The mechanism of SO2‐induced stomatal closure differs from O3 and CO2 responses and is mediated by nonapoptotic cell death in guard cells. (3rd October 2018)

• Record Type: Journal Article
• Authors: Ooi, Lia; Matsuura, Takakazu; Munemasa, Shintaro; Murata, Yoshiyuki; Katsuhara, Maki; Hirayama, Takashi; Mori, Izumi C.
• Is Part Of: Plant, cell and environment. Volume 42:Number 2(2019)
• Page Start: 437
• Page End: 447
• Publication Date: 2018-10-03
• Subjects: airborne pollutants -- nonapoptotic cell death -- stomatal closure -- sulfur dioxide; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.13406
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Plants closing stomata in the presence of harmful gases is believed to be a stress avoidance mechanism. SO2, one of the major airborne pollutants, has long been reported to induce stomatal closure, yet the mechanism remains unknown. Little is known about the stomatal response to airborne pollutants besides O3 . SLOW ANION CHANNEL‐ASSOCIATED 1 ( SLAC1 ) and OPEN STOMATA 1 ( OST1 ) were identified as genes mediating O3 ‐induced closure. SLAC1 and OST1 are also known to mediate stomatal closure in response to CO2, together with RESPIRATORY BURST OXIDASE HOMOLOG s ( RBOH s). The overlaying roles of these genes in response to O3 and CO2 suggested that plants share their molecular regulators for airborne stimuli. Here, we investigated and compared stomatal closure event induced by a wide concentration range of SO2 in Arabidopsis through molecular genetic approaches. O3 ‐ and CO2 ‐insensitive stomata mutants did not show significant differences from the wild type in stomatal sensitivity, guard cell viability, and chlorophyll content revealing that SO2 ‐induced closure is not regulated by the same molecular mechanisms as for O3 and CO2 . Nonapoptotic cell death is shown as the reason for SO2 ‐induced closure, which proposed the closure as a physicochemical process resulted from SO2 distress, instead of a biological protection mechanism. Abstract : Sulfur dioxide (SO2 ) is a major air pollutant known to injure plants and induce stomatal closure. Here, we identified H2 SO3 as the responsible SO2 ‐derived chemical species for the induction of stomatal closure through nonapoptotic cell death in the guard cells. Furthermore, studies utilizing O3 ‐ and CO2 ‐insensitive stomata mutants revealed that the molecular mechanism for SO2 ‐induced stomatal closure is distinct from O3 and CO2 .