Multiple pathways mediate chloroplast singlet oxygen stress signaling.

Chloroplast singlet oxygen initiates multiple pathways to control chloroplast degradation, cell death, and nuclear gene expression. Chloroplasts can respond to stress and changes in the environment by producing reactive oxygen species (ROS). Aside from being cytotoxic, ROS also have signaling capabilities.

The core autophagy machinery is not required for chloroplast singlet oxygen-mediated cell death in the Arabidopsis thaliana plastid ferrochelatase two mutant.

Background: Chloroplasts respond to stress and changes in the environment by producing reactive oxygen species (ROS) that have specific signaling abilities. The ROS singlet oxygen (O) is unique in that it can signal to initiate cellular degradation including the selective degradation of damaged chloroplasts. This chloroplast quality control pathway can be monitored in the Arabidopsis thaliana mutant plastid ferrochelatase two (fc2) that conditionally accumulates chloroplast O under diurnal light cycling conditions leading to rapid chloroplast degradation and eventual cell death.

Chloroplast quality control pathways are dependent on plastid DNA synthesis and nucleotides provided by cytidine triphosphate synthase two.

Reactive oxygen species (ROS) produced in chloroplasts cause oxidative damage, but also signal to initiate chloroplast quality control pathways, cell death, and gene expression. The Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant produces the ROS singlet oxygen in chloroplasts that activates such signaling pathways, but the mechanisms are largely unknown. Here we characterize one fc2 suppressor mutation and map it to CYTIDINE TRIPHOSPHATE SYNTHASE TWO (CTPS2), which encodes one of five enzymes in Arabidopsis necessary for de novo cytoplasmic CTP (and dCTP) synthesis.

Evaluation of antiplasmodial activity of extracts from endemic medicinal plants used to treat malaria in Côte d'Ivoire.

strains had been increasingly resistant to commonly used molecules including artemisinin. It is therefore urges to find new therapeutic alternatives. In this study, the antiplasmodial activity of 21 extracts obtained from seven plants of the and of the Ivorian pharmacopoeia was evaluated on the chloroquine sensitive (NF54) and multi-resistant (K1) reference strains and on clinical isolates as well.