Recipient Organization
PURDUE UNIVERSITY
(N/A)
WEST LAFAYETTE,IN 47907
Performing Department
Horticulture and Landscape Architecture
Non Technical Summary
The paradigm of human health is shifting towards prevention rather than medical intervention to reduce diseases and physiological impairments. Compelling scientific data supports the role of dietary phytonutrients, especially antioxidants, from fresh fruits and vegetables, in maintaining human health and preventing chronic diseases such as cancer, diabetes, osteoporosis, cardiovascular and age-related disorders, including dementia. This knowledge has led to a significant increase in consumption of fruits and vegetable in human diet. However, the availability of fresh produce is limited by their shelf life as substantial losses of fruits and vegetable crops occur during the postharvest period and during transportation from the field to the consumer. These losses are largely due to a myriad of factors that regulate the quality and shelf lives of fruits and vegetables. These factors include genetic variability, physiological parameters (respiration, temperature and water loss, cell wall chemistry, proteins and epidermal waxes, hormonal regulation), and biotic and abiotic stresses. Great strides in post-harvest biology have taken place during the last century, including devising new methods to control losses of perishable horticultural crops. Genome editing holds great promise of developing new varieties with enhanced shelf life, quality, and reduced postharvest losses of the fresh horticultural crops. In spite of these improvements, our understanding of molecular and environmental factors affecting the fruit shell life is still not complete. My research program seeks to understand the molecular mechanisms regulating the shelf life of fresh produce, and evaluating the role of ubiquitous biogenic polyamines in enhancing the phytonutrient quality of fruits. The proposed project will generate new knowledge of fundamental nature and lead to development of better cultivars for high quality fruits. I plan to address issues of postharvest losses and improving phytonutrient levels of horticultural crops for the benefit of human health.
Animal Health Component
40%
Research Effort Categories
Basic
60%
Applied
40%
Developmental
(N/A)
Goals / Objectives
The goal of this proposed research is to pyramid transgenes that contribute to improve fruit quality traits. The specific objective of this project are:Characterize effects of genetic crosses on fruit texture.Characterize effects of genetic crosses on fruit shelf life.Characterize effects of genetic crosses on agronomical traits.Characterize effects of genetic crosses on fruit metabolome, especially desirable phytonutrients.
Project Methods
Specific Procedures:Development of genetically engineered tomato genotypes: During the previous hatch projects, I have developed several genetically engineered tomato genotypes. These include: RNAi silenced pectin methyl esterase (Tieman et al., 1992), polygalacturonase (Tieman and Handa., unpublished results), rhamnogalacturonan lyase (Ochoa-Jiménez et al., 2018), a small HSP (Deng and Handa, unpublished results), mitochondrial and chloroplastic sHSP ( Saad and Handa, unpublished results), and ACS2 (Sobolev et al., 2014). I have also developed HDGS line for lox B (Kausch et al., 2012) and overexpression lines yeast SAMdecarboxylase (Mehta et al., 2002) and Y Spermidine Synthase (Nambeesan et al., 2010) and several small HSPs (Saad and Handa, unpublished results). For the proposed research, two or more genetically engineered genotypes (GEG) will be crossed to develop homozygous GEG for two or more introduced genes (Kausch et al., 2012). The heterozygous hybrid between two independent GEG will be selfed and resulting seeds analyzed for segregation. Genotypes homozygous for 2 genes will be confirmed for genotype as described using PCR and NPTII assays (Kausch et al., 2012). These GEG will be evaluated for various attributes (Tieman et al., 1995).Characterization of GEG for fruit quality, shelf life and yield under greenhouse conditions:GEG will be grown in a greenhouse (Biggs et al., 1986). Fruits at various stages will be harvested and evaluated for the expression of the transgene using PCR (Tieman et al., 1992). Growth and development of plants, including time of flowering, fruit set and ripening will be carefully monitored to evaluate effects of the introduced genetic engineering (GE) on fruit shelf life, textural changes, phytonutrient accumulations, fruit set, fruit ripening, and other fruit-quality-related parameters (Tieman et al., 1995; Mehta et al., 2002, Kausch et al., 2012). Any phenotypic abnormality will be recorded throughout the growing season. The vegetative growth and fruit yield will be determined by harvesting each plant above the roots and determining fresh weight of vegetative shoots and fruits. The average fruit weight will be calculated by dividing total fruit weight by total fruit number, and ripening measured by determining the proportion of green and ripe fruit (Tieman et al., 1995). Plant growth and fertility characteristics will be visually evaluated based on plant size and fruit set , respectively, on a scale of 1-5 with 1 being minimum and 5 being maximum (Tanksley et al. 1996; Nambeesan et al., 2010). Sensitivity to various plant pathogens will be determined as described previously (Nambeesan et al., 2011).Fruit quality attributes: External and internal fruit color will be determined using Hunter Lab Color Difference Meter (Thakur et al., 1996a). Fruit puffiness will be evaluated visually on a scale of 1-5 (1 = very-puffy, 5 = non-puffy). Fruit firmness will be determined using a McCormick Fruit Tech (Yakima, WA) firmness pressure tester that measures the penetration force necessary for the plunger tip to enter the fruit pericarp (Tieman et al., 1994). Total and Soluble solids and pH of the raw juice will be determined from either fresh or frozen pericarp after homogenization (Tieman et al., 1995). An aliquot of the homogenate after centrifugation will be taken with a pH meter (Tieman et al, 1995, Thakur et al., 1996b). Lycopene and polyamine levels will be determined using HPLC as described (Mehta et al., 2002; Nambeesan et al., 2010). Other pigment changes will be determined using a spectrophotometer (Tieman et al., 1992). Fruit texture and cell walls analyses will be conducted (Tieman and Handa, 2014).Statistical Analysis: SAS general linear model procedures will be used to analyze the data.