ABSTRACT
Evaluation of nanoparticle biostimulants in alleviating salinity-induced stress: A study on morphological and molecular responses in potato cultivars

Amirah S. Alahmari1, Mahmoud Magdy2, 3, Ahmed B. El-Mansy4, Nabil S. Awad5, 6, Mohammad E. Eldenary7, Rahma Alshamrani8, Makhdora Almuziny8, Amani Omar Abuzaid8, Nora M. Al Aboud9, and Diaa Abd El Moneim10*
 
Potato (Solanum tuberosum L.), a critical food crop, faces productivity challenges due to salinity stress, which is exacerbated by climate change. This study evaluates the potential of nanoparticle-based biostimulants—salicylic acid (SA), ascorbic acid (AS), and benzoic acid (BA)—to alleviate salinity-induced stress in ‘Spunta’ and ‘Lady Rosetta’ potatoes. The biostimulants were applied at 0.5 mM (T1) and 0.75 mM (T2) concentrations under salinity stress levels of 50 and 100 mg L-1 NaCl. Morphological assessments revealed that T2 treatment significantly improved root length (up to 12.17 cm) and root number (up to 4.17) in both cultivars. Gene expression analysis showed that the MYB1 gene, a key regulator of stress responses, was upregulated under salinity stress in control plants but was significantly downregulated by nanoparticle treatments. This reduction suggests that nanoparticles modulate stress signaling pathways, reducing the need for MYB1 activation. The P5CS gene, involved in proline biosynthesis, was also downregulated by nanoparticle treatments, indicating enhanced osmotic stress tolerance and reduced reliance on proline accumulation. Furthermore, expression of the P450 gene, associated with stress responses, was reduced by nanoparticles, highlighting their role in modulating stress-responsive pathways. The SOS1 gene, crucial for salt tolerance, was significantly reduced under high salt concentrations with nanoparticle treatments, suggesting improved ion homeostasis. Our study confirms that nanoparticle-based biostimulants effectively enhance potato plant resilience to salinity stress by improving growth parameters and modulating stress-related gene expression. These findings underscore the potential of nanotechnology in advancing crop management strategies under challenging environmental conditions.
Keywords: Biostimulants, gene expression, nanoparticles, MYB1 gene, P5CS gene, potato cultivars, salinity stress, Solanum tuberosum, stress response.
1Princess Nourah bint Abdulrahman University, College of Science, Department of Biology, Riyadh 11671, Saudi Arabia.
2Murcia University, Faculty of Biology, Department of Plant Biology, Murcia, 30100, Spain.
3Ain Shams University, Faculty of Agriculture, Department of Genetics, Cairo, 11241, Egypt.
4Arish University, Faculty of Environmental Agricultural Sciences, Department of Plant Production (Vegetable Breeding and Biotechnology Branch), El-Arish 45511, Egypt.
5Misr University for Science and Technology, College of Biotechnology, Giza, 12563, Egypt.
6Aswan University, Faculty of Agriculture and Natural Resources, Department of Genetics, Aswan, 81528, Egypt.
7Horticulture Research Institute, Potato and Vegetatively Propagated Vegetables Research Department (PVPV), Giza, Egypt.
8King Abdulaziz University, Faculty of Science, Department of Biological Sciences, Jeddah, Saudi Arabia.
9Umm Al-Qura University, Faculty of Science, Department of Biology, Makkah, Saudi Arabia.
10Arish University, Faculty of Environmental Agricultural Sciences, Department