Ethylene‐induced stomatal closure in Arabidopsis occurs via AtrbohF‐mediated hydrogen peroxide synthesis

Abstract

SummaryEthylene is a plant hormone that regulates many aspects of growth and development. Despite the well-known association between ethylene and stress signalling, its effects on stomatal movements are largely unexplored. Here, genetic and physiological data are provided that position ethylene into the Arabidopsis guard cell signalling network, and demonstrate a functional link between ethylene and hydrogen peroxide (H 2 O 2 ). In wild-type leaves, ethylene induces stomatal closure that is dependent on H 2 O 2 production in guard cells, generated by the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase AtrbohF. Ethyleneinduced closure is inhibited by the ethylene antagonists 1-MCP and silver. The ethylene receptor mutants etr1-1 and etr1-3 are insensitive to ethylene in terms of stomatal closure and H 2 O 2 production. Stomata of the ethylene signalling ein2-1 and arr2 mutants do not close in response to either ethylene or H 2 O 2 but do generate H 2 O 2 following ethylene challenge. Thus, the data indicate that ethylene and H 2 O 2 signalling in guard cells are mediated by ETR1 via EIN2 and ARR2-dependent pathway(s), and identify AtrbohF as a key mediator of stomatal responses to ethylene.

Ethylene, 1-MCP and the Anti-Transpirant Effect of Active Compound-Film Forming Blend

“…Likewise, the inhibitory effect of Ethylene has also been reported (Tanaka et al, 2005;Desikan et al, 2006;Chen et al, 2013). Similar to the observation of Desikan et al, (2006) andChen et al, (2013, Ethylene indeed triggered stomatal closure. Nonetheless, in the presence of ABA Ethylene might have functioned the other way around.…”

“…To further confirm the involvement of Ethylene on stomatal closure they pretreated intact Arabidopsis leaves with Ethylene negative regulator 1-MCP and silver thiosulfate and it inhibited Ethylene-induced stomatal closure. As reported by Desikan et al, (2006), to cause stomatal closure Ethylene might have induced the generation of H2O2 mediated by the NADPH oxidase isoform AtrbohF. Detailed information on the sole antitranspirant effect of 1 -MCP cannot be found, however a study by Eduardo et al, (2010) displayed the ability of 1-MCP to reduce stomatal conductance of water stressed cotton plants.…”

“…However, its efficiency was found to be compromised by the presence of other naturally occurring stomatal closure inducing active compounds like Ethylene (Tanaka. et al, 2005;Desikan et al, 2006). The role of Ethylene in stomatal closure is not clear, in some species it mediates auxin-induced stomatal opening (Merritt et al, 2001).…”

“…Nevertheless, Tanaka et al (2005) did not show the sole effect of Ethylene in their system. Therefore, to see the effect Ethylene alone, a study conducted by Desikan et al (2006) on Arabidopsis intact leaves evidently showed Ethylene-induced stomatal closure. Furthermore, pre-treatment of leaves with either of Ethylene negative regulators 1-MCP or silver blocked the effect of Ethylene on stomatal closure, indicating Ethylene's effect occurring through its receptors (Desikan et al, 2006).…”

“…Therefore, to see the effect Ethylene alone, a study conducted by Desikan et al (2006) on Arabidopsis intact leaves evidently showed Ethylene-induced stomatal closure. Furthermore, pre-treatment of leaves with either of Ethylene negative regulators 1-MCP or silver blocked the effect of Ethylene on stomatal closure, indicating Ethylene's effect occurring through its receptors (Desikan et al, 2006). If indeed Ethylene somewhat blocks ABA's effect, theoretically the antitranspirant effect of Ethylene negative regulator 1-MCP may depend on the presence of Ethylene and its interaction with ABA.…”