Multi-omics analysis reveals key regulatory defense pathways and genes involved in salt tolerance of rose plants.

Salinity stress causes serious damage to crops worldwide, limiting plant production. However, the metabolic and molecular mechanisms underlying the response to salt stress in rose (Rosa spp.) remain poorly studied. We therefore performed a multi-omics investigation of Rosa hybrida cv. Jardin de Granville (JDG) and Rosa damascena Mill. (DMS) under salt stress to determine the mechanisms underlying rose adaptability to salinity stress. Salt treatment of both JDG and DMS led to the buildup of reactive oxygen species (H2O2). Palisade tissue was more severely damaged in DMS than in JDG, while the relative electrolyte permeability was lower and the soluble protein content was higher in JDG than in DMS. Metabolome profiling revealed significant alterations in phenolic acid, lipids, and flavonoid metabolite levels in JDG and DMS under salt stress. Proteome analysis identified enrichment of flavone and flavonol pathways in JDG under salt stress. RNA sequencing showed that salt stress influenced primary metabolism in DMS, whereas it substantially affected secondary metabolism in JDG. Integrating these datasets revealed that the phenylpropane pathway, especially the flavonoid pathway, is strongly enhanced in rose under salt stress. Consistent with this, weighted gene coexpression network analysis (WGCNA) identified the key regulatory gene chalcone synthase 1 (CHS1), which is important in the phenylpropane pathway. Moreover, luciferase assays indicated that the bHLH74 transcription factor binds to the CHS1 promoter to block its transcription. These results clarify the role of the phenylpropane pathway, especially flavonoid and flavonol metabolism, in the response to salt stress in rose.

Association between glycemic control and the outcome in hospitalized patients with COVID-19.

PURPOSE: Coronavirus disease 2019 (COVID-19) clinical outcome and disease severity affected by several factors; deterioration of glycemic control is one of them. Therefore, achieving optimum blood glucose parameters is hypothesized for better consequences of COVID-19. However, varying data supporting this hypothesis is available in literature. The intention of this study was to investigate the role of glycemic management on the prognosis of hospitalized COVID-19 patients with varying degrees of severity. METHODS: From April 2020 to January 2021, we carried this retrospective cohort in a clinical care facility in Pakistan. RESULTS: Mortality was lowest in patients with HbA1c of less than 7% (53 mmol/mol) (p < 0.001). Similarly, mortality was found lowest in patients with fasting blood glucose less than 126 mg/dl and random blood glucose less than 160 mg/dl (p < 0.001 in each). In contrast, need for admission in critical care was found highest in patients with HbA1c between 7 and 10% (53-86 mmol/mol) (p 0.002). However, participants with blood glucose levels during fasting greater than 200 mg/dl and random blood glucose levels greater than 250 mg/dl were found to have a greater need for invasive mechanical ventilation. Cox regression hazard showed no difference in risk of death and invasive mechanical ventilation based on previous glycemic control. CONCLUSION: Effective diabetic management is correlated with a considerably lower risk of mortality and invasive mechanical ventilation in COVID-19 cases.

Molecular Evidences for the Interactions of Auxin, Gibberellin, and Cytokinin in Bent Peduncle Phenomenon in Rose (Rosa sp.).

In roses (Rosa sp.), peduncle morphology is an important ornamental feature. The common physiological abnormality known as the bent peduncle phenomenon (BPP) seriously decreases the quality of rose flowers and thus the commercial value. Because the molecular mechanisms underlying this condition are poorly understood, we analysed the transcriptional profiles and cellular structures of bent rose peduncles. Numerous differentially expressed genes involved in the auxin, cytokinin, and gibberellin signaling pathways were shown to be associated with bent peduncle. Paraffin sections showed that the cell number on the upper sides of bent peduncles was increased, while the cells on the lower sides were larger than those in normal peduncles. We also investigated the large, deformed sepals that usually accompany BPP and found increased expression level of some auxin-responsive genes and decreased expression level of genes that are involved in cytokinin and gibberellin synthesis in these sepals. Furthermore, removal of the deformed sepals partially relieved BPP. In summary, our findings suggest that auxin, cytokinin, and gibberellin all influence the development of BPP by regulating cell division and expansion. To effectively reduce BPP in roses, more efforts need to be devoted to the molecular regulation of gibberellins and cytokinins in addition to that of auxin.

Petal senescence: a hormone view.

Flowers are highly complex organs that have evolved to enhance the reproductive success of angiosperms. As a key component of flowers, petals play a vital role in attracting pollinators and ensuring successful pollination. Having fulfilled this function, petals senesce through a process that involves many physiological and biochemical changes that also occur during leaf senescence. However, petal senescence is distinct, due to the abundance of secondary metabolites in petals and the fact that petal senescence is irreversible. Various phytohormones are involved in regulating petal senescence, and are thought to act both synergistically and antagonistically. In this regard, there appears to be developmental point during which such regulatory signals are sensed and senescence is initiated. Here, we review current understanding of petal senescence, and discuss associated regulatory mechanisms involving hormone interactions and epigenetic regulation.