Ulva intestinalis Extract Acts as Biostimulant and Modulates Metabolites and Hormone Balance in Basil (Ocimum basilicum L.) and Parsley (Petroselinum crispum L.).

Roberta Paulert,Mariana Mazetto De Carvalho,Miguel Daniel Noseda,Ilaria Marchioni,Laura Pistelli,Lorenzo Mariotti,Paolo Berni,Silvia Malatesta,Roberta Ascrizzi,Maria Eugênia Rabello Duarte,Luisa Pistelli

doi:10.3390/plants10071391

Roberta Paulert, Mariana Mazetto De Carvalho + Show 9 more

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https://doi.org/10.3390/plants10071391

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Abstract

Natural elicitors from macroalgae may affect plant secondary metabolites. Ulvan is a sulfated heteropolysaccharide extracted from green seaweed, acting as both a plant biotic protecting agent, and a plant elicitor, leading to the synthesis of signal molecules. In this work, the aqueous extract of Ulva intestinalis L., mainly composed of ulvan, was used as foliar-spraying treatment and its eliciting effect was investigated in basil (Ocimum basilicum L.) and parsley (Petroselinum crispum L.). Antioxidant metabolites (polyphenols and carotenoids), volatile compounds (both in headspace emissions and hydrodistilled essential oils), and hormones (jasmonic acid, salicylic acid, salicylic acid 2-O-β-D-glucoside, abscisic acid, and azelaic acid) were quantified. The foliar-spraying treatment with U. intestinalis extract increased salicylic acid and its β-glucoside in parsley; in basil, it induced the accumulation of jasmonic and abscisic acids, indicating the presence of a priming effect. In basil, the elicitation caused a change of the essential oil (EO) chemotype from methyl eugenol/eugenol to epi-α-cadinol and increased sesquiterpenes. In parsley EO it caused a significant accumulation of 1,3,8-p-menthatriene, responsible of the typical “parsley-like” smell. In both species, the phenylpropanoids decreased in headspace and EO compositions, while the salicylic acid concentration increased; this could indicate a primarily defensive response to U. intestinalis extract. Due to the evidenced significant biological activity, U. intestinalis extract used as an elicitor may represent a suitable tool to obtain higher amounts of metabolites for optimizing plant flavor metabolites.

Highlights

The aqueous lyophilized extract isolated from U. intestinalis presented 44.6 (±1.7)
The presence of rhamnose, uronic acids and sulfate groups indicates that the polysaccharide ulvan is the main constituent of U. intestinalis extract (UIE)
The analyses performed on U. intestinalis extract (UIE) confirmed that the aqueous extract is mainly composed by the sulfated polysaccharide ulvan

Summary

Introduction

Beneficial effects of spraying seaweed extracts on crop plants have been observed, and there is an increasing interest in oligo- and polysaccharides in plant immunity. Different biological activities are reported, including immunomodulatory properties in fish, human and plant cells [5,6,7], as well as antioxidant ability [4]. These interesting features make ulvan a good candidate as a renewable compound for the development of nanoparticles [8] to be used for medical [5] and agricultural purposes [1,7].

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