الفهرس 
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Abstract
SUMMARY AND CONCLOSION
This work was performed at the Genetics Department, Faculty of Agriculture, Ain Shams University.
The current study aimed to:
Evaluate the gene expression of the ACS gene (LeACSA) and the ACO gene (LeACO1) with a housekeeping gene (LeGAPDH) to investigate their effect on ethylene production and determine the most extended shelf-life, in three different tomatoes cultivars GS(NAKHEELAGRI); Goldstone 5047(NUNHEMS); and GS12(SYNGENTA), in three different maturity stages, mature green (MG), breaker (BR), and full red (FR) using the reverse transcription-polymerase chain reaction method (RTPCR).
This study aims to investigate the heat stress response of three tomato cultivars by quantifying the expression levels of two Heat Shock Factor (HSF) genes. Heat Shock Factors (HSF1 and HSF2) are transcription factors that play crucial roles in regulating the heat stress response in plants. They are part of the heat shock factor family, which consists of several members involved in the transcriptional activation of heat shock proteins (HSPs) and other heat stress-responsive genes. The experiment will employ quantitative Polymerase Chain Reaction (qPCR) to measure the gene expression levels of HSF1 and HSF2 in response to different heat stress treatments.
The results will provide insights into the heat stress tolerance mechanisms of the three tomato cultivars and contribute to a better understanding of their potential for cultivation under high-temperature conditions.
The research process was as follows:
1. Planting tomato seeds with biological replications.
2. Collect three replicates of tomato fruits for each cultivar during and after ripening at three different maturity stages: mature green (MG), breaker (BR), and full red (FR).
3. Extracting RNA from tomato fruit cultivars and synthesizing cDNA.
4. Assess the effects of ethylene synthase systems in three tomato cultivars by examining gene expression of the ACS gene (LeACSA) and the ACO gene (LeACO1) with a housekeeping gene (LeGAPDH).
5. Evaluate the effect of heat shock in three tomato cultivars by examining gene expression of the HSF gene (hsf1) and (hsf2) with a housekeeping gene (LeGAPDH).
6. Quantifying the gene expression using the reverse transcription-polymerase chain reaction method (rtPCR).
7. Evaluating gene expression from cultivated tomato fruit in relation to ethylene production, and heat effect.
8. Set a future baseline for establishing a tomato breeding program with local cultivars based on cultivars with extended shelf lives.
The obtained results were as follows:
Demonstrate that ethylene biosynthesis revealed interspecific variations in tomatoes and is associated with fruit ripening progress. Activation of ACS gene expression in full red-ripe tomatoes caused increased expression LeACS1 gene during the ripening process. The low expression of the LeACO1 gene was the critical step in suppressing ethylene production (FR) in the tomato fruit development stage.
The ACS and ACO genes are proposed to control the expression levels to the development of different fruit ripening processes.
This study aimed to evaluate the optimal control genes for quantifying transcript levels of ACS and ACO, gene expression measurements in different stages of tomato development were normalized using housekeeping genes for the three different commercial cultivars, using real-time RT-PCR technology.
the current study also showed that the goldstone is more tolerant to heat stress conditions through the high gene expression of heat shock genes while the two other cultivars are the least tolerant of stress through decrease in the gene expression of the heat shock genes
This evaluation recommends that the cultivar (Goldstone 5047, NUNHEMS) be used in tomato breeding programs with local tomato cultivars to provide a core cultivar with the most extended shelf-life duration.
In conclusion, this study highlights the upregulation of HSF1 and HSF2 gene expression under heat stress conditions in different tomato cultivars and the ability of each cultivar to produce ethylene for ripening. Goldstone 5047 demonstrates particularly promising performance in terms of fold change values, indicating its potential as a heat-tolerant cultivar and full ripening with potential long shelf-life. These findings contribute to the understanding of the molecular basis of heat stress and ripening responses in tomatoes and provide valuable insights for tomato breeding programs aiming to screen heat-tolerant varieties with longer shelf-life