Drought stress is an important environmental factor limiting plant productivity. In this study, we screened drought-resistant transgenic plants from 65 promoter-pyrabactin resistance 1-like (PYL) abscisic acid (ABA) receptor gene combinations and discovered that pRD29A::PYL9 transgenic lines showed dramatically increased drought resistance and drought-induced leaf senescence in both Arabidopsis and rice. Previous studies suggested that ABA promotes senescence by causing ethylene production. However, we found that ABA promotes leaf senescence in an ethylene-independent manner by activating sucrose nonfermenting 1-related protein kinase 2s (SnRK2s), which subsequently phosphorylate ABA-responsive element-binding factors (ABFs) and Related to ABA-Insensitive 3/VP1 (RAV1) transcription factors. The phosphorylated ABFs and RAV1 up-regulate the expression of senescence-associated genes, partly by up-regulating the expression of Oresara 1. The pyl9 and ABA-insensitive 1-1 single mutants, pyl8-1pyl9 double mutant, and snrk2.2/3/6 triple mutant showed reduced ABA-induced leaf senescence relative to the WT, whereas pRD29A::PYL9 transgenic plants showed enhanced ABA-induced leaf senescence. We found that leaf senescence may benefit drought resistance by helping to generate an osmotic potential gradient, which is increased in pRD29A::PYL9 transgenic plants and causes water to preferentially flow to developing tissues. Our results uncover the molecular mechanism of ABA-induced leaf senescence and suggest an important role of PYL9 and leaf senescence in promoting resistance to extreme drought stress.drought stress | abscisic acid | PYL | dormancy | Arabidopsis C ell and organ senescence causes programmed cell death to regulate the growth and development of organisms. In plants, leaf senescence increases the transfer of nutrients to developing and storage tissues. Recently, studies on transgenic tobacco showed that delayed leaf senescence increases plant resistance to drought stress (1). However, the senescence and abscission of older leaves and subsequent transfer of nutrients are known to increase plant survival under abiotic stresses, including drought, low or high temperatures, and darkness (2, 3). Senescence mainly develops in an age-dependent manner and is also triggered by environmental stresses and phytohormones, such as abscisic acid (ABA), ethylene, salicylic acid, and jasmonic acid, but delayed by cytokinin (4).Senescence-associated genes (SAGs) are induced by leaf senescence. The expression of SAGs is tightly controlled by several senescence-promoting, plant-specific NAC (NAM, ATAF1, and CUC2) transcription factors, such as Oresara 1 (ORE1) (5), Oresara 1 sister 1 (ORS1) (6), and AtNAP (7). Environmental stimuli and phytohormones may regulate leaf senescence through NACs. Phytochrome-interacting factor 4 (PIF4) and PIF5 transcription factors promote dark-induced senescence by activating ORE1 expression (8). The expression of ORE1, AtNAP, and OsNAP (ortholog of AtNAP) is up-regulated by ABA by an unknown molecular m...

Noble metal nanoparticles have been of tremendous interest due to their intriguing size- and shape-dependent plasmonic and catalytic properties. Combining tunable plasmon resonances with superior catalytic activities on the same metallic nanoparticle, however, has long been challenging because nanoplasmonics and nanocatalysis typically require nanoparticles in two drastically different size regimes. Here, we demonstrate that creation of high-index facets on subwavelength metallic nanoparticles provides a unique approach to the integration of desired plasmonic and catalytic properties on the same nanoparticle. Through site-selective surface etching of metallic nanocuboids whose surfaces are dominated by low-index facets, we have controllably fabricated nanorice and nanodumbbell particles, which exhibit drastically enhanced catalytic activities arising from the catalytically active high-index facets abundant on the particle surfaces. The nanorice and nanodumbbell particles also possess appealing tunable plasmonic properties that allow us to gain quantitative insights into nanoparticle-catalyzed reactions with unprecedented sensitivity and detail through time-resolved plasmon-enhanced spectroscopic measurements.

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Heat shock protein 90 (Hsp90) molecular chaperones play important roles in plant growth and responses to environmental stimuli. However, little is known about the genes encoding Hsp90s in common wheat. Here, we report genetic and functional analysis of the genes specifying cytosolic Hsp90s in this species. • Three groups of homoeologous genes (TaHsp90.1, TaHsp90.2 and TaHsp90.3), encoding three types of cytosolic Hsp90, were isolated. The loci containing TaHsp90.1, TaHsp90.2 and TaHsp90.3 genes were assigned to groups 2, 7 and 5 chromosomes, respectively. TaHsp90.1 genes exhibited higher transcript levels in the stamen than in the leaf, root and culm. TaHsp90.2 and TaHsp90.3 genes were more ubiquitously transcribed in the vegetative and reproductive organs examined.• Decreasing the expression of TaHsp90.1 genes through virus-induced gene silencing (VIGS) caused pronounced inhibition of wheat seedling growth, whereas the suppression of TaHsp90.2 or TaHsp90.3 genes via VIGS compromised the hypersensitive resistance response of the wheat variety Suwon 11 to stripe rust fungus.• Our work represents the first systematic determination of wheat genes encoding cytosolic Hsp90s, and provides useful evidence for the functional involvement of cytosolic Hsp90s in the control of seedling growth and disease resistance in common wheat.

SummaryPhosphomannomutase (PMM) catalyzes the interconversion of mannose-6-phosphate and mannose-1-phosphate. However, systematic molecular and functional investigations on PMM from higher plants have hitherto not been reported. In this work, PMM cDNAs were isolated from Arabidopsis, Nicotiana benthamiana, soybean, tomato, rice and wheat. Amino acid sequence comparisons indicated that plant PMM proteins exhibited significant identity to their fungal and mammalian orthologs. In line with the similarity in primary structure, plant PMM complemented the sec53-6 temperature sensitive mutant of Saccharomyces cerevisiae. Histidine-tagged Arabidopsis PMM (AtPMM) purified from Escherichia coli converted mannose-1-phosphate into mannose-6-phosphate and glucose-1-phosphate into glucose-6-phosphate, with the former reaction being more efficient than the latter one. In Arabidopsis and N. benthamiana, PMM was constitutively expressed in both vegetative and reproductive organs. Reducing the PMM expression level through virus-induced gene silencing caused a substantial decrease in ascorbic acid (AsA) content in N. benthamiana leaves. Conversely, raising the PMM expression level in N. benthamiana using viral-vector-mediated ectopic expression led to a 20-50% increase in AsA content. Consistent with this finding, transgenic expression of an AtPMM-GFP fusion protein in Arabidopsis also increased AsA content by 25-33%. Collectively, this study improves our understanding on the molecular and functional properties of plant PMM and provides genetic evidence on the involvement of PMM in the biosynthesis of AsA in Arabidopsis and N. benthamiana plants.

Background: Preoperative hematological markers that indicate nutritional, coagulation, and inflammation statuses have prognostic value for gliomas. This study aimed to investigate hematological markers with regard to tumor grades, isocitrate dehydrogenase mutations (IDH), age, and sex in patients with gliomas.Methods: From 2008 to 2017, patients with a pathological diagnosis of glioma who underwent surgery were retrospectively enrolled in this study. Information from clinical records, including age, sex, preoperative experiment tests (routine blood tests, biochemistry, and coagulation examinations), pathological results, and IDH status, was collected. A univariable survival analysis was performed. Hematological factors such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte-ratio (PLR), and albumin-to-globulin (AGR) were calculated. The prognostic nutrition index (PNI) was calculated as 10 × serum albumin value (g/dl) + 0.005 × peripheral lymphocyte count (per mm3).Results: Our study included 706 patients. The univariate analysis showed that age, IDH-1, and hematological factors were all significantly associated with overall survival (OS) in patients with gliomas. Our results showed that inflammation markers (NLR, PLR, and fibrinogen) were positively associated with age, whereas AGR was negatively associated with age. The PLR was significantly increased, whereas the AGR and PNI were decreased in women with gliomas, as compared with men. We found that inflammation markers increased and nutrition markers decreased with gliomas grade. However, these hematological markers did not significantly differ with IDH status. NLR was the best single hematological marker for distinguishing glioblastoma (GBM) [0.684 (0.645–0.723)], IDH-wt GBM [0.672 (0.631–0.71)] from other gliomas subtypes. Combinations of age with PNI and age with AGR were the best predictors of GBM [0.750 (0.713–0.786)] and IDH-wt GBM [0.759 (0.719–0.798)], respectively.Conclusion: Preoperative hematological marker levels vary among glioma grades and have high predictive values for GBM.

Detection of brain gliomas at the earliest stage is of great importance to improve outcomes, but it remains a most challenging task. In this study, oleic acid capped manganese oxide (MnO) nanoparticles (NPs) were prepared by the thermal decomposition of manganese oleate precursors and then transformed to water-dispersible MnO NPs by replacing oleic acid with N-(trimethoxysilylpropyl) ethylene diamine triacetic acid (TETT) silane. The covalently bonded TETT silane offers MnO NPs colloidal stability and abundant carboxylic functional groups allowing the further conjugation of the glioma-specific moiety, folic acid (FA). Moreover, the thin layer of TETT silane ensures a short distance between external Mn ion and water proton, which endows the FA-conjugated, TETT modified MnO (MnO-TETT-FA) NPs a longitudinal relaxivity as high as 4.83 mM(-1) s(-1). Accordingly, the in vivo magnetic resonance (MR) images demonstrated that MnO-TETT-FA NPs could efficiently enhance the MRI contrast for tiny brain gliomas. More importantly, due to the specificity of FA, MnO-TETT-FA NPs led to a clearer margin of the tiny glioma. This together with the good biocompatibility discloses the great potential of MnO-TETT-FA NPs as effective MRI contrast agents for the early diagnosis of brain gliomas.