Jasmonic acid and salicylic acid play minor roles in stomatal regulation by CO₂, abscisic acid, darkness, vapor pressure deficit and ozone

Abstract

SUMMARY Jasmonic acid (JA) and salicylic acid (SA) regulate stomatal closure, preventing pathogen invasion into plants. However, to what extent abscisic acid (ABA), SA and JA interact, and what the roles of SA and JA are in stomatal responses to environmental cues, remains unclear. Here, by using intact plant gas‐exchange measurements in JA and SA single and double mutants, we show that stomatal responsiveness to CO2, light intensity, ABA, high vapor pressure deficit and ozone either did not or, for some stimuli only, very slightly depended upon JA and SA biosynthesis and signaling mutants, including dde2, sid2, coi1, jai1, myc2 and npr1 alleles. Although the stomata in the mutants studied clearly responded to ABA, CO2, light and ozone, ABA‐triggered stomatal closure in npr1‐1 was slightly accelerated compared with the wild type. Stomatal reopening after ozone pulses was quicker in the coi1‐16 mutant than in the wild type. In intact Arabidopsis plants, spraying with methyl‐JA led to only a modest reduction in stomatal conductance 80 min after treatment, whereas ABA and CO2 induced pronounced stomatal closure within minutes. We could not document a reduction of stomatal conductance after spraying with SA. Coronatine‐induced stomatal opening was initiated slowly after 1.5–2.0 h, and reached a maximum by 3 h after spraying intact plants. Our results suggest that ABA, CO2 and light are major regulators of rapid guard cell signaling, whereas JA and SA could play only minor roles in the whole‐plant stomatal response to environmental cues in Arabidopsis and Solanum lycopersicum (tomato).

Salicylic Acid Improves Antioxidant Defense System and Photosynthetic Performance in Aristotelia chilensis Plants Subjected to Moderate Drought Stress

“…Our results were similar to those reported by Shemi et al [ 64 ] and Habibi et al [ 67 ], where they showed that SA induced stomatal aperture in Z. mays and Hordeum vulgare plants subjected to drought stress. Recently, Zamora et al [ 68 ] showed that Arabidopsis and Solanum lycopersicum plants did not reduce stomatal aperture after SA spraying. The authors also suggested that SA-induced stomatal closure apparently requires high concentrations or prolonged SA treatments.…”

Jasmonic acid enhances osmotic stress responses by MYC2‐mediated inhibition of protein phosphatase 2C1 and response regulators 26 transcription factor in tomato

“…JA enhanced the drought tolerance of tomato JA was not involved in stomatal closure in soybean (Horton, 1991) and played only minor roles in stomatal response to environmental cues in tomato and Arabidopsis (Zamora et al, 2021). However, Suhita et al (2004) confirmed that MeJA promotes H 2 O 2 accumulation in Arabidopsis guard cells, leading to stomatal closure.…”

Jasmonic Acid Boosts Physio-Biochemical Activities in Grewia asiatica L. under Drought Stress

“…We obtained similar results to previously reported studies where the researchers found that drought-stressed Z. mays and Hordeum vulgare plants were shown to open their stomata under JA treatment [ 90 , 91 , 92 ]. Zamora et al [ 93 ] recently demonstrated that spraying JA did not reduce stomatal apertures in Arabidopsis thaliana and Solanum lycopersicum . High concentrations of JA or prolonged treatment times are necessary for stomatal closure induced by JA.…”