Unlocking NUE Potential via PASP-Ca Synergist: Insights into physio-biochemical, enzymatic and molecular analyses of contrasting potato genotypes in aeroponics.

Background: Polyaspartic Acid-Calcium (PASP-Ca) is a versatile and eco-friendly amino acid complex, primarily recognized for bolstering nitrogen use efficiency and crop productivity. However, the core significance of this complex remains enigmatic in potato crop. We hypothesized that simultaneous application of PASP-Ca with potato genotypes characterized by substantial root systems and high genetic potentials for nitrogen-use efficiency (NUE) would best address this knowledge gap. Methods: The synergistic effect of various PASP-Ca treatments on morph physiological, N-related, and enzymatic parameters coupled with their transcript levels (shoot and root) in four potato genotypes having contrasting NUEs under low and high N supplies in aeroponics. Results: PASP-Ca markedly boosted plant growth, yield components, and photosynthetic efficiency, with pronounced effects observed in nitrogen-efficient genotypes, especially Qingshu-9, emphasizing the importance of genotype selection in optimizing nitrogen utilization. Moreover, PASP-Ca treatments, particularly LN-P100 significantly enhances root system architecture (RSA), contributing to expanded root dimensions and improved nutrient acquisition capacity, especially under nitrogen-deficient conditions. Carbohydrate metabolism in potato tubers benefits from PASP-Ca treatment, leading to increased starch content, thereby impacting tuber quality. Among the N-assimilating enzymes, a large genotypic variation was observed for glutamine synthetase (GS), which may be considered a potential trait for improving NUE. Molecular analysis further elucidated the underlying mechanisms, demonstrating the upregulation of essential genes involved in nitrogen metabolism. Conclusions: The potential efficacy of PASP-Ca synergist as a novel accelerant for enhancing potato crop growth, biomass production, and nitrogen utilization efficiency, all coalescing seamlessly with the ethos of sustainable agricultural practices. [ABSTRACT FROM AUTHOR]