GOLDEN 2-LIKE transcription factors for chloroplast development affect ozone tolerance through the regulation of stomatal movement

Abstract

Stomatal movements regulate gas exchange, thus directly affecting the efficiency of photosynthesis and the sensitivity of plants to air pollutants such as ozone. The GARP family transcription factors GOLDEN 2-LIKE1 (GLK1) and GLK2 have known functions in chloroplast development. Here, we show that Arabidopsis thaliana (A. thaliana) plants expressing the chimeric repressors for GLK1 and -2 (GLK1/2-SRDX) exhibited a closed-stomata phenotype and strong tolerance to ozone. By contrast, plants that overexpress GLK1/2 exhibited an open-stomata phenotype and higher sensitivity to ozone. The plants expressing GLK1-SRDX had reduced expression of the genes for inwardly rectifying K + (K + in ) channels and reduced K + in channel activity. Abscisic acid treatment did not affect the stomatal phenotype of 35S:GLK1/2-SRDX plants or the transcriptional activity for K + in channel gene, indicating that GLK1/2 act independently of abscisic acid signaling. Our results indicate that GLK1/2 positively regulate the expression of genes for K + in channels and promote stomatal opening. Because the chimeric GLK1-SRDX repressor driven by a guard cell-specific promoter induced a closed-stomata phenotype without affecting chloroplast development in mesophyll cells, modulating GLK1/2 activity may provide an effective tool to control stomatal movements and thus to confer resistance to air pollutants.

Pollution resistance assessment of existing landscape plants on Beijing streets based on air pollution tolerance index method

“…The mean O 3 concentrations at the three sampling sites were in the order of 130 mg/m 3 (MLP) o 145 mg/m 3 (YGZ) o147 mg/m 3 (BZF), which was negatively related with the mean leaf TCH. It was reported that O 3 would reduce the effect of photosynthetic function in plants (Wang et al, 2015), and stomatal movements regulate gas exchange; which directly affect the efficiency of photosynthesis and the sensitivity of plants to air pollutants such as ozone (Nagatoshi et al, 2016). Our results indicate that the TCH value in plant leaves decreased with higher concentration of SO 2 and O 3 , which is in agreement with previous studies Wei et al, 2014 ).…”

Understanding and improving global crop response to ozone pollution

“…Activation of SLAC1 leads to anion efflux and depolarization of the cell membranes, which subsequently activates potassium‐efflux channels. Recently, GOLDEN 2‐LIKE1 and 2 (GLK1, GLK2) transcriptional factors were shown to be positive regulators of potassium influx channels and stomatal movement (Nagatoshi et al ., ). Repression of GLK1 and GLK2 resulted in reduced stomatal aperture and water loss under O 3 stress, resulting in greater O 3 tolerance.…”

“…A second strategy for increasing O 3 tolerance in crops is to use transgenic approaches to control O 3 entry into leaves, improve detoxification in the apoplast or within cells, or alter the signal transduction pathway. Altering stomatal conductance to restrict O 3 entry into leaves has been suggested as a possible target to improve crop tolerance to O 3 and other air pollutants (Lin et al ., ; Nagatoshi et al ., ); however, this strategy would have the inevitable trade‐off of decreasing the supply of CO 2 to photosynthesis and therefore may not be the most effective strategy for maintaining high yields as well as conferring O 3 tolerance (Ainsworth et al ., ). Perhaps more promising are strategies to enhance detoxification or alter the O 3 signal transduction pathway.…”

Blue Light Regulation of Stomatal Opening and the Plasma Membrane H+-ATPase

“…(AKSs) and GARP transcription factors of GOLDEN 2-LIKE1 (GLK1) and GLK2 bind to the promoter of the K + in channel KAT1 gene and increase the K + in channel expression in guard cells (Takahashi et al, 2013;Nagatoshi et al, 2016). GLKs also positively regulate BLUS1 expression (Nagatoshi et al, 2016).…”

“…GLKs also positively regulate BLUS1 expression (Nagatoshi et al, 2016). These transcriptional regulations contribute to enhance stomatal opening.…”