Evidence map›Paper›PMID 40082754›Full record

ArticleBMC plant biology2025

Total tocopherol levels in maize grain depend on chlorophyll biosynthesis within the embryo.

Sam Herr, Xiaowei Li, Di Wu, Charles T Hunter, Maria Magallanes-Lundback, Joshua C Wood, Nicholas Kaczmar, C Robin Buell, Dean DellaPenna, Michael A Gore

Abstract read
In one paragraph

Article in BMC plant biology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Sam Herr *Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.ORCID http://orcid.org/0000-0002-9887-3082
Xiaowei Li *Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.ORCID http://orcid.org/0000-0002-4850-1301
Di Wu *Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.ORCID http://orcid.org/0000-0002-5775-8029
Charles T HunterUSDA-ARS Chemistry Research Unit, Gainesville, FL, 32608, USA.ORCID http://orcid.org/0000-0002-2652-9485
Maria Magallanes-LundbackDepartment of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.ORCID http://orcid.org/0000-0001-5826-6897
Joshua C WoodCenter for Applied Genetic Technologies, University of Georgia, Athens, GA, 30602, USA.ORCID http://orcid.org/0000-0002-7691-6088
Nicholas KaczmarPlant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.
C Robin BuellCenter for Applied Genetic Technologies, University of Georgia, Athens, GA, 30602, USA.ORCID http://orcid.org/0000-0002-6727-4677
Dean DellaPennaDepartment of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.ORCID http://orcid.org/0000-0001-9505-7883
Michael A GorePlant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA. mag87@cornell.edu.ORCID http://orcid.org/0000-0001-6896-8024

Funding

National Science Foundation, United States IOS-1546657U.S. Department of Agriculture 1013641
6 · The paper itself

Abstract

backgroundTocopherols are a class of lipid-soluble compounds that have multiple functional roles in plants and exhibit vitamin E activity, an essential nutrient for human and animal health. The tocopherol biosynthetic pathway is conserved across the plant kingdom, but source of the key tocopherol pathway precursor, phytol, is unclear. Two protochlorophyllide reductases (POR1 and POR2) were previously identified as loci controlling the natural variation of total tocopherols in maize grain, a non-photosynthetic tissue. POR1 and POR2 are key genes in chlorophyll biosynthesis yet the contribution of the chlorophyll biosynthetic pathway to tocopherol biosynthesis is still not understood.

resultsWe took two approaches to alter the activity of these two POR genes within kernel tissue, physiological treatments and CRISPR/Cas9-mediated knockouts, to determine the role of chlorophyll biosynthesis for tocopherol content. Since light is required for POR enzymatic activity, we imposed a dark treatment on developing kernels, which reduced chlorophyll a and tocopherols levels in embryo tissue by 92-99% and 87-90%, respectively, compared to the light treatment. In CRISPR/Cas9-mediated knockouts, the levels of chlorophyll a and tocopherols in embryos of the por1 por2 double homozygous mutant were reduced by 98-100% and 76-83%, respectively, compared to WT.

conclusionThese findings demonstrate that tocopherol synthesis in maize grain depends almost entirely on phytol derived from chlorophyll biosynthesis within the embryo. POR1 and POR2 activity play crucial roles in chlorophyll biosynthesis, underscoring the importance of POR alleles and their activity in the biofortification of vitamin E levels in non-photosynthetic grain of maize.

Indexed as

ChlorophyllTocopherolsZea maysCRISPR-Cas SystemsEndospermGene Expression Regulation, PlantGene Knockout TechniquesGenes, PlantOxidoreductases Acting on CH-CH Group DonorsRNA, PlantChlorophyllOxidoreductases Acting on CH-CH Group Donorsprotochlorophyllide reductaseRNA, PlantTocopherolsBiofortificationChlorophyllCRISPR/Cas9MaizeTocopherolVitamin E

Identifiers

PMID40082754
PMCPMC11905637

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.