Annual Review of Plant Biology, 59(1), 519-546. doi:10.1146/annurev.arplant.59.032607.092839Pate, J. S., Gunning, B. E. S., & Briarty, L. G. (1969). Ultrastructure and functioning of the transport system of the leguminous root nodule. Planta, 85(1), 11-34. doi:10.1007/bf00387658Ping, J., Liu, Y., Sun, L., Zhao, M., Li, Y., She, M., … Ma, J. (2014). Dt2 Is a Gain-of-Function MADS-Domain Factor Gene That Specifies Semideterminacy in Soybean. The Plant Cell, 26(7), 2831-2842. doi:10.1105/tpc.114.126938Quandt, H.-J. (1993). Transgenic Root Nodules ofVicia hirsuta:A Fast and Efficient System for the Study of Gene Expression in Indeterminate-Type Nodules. Molecular Plant-Microbe Interactions, 6(6), 699. doi:10.1094/mpmi-6-699Roux, B., Rodde, N., Jardinaud, M.-F., Timmers, T., Sauviac, L., Cottret, L., … Gamas, P. (2014). An integrated analysis of plant and bacterial gene expression in symbiotic root nodules using laser-capture microdissection coupled to RNA sequencing. The Plant Journal, 77(6), 817-837. doi:10.1111/tpj.12442Schultz, E. A., & Haughn, G. W. (1991). LEAFY, a Homeotic Gene That Regulates Inflorescence Development in Arabidopsis. The Plant Cell, 771-781. doi:10.1105/tpc.3.8.771Sinharoy, S., & DasGupta, M. (2009). RNA Interference Highlights the Role of CCaMK in Dissemination of Endosymbionts in the Aeschynomeneae Legume Arachis. Molecular Plant-Microbe Interactions®, 22(11), 1466-1475. doi:10.1094/mpmi-22-11-1466Soltis, D. E., Soltis, P. S., Morgan, D. R., Swensen, S. M., Mullin, B. C., Dowd, J. M., & Martin, P. G. (1995). Chloroplast gene sequence data suggest a single origin of the predisposition for symbiotic nitrogen fixation in angiosperms. Proceedings of the National Academy of Sciences, 92(7), 2647-2651. doi:10.1073/pnas.92.7.2647Soyano, T., Kouchi, H., Hirota, A., & Hayashi, M. (2013). NODULE INCEPTION Directly Targets NF-Y Subunit Genes to Regulate Essential Processes of Root Nodule Development in Lotus japonicus. PLoS Genetics, 9(3), e1003352. doi:10.1371/journal.pgen.1003352Suzaki, T., Yoro, E., & Kawaguchi, M. (2015). Leguminous Plants: Inventors of Root Nodules to Accommodate Symbiotic Bacteria. International Review of Cell and Molecular Biology, 111-158. doi:10.1016/bs.ircmb.2015.01.004Takeda, S., Hanano, K., Kariya, A., Shimizu, S., Zhao, L., Matsui, M., … Aida, M. (2011). CUP-SHAPED COTYLEDON1 transcription factor activates the expression of LSH4 and LSH3, two members of the ALOG gene family, in shoot organ boundary cells. The Plant Journal, 66(6), 1066-1077. doi:10.1111/j.1365-313x.2011.04571.xTavakol, E., Okagaki, R., Verderio, G., Shariati J., V., Hussien, A., Bilgic, H., … Rossini, L. (2015). The Barley Uniculme4 Gene Encodes a BLADE-ON-PETIOLE-Like Protein That Controls Tillering and Leaf Patterning. Plant Physiology, 168(1), 164-174. doi:10.1104/pp.114.252882Udvardi, M., & Poole, P. S. (2013). Transport and Metabolism in Legume-Rhizobia Symbioses. Annual Review of Plant Biology, 64(1), 781-805. doi:10.1146/annurev-arplant-050312-120235Van de Velde, W., Guerra, J. C. P., Keyser, A. D., De Rycke, R., Rombauts, S., Maunoury, N., … Goormachtig, S. (2006). Aging in Legume Symbiosis. A Molecular View on Nodule Senescence in Medicago truncatula. Plant Physiology, 141(2), 711-720. doi:10.1104/pp.106.078691Verdier, J., Torres-Jerez, I., Wang, M., Andriankaja, A., Allen, S. N., He, J., … Udvardi, M. K. (2013). Establishment of theLotus japonicusGene Expression Atlas (LjGEA) and its use to explore legume seed maturation. The Plant Journal, 74(2), 351-362. doi:10.1111/tpj.12119WALSH, K. B., McCULLY, M. E., & CANNY, M. J. (1989). Vascular transport and soybean nodule function: nodule xylem is a blind alley, not a throughway. Plant, Cell and Environment, 12(4), 395-405. doi:10.1111/j.1365-3040.1989.tb01955.xWang, Q., Hasson, A., Rossmann, S., & Theres, K. (2015). Divide et impera : boundaries shape the plant body and initiate new meristems. New Phytologist, 209(2), 485-498. doi:10.1111/nph.13641Weng, L., Tian, Z., Feng, X., Li, X., Xu, S., Hu, X., … Yang, J. (2011). Petal Development in Lotus japonicus. Journal of Integrative Plant Biology, 53(10), 770-782. doi:10.1111/j.1744-7909.2011.01072.xWerner, G. D. A., Cornwell, W. K., Sprent, J. I., Kattge, J., & Kiers, E. T. (2014). A single evolutionary innovation drives the deep evolution of symbiotic N2-fixation in angiosperms. Nature Communications, 5(1). doi:10.1038/ncomms5087Wopereis, J., Pajuelo, E., Dazzo, F. B., Jiang, Q., Gresshoff, P. M., de Bruijn, F. J., … Szczyglowski, K. (2000). Short root mutant of Lotus japonicus with a dramatically altered symbiotic phenotype. The Plant Journal, 23(1), 97-114. doi:10.1046/j.1365-313x.2000.00799.xWu, X.-M., Yu, Y., Han, L.-B., Li, C.-L., Wang, H.-Y., Zhong, N.-Q., … Xia, G.-X. (2012). The Tobacco BLADE-ON-PETIOLE2 Gene Mediates Differentiation of the Corolla Abscission Zone by Controlling Longitudinal Cell Expansion. Plant Physiology, 159(2), 835-850. doi:10.1104/pp.112.193482Xu, M., Hu, T., McKim, S. M., Murmu, J., Haughn, G. W., & Hepworth, S. R. (2010). Arabidopsis BLADE-ON-PETIOLE1 and 2 promote floral meristem fate and determinacy in a previously undefined pathway targeting APETALA1 and AGAMOUS-LIKE24. The Plant Journal, 63(6), 974-989. doi:10.1111/j.1365-313x.2010.04299.xXu, C., Park, S. J., Van Eck, J., & Lippman, Z. B. (2016). Control of inflorescence architecture in tomato by BTB/POZ transcriptional regulators. Genes & Development, 30(18), 2048-2061. doi:10.1101/gad.288415.116Yaxley, J. (2001). Leaf and Flower Development in Pea (Pisum sativum L.): Mutants cochleata andunifoliata. Annals of Botany, 88(2), 225-234. doi:10.1006/anbo.2001.1448Žádníková, P., & Simon, R. (2014). How boundaries control plant development. Current Opinion in Plant Biology, 17, 116-125. doi:10.1016/j.pbi.2013.11.013Zhang, S., Sandal, N., Polowick, P. L., Stiller, J., Stougaard, J., & Fobert, P. R. (2003). Proliferating Floral Organs (Pfo ), a Lotus japonicus gene required for specifying floral meristem determinacy and organ identity, encodes an F-box protein. The Plant Journal, 33(4), 607-619. doi:10.1046/j.1365-313x.2003.01660.

Hormonal and transcriptional profiles highlight common and differential host responses to arbuscular mycorrhizal fungi and the regulation of the oxylipin pathway

Arbuscular mycorrhizal (AM) symbioses are mutualistic associations between soil fungi and most vascular plants. The symbiosis significantly affects the host physiology in terms of nutrition and stress resistance. Despite the lack of host range specificity of the interaction, functional diversity between AM fungal species exists. The interaction is finely regulated according to plant and fungal characters, and plant hormones are believed to orchestrate the modifications in the host plant. Using tomato as a model, an integrative analysis of the host response to different mycorrhizal fungi was performed combining multiple hormone determination and transcriptional profiling. Analysis of ethylene-, abscisic acid-, salicylic acid-, and jasmonate-related compounds evidenced common and divergent responses of tomato roots to Glomus mosseae and Glomus intraradices, two fungi differing in their colonization abilities and impact on the host. Both hormonal and transcriptional analyses revealed, among others, regulation of the oxylipin pathway during the AM symbiosis and point to a key regulatory role for jasmonates. In addition, the results suggest that specific responses to particular fungi underlie the differential impact of individual AM fungi on plant physiology, and particularly on its ability to cope with biotic stresses

Genome-wide identification, classification and transcriptional analysis of nitrate and ammonium transporters in Coffea

Abstract Nitrogen (N) is quantitatively the main nutrient required by coffee plants, with acquisition mainly by the roots and mostly exported to coffee beans. Nitrate (NO3–) and ammonium (NH4+) are the most important inorganic sources for N uptake. Several N transporters encoded by different gene families mediate the uptake of these compounds. They have an important role in source preference for N uptake in the root system. In this study, we performed a genome-wide analysis, including in silico expression and phylogenetic analyses of AMT1, AMT2, NRT1/PTR, and NRT2 transporters in the recently sequenced Coffea canephora genome. We analyzed the expression of six selected transporters in Coffea arabica roots submitted to N deficiency. N source preference was also analyzed in C. arabica using isotopes. C. canephora N transporters follow the patterns observed for most eudicots, where each member of the AMT and NRT families has a particular role in N mobilization, and where some of these are modulated by N deficiency. Despite the prevalence of putative nitrate transporters in the Coffea genome, ammonium was the preferential inorganic N source for N-starved C. arabica roots. This data provides an important basis for fundamental and applied studies to depict molecular mechanisms involved in N uptake in coffee trees