Temporal transcriptomics reveal the molecular mechanism of dormancy and germination regulated by temperature in Paris polyphylla seed

The mature seed of Paris polyphylla var.chinensis(PPC)is morphophysiologically dormant and develops differently under warm and cold temperatures.To elucidate the molecular mechanisms underlying temperature-dependent regulation of PPC seed dormancy and germination,we investigated the dynamic changes in PPC seed transcript levels under warm and cold temperature stratifications(WS and CS,respectively)by time-resolved RNA sequencing,focusing on genes related to hormone metabolism and signaling and cell wall remodeling(CWRM)and encoding transcription factors/regulators(TFs/TRs).A total of 48765 and 47836 differentially expressed genes(DEGs)were associated with WS and CS,respectively.Of these,17581 and 16652 DEGs,respectively,unique to WS and CS,and 5386 were common to both temperature stratifications across nine analyzed growth stages.The expression of hormone metabolism and signaling,TF/TR,and CWRM genes were closely associated with temperature.More genes related to gibberellin(GA),cytokinin,auxin,and brassinosteroid biosynthetic were upregulated in WS as compared to CS seeds,while genes related to dormancy release and germination were downregulated in WS seeds.However,only GA and abscisic acid levels were altered in PPC seeds breaking morphophysiological dormancy(MPD).Overall,37 TF and five TR families were upregulated whereas 24 TF and 16 TR families were downregulated in WS as compared to CS seeds.Most CWRM families were highly expressed under WS as compared to CS,suggesting that they promote endosperm weakening and embryo growth of WS seeds and facilitate MPD release and germination.A coexpression analysis revealed positive correlations between TFs/TRs and DEGs involved in hormone metabolism and signaling and CWRM.These results provided a basis for investigating the interaction between the endosperm and underdeveloped embryo in the regulation of PPC seed germination and seedling emergence.

Letting Go is Never Easy:Abscission and Receptor- Like Protein Kinases

Abscission is the process by which plants discard organs in response to environmental cues/stressors, or as part of their normal development. Abscission has been studied throughout the history of the plant sciences and in numerous species. Although long studied at the anatomical and physiological levels, abscission has only been elucidated at the molecular and genetic levels within the last two decades, primarily with the use of the model plant Arabidopsis thaliana. This has led to the discovery of numerous genes involved at all steps of abscission, including key pathways involving receptor-like protein kinases （RLKs）. This review covers the current knowledge of abscission research, highlighting the role of RLKs.

Cell-free microRNA-21: biomarker for intracranial aneurysm rupture

Background:Deregulation of miRNA-21 expression has been reported to be associated with vascular smooth muscle behavior and cytoskeletal stability.This study is aimed to investigate the density of serum miRNA-21 in patients with different phases of intracranial aneurysms(IAs)and explore its warning function for IA rupture.Methods:A total of 16 in 200 IA patients were selected and categorized into 4 groups based on the phase of IA.Microarray study was carried out using serum miRNA and differentially expressed miRNAs were identified.Another 24 samples from a cohort of 360 patients were added and real-time polymerase chain reaction(RT-PCR)was performed on expanded sample size(n=40)for miRNA-21 validation.Potential gene targets of miRNA-21 were screened out from Gene Ontology(GO)database and literatures.Results:Microarray study identified 77 miRNAs with significantly different expression levels between experimental groups and the control group.RT-PCR assays validated significant downregulation of miRNA-21 in experimental groups,among which miRNA-21 expression level of daughter aneurysm group decreased the most.Bioinformatic analyses revealed that several target genes related with miRNA-21 may be involved in IA formation and rupture.Conclusions:This study suggested that miRNA-21 had a protective effect for intracranial vascular wall against remodeling and warning function for intracranial aneurysm rupture.Significant suppression of serum miRNA-21 in IA patients may provide diagnostic clues for aneurysm rupture and guide clinical intervention.