SUMMARYHighly interactive signaling processes constitute a set of parameters intertwining in a continuum mode to shape body formation and development. A sophisticated gene network is required to integrate environmental and endogenous cues in order to modulate flowering. However, the molecular mechanisms that coordinate the circuitries of flowering genes remain unclear. Here using complemented experimental approaches, we uncover the decisive and essential role of HEAT SHOCK PROTEIN 90 (HSP90) in restraining developmental noise to an acceptable limit. Localized depletion of HSP90 mRNAs in the shoot apex resulted in low penetrance of vegetative-to-reproductive phase transition and completely abolished flower formation. Extreme variation in expression of flowering genes was also observed in HSP90 mRNA-depleted transformed plants. Transient heat-shock treatments moderately increased HSP90 mRNA levels and rescued flower arrest. The offspring had a low, nevertheless noticeable failure to promote transition from vegetative into the reproductive phase and showed flower morphological heterogeneity. In floral tissues a moderate variation in HSP90 transcript levels and in the expression of flowering genes was detected. Key flowering proteins comprised clientele of the molecular chaperone demonstrating that the HSP90 is essential during vegetative-to-reproductive phase transition and flower development. Our results uncover that HSP90 consolidates a molecular scaffold able to arrange and organize flowering gene network and protein circuitry, and effectively counterbalance the extent to which developmental noise perturbs phenotypic traits.
RNA silencing refers to a conserved eukaryotic process and is regarded as one of the most important processes in plants, with the ability to regulate gene expression both transcriptionally and post-transcriptionally. Different classes of non-coding RNAs (ncRNAs) constitute key components of the RNA silencing pathways and play pivotal roles in modulating various biological processes as well as host-pathogen interactions. One of the most extensively studied classes of ncRNAs are the 20-24 nucleotide (nt) long microRNAs (miRNAs), which are core components of the endogenous gene silencing pathway. miRNAs act as negative regulators of endogenous gene expression either through mRNA-target cleavage, translational inhibition, or DNA methylation, and are inextricably linked to a plethora of developmental processes, such as leaf pattern formation as well as abiotic and biotic stress responses. In this review, we focus on the role of the RNA silencing pathways in the regulation of developmental processes as well as in the plant responses to biotic stress.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.