Cereal grains are an important source of food and feed. To provide comprehensive spatiotemporal information about biological processes in developing seeds of cultivated barley (Hordeum vulgare L. subsp. vulgare), we performed a transcriptomic study of the embryo, endosperm, and seed maternal tissues collected from grains 4-32 days after pollination. Weighted gene co-expression network and motif enrichment analyses identified specific groups of genes and transcription factors (TFs) potentially regulating barley seed tissue development. We defined a set of tissue-specific marker genes and families of TFs for functional studies of the pathways controlling barley grain development. Assessing selected groups of chromatin regulators revealed that epigenetic processes are highly dynamic and likely play a major role during barley endosperm development. The repressive H3K27me3 modification is globally reduced in endosperm tissues and at specific genes related to development and storage compounds. Altogether, this atlas uncovers the complexity of developmentally regulated gene expression in developing barley grains.

Department of Cell and Systems Biology Centre for the Analysis of Genome Evolution and Function University of Toronto 25 Willcocks St Toronto ON M5S 3B2 Canada

Department of Cell Biology and Genetics Faculty of Science Palacký University Šlechtitelů 27 779 00 Olomouc Czech Republic

Franciszek Górski Institute of Plant Physiology Polish Academy of Sciences Niezapominajek 21 30 239 Kraków Poland

Institute for Developmental Genetics Heinrich Heine University Universitätsstraße 1 40225 Düsseldorf Germany

Institute of Experimental Botany Czech Acad Sci Centre of Plant Structural and Functional Genomics Šlechtitelů 31 779 00 Olomouc Czech Republic

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Alexa A, Rahnenfuhrer J. topGO: enrichment analysis for gene ontology. R package version 2.54.0.10.18129/B9.bioc.topGO DOI

Alizadeh M, Hoy R, Lu B, Song L. Team effort: combinatorial control of seed maturation by transcription factors. Curr Opin Plant Biol. 2021:63:102091. 10.1016/j.pbi.2021.102091 PubMed DOI

Anders S, Huber W. Differential expression analysis for sequence count data. Genome Biol. 2010:11(10):1–12. 10.1186/gb-2010-11-10-r106 PubMed DOI PMC

Baker K, Dhillon T, Colas I, Cook N, Milne I, Milne L, Bayer M, Flavell AJ. Chromatin state analysis of the barley epigenome reveals a higher-order structure defined by H3K27me1 and H3K27me3 abundance. Plant J. 2015:84(1):111–124. 10.1111/tpj.12963 PubMed DOI PMC

Bate NJ, Niu X, Wang Y, Reimann KS, Helentjaris TG. An invertase inhibitor from maize localizes to the embryo surrounding region during early kernel development. Plant Physiol. 2004:134(1):246–254. 10.1104/pp.103.027466 PubMed DOI PMC

Batista RA, Köhler C. Genomic imprinting in plants-revisiting existing models. Genes Dev. 2020:34(1–2):24–36. 10.1101/gad.332924.119 PubMed DOI PMC

Bennet MD, Smith JB, Barclay I. Early seed development in the triticeae. Philos Trans R Soc Lond B Biol Sci. 1975:272(916):199–227. 10.1098/rstb.1975.0083 DOI

Bian J, Deng P, Zhan H, Wu X, Nishantha M, Yan Z, Du X, Nie X, Song W. Transcriptional dynamics of grain development in barley (Hordeum vulgare L.). Int J Mol Sci. 2019:20(4):962. 10.3390/ijms20040962 PubMed DOI PMC

Brown RC, Lemmon BE, Nguyen H. Events during the first four rounds of mitosis establish three developmental domains in the syncytial endosperm of Arabidopsis thaliana. Protoplasma. 2003:222(3–4):167–174. 10.1007/s00709-003-0010-x PubMed DOI

Camacho C, Coulouris G, Avagyan V, Ma N, Papadopoulos J, Bealer K, Madden TL. BLAST+: architecture and applications. BMC Bioinformatics. 2009:10(1):1–9. 10.1186/1471-2105-10-421 PubMed DOI PMC

Carena MJ, ed. Cereals. New York (NY): Springer US; 2009.

Castro-Mondragon JA, Jaeger S, Thieffry D, Thomas-Chollier M, van Helden J. RSAT matrix-clustering: dynamic exploration and redundancy reduction of transcription factor binding motif collections. Nucleic Acids Res. 2017:45(13):e119–e119. 10.1093/nar/gkx314 PubMed DOI PMC

Charlton WL, Keen CL, Merriman C, Lynch P, Greenland AJ, Dickinson HG. Endosperm development in Zea mays; implication of gametic imprinting and paternal excess in regulation of transfer layer development. Development. 1995:121(9):3089–3097. 10.1242/dev.121.9.3089 DOI

Chen C, Li T, Zhu S, Liu Z, Shi Z, Zheng X, Chen R, Huang J, Shen Y, Luo S, et al. . Characterization of imprinted genes in rice reveals conservation of regulation and imprinting with other plant species. Plant Physiol. 2018:177(4):1754–1771. 10.1104/pp.17.01621 PubMed DOI PMC

Chourey PS, Nelson OE. The enzymatic deficiency conditioned by the shrunken-1 mutations in maize. Biochem Genet. 1976:14(11–12):1041–1055. 10.1007/BF00485135 PubMed DOI

Cook F, Hughes A, Nibau C, Orman-Ligeza B, Schatlowski N, Uauy C, Trafford K. Barley lys3 mutants are unique amongst shrunken-endosperm mutants in having abnormally large embryos. J Cereal Sci. 2018:82:16–24. 10.1016/j.jcs.2018.04.013 PubMed DOI PMC

Costa LM, Gutierrez-Marcos JF, Brutnell TP, Greenland AJ, Dickinson HG. The globby1-1 (glo1-1) mutation disrupts nuclear and cell division in the developing maize seed causing alterations in endosperm cell fate and tissue differentiation. Development. 2003:130(20):5009–5017. 10.1242/dev.00692 PubMed DOI

De Camilli P, Chen H, Hyman J, Panepucci E, Bateman A, Brunger AT. The ENTH domain. FEBS Lett. 2002:513(1):11–18. 10.1016/S0014-5793(01)03306-3 PubMed DOI

Doan DNR, Linnestad C, Olsen A. Isolation of molecular markers from the barley endosperm coenocyte and the surrounding nucellus cell layers. Plant Mol Biol. 1996:31(4):877–886. 10.1007/BF00019474 PubMed DOI

Druka A, Muehlbauer G, Druka I, Caldo R, Baumann U, Rostoks N, Schreiber A, Wise R, Close T, Kleinhofs A, et al. . An atlas of gene expression from seed to seed through barley development. Funct Integr Genomics. 2006:6(3):202–211. 10.1007/s10142-006-0025-4 PubMed DOI

Du L, Li N, Chen L, Xu Y, Li Y, Zhang Y, Li C, Li Y. The ubiquitin receptor DA1 regulates seed and organ size by modulating the stability of the ubiquitin-specific protease UBP15/SOD2 in Arabidopsis. Plant Cell. 2014:26(2):665–677. 10.1105/tpc.114.122663 PubMed DOI PMC

Food and Agriculture Organization of the United Nations . https://www.fao.org/home/en/2023

Gendrel AV, Lippman Z, Martienssen R, Colot V. Profiling histone modification patterns in plants using genomic tiling microarrays. Nat Methods. 2005:2(3):213–218. 10.1038/nmeth0305-213 PubMed DOI

Gómez E, Royo J, Guo Y, Thompson R, Hueros G. Establishment of cereal endosperm expression domains identification and properties of a maize transfer cell-specific transcription factor, ZmMRP-1. Plant Cell. 2002:14(3):599–610. 10.1105/tpc.010365 PubMed DOI PMC

Goyal K, Walton LJ, Tunnacliffe A. LEA proteins prevent protein aggregation due to water stress. Biochem J. 2005:388(1):151–157. 10.1042/BJ20041931 PubMed DOI PMC

Gu B, Dong H, Smith C, Cui G, Li Y, Bevan MW. Modulation of receptor-like transmembrane kinase 1 nuclear localization by DA1 peptidases in Arabidopsis. Proc Natl Acad Sci U S A. 2022:119(40):e2205757119. 10.1073/pnas.2205757119 PubMed DOI PMC

Gubatz S, Dercksen VJ, Brüß C, Weschke W, Wobus U. Analysis of barley (Hordeum vulgare) grain development using three-dimensional digital models. Plant J. 2007:52(4):779–790. 10.1111/j.1365-313X.2007.03260.x PubMed DOI

Heinz S, Benner C, Spann N, Bertolino E, Lin YC, Laslo P, Cheng JX, Murre C, Singh H, Glass CK. Simple combinations of lineage-determining transcription factors prime cis-regulatory elements required for macrophage and B cell identities. Mol Cell. 2010:38(4):576. 10.1016/j.molcel.2010.05.004 PubMed DOI PMC

Hertig C, Melzer M, Rutten T, Erbe S, Hensel G, Kumlehn J, Weschke W, Weber H, Thiel J. Barley HISTIDINE KINASE 1 (HvHK1) coordinates transfer cell specification in the young endosperm. Plant J. 2020:103(5):1869–1884. 10.1111/tpj.14875 PubMed DOI

Hertig C, Rutten T, Melzer M, Schippers JHM, Thiel J. Dissection of developmental programs and regulatory modules directing endosperm transfer cell and aleurone identity in the syncytial endosperm of barley. Plants. 2023:12(8):1594. 10.3390/plants12081594 PubMed DOI PMC

Hueros G, Royo J, Maitz M, Salamini F, Thompson RD. Evidence for factors regulating transfer cell-specific expression in maize endosperm. Plant Mol Biol. 1999:41(3):403–414. 10.1023/A:1006331707605 PubMed DOI

Jiang D, Borg M, Lorković ZJ, Montgomery SA, Osakabe A, Yelagandula R, Axelsson E, Berger F. The evolution and functional divergence of the histone H2B family in plants. PLoS Genet. 2020:16(7):e1008964. 10.1371/journal.pgen.1008964 PubMed DOI PMC

Jin J, Tian F, Yang DC, Meng YQ, Kong L, Luo J, Gao G. PlantTFDB 4.0: toward a central hub for transcription factors and regulatory interactions in plants. Nucleic Acids Res. 2017:45(D1):D1040–D1045. 10.1093/nar/gkw982 PubMed DOI PMC

Kalla R, Shimamoto K, Potter R, Nielsen PS, Linnestad C, Olsen O-A. The promoter of the barley aleurone-specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell-specific expression in transgenic rice. Plant J. 1994:6(6):849–860. 10.1046/j.1365-313X.1994.6060849.x PubMed DOI

Kanegae H, Miyoshi K, Hirose T, Tsuchimoto S, Mori M, Nagato Y, Takano M. Expressions of rice sucrose non-fermenting-1 related protein kinase 1 genes are differently regulated during the caryopsis development. Plant Physiol Biochem. 2005:43(7):669–679. 10.1016/j.plaphy.2005.06.004 PubMed DOI

Kiesselbach TA, Walker ER. Structure of certain specialized tissue in the kernel of corn. Am J Bot. 1952:39(8):561–569. 10.1002/j.1537-2197.1952.tb13069.x DOI

Kim D, Paggi JM, Park C, Bennett C, Salzberg SL. Graph-based genome alignment and genotyping with HISAT2 and HISAT-genotype. Nat Biotechnol. 2019:37(8):907–915. 10.1038/s41587-019-0201-4 PubMed DOI PMC

Kovacik M, Nowicka A, Pecinka A. Isolation of high purity tissues from developing barley seeds. J Vis Exp. 2020(164):e61681. 10.3791/61681 PubMed DOI

Langfelder P, Horvath S. WGCNA: an R package for weighted correlation network analysis. BMC Bioinformatics. 2008:9(1):559. 10.1186/1471-2105-9-559 PubMed DOI PMC

Langfelder P, Horvath S. Fast {R} functions for robust correlations and hierarchical clustering. J Stat Softw. 2012:46(11):1–17. 10.18637/jss.v046.i11 PubMed DOI PMC

Langfelder P, Zhang B, Horvath S. Defining clusters from a hierarchical cluster tree: the dynamic tree cut package for R. Bioinformatics. 2008:24(5):719–720. 10.1093/bioinformatics/btm563 PubMed DOI

Larsson, J. (2020). eulerr: area-proportional Euler and Venn diagrams with ellipses.

Le BH, Cheng C, Bui AQ, Wagmaister JA, Henry KF, Pelletier J, Kwong L, Belmonte M, Kirkbride R, Horvath S, et al. . Global analysis of gene activity during Arabidopsis seed development and identification of seed-specific transcription factors. Proc Natl Acad Sci U S A. 2010:107(18):8063–8070. 10.1073/pnas.1003530107 PubMed DOI PMC

Leah R, Tommerup H, Svendsen I, Mundy J. Biochemical and molecular characterization of three barley seed proteins with antifungal properties. J Biol Chem. 1991:266(3):1564–1573. 10.1016/S0021-9258(18)52331-0 PubMed DOI

Liao Y, Smyth GK, Shi W. The subread aligner: fast, accurate and scalable read mapping by seed-and-vote. Nucleic Acids Res. 2013:41(10):e108–e108. 10.1093/nar/gkt214 PubMed DOI PMC

Love MI, Huber W, Anders S. Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biol. 2014:15(12):550. 10.1186/s13059-014-0550-8 PubMed DOI PMC

Luo M, Taylor JM, Spriggs A, Zhang H, Wu X, Russell S, Singh M, Koltunow A. A genome-wide survey of imprinted genes in rice seeds reveals imprinting primarily occurs in the endosperm. PLoS Genet. 2011:7(6):e1002125. 10.1371/journal.pgen.1002125 PubMed DOI PMC

Magnard JL, Lehouque G, Massonneau A, Frangne N, Heckel T, Gutierrez-Marcos JF, Perez P, Dumas C, Rogowsky PM. ZmEBE genes show a novel, continuous expression pattern in the central cell before fertilization and in specific domains of the resulting endosperm after fertilization. Plant Mol Biol. 2003:53(6):821–836. 10.1023/B:PLAN.0000023672.37089.00 PubMed DOI

Martin M. Cutadapt removes adapter sequences from high-throughput sequencing reads. EMBnet J. 2011:17(1):10–12. 10.14806/ej.17.1.200 DOI

Mascher M. Pseudomolecules and annotation of the third version of the reference genome sequence assembly of barley cv. Morex [Morex V3], 2021. http://doi:10.5447/ipk/2021/3 DOI

Mena M, Vicente-Carbajosa J, Schmidt RJ, Carbonero P. An endosperm-specific DOF protein from barley, highly conserved in wheat, binds to and activates transcription from the prolamin-box of a native B-hordein promoter in barley endosperm. Plant J. 1998:16(1):53–62. 10.1046/j.1365-313x.1998.00275.x PubMed DOI

Mozgova I, Hennig L. The polycomb group protein regulatory network. Annu Rev Plant Biol. 2015:66(1):269–296. 10.1146/annurev-arplant-043014-115627 PubMed DOI

Nowicka A, Ferková Ľ, Said M, Kovacik M, Zwyrtková J, Baroux C, Pecinka A. Non-Rabl chromosome organization in endoreduplicated nuclei of barley embryo and endosperm tissues. J Exp Bot. 2023:74(8):2527–2541. 10.1093/jxb/erad036 PubMed DOI

Nowicka A, Sahu PP, Kovacik M, Weigt D, Tokarz B, Krugman T, Pecinka A. Endopolyploidy variation in wild barley seeds across environmental gradients in Israel. Genes (Basel). 2021:12(5):711. 10.3390/genes12050711 PubMed DOI PMC

Olsen O-A. ENDOSPERM DEVELOPMENT: cellularization and cell fate specification. Annu Rev Plant Biol. 2001:52(1):233–267. 10.1146/annurev.arplant.52.1.233 PubMed DOI

Opsahl-Ferstad HG, Le Deunff E, Dumas C, Rogowsky PM. Zmesr, a novel endosperm-specific gene expressed in a restricted region around the maize embryo. Plant J. 1997:12(1):235–246. 10.1046/j.1365-313X.1997.12010235.x PubMed DOI

Peirats-Llobet M, Yi C, Liew LC, Berkowitz O, Narsai R, Lewsey MG, Whelan J. Spatially resolved transcriptomic analysis of the germinating barley grain. Nucleic Acids Res. 2023:51(15):7798–7819. 10.1093/nar/gkad521 PubMed DOI PMC

Peng Y, Chen L, Lu Y, Wu Y, Dumenil J, Zhu Z, Bevan MW, Lia Y. The ubiquitin receptors DA1, DAR1, and DAR2 redundantly regulate endoreduplication by modulating the stability of TCP14/15 in Arabidopsis. Plant Cell. 2015:27(3):649–662. 10.1105/tpc.114.132274 PubMed DOI PMC

Probst AV, Desvoyes B, Gutierrez C. Similar yet critically different: the distribution, dynamics and function of histone variants. J Exp Bot. 2020:71(17):5191–5204. 10.1093/jxb/eraa230 PubMed DOI

R Core Team . https://www.r-project.org/2020

Radchuk VV, Borisjuk L, Sreenivasulu N, Merx K, Mock HP, Rolletschek H, Wobus U, Weschke W. Spatiotemporal profiling of starch biosynthesis and degradation in the developing barley grain. Plant Physiol. 2009:150(1):190–204. 10.1104/pp.108.133520 PubMed DOI PMC

Radchuk V, Weier D, Radchuk R, Weschke W, Weber H. Development of maternal seed tissue in barley is mediated by regulated cell expansion and cell disintegration and coordinated with endosperm growth. J Exp Bot. 2011:62(3):1217–1227. 10.1093/jxb/erq348 PubMed DOI PMC

Raudvere U, Kolberg L, Kuzmin I, Arak T, Adler P, Peterson H, Vilo J. G:profiler: a web server for functional enrichment analysis and conversions of gene lists (2019 update). Nucleic Acids Res. 2019:47(W1):W191–W198. 10.1093/nar/gkz369 PubMed DOI PMC

Roberts IN, Caputo C, Criado MV, Funk C. Senescence-associated proteases in plants. Physiol Plant. 2012:145(1):130–139. 10.1111/j.1399-3054.2012.01574.x PubMed DOI

Sano N, Rajjou L, North HM. Lost in translation: physiological roles of stored mRNAs in seed germination. Plants (Basel). 2020:9(3):347–361. 10.3390/plants9030347 PubMed DOI PMC

Serna A, Maitz M, O’Connell T, Santandrea G, Thevissen K, Tienens K, Hueros G, Faleri C, Cai G, Lottspeich F, et al. . Maize endosperm secretes a novel antifungal protein into adjacent maternal tissue. Plant J. 2001:25(6):687–698. 10.1046/j.1365-313x.2001.01004.x PubMed DOI

Sosso D, Wisniewski JP, Khaled AS, Hueros G, Gerentes D, Paul W, Rogowsky PM. The vpp1, Esr6a, Esr6b and OCL4 promoters are active in distinct domains of maize endosperm. Plant Sci. 2010:179(1–2):86–96. 10.1016/j.plantsci.2010.04.006 DOI

Sreenivasulu N, Usadel B, Winter A, Radchuk V, Scholz U, Stein N, Weschke W, Strickert M, Close TJ, Stitt M, et al. . Barley grain maturation and germination: metabolic pathway and regulatory network commonalities and differences highlighted by new MapMan/PageMan profiling tools. Plant Physiol. 2008:146(4):1738–1758. 10.1104/pp.107.111781 PubMed DOI PMC

Stewart Gillmor C, Silva-Ortega CO, Willmann MR, Buendía-Monreal M, Poethig RS. The Arabidopsis mediator CDK8 module genes CCT (MED12) and GCT (MED13) are global regulators of developmental phase transitions. Development. 2014:141(23):4580–4589. 10.1242/dev.111229 PubMed DOI PMC

Strejčková B, Čegan R, Pecinka A, Milec Z, Šafář J. Identification of polycomb repressive complex 1 and 2 core components in hexaploid bread wheat. BMC Plant Biol. 2020:20(S1):1–13. 10.1186/s12870-020-02384-6 PubMed DOI PMC

Supek F, Bošnjak M, Škunca N, Šmuc T. REVIGO summarizes and visualizes long lists of gene ontology terms. PLoS One. 2011:6(7):e21800. 10.1371/journal.pone.0021800 PubMed DOI PMC

The International Barley Genome Sequencing Consortium . A physical, genetic and functional sequence assembly of the barley genome. Nature. 2012:491(7426):711–716. 10.1038/nature11543 PubMed DOI

Thiel J, Koppolu R, Trautewig C, Hertig C, Kale SM, Erbe S, Mascher M, Himmelbach A, Rutten T, Esteban E, et al. . Transcriptional landscapes of floral meristems in barley. Sci Adv. 2021:7(18):eabf0832. 10.1126/sciadv.abf0832 PubMed DOI PMC

Tibshirani R, Walther G, Hastie T. Estimating the number of clusters in a data set via the gap statistic. J R Stat Soc Ser B Stat Methodol. 2001:63(2):411–423. 10.1111/1467-9868.00293 DOI

Toufighi K, Brady SM, Austin R, Ly E, Provart NJ. The botany array resource: e-northerns, expression angling, and promoter analyses. Plant J. 2005:43(1):153–163. 10.1111/j.1365-313X.2005.02437.x PubMed DOI

Tu S, Li M, Chen H, Tan F, Xu J, Waxman DJ, Zhang Y, Shao Z. MAnorm2 for quantitatively comparing groups of ChIP-seq samples. Genome Res. 2021:31(1):131–145. 10.1101/gr.262675.120 PubMed DOI PMC

Van der Auwera GA, O’Connor BD. Genomics in the cloud: using Docker, GATK, and WDL in Terra. Sebastopol (CA): O’Reilly Media; 2020.

Vishal B, Kumar PP. Regulation of seed germination and abiotic stresses by gibberellins and abscisic acid. Front Plant Sci. 2018:9:838. 10.3389/fpls.2018.00838 PubMed DOI PMC

Waters AJ, Makarevitch I, Eichten SR, Swanson-Wagner RA, Yeh CT, Xu W, Schnable PS, Vaughn MW, Gehring M, Springer NM. Parent-of-origin effects on gene expression and DNA methylation in the maize endosperm. Plant Cell. 2011:23(12):4221–4233. 10.1105/tpc.111.092668 PubMed DOI PMC

Weschke W, Panitz R, Gubatz S, Wang Q, Radchuk R, Weber H, Wobus U. The role of invertases and hexose transporters in controlling sugar ratios in maternal and filial tissues of barley caryopses during early development. Plant J. 2003:33(2):395–411. 10.1046/j.1365-313X.2003.01633.x PubMed DOI

Yanagisawa S, Sheen J. Involvement of maize dof zinc finger proteins in tissue-specific and light-regulated gene expression. Plant Cell. 1998:10(1):75–89. 10.1105/tpc.10.1.75 PubMed DOI PMC

Yang G, Liu Z, Gao L, Yu K, Feng M, Yao Y, Peng H, Hu Z, Sun Q, Ni Z, et al. . Genomic imprinting was evolutionarily conserved during wheat polyploidization. Plant Cell. 2018:30(1):37–47. 10.1105/tpc.17.00837 PubMed DOI PMC

Yon Rhee S, Wood V, Dolinski K, Draghici S. Use and misuse of the gene ontology annotations. Nat Rev Genet. 2008:9(7):509–515. 10.1038/nrg2363 PubMed DOI

Zhang S, Laurie AE, Ae W, Meng L, Lemaux PG. Similarity of expression patterns of knotted1 and ZmLEC1 during somatic and zygotic embryogenesis in maize (Zea mays L.). Planta. 2002:215(2):191–194. 10.1007/s00425-002-0735-3 PubMed DOI

Zhang Y, Liu T, Meyer CA, Eeckhoute J, Johnson DS, Bernstein BE, Nussbaum C, Myers RM, Brown M, Li W, et al. . Model-based analysis of ChIP-seq (MACS). Genome Biol. 2008:9(9):1–9. 10.1186/gb-2008-9-9-r137 PubMed DOI PMC

Zhang H, Sreenivasulu N, Weschke W, Stein N, Rudd S, Radchuk V, Potokina E, Scholz U, Schweizer P, Zierold U, et al. . Large-scale analysis of the barley transcriptome based on expressed sequence tags. Plant J. 2004:40(2):276–290. 10.1111/j.1365-313X.2004.02209.x PubMed DOI

Zhang M, Zhao H, Xie S, Chen J, Xu Y, Wang K, Zhao H, Guan H, Hu X, Jiao Y, et al. . Extensive, clustered parental imprinting of protein-coding and noncoding RNAs in developing maize endosperm. Proc Natl Acad Sci U S A. 2011:108(50):20042–20047. 10.1073/pnas.1112186108 PubMed DOI PMC

Zöllner NR, Bezrutczyk M, Laureyns R, Nelissen H, Simon R, Frommer WB. An RNA in situ hybridization protocol optimized for monocot tissue. STAR Protoc. 2021:2(2):100398. 10.1016/j.xpro.2021.100398 PubMed DOI PMC

Core promoterome of barley embryo