About

Michael Mazourek is an Associate Professor in the School of Integrative Plant Science, specializing in Plant Breeding and Genetics within the Horticulture Section. His research focuses on vegetable breeding aimed at improving flavor, resilience, and adaptation of crops for production in the Northeastern US. He conducts selection in ecologically managed systems to better understand the parallels between artificial and natural selection, with an emphasis on genomics and chemistry that underlie plant adaptation to biotic environments. His work encompasses crops such as peppers, squash, cucumber, watermelon, pumpkin, peas, and beans, utilizing tools like genomics, genetics, molecular biology, on-farm trials, and analytical chemistry. Mazourek's goal is to develop new varieties that require fewer synthetic inputs and to identify genetic factors that contribute to crop resilience and flavor, sharing his germplasm and knowledge with local and global communities.

Research topics

• Biology
• Botany
• Genetics
• Computer Science
• Business
• Agroforestry
• Environmental science
• Database
• Computational biology
• Economics
• Biotechnology
• Geography
• Agronomy
• Biochemistry
• Cell biology
• Ecology
• Agricultural science

Selected publications

• The USDA-SCRI CucCAP Projects: Building Genomic, Breeding and Disease Management Tools for Cucurbit Crops

  Journal of the American Society for Horticultural Science · 2026-02-18

  articleOpen access

  Cucurbit crops including watermelon ( Citrullus lanatus ), melon ( Cucumis melo ), cucumber ( Cucumis sativus ), squash, and pumpkin ( Cucurbita spp.) make important nutritional and flavorful contributions to the human diet. The primary challenge for US cucurbit production is disease caused by numerous fungal, oomycete, bacterial, and viral pathogens that reduce crop yield and quality and engender costly control measures. The USDA National Institute of Food and Agriculture–Specialty Crop Research Initiative funded CucCAP (Cucurbit Coordinated Agricultural Project) projects “CucCAP: Leveraging applied genomics to improve disease resistance in cucurbit crops” and “CucCAP2: Harnessing genomic resources for disease resistance and management in cucurbit crops–Bringing the tools to the field” brought together members of the cucurbit community across the country with expertise in genomics, bioinformatics, breeding, genetics, plant pathology, integrated disease management, and economics to address these disease challenges. Collectively, the projects produced extensive genomic resources and bioinformatic tools including genome assemblies and pan-genomes for cucurbit species; genetically characterized the full US National Plant Germplasm System (NPGS) collections for watermelon, melon, cucumber, and squash; developed deeply resequenced core populations for these crops; identified single nucleotide polymorphism and structural variants; and developed the Cucurbit Genomics database (CuGenDB, http://cucurbitgenomics.org/v2/ ). New sources of resistance were identified for 17 cucurbit crop/disease combinations; quantitative trait loci were mapped and molecular markers developed for 24 combinations; and 15 breeding lines with resistances to various diseases were released. New detection methodology was developed for several pathogens; extensive disease monitoring and multilocation disease management trials and resistance tests were performed; a centralized web portal ( https://cuccap.org ) was developed to provide cucurbit disease information in English and Spanish; and disease management information was shared with growers, commodity groups and industry organizations through publications and presentations at conferences, field days, and extension schools delivered at more than 100 venues in 24 states. The CucCAP projects were carried out through joint efforts among 26 university and USDA coinvestigators and their research groups along with valued input and assistance from NPGS cucurbit crop curators, seed industry collaborators, cucurbit growers, external evaluators, and international collaborators. In addition to the specific genomic, breeding, and disease management outputs, the CucCAP projects have had broader impacts including use of the new genomic tools to provide insights into cucurbit biology, synergistic effects resulting from a more cohesive cucurbit community, and scientific training of a cadre of students and postdoctoral researchers.

  PublisherDOI

• Evaluation of an Integrated Management Program in Partially Resistant Processing Pumpkin Breeding Lines to Manage Powdery Mildew, 2023

  Plant Health Progress · 2025-01-01

  article

  Cucurbit powdery mildew, caused by the fungus Podosphaera xanthii, is a common disease of pumpkin in North America. This report evaluates the efficacy of integrating biorational fungicides with partially resistant processing pumpkin germplasm for the management of powdery mildew. The trial was conducted in 2023 in Geneva, NY, on Cucurbita moschata breeding lines. Results from this trial are expected to help in managing powdery mildew of cucurbits.

  PublisherDOI

• Meta genetic analysis of melon sweetness

  Theoretical and Applied Genetics · 2025-03-11 · 6 citations

  reviewOpen access

  Abstract Key message Through meta-genetic analysis of Cucumis melo sweetness, we expand the description of the complex genetic architecture of this trait. Integration of extensive new results with published QTL data provides an outline towards construction of a melon sweetness pan-QTLome. Abstract An ultimate objective in crop genetics is describing the complete repertoire of genes and alleles that shape the phenotypic variation of a quantitative trait within a species. Flesh sweetness is a primary determinant of fruit quality and consumer acceptance of melons . Cucumis melo is a diverse species that, among other traits, displays extensive variation in total soluble solids (TSS) content in fruit flesh, ranging from 2 0 Brix in non-sweet to 18 0 Brix in sweet accessions. We present here meta-genetic analysis of TSS and sugar variation in melon, using six different populations and fruit measurements collected from more than 30,000 open-field and greenhouse-grown plants, integrated with 15 published melon sweetness-related quantitative trait loci (QTL) studies. Starting with characterization of sugar composition variation across 180 diverse accessions that represent 3 subspecies and 12 of their cultivar-groups, we mapped TSS and sugar QTLs, and confirmed that sucrose accumulation is the key variable explaining TSS variation. All modes-of-inheritance for TSS were displayed by multi-season analysis of a broad half-diallel population derived from 20 diverse founders, with significant prevalence of the additive component. Through parallel genetic mapping in four advanced bi-parental populations, we identified common as well as unique TSS QTLs in 12 chromosomal regions. We demonstrate the cumulative less-than-additive nature of favorable TSS QTL alleles and the potential of a QTL-stacking approach. Using our broad dataset, we were additionally able to show that TSS variation displays weak genetic correlations with melon fruit size and ripening behavior, supporting effective breeding for sweetness per se. Our integrated analysis, combined with additional layers of published QTL data, broadens the perspective on the complex genetic landscape of melon sweetness and proposes a scheme towards future construction of a crop community-driven melon sweetness pan-QTLome.

  PublisherOA PDFDOI

• Processing Pumpkin (Cucurbita moschata Duchesne) Breeding Lines with Resistance to Powdery Mildew and Their Canning Quality

  HortScience · 2025-03-14

  articleOpen access

  Processing pumpkin ( Cucurbita moschata Duch.) is an economically important crop in the United States, and commercial cultivars are susceptible to cucurbit powdery mildew (CPM). Ideally, CPM would be managed with fungicides and host resistance; however, this combination of tools is currently inaccessible to growers of processing pumpkin. The objectives of this study were to identify CPM-resistant processing pumpkin breeding lines and evaluate their canning quality. An industry standard and CPM-susceptible processing pumpkin cultivar Dickinson was crossed with Bugle, a butternut squash that is resistant to CPM and carries the common resistance gene Pm-0 . Each line evaluated was homozygous for Pm-0 and was developed by selecting lines following three backcrosses to ‘Dickinson’. Two lines with moderate and high levels of resistance were identified by a field trial in 2022 and assessed again in 2023. The same two lines were processed and canned along with ‘Dickinson’ and ‘Bugle’. Their canning qualities were assessed and compared with a store-bought commercial standard. The dry matter (%), pH, moisture (%), soluble solids (°Brix), consistency, color, water activity, alcohol insoluble residue (AIR), and ratio of AIR to total solids were measured. The results indicated that the purées from both breeding lines more closely resembled ‘Dickinson’ and the commercial standard than ‘Bugle’. We concluded that effective CPM resistance has been bred into a commercially promising processing pumpkin background.

  PublisherDOI

• Phytoene synthase modulates seed longevity via β-carotene derived metabolites

  PLANT PHYSIOLOGY · 2025-11-15 · 1 citations

  article

  Seed longevity, the seed's ability to stay viable over time, is an important trait in agriculture that remains a fundamental topic in plant biology. Here, we discovered a function of carotenoid metabolites in prolonging seed lifespan. We found that phytoene synthase (PSY), a major rate-limiting enzyme in carotenoid biosynthesis, modulated seed storability in Arabidopsis (Arabidopsis thaliana) under both natural and artificial aging conditions. Seeds from PSY overexpression lines exhibited significantly enhanced lifespan with low levels of reactive oxygen species (ROS), a major factor affecting longevity. In contrast, seeds from psy mutants had decreased viability with high ROS levels. Both lutein and β-carotene were detected in seeds. However, only β-carotene and its derived apocarotenoids, β-cyclocitral and β-ionone, improved seed lifespan. Seeds from a carotenoid cleavage dioxygenase 1 and 4 (ccd1/4) double mutant and ccd1/4 PSY overexpressing lines had significantly reduced seed longevity, supporting that β-carotene cleavage is necessary for preserving seed lifespan. Comparative proteomic analysis identified TIP2;2, an aquaporin protein, with differential abundances in seeds of PSY overexpression and psy mutant lines. The tip2;2 mutant had reduced seed longevity, and its promoter was transactivated by apocarotenoids. Overexpression of PSY in tip2;2 failed to fully reverse the effects of the mutation, indicating that TIP2;2 is required for the PSY-regulated seed longevity. This study uncovers a role of apocarotenoids in protecting seed longevity and highlights the importance of seed carotenoid production in strengthening agriculture.

  PublisherDOI

• <i>Phytoene synthase</i> modulates seed longevity via the action of β-carotene derived metabolites

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-06-09 · 2 citations

  preprintOpen access

  Abstract Seed longevity, the seed’s ability to stay viable over time, is an important trait in agriculture. Despite extensive research, seed longevity remains one of the fundamental topics in plant biology. Here, we discovered the novel role of carotenoid metabolites in prolonging seed lifespan. We found that phytoene synthase ( PSY ), the gene encoding a major rate-limiting enzyme in carotenoid biosynthesis, modulated seed storability in Arabidopsis under both natural and artificial aging conditions. Seeds from the PSY overexpression (OE) lines exhibited significantly enhanced lifespan with low levels of reactive oxygen species (ROS), a major factor affecting longevity, whereas those from the psy mutants had decreased viability with high ROS levels. While lutein and β-carotene were detected in seeds, only β-carotene and its derived apocarotenoids, i.e. β-cyclocitral and β-ionone, were found to improve seed lifespan. Notably, the carotenoid cleavage dioxygenase 1 and 4 ( ccd1 ccd4 ) double mutant and PSY ccd1 ccd4 seeds showed significantly reduced seed longevity, indicating that β-carotene cleavage is necessary for or it is apocarotenoids playing the role in preserving seed lifespan. Comparative proteomic analysis identified TIP2;2, an aquaporin protein, which showed differential abundances in seeds of PSY OE and psy mutant vs wild type. The mutant tip2;2 had reduced seed longevity, and its promoter was transactivated by apocarotenoids. Collectively, this study uncovers a novel role of apocarotenoids in protecting seed longevity and highlights the importance of seed carotenoid production in strengthening agriculture. One Sentence Summary Phytoene synthase , the gene encoding a major rate-limiting enzyme in carotenoid biosynthesis, modulates seed longevity via β-carotene derived apocarotenoids and an aquaporin protein TIP2;2 identified is a new player that responds to apocarotenoid signaling and influences seed longevity.

  PublisherOA PDFDOI

• <scp>GLKs</scp> directly regulate carotenoid biosynthesis via interacting with <scp>GBFs</scp> in plants

  New Phytologist · 2025-02-14 · 18 citations

  articleOpen access

  Carotenoids are vital photosynthetic pigments for plants. Golden2-like transcription factors (GLKs) are widely recognized as major regulators of Chl biosynthesis and chloroplast development. However, despite GLKs being subjected to intensive investigations, whether GLKs directly regulate carotenoid biosynthesis and the molecular mechanisms by which GLKs transcriptionally activate their target genes remain unclear. Here, we report that GLKs directly regulate carotenoid biosynthesis and activate their target genes in a G-box binding factor (GBF)-dependent manner in Arabidopsis. Both in vitro and in vivo studies reveal that GLKs physically interact with GBFs to activate transcription of phytoene synthase (PSY), the gene encoding a rate-limiting enzyme for carotenoid biosynthesis. While GLKs possess transactivation activity, they depend on GBFs to directly bind to the G-box motif to modulate PSY expression. Loss of GBFs impairs GLK function in regulating carotenoid and Chl biosynthesis. Since the G-box motif is an enriched motif in the promoters of GLK-regulated genes, the GLK-GBF regulatory module likely serves as a common mechanism underlying GLK-regulated photosynthetic pigment biosynthesis and chloroplast development. Our findings uncover a novel regulatory machinery of carotenoid biosynthesis, discover a molecular mechanism of transcriptional regulation by GLKs, and divulge GLKs as important regulators to coordinate photosynthetic pigment synthesis in plants.

  PublisherOA PDFDOI

• Characterization of the USDA Cucurbita pepo, C. moschata, and C. maxima germplasm collections

  Frontiers in Plant Science · 2023-03-13 · 17 citations

  articleOpen accessSenior authorCorresponding

  The Cucurbita genus is home to a number of economically and culturally important species. We present the analysis of genotype data generated through genotyping-by-sequencing of the USDA germplasm collections of Cucurbita pepo , C. moschata , and C. maxima . These collections include a mixture of wild, landrace, and cultivated specimens from all over the world. Roughly 1,500 - 32,000 high-quality single nucleotide polymorphisms (SNPs) were called in each of the collections, which ranged in size from 314 to 829 accessions. Genomic analyses were conducted to characterize the diversity in each of the species. Analysis revealed extensive structure corresponding to a combination of geographical origin and morphotype/market class. Genome-wide associate studies (GWAS) were conducted using both historical and contemporary data. Signals were observed for several traits, but the strongest was for the bush ( Bu ) gene in C. pepo . Analysis of genomic heritability, together with population structure and GWAS results, was used to demonstrate a close alignment of seed size in C. pepo , maturity in C. moschata , and plant habit in C. maxima with genetic subgroups. These data represent a large, valuable collection of sequenced Cucurbita that can be used to direct the maintenance of genetic diversity, for developing breeding resources, and to help prioritize whole-genome re-sequencing.

  PublisherOA PDFDOI

• Co-chaperoning of chlorophyll and carotenoid biosynthesis by ORANGE family proteins in plants

  Molecular Plant · 2023-05-17 · 69 citations

  articleOpen access
  PublisherOA PDFDOI

• Mapping of the bs5 and bs6 non-race-specific recessive resistances against bacterial spot of pepper

  Frontiers in Plant Science · 2023-05-19 · 7 citations

  articleOpen access

  Bacterial spot caused by Xanthomonas euvesicatoria is a major disease of pepper ( Capsicum annuum L.) in warm and humid production environments. Use of genetically resistant cultivars is an effective approach to manage bacterial spot. Two recessive resistance genes, bs5 and bs6 , confer non-race-specific resistance against bacterial spot. The objective of our study was to map these two loci in the pepper genome. We used a genotyping-by-sequencing approach to initially map the position of the two resistances. Segregating populations for bs5 and bs6 were developed by crossing susceptible Early CalWonder (ECW) with near-isogenic lines ECW50R ( bs5 introgression) or ECW60R ( bs6 introgression). Following fine-mapping, bs5 was delimited to a ~535 Kbp interval on chromosome 3, and bs6 to a ~666 Kbp interval in chromosome 6. We identified 14 and 8 candidate resistance genes for bs5 and bs6 , respectively, based on predicted protein coding polymorphisms between ECW and the corresponding resistant parent. This research enhances marker-assisted selection of bs5 and bs6 in breeding programs and is a crucial step towards elucidating the molecular mechanisms underlying the resistances.

  PublisherOA PDFDOI

Frequent coauthors

• Molly Jahn

  University of Wisconsin–Madison

  49 shared

• James R. Myers

  Oregon State University

  30 shared

• Michael Glos

  28 shared

• George J. Moriarty

  Cornell University

  27 shared

• Mary Kreitinger

  26 shared

• Danya Rumore

  Chicago Kent College of Law

  25 shared

• Elizabeth Henderson

  Queen's University Belfast

  25 shared

• Ammie Chickering

  Oregon State University

  25 shared

Education

• Ph.D., Plant Breeding

  Cornell University

  2005

• M.S., Plant Breeding

  Cornell University

  2001

• B.S., Agricultural Science

  University of Wisconsin-Madison

  1998

Awards & honors

• Grist 50: The 50 People You'll Be Talking About in 2016 (201…
• Grist Featured in USA Pavilion “American Food 2.0” World Foo…
• Honeynut Squash #39 on the Saveur 100 (2015)
• Saveur Magazine Organic Seed Alliance Faces of Public Plant…