RING finger ubiquitin E3 ligase CsCHYR1 targets CsATAF1 for degradation to modulate the drought stress response of cucumber through the ABA-dependent pathway.

CsCHYR1 (CHY ZINC-FINGER AND RING PROTEIN1) encodes a RING (Really Interesting New Gene) finger E3 ubiquitin ligase involved in ubiquitin-mediated protein degradation and plays an important role for cucumber to resist drought stress. Here, we obtain one of the candidate proteins CsCHYR1 that probably interacts with CsATAF1 by yeast-two hybrid screening. Subsequently, it is verified that CsCHYR1 interacts with CsATAF1 and has self-ubiquitination activity. When the cysteine residue at 180 in the RING domain of CsCHYR1 is replaced by serine or alanine, ubiquitin could not be transported from E2 to the substrate. CsCHYR1 ubiquitinates CsATAF1 and affects the stability of CsATAF1 when plants are subjected to drought stress. The expression level of CsCHYR1 is increased by 4-fold after ABA treatment at 9 h. The Atchyr1 mutants perform an ABA-hyposensitive phenotype and have a lower survival rate than Col-0 and CsCHYR1 Atchyr1 lines. In addition, CsCHYR1 interacts with CsSnRK2.6. Therefore, our study reveals a CsSnRK2.6-CsCHYR1-CsATAF1 complex to promote the drought stress response by decreasing CsATAF1 protein accumulation and inducing stomatal closure. Those findings provide new ideas for cucumber germplasm innovation from the perspective of biochemistry and molecular biology.

SoHSC70 positively regulates thermotolerance by alleviating cell membrane damage, reducing ROS accumulation, and improving activities of antioxidant enzymes.

High temperature is a major environmental factor affecting plant growth. Heat shock proteins (Hsps) are molecular chaperones that play important roles in improving plant thermotolerance during heat stress. Spinach (Spinacia oleracea) is very sensitive to high temperature; however, the specific function of Hsps in spinach is unclear. In this study, cytosolic heat shock 70 protein (SoHSC70), which was induced by heat stress, was cloned from spinach. Overexpressing SoHSC70 in spinach calli and Arabidopsis enhanced their thermotolerance. In contrast, spinach seedlings with silenced SoHSC70 by virus-induced gene silencing (VIGS) showed more sensitivity to heat stress. Further analysis revealed that overexpressing SoHSC70 altered relative electrical conductivity (REC), malondialdehyde (MDA) content, photosynthetic rate, reactive oxygen species (ROS) accumulation and the activities of antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) after the heat treatment. Taken together, our results suggest that overexpressing SoHSC70 positively affects heat tolerance by reducing membrane damage and ROS accumulation and improving activities of antioxidant enzymes.

PvNAC1 increases biomass and enhances salt tolerance by decreasing Na+ accumulation and promoting ROS scavenging in switchgrass (Panicum virgatum L.).

Switchgrass (Panicum virgatum L.) is a bioenergy crop; thus, it is important to improve biomass to effectively produce bioethanol, particularly under adverse stress conditions. NAC transcription factors are involved in the abiotic stress response. PvNAC1 was isolated in the nucleus of switchgrass, with its C-terminal region containing a transcriptional activation domain. PvNAC1 expression was induced by dehydration, salt, H2O2, and abscisic acid treatments. Overexpressing (OE) PvNAC1 improved growth performance, leading to significantly taller and heavier (dry weight) plants. Moreover, cellulose content was significantly higher in OE plants, indicating that PvNAC1 plays an important role regulating growth and bioethanol production. PvNAC1 RNA interference (RNAi) switchgrass plants exhibited reduced dry weight and cellulose content. OE PvNAC1 enhanced tolerance to salt stress, through higher reactive oxygen species scavenging ability and less Na+ and more K+ accumulation in roots and shoots. RNAi plants were more sensitive to salt stress. The quantitative polymerase chain reaction results revealed that some stress responsive genes, three antioxidant enzymatic genes, and an ion homeostasis-related gene were upregulated in OE plants and downregulated in RNAi plants. These results show that PvNAC1 functions as a transcriptional activator in response to salt stress and growth.

Alginate-derived oligosaccharides promote water stress tolerance in cucumber (Cucumis sativus L.).

Marine alginate-derived oligosaccharides (ADOs) are prepared from degraded alginate. Our experiments were carried out to determine the mechanism of ADOs to improve resistance to water stress in cucumber (Cucumis sativus L.). We evaluated the effects of ADOs on physiological indices, photosynthesis, reactive oxygen species (ROS) levels, antioxidant enzyme activities, and relative expression levels of drought resistance genes. The growth of drought stressed cucumber decreased markedly. However, treatment with ADOs significantly improved the diameter, fresh weight, photosynthetic rate, transpiration rate, stomatal conductance, maximum quantum yield of photosystem II (Fv/Fm) and chlorophyll degradation; thus, reversing the effects of drought stress. Moreover, the antioxidant levels and ROS scavenging enzyme activities also increased in response to the ADOs. Additionally, the genes involved in abscisic aid (ABA) signaling and the drought stress response, such as superoxide dismutase [Cu-Zn] (CsSOD(Cu-Zn)), the peroxidase superfamily protein (CsPOD3), ABA deficient 2 (CsABA2), responsive to ABA 18 (CsRAB18), abscisic acid insensitive 5 (CsABI5), responsive to dehydration 22 (CsRD22), and responsive to dehydration 29A (CsRD29A) were upregulated by ADOs. The ABA content was also improved by ADOs. Our results suggest that ADOs induced the expression of some antioxidant enzyme synthetic genes involved in the ABA signaling pathway by stimulating ABA synthesis to improve the drought resistance capacity in cucumber.

Efficacy of autologous bone marrow buffy coat grafting combined with core decompression in patients with avascular necrosis of femoral head: a prospective, double-blinded, randomized, controlled study.

INTRODUCTION: Avascular necrosis of femoral head (ANFH) is a progressive disease that often leads to hip joint dysfunction and even disability in young patients. Although the standard treatment, which is core decompression, has the advantage of minimal invasion, the efficacy is variable. Recent studies have shown that implantation of bone marrow containing osteogenic precursors into necrotic lesion of ANFH may be promising for the treatment of ANFH. METHODS: A prospective, double-blinded, randomized controlled trial was conducted to examine the effect of bone-marrow buffy coat (BBC) grafting combined with core decompression for the treatment of ANFH. Forty-five patients (53 hips) with Ficat stage I to III ANFH were recruited. The hips were allocated to the control group (core decompression + autologous bone graft) or treatment group (core decompression + autologous bone graft with BBC). Both patients and assessors were blinded to the treatment options. The clinical symptoms and disease progression were assessed as the primary and secondary outcomes. RESULTS: At the final follow-up (24 months), there was a significant relief in pain (P <0.05) and clinical joint symptoms as measured by the Lequesne index (P <0.05) and Western Ontario and McMaster Universities Arthritis Index (P <0.05) in the treatment group. In addition, 33.3% of the hips in the control group have deteriorated to the next stage after 24 months post-procedure, whereas only 8% in the treatment group had further deterioration (P <0.05). More importantly, the non-progression rates for stage I/II hips were 100% in the treatment group and 66.7% in the control group. CONCLUSION: Implantation of the autologous BBC grafting combined with core decompression is effective to prevent further progression for the early stages of ANFH. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01613612. Registered 13 December 2011.

The expression of cytoglobin as a prognostic factor in gliomas: a retrospective analysis of 88 patients.

BACKGROUND: Evidence suggests that cytoglobin (Cygb) may function as a tumor suppressor gene. METHODS: We immunohistochemically evaluated the expression of Cygb, phosphatidylinositol-3 kinase (PI-3K), phosphorylated (p)-Akt, Interleukin-6 (IL-6), tumor necrosis factor-α (TNFα) and vascular endothelial growth factor (VEGF) in 88 patients with 41 high-grade gliomas and 47 low-grade gliomas. Intratumoral microvessel density (IMD) was also determined and associated with clinicopathological factors. RESULTS: Low expression of Cygb was significantly associated with the higher histological grading and tumor recurrence. A significant negative correlation emerged between Cygb expression and PI3K, p-Akt, IL-6, TNFα or VEGF expression. Cygb expression was negatively correlated with IMD. There was a positive correlation between PI3K, p-Akt, IL-6, TNFα and VEGF expression with IMD.High histologic grade, tumor recurrence, decreased Cygb expression, increased PI3K expression, increased p-Akt expression and increased VEGF expression correlated with patients' overall survival in univariate analysis. However, only histological grading and Cygb expression exhibited a relationship with survival of patients as independent prognostic factors of glioma by multivariate analysis. CONCLUSIONS: Cygb loss may contribute to tumor recurrence and a worse prognosis in gliomas. Cygb may serve as an independent predictive factor for prognosis of glioma patients.