PR020

Repeat dipeptides such as poly(proline‐arginine) (polyPR) are generated from the hexanucleotide GGGGCC repeat expansions in the C9orf72 gene. These dipeptides are often considered as the genetic cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In the study, fluorescein isothiocyanate (FITC) labeled PR20 is used to investigate PR20‐induced cell death. The findings reveal that the cell death induced by PR20 is dependent on its nuclear distribution and can be blocked by a nuclear import inhibitor called importazole. Further investigation reveals that BRD4 inhibitors, such as JQ‐1 and I‐BET762, restrict cytoplasmic localization of PR20, thereby reducing its cytotoxic effect. Mechanistically, the inhibition of BRD4 leads to an increase in the expression of numerous histones, resulting in the accumulation of histones in the cytoplasm. These cytoplasmic histones associate with PR20 and limit its distribution within the nucleus. Notably, the ectopic expression of histones alone is enough to confer protection to cells treated with PR20. In addition, phenylephrine (PE) induces cellular hypertrophy and cytoplasmic distribution of histone, which also helps protect cells from PR20‐induced cell death. The research suggests that temporarily inducing the presence of cytoplasmic histones may alleviate the neurotoxic effects of dipeptide repeat proteins.

Plant growth promoting rhizobacteria (PGPR) have been intensively investigated in agricultural crops for decades. Nevertheless, little information is available on the application of Sphingomonas spp. as a PGPR particularly in vegetables, despite of potential plant growth promoting traits of this group. This study investigated the role of Sphingomonas panaciterrae (PB20) on growth and nutritional profile of spinach applied through seed priming (SP), soil drenching (SD), foliar application (FA), and bacterial culture filtrate foliar (BCF) applications. The results showed that, depending on different methods of application, PB20 significantly increased plant height (19.57-65.65 %), fresh weight (7.26-37.41 %), total chlorophyll (71.14-192.54 %), carotenoid (67.10-211.67 %) antioxidant (55.99-207.04), vitamin C (8.1-94.6 %) and protein content (6.7-21.5 %) compared to control in the edible part of spinach. Among the mineral nutrients, root nitrogen (N) showed greater response to bacterial application (18.65%-46.15 % increase over control) than shoot nitrogen (6.70%-21.52 % increased over control). Likewise, in all methods of application, phosphorus (P) content showed significant increase over control both in root (42.79-78.48 %) and in shoot (3.57-27.0 %). Seed priming and foliar application of PB20 increased the shoot calcium (Ca) content compared to control. BCF foliar application yielded maximum magnesium (Mg), iron (Fe) and zinc (Zn) in shoot. However, seed priming resulted in maximum Fe in root. Overall, seed priming outperformed in growth, vitamin C, antioxidants, N and P uptake, while BCF foliar application resulted in better uptake of several nutrients. Multivariate analysis validated the positive association of most of the growth parameters with SP while several nutrients with FA and BCF. Based on the findings it is evident that this rhizobacteria PB20 has the potentiality to be applied as a biofertilizer to produce nutrient-enriched spinach with an improved yield. Farmers can conveniently incorporate PR20 through seed priming before planting of spinach, with additional benefits through foliar spray.