Identification of ovule and seed genes from Citrus clementina

[EN] Seedlessness is a highly desirable trait in fresh fruit. Citrus varieties, such as Clementine mandarin and other related species, show parthenocarpic fruit development without seeds due to self-incompatibility. In spite of that, these fruits frequently contain seeds as a result of cross-pollination by insects with compatible pollen from other citrus cultivars grown nearby. To solve this problem using a biotechnological approach we aim at the destruction of ovules and/or seeds by directing the expression of a toxic gene using the promoter of an ovule and/or seed specific gene. With the purpose of isolating this kind of genes we constructed two cDNA libraries from ovules and seeds at different developmental stages of the Clementine mandarin (Citrus clementina cv. Clemenules). A total of 1,014 ESTs from the ovule library and 1,042 ESTs from the seed library were generated, with a novelty percentage of 27% and 36% among the Spanish Citrus Functional Genomic Project (CFGP) ESTs database, respectively. Quantitative PCR analysis confirmed nearly specific expression in ovule and/or seed of two genes, TRANSPARENT TESTA16 (CcTT16) and TRANSPARENT TESTA7 (CcTT7). Expression of these two genes is restricted to early seed development, and is localized in the embryo sac and endothelium. The promoters of those genes may be useful to genetically engineer citrus species to avoid seed formation in fruits of commercial varieties.The authors thank Dr. L. Navarro and J. Juarez, from the Instituto Valenciano de Investigaciones Agrarias (Generalitat Valenciana), for the use of the Clementine orchard and Fortune pollen; Dr. J Forment and the Genomics Facility at the IBMCP for sequence analysis and maintenance of to the CFGP database; and Drs. F Tadeo and J Carbonell for critical reading of the manuscript. This work was supported by grants from the Conselleria de Agricultura, Pesca y Alimentacion (Generalitat Valenciana) and Spanish Ministerio de Ciencia y Tecnologia (research grant GEN2001-4885-C05). A.G-L. received a PhD fellowship from the Conselleria de Agricultura, Pesca y Alimentacion.García Lor, A.; Garcia Martinez, JL.; Perez Amador, MA. (2012). Identification of ovule and seed genes from Citrus clementina. Tree Genetics and Genomes. 8(2):227-235. doi:10.1007/s11295-011-0435-xS22723582Al-Shahrour F, Diaz-Uriarte R, Dopazo J (2005) Discovering molecular functions significantly related to phenotypes by combining gene expression data and biological information. Bioinformatics 21:2988–2993Al-Shahrour F, Minguez P, Tarraga J, Montaner D, Alloza E, Vaquerizas JMM, Conde L, Blaschke C, Vera J, Dopazo J (2006) BABELOMICS: a systems biology perspective in the functional annotation of genome-scale experiments. 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On the way to ovules: The hormonal regulation of ovule development

[EN] This review focuses on the hormonal regulation of ovule development, especially on ovule initiation, patterning, and morphogenesis. Understanding of the genetic and molecular basis of ovule development is essential from both the scientific and economic perspective. The ovule represents an attractive system to study lateral organ development in plants, and, since ovules are the precursors of seeds, full comprehension of this process can be the key to the improvement of crops, especially those depending on high production of seeds and grains. Ovule initiation, patterning, and morphogenesis are governed by complex genetic and hormonal networks involving auxins, cytokinins, brassinosteroids, and gibberellins. These coordinate the determination of the ovule number, size, and shape through the regulation of the number of ovule primordia that arise from the placenta and/or ensuring their correct development into mature functional ovules. Here we summarize the current knowledge of how ovules are formed, paying special attention to the roles of these four plant hormones.This work was supported by the Spanish Ministry for Science and Innovation-FEDER under [grant BIO2017-83138R].Barro-Trastoy, D.; Gómez, MD.; Tornero Feliciano, P.; Perez Amador, MA. (2020). On the way to ovules: The hormonal regulation of ovule development. Critical Reviews in Plant Sciences. 39(5):431-456. https://doi.org/10.1080/07352689.2020.1820203S431456395Aida, 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., 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.9.6.841Armenta-Medina, A., & Gillmor, C. S. (2019). 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Gibberellins Regulate Ovule Integument Development by Interfering with the Transcription Factor ATS

[EN] Gibberellins (GAs) are plant hormones that regulate most plant life cycle aspects, including flowering and fruit development. Here, we demonstrate the implication of GAs in ovule development. DELLA proteins, negative GA response regulators, act as positive factors for ovule integument development in a mechanism that involves transcription factor ABERRANT TESTA SHAPE (ATS). The seeds of the della global mutant, a complete loss-of-function of DELLA, and the ats-1 mutant are remarkably similar, with a round shape, a disorganized testa, and viviparism. These defects are the result of an alteration in integuments that fail to fully develop and are shorter than in wild-type plants. ats-1 also shows some GA-related phenotypes, for example, higher germination rates and early flowering. In fact, ats-1 has elevated GA levels due to the activation of GA biosynthesis genes, which indicates that ATS inhibits GA biosynthesis. Moreover, DELLAs and ATS proteins interact, which suggests the formation of a transcriptional complex that regulates the expression of genes involved in integument growth. Therefore, the repression of GA biosynthesis by ATS would result in the stabilization of DELLAs to ensure correct ATS-DELLA complex formation. The requirement of both activities to coordinate proper ovule development strongly argues that the ATS-DELLA complex acts as a key molecular factor. This work provides the first evidence for a role of GAs in ovule and seed development.This work was supported by grants BIO2011-26302 and BIO2014-55946 from the Spanish Ministry of Science and Innovation and the Spanish Ministry of Economy and Competitiveness, respectively, and ACOMP/2013/048 and ACOMP/2014/106 from the Generalitat Valenciana to M.A.P.-A. R.S. received a PhD fellowship from the Spanish Ministry of Science and Innovation.Gómez Jiménez, MD.; Ventimilla-Llora, D.; Sacristán Tarrazó, R.; Perez Amador, MA. (2016). Gibberellins Regulate Ovule Integument Development by Interfering with the Transcription Factor ATS. Plant Physiology. 172(4):2403-2415. doi:10.1104/pp.16.01231S24032415172

RGL2 controls flower development, ovule number and fertility in Arabidopsis

[EN] DELLA proteins are a group of plant specific GRAS proteins of transcriptional regulators that have a key role in gibberellin (GA) signaling. In Arabidopsis, the DELLA family is formed by five members. The complexity of this gene family raises the question on whether single DELLA proteins have specific or overlapping functions in the control of several GA-dependent developmental processes. To better understand the roles played by RGL2, one of the DELLA proteins in Arabidopsis, two transgenic lines that express fusion proteins of Venus-RGL2 and a dominant version of RGL2, YPet-rgl2A17, were generated by recombineering strategy using a genomic clone that contained the RGL2 gene. The dominant YPet-rg12 Delta 17 protein is not degraded by GAs, and therefore it blocks the RGL2-dependent GA signaling and hence RGL2-dependent development. The RGL2 role in seed germination was further confirmed using these genetic tools, while new functions of RGL2 in plant development were uncovered. RGL2 has a clear function in the regulation of flower development, particularly stamen growth and anther dehiscence, which has a great impact in fertility. Moreover, the increased ovule number in the YPet-rg12 Delta 17 line points out the role of RGL2 in the determination of ovule number.We wish to thank Ms. J. Yun,M.A. Argomániz for technical assistance, and the IBMCP microscopy facility. Edit Syndicate (http://www.editsyndicate.com/) provided proofreading of the manuscript. This work was supported by grants from the Spanish Ministry of Economy and Competitiveness-FEDER [BI02011-26302 and BI02014-55946] and Generalitat Valenciana [ACOMP/2013/048 and ACOMP/2014/106] to M.A.P-A. and National Science Foundation [MCB-0923727] to J.M.A. MAP-A. received a fellowship of the 'Salvador de Madariaga' program from Spanish Ministry of Science and Innovation.Gómez Jiménez, MD.; Fuster Almunia, C.; Ocaña-Cuesta, J.; Alonso, J.; Perez Amador, MA. (2019). RGL2 controls flower development, ovule number and fertility in Arabidopsis. Plant Science. 281:82-92. https://doi.org/10.1016/j.plantsci.2019.01.014S829228

Molecular program of senescence in dry and fleshy fruit

[EN] Fruits of angiosperms can be divided into dry and fleshy fruits, depending on their dispersal strategies. Despite their apparently different developmental programmes, researchers have attempted to compare dry and fleshy fruits to establish analogies of the distinct biochemical and physiological processes that occur. But what are the common and specific phenomena in both biological strategies? Is valve dehiscence and senescence of dry fruits comparable to final ripening of fleshy fruits, when seeds become mature and fruits are competent for seed dispersal, or to over-ripening when advanced senescence occurs? We briefly review current knowledge on dry and fleshy fruit development, which has been extensively reported recently, and is the topic of this special issue. We compare the processes taking place in Arabidopsis (dry) and tomato (fleshy) fruit during final development steps using transcriptome data to establish possible analogies. Interestingly, the transcriptomic programme of Arabidopsis silique shares little similarity in gene number to tomato fruit ripening or over-ripening. In contrast, the biological processes carried out by these common genes from ripening and over-ripening programmes are similar, as most biological processes are shared during both programmes. On the other hand, several biological terms are specific of Arabidopsis and tomato ripening, including senescence, but little or no specific processes occur during Arabidopsis and tomato over-ripening. These suggest a closer analogy between silique senescence and ripening than over-ripening, but a major common biological programme between Arabidopsis silique senescence and the last steps of tomato development, irrespective of its distinction between ripening and over-ripening.We wish to thank Dr J. Carbonell for critically reading the manuscript. We also thank Clara Pons for the preliminary tomato microarray data mining. Our work has been supported by grants BIO2008-01039 and BIO2011-26302 from the Spanish Ministry of Science and Innovation and ACOMP/2010/079, ACOMP/2011/287, and ACOMP/2013/048 from the Generalitat Valenciana.Gómez Jiménez, MD.; Vera Sirera, FJ.; Perez Amador, MA. (2014). Molecular program of senescence in dry and fleshy fruit. Journal of Experimental Botany. 65(16):4515-4526. https://doi.org/10.1093/jxb/eru093S45154526651

Role of the gibberellin receptors GID1 during fruit-set in Arabidopsis

[EN] Gibberellins (GAs) play a critical role in fruit-set and fruit growth. Gibberellin is perceived by its nuclear receptors GA INSENSITIVE DWARF1s (GID1s), which then trigger degradation of downstream repressors DELLAs. To understand the role of the three GA receptor genes (GID1A, GID1B and GID1C) in Arabidopsis during fruit initiation, we have examined their temporal and spatial localization, in combination with analysis of mutant phenotypes. Distinct expression patterns are revealed for each GID1: GID1A is expressed throughout the whole pistil, while GID1B is expressed in ovules, and GID1C is expressed in valves. Functional study of gid1 mutant combinations confirms that GID1A plays a major role during fruit-set and growth, whereas GID1B and GID1C have specific roles in seed development and pod elongation, respectively. Therefore, in ovules, GA perception is mediated by GID1A and GID1B, while GID1A and GID1C are involved in GA perception in valves. To identify tissue-specific interactions between GID1s and DELLAs, we analyzed spatial expression patterns of four DELLA genes that have a role in fruit initiation (GAI, RGA, RGL1 and RGL2). Our data suggest that GID1A can interact with RGA and GAI in all tissues, whereas GID1C-RGL1 and GID1B-RGL2 interactions only occur in valves and ovules, respectively. These results uncover specific functions of each GID1-DELLA in the different GA-dependent processes that occur upon fruit-set. In addition, the distribution of GA receptors in valves along with lack of expression of GA biosynthesis genes in this tissue, strongly suggests transport of GAs from the developing seeds to promote fruit growth.We wish to thank Dr Masatoshi Nakajima (University of Tokyo, Japan) for providing the pGID1:GID1-GUS lines, and Dr Peter Hedden (Rothamsted Research, UK) for the pGA20ox:GA20ox-GUS lines. We also thank Ms C. Fuster and M. A. Argomaniz for technical assistance. This work has been supported by grants BIO2008-01039 and BIO2011-26302 from the Spanish Ministry of Science and Innovation and ACOMP/2010/079 and ACOMP/2011/287 from the Generalitat Valenciana for M. A. P.-A. and USDA grants 2010-65116-20460 and 2014-67013-21548 for T. P. S. C. G.-G. received a JAE PhD fellowship from the Spanish Council for Scientific Research (CSIC).Gallego Giraldo, C.; Hu, J.; Urbez Lagunas, C.; Gómez Jiménez, MD.; Sun, TP.; Perez Amador, MA. (2014). Role of the gibberellin receptors GID1 during fruit-set in Arabidopsis. Plant Journal. 79(6):1020-1032. doi:10.1111/tpj.12603S1020103279

Arabidopsis Heat Stress-Induced Proteins Are Enriched in Electrostatically Charged Amino Acids and Intrinsically Disordered Regions

[EN] Comparison of the proteins of thermophilic, mesophilic, and psychrophilic prokaryotes has revealed several features characteristic to proteins adapted to high temperatures, which increase their thermostability. These characteristics include a profusion of disulfide bonds, salt bridges, hydrogen bonds, and hydrophobic interactions, and a depletion in intrinsically disordered regions. It is unclear, however, whether such differences can also be observed in eukaryotic proteins or when comparing proteins that are adapted to temperatures that are more subtly different. When an organism is exposed to high temperatures, a subset of its proteins is overexpressed (heat-induced proteins), whereas others are either repressed (heat-repressed proteins) or remain unaffected. Here, we determine the expression levels of all genes in the eukaryotic model system Arabidopsis thaliana at 22 and 37 degrees C, and compare both the amino acid compositions and levels of intrinsic disorder of heat-induced and heat-repressed proteins. We show that, compared to heat-repressed proteins, heat-induced proteins are enriched in electrostatically charged amino acids and depleted in polar amino acids, mirroring thermophile proteins. However, in contrast with thermophile proteins, heat-induced proteins are enriched in intrinsically disordered regions, and depleted in hydrophobic amino acids. Our results indicate that temperature adaptation at the level of amino acid composition and intrinsic disorder can be observed not only in proteins of thermophilic organisms, but also in eukaryotic heat-induced proteins; the underlying adaptation pathways, however, are similar but not the same.D.A.-P. and F.F. were supported by funds from the University of Nevada, Reno, and by pilot grants from Nevada INBRE (P20GM103440) and the Smooth Muscle Plasticity COBRE from the University of Nevada, Reno (5P30GM110767-04), both funded by the National Institute of General Medical Sciences (National Institutes of Health). M.X.R.-G. and M.A.F. were supported by grants from Science Foundation Ireland (12/IP/1637) and the Spanish Ministerio de Economia y Competitividad, Spain (MINECO-FEDER; BFU201236346 and BFU2015-66073-P) to MAF. MXRG was supported by a JAE DOC fellowship from the MINECO, Spain. 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Arabidopsis copper transport protein COPT2 participates in the crosstalk between iron deficiency responses and low phosphate signaling

[EN] Copper and iron are essential micronutrients for most living organisms because they participate as cofactors in biological processes, including respiration, photosynthesis, and oxidative stress protection. In many eukaryotic organisms, including yeast (Saccharomyces cerevisiae) and mammals, copper and iron homeostases are highly interconnected; yet, such interdependence is not well established in higher plants. Here, we propose that COPT2, a high-affinity copper transport protein, functions under copper and iron deficiencies in Arabidopsis (Arabidopsis thaliana). COPT2 is a plasma membrane protein that functions in copper acquisition and distribution. Characterization of the COPT2 expression pattern indicates a synergic response to copper and iron limitation in roots. We characterized a knockout of COPT2, copt2-1, that leads to increased resistance to simultaneous copper and iron deficiencies, measured as reduced leaf chlorosis and improved maintenance of the photosynthetic apparatus. We propose that COPT2 could play a dual role under iron deficiency. First, COPT2 participates in the attenuation of copper deficiency responses driven by iron limitation, possibly to minimize further iron consumption. Second, global expression analyses of copt2-1 versus wild-type Arabidopsis plants indicate that low-phosphate responses increase in the mutant. These results open up new biotechnological approaches to fight iron deficiency in crops.This work was supported by the Spanish Ministry of Economy and Competitiveness (grant nos. BIO2011-24848 and CSD2007-00057 to L. P. and predoctoral Formacion Personal Investigador fellowships to A. P.-G and A. G.-M.) and by the European Regional Developmental Fund of the European Union.Perea García, A.; Garcia Molina, A.; Andres-Colas, N.; Vera Sirera, FJ.; Perez Amador, MA.; Puig, S.; Penarrubia, L. (2013). Arabidopsis copper transport protein COPT2 participates in the crosstalk between iron deficiency responses and low phosphate signaling. Plant Physiology. 162(1):180-194. https://doi.org/10.1104/pp.112.212407S180194162

Bud sprouting and floral induction and expression of FT in loquat [Eriobotrya japonica (Thunb.) Lindl.]

[EN] EjFT1 and EjFT2 genes were isolated and sequenced from leaves of loquat. EjFT1 is involved in bud sprouting and leaf development, and EjFT2 in floral bud induction. Loquat [Eriobotrya japonica (Thunb.) Lindl.] is an evergreen species belonging to the family Rosaceae, such as apple and pear, whose reproductive development, in contrast with these species, is a continuous process that is not interrupted by winter dormancy. Thus, the study of the mechanism of flowering in loquat has the potential to uncover the environmental and genetic networks that trigger flowering more accurately, contributing for a better understanding of the Rosaceae floral process. As a first step toward understanding the molecular mechanisms controlling flowering, extensive defoliation and defruiting assays, together with molecular studies of the key FLOWERING LOCUS T (FT) gene, were carried out. FT exhibited two peaks of expression in leaves, the first one in early to mid-May, the second one in mid-June. Two FT genes, EjFT1 and EjFT2, were isolated and sequenced and studied their expression. Expression of EjFT1 and EjFT2 peaks in mid-May, at bud sprouting. EjFT2 expression peaks again in mid-June, coinciding with the floral bud inductive period. Thus, when all leaves of the tree were continuously removed from early to late May vegetative apex differentiated into panicle, but when defoliation was performed from early to late June apex did not differentiate. On the other hand, fruit removal advanced EjFT1 expression in old leaves and the sooner the fruit detached, the sooner the bud sprouted. Accordingly, results strongly suggest that EjFT1 might be related to bud sprouting and leaf development, while EjFT2 might be involved in floral bud induction. An integrative model for FT functions in loquat is discussed.This work was supported by Grants BIO2011-26302 (Spanish Ministry of Science and Innovation) for M. A. Perez-Amador, and RTA2013-00024-C02-02 (Instituto Nacional de Investigaciones y Tecnologia Agraria y Alimentaria-Ministerio de Economia y Competitividad) for C. Reig. The authors thank Dr. P. M. Hernandez-Delgado and Dr. V. Galan (Insituto Canario de Iinvestigaciones Agrarias, Tenerife, Spain) for their collaboration and Debra Westall (Universidad Politecnica de Valencia) for revising the manuscript.Reig Valor, C.; Gil-Muñoz, F.; Vera-Sirera, F.; Garcia-Lorca, A.; Martínez Fuentes, A.; Mesejo Conejos, C.; Perez Amador, MA.... (2017). Bud sprouting and floral induction and expression of FT in loquat [Eriobotrya japonica (Thunb.) Lindl.]. Planta. 246(5):915-925. https://doi.org/10.1007/s00425-017-2740-6S9159252465Agustí M, Reig C (2006) Fisiología. In: Agustí M, Reig C, Undurraga P (eds) El cultivo del níspero japonés. Gráficas Alcoy, Alcoy, pp 97–129Batten DJ, McConchie CA (1995) Floral induction in growing buds of lychee (Litchi chinensis) and mango (Mangifera indica). Aust J Plant Physiol 22:783–791Bernier G, Kinet J-M, Sachs RM (1981) The flowering process at the shoot apex: macromorphological events. In: Bernier G, Kinet J-M, Sachs RM (eds) The physiology of flowering, vol II. Transition to reproductive growth. CRC Press, Boca Raton, pp 21–34Bustin SA (2002) Quantification of mRNA using real-time reverse transcription PCR (RT-PCR): trends and problems. J Mol Endocrinol 29:23–39Carmona MJ, Calomje M, Martínez-Zapater JM (2007) The FT/TFL1 gene family in grapevine. Plant Mol Biol 63:637–650Chen Y, Jiang P, Thammannagowda S, Liang H, Wild GD (2013) Characterization of peach TFL1 and comparison with FT/TFL1 gene families of the Rosaceae. J Am Soc Hortic Sci 138:12–17Doyle JJ, Doyle JL (1987) A rapid isolation procedure for small quantities of fresh leaf tissue. Phytochem Bull 19:11–15Endo T, Shimada T, Fujii H, Kobayashi Y, Araki T, Omura M (2005) Ectopic expression of an FT homolog from Citrus confers an early flowering phenotype on trifoliate orange (Poncirus trifoliata L. Raf.). Transgenic Res 14:703–712Esumi T, Tao R, Yanemori K (2005) Isolation of LEAFY and TERMINAL FLOWER 1 homologues from six fruit tree species in the subfamily Maloideae of the Rosaceae. Sex Plant Reprod 17:277–287Esumi T, Hagihara C, Kitamura Y, Yamane H, Tao R (2009) Identification of an FT ortholog in Japanese apricot (Prunus mume Sieb. et Zucc.). J Hortic Sci Biotechnol 84:149–154Evans RC, Campbell CS (2002) The origin of the apple subfamily (Maloideae; Rosaceae) is clarified by DNA sequence data from duplicated GBSSI genes. Am J Bot 89:1478–1484Fatta del Bosco G (1961) Indagini sull’epoca di differenziazione delle gemme nel nespolo del giappone. Riv Ortoflorofruttic Ital XLV 2:104–118Gisbert AD, Martínez-Calvo J, Llácer G, Badenes ML, Romero C (2009) Development of two loquat [Eriobotrya japonica (Thunb.) Lindl.] linkage maps based on AFLPs and SSR markers from different Rosaceae species. Mol Breed 23:523–538Hanke M-V, Flachowsky H, Peil A, Hättasch C (2007) No flower no fruit—genetic potential to trigger flowering in fruit trees. Genes Genomes Genom 1:1–20Hättasch C, Flachowsky H, Kaptrska D, Hank M-V (2008) Isolation of flowering genes and seasonal changes in their transcript levels related to flower induction and initiation in apple (Malus domestica). Tree Physiol 28:1459–1466Hiraoka K, Yamaguchi A, Abe M, Araki T (2013) The florigen genes FT and TSF modulate lateral shoot outgrowth in Arabidopsis thaliana. 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alpha 2-COP is involved in early secretory traffic in Arabidopsis and is required for plant growth

[EN] COP (coat protein) I-coated vesicles mediate intra-Golgi transport and retrograde transport from the Golgi to the endoplasmic reticulum. These vesicles form through the action of the small GTPase ADP-ribosylation factor 1 (ARF1) and the COPI heptameric protein complex (coatomer), which consists of seven subunits (alpha-, beta-, beta' -, gamma-, delta-, epsilon- and xi-COP). In contrast to mammals and yeast, several isoforms for coatomer subunits, with the exception of gamma and delta, have been identified in Arabidopsis. To understand the role of COPI proteins in plant biology, we have identified and characterized a loss-of-function mutant of alpha 2-COP, an Arabidopsis alpha-COP isoform. The alpha 2-cop mutant displayed defects in plant growth, including small rosettes, stems and roots and mislocalization of p24 delta 5, a protein of the p24 family containing a C-terminal dilysine motif involved in COPI binding. The alpha 2-cop mutant also exhibited abnormal morphology of the Golgi apparatus. Global expression analysis of the alpha 2-cop mutant revealed altered expression of plant cell wall-associated genes. In addition, a strong upregulation of SEC31A, which encodes a subunit of the COPII coat, was observed in the alpha 2-cop mutant; this also occurs in a mutant of a gene upstream of COPI assembly, GNL1, which encodes an ARF-guanine nucleotide exchange factor (GEF). These findings suggest that loss of alpha 2-COP affects the expression of secretory pathway genes.Antibody against alpha-COP was kindly provided by Prof. F. Wieland. This work was supported by the Ministerio de Economia y Competitividad (grant number. BFU2012-33883 to FA and MJM; grant numbers BIO2011-26302 and BIO2014-55946-P to MP), the Generalitat Valenciana (grant numbers ISIC/2013/004 and GVACOMP2014-202 to FA and MJM) and the Research Grants Council (grant number AoE/M-05/12 to LJ). NP and CB were recipients of a fellowship from Ministerio de Educacion (FPU program). We thank the Salk Institute Genomic Analysis Laboratory for providing the sequence-indexed Arabidopsis T-DNA insertion mutants and the microscopy and genomics section of SCSIE (University of Valencia).Gimeno-Ferrer, F.; Pastor-Cantizano, N.; Bernat-Silvestre, C.; Selvi-Martinez, P.; Vera Sirera, FJ.; Gao, C.; Perez Amador, MA.... (2017). alpha 2-COP is involved in early secretory traffic in Arabidopsis and is required for plant growth. Journal of Experimental Botany. 68(3):391-401. https://doi.org/10.1093/jxb/erw446S39140168