title: Carbon deprivation-driven transcriptome reprogramming in detached developmentally arresting Arabidopsis inflorescences.
abstract: Senescence is genetically controlled and activated in mature tissues during aging. However, immature plant tissues also display senescence-like symptoms when continuously exposed to adverse energy-depleting conditions. We used detached dark-held immature inflorescences of Arabidopsis (Arabidopsis thaliana) to understand the metabolic reprogramming occurring in immature tissues transitioning from rapid growth to precocious senescence. Macroscopic growth of the detached inflorescences rapidly ceased upon placement in water in the dark at 21°C. Inflorescences were completely degreened by 120 h of dark incubation and by 24 h had already lost 24% of their chlorophyll and 34% of their protein content. Comparative transcriptome profiling at 24 h revealed that inflorescence response at 24 h had a large carbon-deprivation component. Genes that positively regulate developmental senescence (ARABIDOPSIS NAC DOMAIN CONTAINING PROTEIN92) and shade-avoidance syndrome (PHYTOCHROME INTERACTING FACTOR4 [PIF4] and PIF5) were up-regulated within 24 h. Mutations in these genes delayed degreening of the inflorescences. Their up-regulation was suppressed in dark-held inflorescences by glucose treatment, which promoted macroscopic growth and development and inhibited degreening of the inflorescences. Detached inflorescences held in the dark for 4 d were still able to reinitiate development to produce siliques upon being brought out to the light, indicating that the transcriptional reprogramming at 24 h was adaptive and reversible. Our results suggest that the response of detached immature tissues to dark storage involves interactions between carbohydrate status sensing and light deprivation signaling and that the dark-adaptive response of the tissues appears to utilize some of the same key regulators as developmental senescence.
authors.affiliation: The New Zealand Institute for Plant Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand.
authors.forename: Alice
authors.initials: A
authors.lastname: Trivellini
authors.forename: Rubina
authors.initials: R
authors.lastname: Jibran
authors.forename: Lyn M
authors.initials: LM
authors.lastname: Watson
authors.forename: Erin M
authors.initials: EM
authors.lastname: O'Donoghue
authors.forename: Antonio
authors.initials: A
authors.lastname: Ferrante
authors.forename: Kerry L
authors.initials: KL
authors.lastname: Sullivan
authors.forename: Paul P
authors.initials: PP
authors.lastname: Dijkwel
authors.forename: Donald A
authors.initials: DA
authors.lastname: Hunter
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D050260:Carbohydrate Metabolism / Q000187:drug effects / Q000235:genetics; D002244:Carbon / Q000172:deficiency*; D003624:Darkness; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D005947:Glucose / Q000494:pharmacology; D056626:Inflorescence / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D008954:Models, Biological; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012984:Software; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics*; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D012333:RNA, Messenger; D014157:Transcription Factors; D002244:Carbon; D005947:Glucose