{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T17:57:49Z","timestamp":1779299869082,"version":"3.51.4"},"reference-count":30,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2017,11,24]],"date-time":"2017-11-24T00:00:00Z","timestamp":1511481600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Maize (Zea mays L.) is a staple food in many parts of Africa, but the endosperm generally contains low levels of the pro-vitamin A carotenoid \u03b2-carotene, leading to vitamin A deficiency disease in populations relying on cereal-based diets. However, maize endosperm does accumulate high levels of other carotenoids, including zeaxanthin, which is derived from \u03b2-carotene via two hydroxylation reactions. Blocking these reactions could therefore improve the endosperm \u03b2-carotene content. Accordingly, we used RNA interference (RNAi) to silence the endogenous ZmBCH1 and ZmBCH2 genes, which encode two non-heme di-iron carotenoid \u03b2-hydroxylases. The genes were silenced in a range of maize genetic backgrounds by introgressing the RNAi cassette, allowing us to determine the impact of ZmBCH1\/ZmBCH2 silencing in diverse hybrids. The \u03b2-carotene content of the endosperm increased substantially in all hybrids in which ZmBCH2 was silenced, regardless of whether or not ZmBCH1 was silenced simultaneously. However, the \u03b2-carotene content did not change significantly in C17 hybrids (M7 \u00d7 C17 and M13 \u00d7 C17) compared to C17 alone, because ZmBCH2 is already expressed at negligible levels in the C17 parent. Our data indicate that ZmBCH2 is primarily responsible for the conversion of \u03b2-carotene to zeaxanthin in maize endosperm.<\/jats:p>","DOI":"10.3390\/ijms18122515","type":"journal-article","created":{"date-parts":[[2017,11,24]],"date-time":"2017-11-24T11:29:33Z","timestamp":1511522973000},"page":"2515","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":29,"title":["The Silencing of Carotenoid \u03b2-Hydroxylases by RNA Interference in Different Maize Genetic Backgrounds Increases the \u03b2-Carotene Content of the Endosperm"],"prefix":"10.3390","volume":"18","author":[{"given":"Judit","family":"Berman","sequence":"first","affiliation":[{"name":"Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Av. Alcalde Rovira Roure, 191, 25198 Lleida, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Uxue","family":"Zorrilla-L\u00f3pez","sequence":"additional","affiliation":[{"name":"Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Av. Alcalde Rovira Roure, 191, 25198 Lleida, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gerhard","family":"Sandmann","sequence":"additional","affiliation":[{"name":"Biosynthesis Group, Molecular Biosciences, Johann Wolfgang Goethe Universit\u00e4t, 60054 Frankfurt, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Teresa","family":"Capell","sequence":"additional","affiliation":[{"name":"Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Av. Alcalde Rovira Roure, 191, 25198 Lleida, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paul","family":"Christou","sequence":"additional","affiliation":[{"name":"Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Av. Alcalde Rovira Roure, 191, 25198 Lleida, Spain"},{"name":"ICREA, Catalan Institute for Research and Advanced Studies, Passeig Llu\u00eds Companys 23, 08010 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2834-2742","authenticated-orcid":false,"given":"Changfu","family":"Zhu","sequence":"additional","affiliation":[{"name":"Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Av. Alcalde Rovira Roure, 191, 25198 Lleida, Spain"},{"name":"School of Life Sciences, Changchun Normal University, Changchun 130032, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,11,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1007\/s11627-011-9363-6","article-title":"A golden era\u2014Pro-vitamin A enhancement in diverse crops","volume":"47","author":"Bai","year":"2011","journal-title":"In Vitro Cell. Dev. Biol. Plant"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"532","DOI":"10.1016\/j.tplants.2011.08.001","article-title":"Nutritious crops producing multiple carotenoids\u2014A metabolic balancing act","volume":"16","author":"Bai","year":"2011","journal-title":"Trends Plant Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"727","DOI":"10.1007\/s11101-014-9373-1","article-title":"Nutritionally important carotenoids as consumer products","volume":"14","author":"Berman","year":"2015","journal-title":"Phytochem. Rev."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"548","DOI":"10.1016\/j.tplants.2007.09.007","article-title":"Transgenic strategies for the nutritional enhancement of plants","volume":"12","author":"Zhu","year":"2007","journal-title":"Trends Plant Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1007\/s11103-013-0027-2","article-title":"Can the world afford to ignore biotechnology solutions that address food insecurity?","volume":"83","author":"Berman","year":"2013","journal-title":"Plant Mol. Biol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.plantsci.2010.03.009","article-title":"Travel advice on the road to carotenoids in plants","volume":"179","author":"Sanahuja","year":"2010","journal-title":"Plant Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1146\/annurev-arplant-050213-035825","article-title":"Engineering complex metabolic pathways in plants","volume":"65","author":"Blancquaert","year":"2014","journal-title":"Annu. Rev. Plant Biol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1016\/j.abb.2010.06.016","article-title":"Supply of precursors for carotenoid biosynthesis in plants","volume":"504","year":"2010","journal-title":"Arch. Biochem. Biophys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1093\/pcp\/pcp005","article-title":"The evolution and function of carotenoid hydroxylases in Arabidopsis","volume":"50","author":"Kim","year":"2009","journal-title":"Plant Cell Physiol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1016\/j.phytochem.2009.10.011","article-title":"Over-expression of Arabidopsis thaliana carotenoid hydroxylases individually and in combination with a beta-carotene ketolase provides insight into in vivo functions","volume":"71","author":"Kim","year":"2010","journal-title":"Phytochemistry"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1947","DOI":"10.1105\/tpc.105.039966","article-title":"A chromoplast-specific carotenoid biosynthesis pathway is revealed by cloning of the tomato white-flower locus","volume":"18","author":"Galpaz","year":"2006","journal-title":"Plant Cell"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1007\/s11248-010-9387-4","article-title":"Overexpression of CrtR-b2 (carotene \u03b2 hydroxylase 2) from S. lycopersicum L. differentially affects xanthophyll synthesis and accumulation in transgenic tomato plants","volume":"20","author":"Stigliani","year":"2011","journal-title":"Transgenic Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"851","DOI":"10.1093\/pcp\/pcr037","article-title":"Characterization of P450 carotenoid \u03b2- and epsilon-hydroxylases of tomato and transcriptional regulation of xanthophyll biosynthesis in root, leaf, petal and fruit","volume":"52","author":"Stigliani","year":"2011","journal-title":"Plant Cell Physiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.abb.2006.11.019","article-title":"Escherichia coli as a platform for functional expression of plant P450 carotene hydroxylases","volume":"458","author":"Quinlan","year":"2007","journal-title":"Arch. Biochem. Biophys."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"987","DOI":"10.1093\/pcp\/pcs041","article-title":"Rice carotenoid \u03b2-ring hydroxylase CYP97A4 is involved in lutein biosynthesis","volume":"53","author":"Lv","year":"2012","journal-title":"Plant Cell Physiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1635","DOI":"10.1104\/pp.109.145177","article-title":"Metabolite sorting of a germplasm collection reveals the hydroxylase 3 locus as a new target for maize provitamin A biofortification","volume":"151","author":"Vallabhaneni","year":"2009","journal-title":"Plant Physiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.1007\/s11248-010-9381-x","article-title":"Cloning and functional characterization of the maize carotenoid isomerase and \u03b2-carotene hydroxylase genes and their regulation during endosperm maturation","volume":"19","author":"Li","year":"2010","journal-title":"Transgenic Res."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1038\/ng.551","article-title":"Rare genetic variation at Zea mays crtRB1 increases \u03b2-carotene in maize grain","volume":"42","author":"Yan","year":"2010","journal-title":"Nat. Genet."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"260","DOI":"10.1111\/j.1744-7909.2012.01106.x","article-title":"ZmcrtRB3 encodes a carotenoid hydroxylase that affects the accumulation of \u03b1-carotene in maize kernel","volume":"54","author":"Zhou","year":"2012","journal-title":"J. Integr. Plant Biol."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Chang, S., Berman, J., Sheng, Y., Wang, Y., Capell, T., Shi, L., Ni, X., Sandmann, G., Christou, P., and Zhu, C. (2015). Cloning and functional characterization of the maize (Zea mays L.) carotenoid epsilon hydroxylase gene. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0128758"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1007\/s00122-012-1987-3","article-title":"Validation of the effects of molecular marker polymorphisms in LcyE and CrtRB1 on provitamin A concentrations for 26 tropical maize populations","volume":"126","author":"Babu","year":"2013","journal-title":"Theor. Appl. Genet."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1699","DOI":"10.1534\/genetics.114.169979","article-title":"A foundation for provitamin A biofortification of maize: Genome-wide association and genomic prediction models of carotenoid levels","volume":"198","author":"Owens","year":"2014","journal-title":"Genetics"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1007\/BF02986245","article-title":"Enhancing beta-carotene content in potato by RNAi-mediated silencing of the beta-carotene hydroxylase gene","volume":"84","author":"Conlin","year":"2007","journal-title":"Am. J. Potato Res."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Diretto, G., Welsch, R., Tavazza, R., Mourgues, F., Pizzichini, D., Beyer, P., and Giuliano, G. (2007). Silencing of beta-carotene hydroxylase increases total carotenoid and beta-carotene levels in potato tubers. BMC Plant Biol., 7.","DOI":"10.1186\/1471-2229-7-11"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1111\/pbi.12112","article-title":"Metabolic engineering of \u03b2-carotene in orange fruit increases its in vivo antioxidant properties","volume":"12","author":"Pons","year":"2014","journal-title":"Plant Biotechnol. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"9083","DOI":"10.1021\/acs.jafc.5b04279","article-title":"Metabolic engineering of wheat provitamin A by simultaneously overexpressing CrtB and silencing carotenoid hydroxylase (TaHYD)","volume":"63","author":"Zeng","year":"2015","journal-title":"J. Agric. Food Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"330","DOI":"10.1126\/science.1150255","article-title":"Natural genetic variation in lycopene epsilon cyclase tapped for maize biofortification","volume":"319","author":"Harjes","year":"2008","journal-title":"Science"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"18232","DOI":"10.1073\/pnas.0809737105","article-title":"Combinatorial genetic transformation generates a library of metabolic phenotypes for the carotenoid pathway in maize","volume":"105","author":"Zhu","year":"2008","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1111\/j.1467-7652.2010.00554.x","article-title":"Synergistic metabolism in hybrid corn indicates bottlenecks in the carotenoid pathway and leads to the accumulation of extraordinary levels of the nutritionally important carotenoid zeaxanthin","volume":"9","author":"Naqvi","year":"2011","journal-title":"Plant Biotechnol. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"933","DOI":"10.1007\/s00299-017-2126-z","article-title":"The Arabidopsis ORANGE (AtOR) gene promotes carotenoid accumulation in transgenic corn hybrids derived from parental lines with limited carotenoid pools","volume":"36","author":"Berman","year":"2017","journal-title":"Plant Cell Rep."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/18\/12\/2515\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:51:12Z","timestamp":1760208672000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/18\/12\/2515"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,11,24]]},"references-count":30,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2017,12]]}},"alternative-id":["ijms18122515"],"URL":"https:\/\/doi.org\/10.3390\/ijms18122515","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,11,24]]}}}