About

John Jifon, Ph.D., is a professor in the Department of Horticultural Sciences at the Texas A&M AgriLife Research and Extension Center in Weslaco. His research focuses on the environmental stress physiology of plants, specifically investigating the physiological, biochemical, and molecular mechanisms and traits that confer tolerance to environmental stresses such as drought, radiation and temperature extremes, and nutrient imbalance. A key aspect of his work involves using integrated measurements at the leaf, whole-plant, and stand levels to study factors that influence photosynthetic efficiency, water and nutrient use efficiency, assimilate partitioning, yield, and quality. The aim of his research is to utilize the information gained to develop practical strategies for optimizing productivity and quality by enhancing plant tolerance to environmental stresses. Dr. Jifon’s work contributes to understanding how plants respond to challenging environmental conditions and seeks to improve plant resilience, ultimately supporting agricultural productivity and sustainability.

Research topics

• Biology
• Horticulture
• Agronomy
• Biochemistry
• Chemistry
• Botany
• Food science
• Computational biology
• Mathematics
• Biotechnology
• Statistics
• Materials science
• Bioinformatics

Selected publications

• Profiling carotenoid and sugar contents in unique Cucumis melo L. cultigens harvested from different climatic regions of the United States

  Journal of Food Composition and Analysis · 2021 · 30 citations

  • Biology
  • Horticulture
  • Botany
  DOI

• Transition of aromatic volatile and transcriptome profiles during melon fruit ripening

  Plant Science · 2020 · 30 citations

  • Biology
  • Food science
  • Botany
  DOI

• Stability of yield and its components in grafted tomato tested across multiple environments in Texas

  Scientific Reports · 2020 · 24 citations

  • Horticulture
  • Biology
  • Chemistry

  Grafting with vigorous rootstocks could offer tomato growers in Texas sustainable and efficient option to achieve reliable yield across a range of production systems and locations. Genotypes (G) of grafted and non-grafted tomato were grown in different environments (E) in the 2017 and 2018 spring seasons. The objectives of the study were to (i) evaluate the effects of production system and grafting on tomato yield traits, (ii) determine the size of genotypic and genotype by environment interaction (G × E) variance components, and (iii) evaluate the relative stability of tested genotypes for yield and its components across production environments. In 2017, genotypes were non-grafted 'TAMU Hot Ty' (TAM) and 'Tycoon' (TY) and each grafted on commercial tomato rootstocks 'Estamino' (TAM/ES, TY/ES) and 'Multifort' (TAM/MU, TY/MU) while in 2018, TAM and 'HM1823' (HM) were grafted on 'Estamino' (TAM/ES, HM/ES) and 'Multifort' (TAM/MU, HM/MU). Testing environments were high tunnel (HT) and open-field (OF) in Uvalde in 2017 while in 2018, these were HT and OF in Lubbock (LU-HT, LU-OF), Overton (OV-HT, OV-OF), Uvalde (UV-HT, UV-OF), and Weslaco (WE-HT, WE-OF). Total and marketable yields, fruit number per plant, and average fruit weight were significantly affected by E, G, and G × E interaction. Environmental component contributed 71-86% to the total variation for all these traits, while genotype explained 1.5-10.8%, and the contribution of G × E ranged between 4.3 to 6.7%. Estimation of the univariate statistic parameters and genotype plus genotype × environment (GGE) biplot analysis indicated that HM/MU and HM/ES were the most stable graft combination with the highest total and marketable yields, while TAM/ES was very unstable for yields across test environments. TAM/MU was stable but with yield lower than the grand mean. These results suggest that high tomato yields could be consistently achieved with grafted combination (HM/MU and HM/ES) especially under high tunnel production system across the regions of Texas.

  DOI

• Unprecedented enhancement of recombinant protein production in sugarcane culms using a combinatorial promoter stacking system

  Scientific Reports · 2020 · 53 citations

  • Biotechnology
  • Computational biology
  • Biology

  Plants represent a safe and cost-effective platform for producing high-value proteins with pharmaceutical properties; however, the ability to accumulate these in commercially viable quantities is challenging. Ideal crops to serve as biofactories would include low-input, fast-growing, high-biomass species such as sugarcane. The objective of this study was to develop an efficient expression system to enable large-scale production of high-value recombinant proteins in sugarcane culms. Bovine lysozyme (BvLz) is a potent broad-spectrum antimicrobial enzyme used in the food, cosmetics and agricultural industries. Here, we report a novel strategy to achieve high-level expression of recombinant proteins using a combinatorial stacked promoter system. We demonstrate this by co-expressing BvLz under the control of multiple constitutive and culm-regulated promoters on separate expression vectors and combinatorial plant transformation. BvLz accumulation reached 1.4% of total soluble protein (TSP) (10.0 mg BvLz/kg culm mass) in stacked multiple promoter:BvLz lines, compared to 0.07% of TSP (0.56 mg/kg) in single promoter:BvLz lines. BvLz accumulation was further boosted to 11.5% of TSP (82.5 mg/kg) through event stacking by re-transforming the stacked promoter:BvLz lines with additional BvLz expression vectors. The protein accumulation achieved with the combinatorial promoter stacking expression system was stable in multiple vegetative propagations, demonstrating the feasibility of using sugarcane as a biofactory for producing high-value proteins and bioproducts.

  PublisherOA PDFDOI

• Nanoparticle-Mediated Seed Priming Improves Germination, Growth, Yield, and Quality of Watermelons (Citrullus lanatus) at multi-locations in Texas

  Scientific Reports · 2020 · 389 citations

  • Horticulture
  • Biology
  • Agronomy

  Seed priming uses treatments to improve seed germination and thus potentially increase growth and yield. Low-cost, environmentally friendly, effective seed treatment remain to be optimized and tested for high-value specialty crop like watermelon (Citrullus lanatus) in multi-locations. This remains a particularly acute problem for triploids, which produce desirable seedless watermelons, but show low germination rates. In the present study, turmeric oil nanoemulsions (TNE) and silver nanoparticles (AgNPs) synthesized from agro-industrial byproducts were used as nanopriming agents for diploid (Riverside) and triploid (Maxima) watermelon seeds. Internalization of nanomaterials was confirmed by neutron activation analysis, transmission electron microscopy, and gas chromatography-mass spectrometry. The seedling emergence rate at 14 days after sowing was significantly higher in AgNP-treated triploid seeds compared to other treatments. Soluble sugar (glucose and fructose) contents were enhanced during germination in the AgNP-treated seeds at 96 h. Seedlings grown in the greenhouse were transplanted at four locations in Texas: Edinburg, Pecos, Grapeland, and Snook in 2017. At Snook, higher yield 31.6% and 35.6% compared to control were observed in AgNP-treated Riverside and Maxima watermelons, respectively. To validate the first-year results, treated and untreated seeds of both cultivars were sown in Weslaco, Texas in 2018. While seed emegence and stand establishments were enhanced by seed priming, total phenolics radical-scavenging activities, and macro- and microelements in the watermelon fruits were not significantly different from the control. The results of the present study demonstracted that seed priming with AgNPs can enhance seed germination, growth, and yield while maintaining fruit quality through an eco-friendly and sustainable nanotechnological approach.

  DOI

Frequent coauthors

• Kevin M. Crosby

  Texas A&M University

  58 shared

• James P. Syvertsen

  University of Florida

  55 shared

• Daniel I. Leskovar

  Texas A&M University at Qatar

  48 shared

• Bhimanagouda S. Patil

  Texas A&M University

  40 shared

• Gene E. Lester

  Agricultural Research Service

  39 shared

• G.K. Jayaprakasha

  Texas A&M University

  21 shared

• Paul Brierley

  Texas A&M University

  19 shared

• Gordon Rogers

  University of Sydney

  17 shared

Education

• Ph.D., Plant Physiology

  Cornell University

  1999

• M.S., Physiological Ecology

  Mississippi State University

  1994

• B.S., Ecological Science

  The University of Edinburgh

  1991

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• Raymond Carrollh-119
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• Kim Dunbarh-103