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Drought stress is considered one of the main factors that reduce plant growth, development and production. Therefore, studying plants during drought stress is highly useful to discover the newly gained characteristics of plants. The potato is considered one of the most important crop with economic value in Egypt and over the whole world. The main target is the proline-rich protein extracted from potato plants under drought stress. A stress experiment was applied to two potato (Solanum tuberosum L.) cultivars Desiree and Diamante. The stress experiment was conducted by polyethylene glycol (PEG) 4000; the used water potentials were: zero (control), (PEG 2%), (PEG 4%) and (PEG 8%), after drought stress, the solutes accumulation in the two potato cultivars were determined. Increasing drought stress through elevating PEG decreased leaf area as well as shoot and root lengths. Incontorary, the chlorophyll and proline contents increased with increasing PEG treatments. The proline-rich protein gene was cloned to the pGEM-T Easy vector and was submitted to the gene bank to be used later for enhancing drought resistence in other cultivars. [ABSTRACT FROM AUTHOR]

Worldwide, potato (Solanum tuberosum L.) is one of the most essential agro-economically food crops. To ensure its presence throughout the year for food processors and to extend its shelf life, it should be stored in cold temperatures. Despite the benefits of storage at low temperatures, it causes undesirable phenomena; one of them is cold-induced sweetening, which reduces the quality and the commercial value of the potato tubers. In this study, the CRISPR technology ″Clustered Regularly Interspaced Short Palindromic Repeats″ has been used in potato cultivar Desiree via Agrobacterium-mediatied transformation to edit starch phosphorylase gene that is responsible for starch degradation in cold temperature storage, after regeneration steps. The regenerated plants were used in the screening of genome editing by Sanger sequencing and the ICE program. Screening results showed that Desiree 2 (DE2), Desiree 7 (DE7) and Desiree 27 (DE27) lines have mutations in sgRNA sequence that indicated a significant reduction in reduced sugar contents of tubers after cold storage for 90 and 120 days. The reduction mean values were 29.224, 35.078 and 35.862 in DE2, DE7 and DE27 respectively after 90 days and 83.212, 56.674 and 34.109 after 120 days without visible differences in plant morphology and tubers. [ABSTRACT FROM AUTHOR]

Potato tuber starch characteristic is influenced by the ratio of amylose to amylopectin, which is affected by the granule-bound starch synthase (GBSS) gene. GBSS gene expression was decreased in the leaves of the Desiree potato variety utilizing genome editing using CRISPR-Cas9. Constructs encoding Cas9 gene and sgRNAs targeting GBSS gene were inserted into plant leaves using Agrobacterium-mediated transformation delivery. The results obtained lines with mutations in GBSS genes accounting for 21% of regenerated shoots. The identification of mutations within one base pair of the used guide sequence provided further evidence of the considerable similarity between the target region around the protospacer adjacent motif (PAM) position and the used guide sequence. Transforming DNA into potato leaves produced mutants that lacked the Cas9 gene. Using microscopic inspection of iodine-stained starch granules, the increase of amylopectin in the starch granules of editing potato tubers was evaluated. [ABSTRACT FROM AUTHOR]