TY - JOUR
T1 - Targeted for destruction
T2 - degradation of singlet oxygen-damaged chloroplasts
AU - Lemke, Matthew D.
AU - Woodson, Jesse D.
N1 - Publisher Copyright:
© 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.
PY - 2022
Y1 - 2022
N2 - Photosynthesis is an essential process that plants must regulate to survive in dynamic environments. Thus, chloroplasts (the sites of photosynthesis in plant and algae cells) use multiple signaling mechanisms to report their health to the cell. Such signals are poorly understood but often involve reactive oxygen species (ROS) produced from the photosynthetic light reactions. One ROS, singlet oxygen (1O2), can signal to initiate chloroplast degradation, but the cellular machinery involved in identifying and degrading damaged chloroplasts (i.e., chloroplast quality control pathways) is unknown. To provide mechanistic insight into these pathways, two recent studies have investigated degrading chloroplasts in the Arabidopsis thaliana 1O2 over-producing plastid ferrochelatase two (fc2) mutant. First, a structural analysis of degrading chloroplasts was performed with electron microscopy, which demonstrated that damaged chloroplasts can protrude into the central vacuole compartment with structures reminiscent of fission-type microautophagy. 1O2-stressed chloroplasts swelled before these interactions, which may be a mechanism for their selective degradation. Second, the roles of autophagosomes and canonical autophagy (macroautophagy) were shown to be dispensable for 1O2-initiated chloroplast degradation. Instead, putative fission-type microautophagy genes were induced by chloroplast 1O2. Here, we discuss how these studies implicate this poorly understood cellular degradation pathway in the dismantling of 1O2-damaged chloroplasts.
AB - Photosynthesis is an essential process that plants must regulate to survive in dynamic environments. Thus, chloroplasts (the sites of photosynthesis in plant and algae cells) use multiple signaling mechanisms to report their health to the cell. Such signals are poorly understood but often involve reactive oxygen species (ROS) produced from the photosynthetic light reactions. One ROS, singlet oxygen (1O2), can signal to initiate chloroplast degradation, but the cellular machinery involved in identifying and degrading damaged chloroplasts (i.e., chloroplast quality control pathways) is unknown. To provide mechanistic insight into these pathways, two recent studies have investigated degrading chloroplasts in the Arabidopsis thaliana 1O2 over-producing plastid ferrochelatase two (fc2) mutant. First, a structural analysis of degrading chloroplasts was performed with electron microscopy, which demonstrated that damaged chloroplasts can protrude into the central vacuole compartment with structures reminiscent of fission-type microautophagy. 1O2-stressed chloroplasts swelled before these interactions, which may be a mechanism for their selective degradation. Second, the roles of autophagosomes and canonical autophagy (macroautophagy) were shown to be dispensable for 1O2-initiated chloroplast degradation. Instead, putative fission-type microautophagy genes were induced by chloroplast 1O2. Here, we discuss how these studies implicate this poorly understood cellular degradation pathway in the dismantling of 1O2-damaged chloroplasts.
KW - Autophagy
KW - cellular degradation
KW - chloroplast
KW - photosynthesis
KW - reactive oxygen species
KW - signaling
UR - http://www.scopus.com/inward/record.url?scp=85131578817&partnerID=8YFLogxK
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U2 - 10.1080/15592324.2022.2084955
DO - 10.1080/15592324.2022.2084955
M3 - Article
C2 - 35676885
AN - SCOPUS:85131578817
SN - 1559-2316
VL - 17
JO - Plant Signaling and Behavior
JF - Plant Signaling and Behavior
IS - 1
M1 - 2084955
ER -