Seaweed Extract-Stimulated Priming in Arabidopsis thaliana and Solanum lycopersicum

Abstract

Plant priming is an induced physiological state where plants are protected from biotic and abiotic stresses. Whether seaweed extracts promote priming is largely unknown as is the mechanism by which priming may occur. In this study, we examined the effect of a seaweed extract (SWE) on two distinct stages of plant priming (priming phase and post-challenge primed state) by characterising (i) plant gene expression responses using qRT-PCR and (ii) signal transduction responses by evaluating reactive oxygen species (ROS) production. The SWE is made from the brown algae Ascophyllum nodosum and Durvillaea potatorum. The priming phase was examined using both Arabidopsis thaliana and Solanum lycopersicum. At this stage, the SWE up-regulated key priming-related genes, such as those related to systemic acquired resistance (SAR) and activated the production of ROS. These responses were found to be temporal (lasting 3 days). The post-challenge primed state was examined using A. thaliana challenged with a root pathogen. Similarly, defence response-related genes, such as PR1 and NPR1, were up-regulated and ROS production was activated (lasting 5 days). This study found that SWE induces plant priming-like responses by (i) up-regulating genes associated with plant defence responses and (ii) increasing production of ROS associated with signalling responses.

Comparative metabolomic profiling of Arabidopsis thaliana roots and leaves reveals complex response mechanisms induced by a seaweed extract

“…Although differences existed between metabolomic profiles of root and leaves, many common up-accumulated metabolites were detected, which are directly involved in various fundamental growth and defence pathways. The mode of actions of SWE is likely to associate with induced priming and systemic mechanisms that have been demonstrated at the transcriptomic level in our previous studies (Islam et al, 2020;Islam et al, 2021).…”

“…Seeds of Arabidopsis thaliana ecotype Ler (LEHLE, Texas, USA, http://www.arabidopsis.com ) were sterilized and grown following the method of Islam et al. (2020) and Islam et al. (2021) .…”

“…In previous research (Islam et al, 2021), we showed that application of an extract derived from A. nodosum and D. potatorum promoted the expression of a number of key stressand priming-related genes in Arabidopsis. However, the underlying mechanisms by which the activation of these genes then affords protection against stress remain largely unknown.…”

“…Seeds of Arabidopsis thaliana ecotype Ler (LEHLE, Texas, USA, http://www.arabidopsis.com) were sterilized and grown following the method of Islam et al (2020) and Islam et al (2021). Arabidopsis seeds were sterilized in 1 mL of a solution containing 500 µL of ethanol 100% and 5 µL of H 2 O 2 30%, suspended in water agar 0.2% (w/v) and stratified at 4°C for two days.…”

“…Hence, this current study was conducted to investigate, using an untargeted approach, the metabolomic profiles of Arabidopsis following application of seaweed extract to the roots. In addition to previous transcriptomic and gene expression data ( Islam et al., 2020 ; Islam et al., 2021 ), we now provide a thorough interpretation of the complex relationships between metabolites and associated pathways with plant growth and their potential to provide resistance under adverse conditions. Such fundamental findings will contribute to developing biostimulants for sustainable use in agriculture.…”