Biology subjects

Cortleven, A.

Publications and source records attributed to Cortleven, A..

3 recordsLinked to original sources

bioRxiv2021

The transcriptomic landscape of the photoperiodic stress response in Arabidopsis thaliana resembles the response to pathogen infection.

Plants are exposed to regular diurnal rhythms of light and dark. Changes in the photoperiod by the prolongation of the light period cause photoperiod stress in short day-adapted Arabidopsis thaliana. Here we report on the transcriptional response to photoperiod stress of wild-type A. thaliana and photoperiod stress-sensitive cytokinin signalling and clock mutants. Transcriptomic changes induced by photoperiod stress included numerous changes in reactive oxygen (ROS)-related transcripts and showed a strong overlap with changes occurring in response to ozone stress and pathogen attack, which have in common the induction of an apoplastic oxidative burst. A core set of photoperiod stress-responsive genes has been identified, including salicylic acid (SA) biosynthesis and signalling genes. Genetic analysis revealed a central role for NPR1 in the photoperiod stress response as npr1-1 mutants were stress-insensitive. Photoperiod stress treatment led to a strong increase in camalexin levels which is consistent with shared photoperiod stress and pathogen response pathways. Photoperiod stress induced resistance of Arabidopsis plants to a subsequent infection by Pseudomonas syringae cv. tomato DC3000 indicating priming of the defence response. Together, photoperiod stress causes transcriptional reprogramming resembling plant pathogen defence responses and induces systemic acquired resistance in the absence of a pathogen. One sentence summaryPhotoperiod stress results in significant dynamic transcriptomic changes related to oxidative stress similar to those caused by pathogen attack and primes the defence response against a subsequent pathogen infection.

plant biology↗

bioRxiv2020

Photoperiod stress alters the cellular redox status and is associated with an increased peroxidase and decreased catalase activity

Periodic changes of light and dark regulate numerous processes in plants. Recently, a novel type of stress caused by an extended light period has been discovered in Arabidopsis and was named photoperiod stress. Photoperiod stress causes the induction of numerous stress response genes during the night following the extended light period of which many are indicators of oxidative stress. The next day, stress-sensitive genotypes display reduced photosynthetic efficiency and programmed cell death in leaves. Here, we have analysed further the consequences of photoperiod stress and report that it causes changes of the cellular redox status. A prolonged light period caused a strong reduction of the AsA redox during the following night indicating that it induces an oxidizing cellular environment. Further, photoperiod stress was associated with an increased activity of peroxidases and a decreased activity of catalases. Increased peroxidase activity was localized to the apoplast and might be causal for the oxidative stress induced by photoperiod stress.

plant biology↗

bioRxiv2020

Root-derived trans-zeatin cytokinin protects Arabidopsis plants against photoperiod stress

Recently, a novel type of abiotic stress caused by a prolongation of the light period - coined photoperiod stress - has been described in Arabidopsis. During the night after the prolongation of the light period, stress and cell death marker genes are induced. The next day, strongly stressed plants display a reduced photosynthetic efficiency and leaf cells eventually enter programmed cell death. The phytohormone cytokinin (CK) acts as a negative regulator of this photoperiod stress syndrome. In this study, we show that Arabidopsis wild-type plants increase the CK concentration in response to photoperiod stress. Analysis of cytokinin synthesis and transport mutants revealed that root-derived trans-zeatin (tZ)-type CKs protect against photoperiod stress. The CK signaling proteins ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 2 (AHP2), AHP3 and AHP5 and transcription factors ARABIDOPSIS RESPONSE REGULATOR 2 (ARR2), ARR10 and ARR12 are required for the protective activity of CK. Analysis of higher order B-type arr mutants suggested that a complex regulatory circuit exists in which the loss of ARR10 or ARR12 can rescue the arr2 phenotype. Together the results revealed the role of root-derived CK acting in the shoot through the two-component signaling system to protect from the negative consequences of strong photoperiod stress.

plant biology↗