Heterotrimeric G protein mediates ethylene‐induced stomatal closure via hydrogen peroxide synthesis in Arabidopsis

Abstract

These authors contributed equally to this work. SUMMARYHeterotrimeric G proteins function as key players in hydrogen peroxide (H 2 O 2 ) production in plant cells, but whether G proteins mediate ethylene-induced H 2 O 2 production and stomatal closure are not clear. Here, evidences are provided to show the Ga subunit GPA1 as a missing link between ethylene and H 2 O 2 in guard cell ethylene signalling. In wild-type leaves, ethylene-triggered H 2 O 2 synthesis and stomatal closure were dependent on activation of Ga. GPA1 mutants showed the defect of ethylene-induced H 2 O 2 production and stomatal closure, whereas wGa and cGa overexpression lines showed faster stomatal closure and H 2 O 2 production in response to ethylene. Ethylene-triggered H 2 O 2 generation and stomatal closure were impaired in RAN1, ETR1, ERS1 and EIN4 mutants but not impaired in ETR2 and ERS2 mutants. Ga activator and H 2 O 2 rescued the defect of RAN1 and EIN4 mutants or etr1-3 in ethylene-induced H 2 O 2 production and stomatal closure, but only rescued the defect of ERS1 mutants or etr1-1 and etr1-9 in ethylene-induced H 2 O 2 production. Stomata of CTR1 mutants showed constitutive H 2 O 2 production and stomatal closure, but which could be abolished by Ga inhibitor. Stomata of EIN2, EIN3 and ARR2 mutants did not close in responses to ethylene, Ga activator or H 2 O 2 , but do generate H 2 O 2 following challenge of ethylene or Ga activator. The data indicate that Ga mediates ethylene-induced stomatal closure via H 2 O 2 production, and acts downstream of RAN1, ETR1, ERS1, EIN4 and CTR1 and upstream of EIN2, EIN3 and ARR2. The data also show that ETR1 and ERS1 mediate both ethylene and H 2 O 2 signalling in guard cells.

The Coiled-Coil and Nucleotide Binding Domains of BROWN PLANTHOPPER RESISTANCE14 Function in Signaling and Resistance against Planthopper in Rice

“…ROS production is a key early defense response in plant innate immunity (Boller and Felix, 2009), and rapid ROS accumulation plays a central signaling role in response to pathogen invasion (Foyer and Noctor, 2005;Mittler et al, 2011;Ge et al, 2015). In this study, the CC and NB domains, as well as the FL BPH14 protein, enhanced intracellular ROS accumulation, suggesting that ROS contribute to the BPH resistance conferred by BPH14.…”

Long-Term Overgrazing-Induced Memory Decreases Photosynthesis of Clonal Offspring in a Perennial Grassland Plant

“…The down-regulated expression of gene related to stomatal regulation, for example, ETR1 , may have contributed to the adaptive changes in the photosynthesis. Previously, some studies had proved that the ETR1 gene played key roles in guard cell movement and stomata opening under multiple stresses (Desikan et al, 2005; Ge et al, 2015). In this research, we further speculate that smaller leaf stomata mediated by gene regulation may reduce the loss of water and improve plant fitness in grazing-induced dry habitats of semi-arid grasslands (Escalona et al, 1999; von Caemmerer et al, 2004).…”

Abscisic Acid-Induced Reactive Oxygen Species Are Modulated by Flavonols to Control Stomata Aperture

“…Induction of flavonol accumulation in Arabidopsis guard cells was observed after treatment with the plant growth regulator 5-aminolevulinic acid , which decreased ROS levels and ABA-induced stomatal closure. It is worth noting that some studies employing short-term ethylene treatments, which are too short for flavonol levels to be elevated, report enhanced closing of guard cells in Arachis hypogea and Arabidopsis (Pallas and Kays, 1982;Desikan et al, 2006;Ge et al, 2015), suggesting a second unlinked ethylene response in these guard cells. Together, these studies show that flavonols are regulated to modulate ROS signaling and guard cell aperture.…”