Induced freezing tolerance and free amino acids perturbation of spinach by exogenous proline

Abstract

The objective of this study was to investigate whether exogenous proline (Pro) could confer freezing tolerance of spinach and determine fluctuations of free amino acids in spinach leaf tissues under freeze-induced stress. Treatment with Pro (10 mM) resulted in more accumulation of Pro (~2.6-fold) in Pro-treated spinaches compared to untreated ones. These Pro-pretreated spinaches were more freezing-tolerant, showing more turgid leaves and petioles compared to untreated controls. However, when spinaches pre-treated with or without Pro were subjected to freezing, there was no significant difference in overall amino acid contents, emphasizing the role of Pro as an osmoprotectant. Freezing stress prompted intensification of total amino acid contents irrespective of pretreatment with Pro. Asp, Glu, Ala, and Val were the most abundant free amino acids due to increased protein degradation and nitrogen mobilization for plant survival under freezing stress. Arg, a precursor for the synthesis of polyamines in plants, was profoundly enhanced under freezing stress. This implies that Arg plays an important role in modulating freezing tolerance. Gly, Leu, and Ile were maintained at relatively low levels in all treatments. However, Ser, Tyr, and Lys as primary constituents of dehydrins were accumulated under freezing stress, suggesting that they might play a role in increasing cryoprotective activity under freezing stress.

Assessment of proline function in higher plants under extreme temperatures

“…lysine, leucine, and arginine, also increased 2.8‐fold and may contribute toward freezing tolerance in spinach (Shin et al . 2018).…”

“…On the other hand, exogenous application of proline has been shown to mitigate some stresses, including heat and cold stress (Liang et al 2013;Shin et al 2018;Priya et al 2019;Mattioli et al 2020). Proline application can decrease oxidative stress damage and membrane injury, increase antioxidant enzymes, leaf water content, and photosynthesis under stress (Priya et al 2019;Shakeri et al 2019;Ghosh et al 2022).…”

Pure Organic Active Compounds Against Abiotic Stress: A Biostimulant Overview

“…Proline also improved salt tolerance with both foliar spray and root treatment in Vigna radiata ( Hossain et al, 2011 ), rice ( O. sativa L.) ( Roy et al, 1993 ), Vicia faba L. ( Gadallah, 1999 ) and tomato ( Lycopersicon esculentum L.) ( Heuer, 2003 ). It was also effective against freezing damage in spinach ( Spinacia oleraceae ) ( Shin et al, 2018 ) and against oxidative stress in Vitis vinifera L. ( Ozden et al, 2009 ). Several authors reported that the exogenous application of Pro improved growth and photosynthetic capacity, and Ali et al (2008) observed that it promoted the uptake of essential nutrients.…”

Survival analysis of Electrical Power Distribution systems using Weibull Regression

“…Statistical methods are used to model problems involving death or failure in different areas, such as Medicine (Cheng et al, 2018;Ferlay et al, 2015), Engineering (Luo et al, 2018), Agricultural and Biological Sciences (Shin et al, 2018) according to the arrange and the distribution that the data follows. For studies involving covariates, as climatic events, regressions are an alternative.…”