Evaluation of the Potential Use of a Collagen-Based Protein Hydrolysate as a Plant Multi-Stress Protectant

Abstract

Protein hydrolysates (PHs) are a class of plant biostimulants used in the agricultural practice to improve crop performance. In this study, we have assessed the capacity of a commercial PH derived from bovine collagen to mitigate drought, hypoxic, and Fe deficiency stress in Zea mays. As for the drought and hypoxic stresses, hydroponically grown plants treated with the PH exhibited an increased growth and absorption area of the roots compared with those treated with inorganic nitrogen. In the case of Fe deficiency, plants supplied with the PH mixed with FeCl3 showed a faster recovery from deficiency compared to plants supplied with FeCl3 alone or with FeEDTA, resulting in higher SPAD values, a greater concentration of Fe in the leaves and modulation in the expression of genes related to Fe. Moreover, through the analysis of circular dichroism spectra, we assessed that the PH interacts with Fe in a dose-dependent manner. Various hypothesis about the mechanisms of action of the collagen-based PH as stress protectant particularly in Fe-deficiency, are discussed.

A Bibliometric Analysis of the Scientific Literature on Biostimulants

“…In principle, the use of biostimulants could represent an economically viable option for farmers to meet the growing quality standards and consumers' expectations in terms of sustainability and environment protection, as it has been associated with reductions in production costs and increases in product quality [10,13]. Biostimulants can perform numerous agronomic functions, such as boosting the growth and development of plants during their entire life cycle [16]; increasing soil fertility, in particular by promoting the development of soil microorganisms [17,18]; increasing the resistance of plants to abiotic stresses, such as heat, cold or lack of water, [19] and biotic stresses, such as parasites including viruses, bacteria, and insects [20,21]; improving the use efficiency of nutrients by plants [5]; and improving crop quality [22] and yield [23,24]. With the agricultural industry experiencing an extraordinary increase in fertiliser prices [25], biostimulants could help reduce the use of agricultural inputs and, therefore, reduce production costs.…”

Chemical Characterization of a Collagen-Derived Protein Hydrolysate and Biostimulant Activity Assessment of Its Peptidic Components

“…In this regard, substances that act at low concentrations to induce plant metabolic responses could be valuable tools to improve crop fitness and/or resilience. Biostimulants are products used at low dosage to stimulate nutrient uptake and assimilation, to improve stress tolerance or quality traits regardless of their nutrient content. − Protein hydrolysates (PHs), humic substances, chitin and chitosan derivatives, plant growth promoting bacteria, seaweed extracts, , and many other products, as unrelated as they might seem, are all classified as biostimulants when they meet the abovementioned criteria.…”

“…The physiological processes improved by the application of biostimulants are often related with the stimulation of enzymes involved in N uptake and assimilation, the increase in micronutrient accumulation, a rewired hormonal activity, that is, the induction of phytohormone synthesis or a modified hormonal signaling, and protection from oxidative stress. ,− However, because these products are particularly complex matrices, knowledge of their mode of action at the biochemical and molecular levels is still largely elusive and scarce information is available on the nature of the active molecules responsible for their biostimulant activity . The application of a reductionist approach seems convenient to identify the active components of a biostimulant and to study their mechanisms of action.…”

“…We have previously characterized the biological effects of a commercial CDPH (produced by the SICIT group) showing that at low concentrations ( i.e. , total N about 5–15 mg·L –1 ) it causes a remarkable enhancement of maize root growth, increases the uptake of several mineral nutrients, and acts as a protectant against drought, hypoxic stress, and Fe deficiency stress. , …”

“…8,9,11 We have previously characterized the biological effects of a commercial CDPH (produced by the SICIT group) showing that at low concentrations (i.e., total N about 5−15 mg•L −1 ) it causes a remarkable enhancement of maize root growth, increases the uptake of several mineral nutrients, and acts as a protectant against drought, hypoxic stress, and Fe deficiency stress. 3,8 The aim of this study was to evaluate the plant growth stimulatory activity of the different fractions of the CDPH, subdivided based on their molecular size (AAs and peptides of different lengths), and to assess the nature of the bioactive peptides. We have chemically characterized the CDPH by applying different methods of fractioning and circular dichroism (CD) and we have used mass spectrometry (MS) to identify the peptide species present in the product.…”