Bioassay to detect Ascophyllum nodosum extract-induced cytokinin-like activity in Arabidopsis thaliana

Abstract

Ascophyllum nodosum, a brown macroalga, is the most widely used seaweed in agriculture. We report a rapid method for the detection of cytokinin-like activity in plants treated with a commercial A. nodosum liquid concentrate (Stimplex®) using a transgenic line of Arabidopsis carrying the ARR5 promoter fused to ß-glucuronidase (GUS) reporter gene. Based on GUS activity assay, an increase in cytokinin-like activity was detected in plants grown in vitro treated with 3 mL L −1 Stimplex®, whereas foliar spray treatments showed similar cytokinin-like activity at a concentration of 5 mL L −1 . Histochemical staining showed Stimplex®-induced GUS activity in leaf as well as in the root tissues. Taken together, our results suggest that Stimplex® contains compounds that may elicit endogenous cytokinin-like activity. Furthermore, it is shown that this bioassay can be used for rapid screening of extracts that can stimulate cytokinin-like activities using Arabidopsis AAR5::GUS reporter transgenic plants.

Agricultural uses of plant biostimulants

“…Increases in lateral root formation (Vernieri et al 2005), total root volume (Slávik 2005;Mancuso et al 2006), and root length (Zodape et al 2011) have been observed and attributed to the presence of phytohormones such as auxins and cytokinins in seaweed extracts (Khan et al 2011a(Khan et al , 2011b. Seaweed extract application also stimulated mineral nutrient uptake in plants such as lettuce (Crouch et al 1990), grape (Mancuso et al 2006), soybean (Rathore et al 2009), tomato (Zodape et al 2011), and winter rapeseed (Jannin et al 2013) with increased accumulation of both macro-(N, P, K, Ca, S) and micro-nutrients (Mg, Zn, Mn, Fe) reported (Crouch et al 1990, Mancuso et al 2006, Rathore et al 2009Zodape et al 2011).…”

“…Oligo-alginates derived from brown seaweeds enhanced nitrogen assimilation and basal metabolism in plants (Khan et al 2011a;Sarfaraz et al 2011), and oligocarrageenans derived from red algae enhanced photosynthesis, nitrogen assimilation, basal metabolism, cell division, and protection against viral, fungal, and bacterial infections in tobacco (Nicotiana tabacum) and chickpea (Cicer arietinum) (Bi et al 2011;Castro et al 2012;Vera et al 2012). (González et al 2013) speculate that oligo-alginates and oligo-carrageenans may interact with plasma membrane receptors that use a co-receptor involved in signal transduction leading to simultaneous activation of plant growth and defense against pathogens as has been observed with brassinosteroid-dependent and microbial-associated molecular patterns (MAMPs)-dependent signaling pathways, which have a common co-receptor (Kemmerling et al 2011).…”

Seaweed Extract Ascophyllum nodosum (L.) on the Growth of Watermelon Plants

“…A relation to the results of the study with the possible increase in the production of endogenous cytokinin that is induced by the extract of A. nodosum (L.) is possible, as proposed by Khan et al [21], when studied the effect of the extract of this alga on plants of Arabidopsis thaliana. Thus, cytokinin is a hormone synthesized in greater amounts in the roots of the plants, being transported by the xylem to the plant aerial part, stimulating its development [17].…”

“…For Khan et al [21] and Craigie [22], although in small amounts of A. nodosum (L.) extract can cause positive effect on plant development, due to biostimulants derived from this alga are constituted by several hormones [23,24] having also other unidentified compounds with similar activity to plant hormones, being able to alter plant development.…”

IN VITRO GROWTH RATE OF Kappaphycus alvarezii MICROPROPAGULE AND EMBRYO BY ENRICHMENT MEDIUM WITH SEAWEED EXTRACT

“…Zodape et al (2008;2009) have taken advantage of this seaweed extract on okra plants and cultivation of wheat. In addition, some researcher haves conducted assessments of fertilizer derived from seaweed Ascophyllum nodosum, among others, which can be used as fertilizer in cultivation of seaweed K. alvarezii (Loureiro et al, 2010) and to test the animal manure livestock, as well as fertilizer in higher plants (Khan et al, 2011).…”