A5040746765- Antioxidant Activity and Oxidative Stress
- Photosynthetic Processes and Mechanisms
- Genetic Mapping and Diversity in Plants and Animals
- Lipid metabolism and biosynthesis
- Genetic and phenotypic traits in livestock
- Plant biochemistry and biosynthesis
- Genetics and Plant Breeding
- Plant tissue culture and regeneration
- Alkaloids: synthesis and pharmacology
- Plant-Microbe Interactions and Immunity
- Microbial Natural Products and Biosynthesis
- Nitrogen and Sulfur Effects on Brassica
- Transgenic Plants and Applications
- Plant Pathogens and Fungal Diseases
- CRISPR and Genetic Engineering
- Phytase and its Applications
- Berry genetics and cultivation research
- Plant Reproductive Biology
- Plant Micronutrient Interactions and Effects
- Plant Molecular Biology Research
- Sunflower and Safflower Cultivation
- Meat and Animal Product Quality
- Coenzyme Q10 studies and effects
- Cancer therapeutics and mechanisms
- Nutritional Studies and Diet
Michigan State University
2013-2025
Tocopherols (vitamin E) are lipophilic antioxidants synthesized by all plants and particularly abundant in seeds. Despite cloning of the complete suite tocopherol biosynthetic enzymes successful engineering content composition Arabidopsis thaliana leaves seeds, functions tocopherols have remained elusive. To address this issue, we isolated characterized two VITAMIN E loci (VTE1 VTE2) that when mutated result deficiency tissues. vte1 disrupts cyclase activity accumulates a redox-active...
Summary Arabidopsis thaliana has nine genes that constitute a family of putative carotenoid cleavage dioxygenases ( CCDs ). While five members the are believed to be involved in synthesis phytohormone abscisic acid, functions other four enzymes less clear. Recently two enzymes, CCD7/MAX3 and CCD8/MAX4, have been implicated novel apocarotenoid hormone controls lateral shoot growth. Here, we report on molecular genetic interactions between CCD1 , CCD8/MAX4 . distinguishes itself from reported...
Abstract Efforts are underway for development of crops with improved levels provitamin A carotenoids to help combat dietary vitamin deficiency. As a global staple crop considerable variation in kernel carotenoid composition, maize (Zea mays L.) could have widespread impact. We performed genome-wide association study (GWAS) quantified seed across panel inbreds ranging from light yellow dark orange grain color identify some the key genes controlling composition. Significant associations at...
Lutein, a dihydroxy xanthophyll, is the most abundant carotenoid in plant photosynthetic tissues and plays crucial structural functional roles light-harvesting complexes. Carotenoid beta-and epsilon-hydroxylases catalyze formation of lutein from alpha-carotene (beta,epsilon-carotene). In contrast to well studied beta-hydroxylases that have been cloned characterized many organisms, epsilon-hydroxylase has only genetically defined by lut1 mutation Arabidopsis. We isolated LUT1 gene positional...
Experimental approaches targeting carotenoid biosynthetic enzymes have successfully increased the seed β-carotene content of crops. However, linkage analysis carotenoids in Arabidopsis thaliana recombinant inbred populations showed that only 21% quantitative trait loci, including those for β-carotene, encode their intervals. Thus, numerous loci remain uncharacterized and underutilized biofortification approaches. Linkage mapping genome-wide association studies identified CAROTENOID cleavage...
Tocopherols and tocotrienols, collectively known as tocochromanols, are the major lipid-soluble antioxidants in maize (Zea mays L.) grain. Given that individual tocochromanols differ their degree of vitamin E activity, variation for tocochromanol composition content grain from among diverse inbred lines has important nutritional health implications enhancing antioxidant contents maize-derived foods through plant breeding. Toward this end, we conducted a genome-wide association study six...
The natural diversity of plant metabolism has long been a source for human medicines. One group plant-derived compounds, the monoterpene indole alkaloids (MIAs), includes well-documented therapeutic agents used in treatment cancer (vinblastine, vincristine, camptothecin), hypertension (reserpine, ajmalicine), malaria (quinine), and as analgesics (7-hydroxymitragynine). Our understanding biochemical pathways that synthesize these commercially relevant compounds is incomplete due part to lack...
Camptothecin is a monoterpene indole alkaloid (MIA) used to produce semisynthetic antitumor drugs. We investigated camptothecin synthesis in Camptotheca acuminata by combining transcriptome and expression data with reverse genetics, biochemistry, metabolite profiling. RNAi silencing of enzymes required for the seco-iridoid (monoterpene) components identified transcriptional crosstalk coordinating their roots. Metabolite profiling labeling studies wild-type lines plausible intermediates...
Tocopherols, tocotrienols, and plastochromanols (collectively termed tocochromanols) are lipid-soluble antioxidants synthesized by all plants. Their dietary intake, primarily from seed oils, provides vitamin E other health benefits. Tocochromanol biosynthesis has been dissected in the dicot Arabidopsis thaliana, which green, photosynthetic seeds, but our understanding of tocochromanol accumulation major crops, whose seeds nonphotosynthetic, remains limited. To understand genetic control...
Summary Expression of industrial enzymes in transgenic plants offers an alternative system to fungal fermentation for large‐scale production. Very high levels expression are required make the cost‐effective. We tested several parameters determine best method achieving a laccase gene. Transgenic maize were generated using Agrobacterium ‐mediated system. The molecular that induced highest embryo‐preferred globulin 1 promoter and targeting protein cell wall. Two independent events yielded...
Lutein and zeaxanthin are dihydroxy xanthophylls that produced from their corresponding carotene precursors by the action of β- ε-ring carotenoid hydroxylases. Two genes encode β-ring hydroxylases (β-hydroxylases 1 2) have been identified in Arabidopsis genome highly active toward β-rings but only weakly ε-rings. A third distinct activity required for hydroxylation has defined mutation LUTEIN1 (LUT1) locus, LUT1 not yet cloned. To address individual overlapping functions three hydroxylase...
Abstract Tocochromanols (tocopherols and tocotrienols, collectively vitamin E) are lipid-soluble antioxidants important for both plant fitness human health. The main dietary sources of E seed oils that often accumulate high levels tocopherol isoforms with lower activity. tocochromanol biosynthetic pathway is conserved across species but an integrated view the genes mechanisms underlying natural variation in most cereal crops remains limited. To address this issue, we utilized mapping...
We measured the DeltaPsi and DeltapH components of transthylakoid proton motive force (pmf) in light-adapted, intact tobacco leaves response to moderate heat. The causes an electrochromic shift (ECS) carotenoid absorbance spectra. light-dark difference spectrum has a peak at 518 nm two pmf were separated by following ECS for 25 s after turning light off. signal was deconvoluted subtracting effects zeaxanthin formation (peak 505 nm) qE-related changes 535 from 520 nm. Heat reduced while...
Elucidation of the carotenoid biosynthetic pathway has enabled altering composition and content carotenoids in various plants, but to achieve desired nutritional impacts, genetic components regulating homeostasis seed, plant organ consumed greatest abundance, must be elucidated. We used a combination linkage mapping, genome-wide association studies (GWAS), pathway-level analysis identify nine loci that impact natural variation seed Arabidopsis (Arabidopsis thaliana). ZEAXANTHIN EPOXIDASE...
Abstract Sweet corn ( Zea mays L.) is highly consumed in the United States, but does not make major contributions to daily intake of carotenoids (provitamin A carotenoids, lutein and zeaxanthin) that would help prevention health complications. genome‐wide association study seven kernel twelve derivative traits was conducted a sweet inbred line panel ranging from light dark yellow endosperm color elucidate genetic basis carotenoid levels fresh kernels. In agreement with earlier studies maize...
Abstract Vitamin A deficiency remains prevalent in parts of Asia, Latin America, and sub-Saharan Africa where maize (Zea mays) is a food staple. Extensive natural variation exists for carotenoids grain. Here, to understand its genetic basis, we conducted joint linkage genome-wide association study the US nested mapping panel. Eleven 44 detected quantitative trait loci (QTL) were resolved individual genes. Six these correlated expression effect QTL (ceeQTL), showing strong correlations...
Vitamin E is an essential nutrient for humans and obtained primarily from food, especially oil, derived the seed of plants. Genes encoding committed steps in vitamin synthesis plants (VTE, loci 1-5) have been isolated used tocopherol pathway engineering with various degrees success. As a complement to such approaches we quantitative trait analysis two sets Arabidopsis thaliana recombinant inbred lines identified 14 QVE (quantitative E) affecting content composition seeds. Five intervals...
Sweet corn ( L.), a highly consumed fresh vegetable in the United States, varies for tocochromanol (tocopherol and tocotrienol) levels but makes only limited contribution to daily intake of vitamin E antioxidants. We performed genome-wide association study six compounds 14 derivative traits across sweet inbred line panel identify genes associated with natural variation tocochromanols kernels. Concordant prior studies mature maize kernels, an was detected between γ-tocopherol...
Significance Tocopherols (vitamin E) are plant-synthesized, lipid-soluble antioxidants whose dietary intake, primarily from seed oils, is essential for human health. contain a phytol-derived hydrophobic tail in vivo source has been elusive. The most significant genome-wide association signal Arabidopsis tocopherols identified an uncharacterized, seed-specific esterase (VTE7) localized to the chloroplast envelope, where tocopherol synthesis occurs. VTE7 disruption and overexpression had large...
Tocopherol synthesis requires phytyl diphosphate derived from phytol esterified to chlorophyll metabolites. The >600-member Arabidopsis thaliana α/β hydrolase (ABH) gene family contains 4 members that can release metabolites in vitro; however, only pheophytinase (PPH) affects tocopherol when mutated, reducing seed tocopherols by 5%. We report the biochemical analysis of 2 previously uncharacterized ABHs, dephytylase (CLD2) and CLD3, their respective mutants singly combinations with pph cld1...
Tocopherols are a class of lipid-soluble compounds that have multiple functional roles in plants and exhibit vitamin E activity, an essential nutrient for human animal health. The tocopherol biosynthetic pathway is conserved across the plant kingdom, but source key precursor, phytol, unclear. Two protochlorophyllide reductases (POR1 POR2) were previously identified as loci controlling natural variation total tocopherols maize grain, non-photosynthetic tissue. POR1 POR2 genes chlorophyll...
Domestication of cranberry and blueberry began in the United States early 1800s 1900s, respectively, part owing to their flavors health-promoting benefits are now cultivated consumed worldwide. The industry continues face a wide variety production challenges (e.g. disease pressures), as well demand for higher-yielding cultivars with improved fruit quality characteristics. Unfortunately, molecular tools help guide breeding efforts these species have been relatively limited compared those...
tie-dyed1 (tdy1) and sucrose export defective1 (sxd1) are recessive maize (Zea mays) mutants with nonclonal chlorotic leaf sectors that hyperaccumulate starch soluble sugars. In addition, both display similar growth-related defects such as reduced plant height inflorescence development due to the retention of carbohydrates in leaves. As tdy1 sxd1 only variegated known accumulate any plant, we investigated whether Tdy1 Sxd1 function same pathway. Using aniline blue staining for callose...
Maize white seedling 3 (w3) has been used to study carotenoid deficiency for almost 100 years, although the molecular basis of mutation remained unknown. Here we show that w3 phenotype is caused by disruption maize gene homogentisate solanesyl transferase (HST), which catalyzes first and committed step in plastoquinone-9 (PQ-9) biosynthesis plastid. The resulting PQ-9 prohibits photosynthetic electron transfer eliminates as an oxidant enzymatic desaturation phytoene during synthesis. As a...