The mitotic exit mediated by small GTPase Tem1 is essential for the pathogenicity of Fusarium graminearum.

The mitotic exit is a key step in cell cycle, but the mechanism of mitotic exit network in the wheat head blight fungus Fusarium graminearum remains unclear. F. graminearum infects wheat spikelets and colonizes the entire head by growing through the rachis node at the bottom of each spikelet. In this study, we found that a small GTPase FgTem1 plays an important role in F. graminearum pathogenicity and functions in regulating the formation of infection structures and invasive hyphal growth on wheat spikelets and wheat coleoptiles, but plays only little roles in vegetative growth and conidiation of the phytopathogen. FgTem1 localizes to both the inner nuclear periphery and the spindle pole bodies, and negatively regulates mitotic exit in F. graminearum. Furthermore, the regulatory mechanisms of FgTem1 have been further investigated by high-throughput co-immunoprecipitation and genetic strategies. The septins FgCdc10 and FgCdc11 were demonstrated to interact with the dominant negative form of FgTem1, and FgCdc11 was found to regulate the localization of FgTem1. The cell cycle arrest protein FgBub2-FgBfa1 complex was shown to act as the GTPase-activating protein (GAP) for FgTem1. We further demonstrated that a direct interaction exists between FgBub2 and FgBfa1 which crucially promotes conidiation, pathogenicity and DON production, and negatively regulates septum formation and nuclear division in F. graminearum. Deletion of FgBUB2 and FgBFA1 genes caused fewer perithecia and immature asci formations, and dramatically down-regulated trichothecene biosynthesis (TRI) gene expressions. Double deletion of FgBUB2/FgBFA1 genes showed that FgBUB2 and FgBFA1 have little functional redundancy in F. graminearum. In summary, we systemically demonstrated that FgTem1 and its GAP FgBub2-FgBfa1 complex are required for fungal development and pathogenicity in F. graminearum.

Natural variations in the Cis-elements of GhRPRS1 contributing to petal colour diversity in cotton.

The cotton genus comprises both diploid and allotetraploid species, and the diversity in petal colour within this genus offers valuable targets for studying orthologous gene function differentiation and evolution. However, the genetic basis for this diversity in petal colour remains largely unknown. The red petal colour primarily comes from C, G, K, and D genome species, and it is likely that the common ancestor of cotton had red petals. Here, by employing a clone mapping strategy, we mapped the red petal trait to a specific region on chromosome A07 in upland cotton. Genomic comparisons and phylogenetic analyses revealed that the red petal phenotype introgressed from G. bickii. Transcriptome analysis indicated that GhRPRS1, which encodes a glutathione S-transferase, was the causative gene for the red petal colour. Knocking out GhRPRS1 resulted in white petals and the absence of red spots, while overexpression of both genotypes of GhRPRS1 led to red petals. Further analysis suggested that GhRPRS1 played a role in transporting pelargonidin-3-O-glucoside and cyanidin-3-O-glucoside. Promoter activity analysis indicated that variations in the promoter, but not in the gene body of GhRPRS1, have led to different petal colours within the genus. Our findings provide new insights into orthologous gene evolution as well as new strategies for modifying promoters in cotton breeding.

A novel single nucleotide mutation of TFL1 alters the plant architecture of Gossypium arboreum through changing the pre-mRNA splicing.

KEY MESSAGE: A single nucleotide mutation from G to A at the 201st position changed the 5' splice site and deleted 31 amino acids in the first exon of GaTFL1. Growth habit is an important agronomic trait that plays a decisive role in the plant architecture and crop yield. Cotton (Gossypium) tends to indeterminate growth, which is unsuitable for the once-over mechanical harvest system. Here, we identified a determinate growth mutant (dt1) in Gossypium arboreum by EMS mutagenesis, in which the main axis was terminated with the shoot apical meristem (SAM) converted into flowers. The map-based cloning of the dt1 locus showed a single nucleotide mutation from G to A at the 201st positions in TERMINAL FLOWER 1 (GaTFL1), which changed the alternative RNA 5' splice site and resulted in 31 amino acids deletion and loss of function of GaTFL1. Comparative transcriptomic RNA-Seq analysis identified many transporters responsible for the phytohormones, auxin, sugar, and flavonoids, which may function downstream of GaTFL1 to involve the plant architecture regulation. These findings indicate a novel alternative splicing mechanism involved in the post-transcriptional modification and TFL1 may function upstream of the auxin and sugar pathways through mediating their transport to determine the SAM fate and coordinate the vegetative and reproductive development from the SAM of the plant, which provides clues for the TFL1 mechanism in plant development regulation and provide research strategies for plant architecture improvement.

Estimation precision for a normalized response matrix in linear polarization calibration.

The purpose of polarization calibration is to obtain the response matrix of an instrument such that the subsequent observation data can be corrected. The calibration precision, however, is partially restricted by the noise of the detector. We investigate the precision of the normalized response matrix in the presence of signal-independent additive noise or signal-dependent Poisson shot noise. The influences of the source intensity, type of noise, and calibration configuration on the precision are analyzed. We compare the theoretical model and the experimental measurements of the polarization calibration to show that the relative difference between the two is less than 16%. From this result, we can use the model to determine the minimum source intensity and choose the optimal configurations that provide the required precision.

Small GTPase Rab7-mediated FgAtg9 trafficking is essential for autophagy-dependent development and pathogenicity in Fusarium graminearum.

Fusarium graminearum is a fungal pathogen that causes Fusarium head blight (FHB) in wheat and barley. Autophagy is a highly conserved vacuolar degradation pathway essential for cellular homeostasis in which Atg9 serves as a multispanning membrane protein important for generating membranes for the formation of phagophore assembly site. However, the mechanism of autophagy or autophagosome formation in phytopathogens awaits further clarifications. In this study, we identified and characterized the Atg9 homolog (FgAtg9) in F. graminearum by live cell imaging, biochemical and genetic analyses. We find that GFP-FgAtg9 localizes to late endosomes and trans-Golgi network under both nutrient-rich and nitrogen starvation conditions and also show its dynamic actin-dependent trafficking in the cell. Further targeted gene deletion of FgATG9 demonstrates that it is important for growth, aerial hyphae development, and pathogenicity in F. graminearum. Furthermore, the deletion mutant (ΔFgatg9) shows severe defects in autophagy and lipid metabolism in response to carbon starvation. Interestingly, small GTPase FgRab7 is found to be required for the dynamic trafficking of FgAtg9, and co-immunoprecipitation (Co-IP) assays show that FgAtg9 associates with FgRab7 in vivo. Finally, heterologous complementation assay shows that Atg9 is functionally conserved in F. graminearum and Magnaporthe oryzae. Taken together, we conclude that FgAtg9 is essential for autophagy-dependent development and pathogenicity of F. graminearum, which may be regulated by the small GTPase FgRab7.

Protective effects of irisin on hypoxia-reoxygenation injury in hyperglycemia-treated cardiomyocytes: Role of AMPK pathway and mitochondrial protection.

Recent evidence has verified the cardioprotective actions of irisin in different diseases models. However, the beneficial action of irisin on hypoxia-reoxygenation (HR) injury under high glucose stress has not been described. Herein our research investigated the influence of irisin on HR-triggered cardiomyocyte death under high glucose stress. HR model was established in vitro under high glucose treatment. The results illuminated that HR injury augmented apoptotic ratio of cardiomyocyte under high glucose stress; this effect could be abolished by irisin via modulating mitochondrial function. Irisin treatment attenuated cellular redox stress, improved cellular ATP biogenetics, sustained mitochondria potential, and impaired mitochondrion-related cell death. At the molecular levels, irisin treatment activated the 5'-adenosine monophosphate-activated protein kinase (AMPK) pathway and the latter protected cardiomyocyte and mitochondria against HR injury under high glucose stress. Altogether, our results indicated a novel role of irisin in HR-treated cardiomyocyte under high glucose stress. Irisin-activated AMPK pathway and the latter sustained cardiomyocyte viability and mitochondrial function.

FgSec2A, a guanine nucleotide exchange factor of FgRab8, is important for polarized growth, pathogenicity and deoxynivalenol production in Fusarium graminearum.

Sec4/Rab8 is one of the well-studied members of the Rab GTPase family, previous studies have shown that Sec4/Rab8 crucially promotes the pathogenesis of phytopathogens, but the upstream regulators of Rab8 are still unknown. Here, we have identified two Sec2 homologues FgSec2A and FgSec2B in devastating fungal pathogen Fusarium graminearum and investigated their functions and interactions with FgRab8 by live-cell imaging, genetic and functional analyses. Yeast two-hybrid assay shows that FgSec2A specifically interacts with FgRab8DN(N123I) and itself. Importantly, FgSec2A is required for growth, conidiation, DON production and virulence of F. graminearum. Live-cell imaging shows that FgSec2A and FgSec2B are both localized to the tip region of hyphae and conidia. Both N-terminal region and Sec2 domain of FgSec2A are essential for its function, but not for localization, whereas the C-terminal region is important for its polarized localization. Furthermore, constitutively active FgRab8CA(Q69L) partially rescues the defects of ΔFgsec2A. Consistently, FgSec2A is required for the polarized localization of FgRab8. Finally, FgSec2A and FgSec2B show partial functions, but FgSec2A does not interact and co-localize with FgSec2B. Taken together, these results indicate that FgSec2A acts as a FgRab8 guanine nucleotide exchange factor and is necessary for polarized growth, DON production and pathogenicity in F. graminearum.

Clinical characteristics and outcome correlates of Chinese patients with takotsubo syndrome: Results from the first Chinese takotsubo syndrome registry.

OBJECTIVE: To investigate clinical features and outcomes of Chinese patients with Takotsubo syndrome (TTS). METHODS: We established the first Chinese Registry of Takotsubo Syndrome (ChiTTS Registry) and analyzed demographic, clinical, therapeutical, and outcome data to characterize clinical and outcome features of Chinese TTS patients. RESULTS: In 112 enrolled patients in the ChiTTS registry from 02/01/2016 to 12/28/2021, the mean age was 59.4 ± 18.7 years old, and 27.7% were men. A total of 41.1% patients experienced respiratory and circulatory complications during hospitalization, and 17.3% patients developed cardiogenic shock. Physical triggers, dyspnea, tachycardia, and younger age (< 70 years old) predicted in-hospital complications. The MACCE rate during follow up was 13.9% per patient per year and the rate of all-cause death was 12.8% per patient per year. TTS patients with in-hospital complications developed more long-term MACCE (24.6% vs. 6.6% per patient-year, P < 0.001) and higher all-cause mortality (21.9% vs. 6.6% per patient-year, P = 0.001) than those without. The Kaplan-Meier survival analysis showed that more MACCE occurred in TTS patients with tachycardia during 3-year follow-up (HR 4.18; 95% CI 1.80-9.74; log-rank test P < 0.001). Among all medications at discharge, only beta-blocker was associated with reduced long-term MACCE (HR: 0.35; 95% CI: 0.12-0.996; P = 0.049). CONCLUSION: We investigated clinical and outcome features of patients in the first Chinese TTS Registry. Tachycardiac TTS patients developed more inpatient and long-term adverse cardiovascular events.

Trehalose Phosphate Synthase Complex-Mediated Regulation of Trehalose 6-Phosphate Homeostasis Is Critical for Development and Pathogenesis in Magnaporthe oryzae.

Trehalose biosynthesis pathway is a potential target for antifungal drug development, and trehalose 6-phosphate (T6P) accumulation is widely known to have toxic effects on cells. However, how organisms maintain a safe T6P level and cope with its cytotoxicity effects when accumulated have not been reported. Herein, we unveil the mechanism by which the rice blast fungus Magnaporthe oryzae avoids T6P accumulation and the genetic and physiological adjustments it undergoes to self-adjust the metabolite level when it is unavoidably accumulated. We found that T6P accumulation leads to defects in fugal development and pathogenicity. The accumulated T6P impairs cell wall assembly by disrupting actin organization. The disorganization of actin impairs the distribution of chitin synthases, thereby disrupting cell wall polymer distribution. Additionally, accumulation of T6P compromise energy metabolism. M. oryzae was able to overcome the effects of T6P accumulation by self-mutation of its MoTPS3 gene at two different mutation sites. We further show that mutation of MoTPS3 suppresses MoTps1 activity to reduce the intracellular level of T6P and partially restore ΔMotps2 defects. Overall, our results provide insights into the cytotoxicity effects of T6P accumulation and uncover a spontaneous mutation strategy to rebalance accumulated T6P in M. oryzae. IMPORTANCE M. oryzae, the causative agent of the rice blast disease, threatens rice production worldwide. Our results revealed that T6P accumulation, caused by the disruption of MoTPS2, has toxic effects on fugal development and pathogenesis in M. oryzae. The accumulated T6P impairs the distribution of cell wall polymers via actin organization and therefore disrupts cell wall structure. M. oryzae uses a spontaneous mutation to restore T6P cytotoxicity. Seven spontaneous mutation sites were found, and a mutation in MoTPS3 was further identified. The spontaneous mutation in MoTPS3 can partially rescue ΔMotps2 defects by suppressing MoTps1 activity to alleviate T6P cytotoxicity. This study provides clear evidence for better understanding of T6P cytotoxicity and how the fungus protects itself from T6P's toxic effects when it has accumulated to severely high levels.

NR5A2 Promotes Cell Growth and Resistance to Temozolomide Through Regulating Notch Signal Pathway in Glioma.

BACKGROUND: Glioma is a fatal primary malignant tumor. We aimed to explore the effect of nuclear receptor subfamily 5 group A member 2 (NR5A2) on glioma. METHODS: NR5A2 expression in glioma tissues and cells was detected using qRT-PCR and immunohistochemistry (IHC)/Western blot. SPSS 22.0 was performed to explore the relationship between NR5A2 expression and glioma clinicopathologic features. The down-expressed plasmid of NR5A2 was transfected into glioma cells, and the cell viability, proliferation, apoptosis, migration, and invasion were respectively determined by MTT, EdU, flow cytometry, wound healing and transwell assays. Cell cycle was analyzed using flow cytometry. Temozolomide (TMZ)-resistant glioma cells were established to define the effect of NR5A2 on drug resistance. The expressions of Notch pathway-related proteins were assessed by Western blot. Glioma nude mice model was constructed to explore the role of NR5A2 played in vivo. RESULTS: NR5A2 was highly expressed in glioma tissues and cell lines. NR5A2 overexpression was related to the poor prognosis of glioma patients. NR5A2 knockdown inhibited cell viability, proliferation, migration, and invasion, induced cell cycle arrest and promoted cell apoptosis in U138 and U251 cells. In U138/TMZ and U251/TMZ cell lines, NR5A2 upregulation enhanced TMZ resistance while NR5A2 downregulation reduced it. The knockdown of NR5A2 influenced the expressions of Notch pathway-related proteins. NR5A2 knockdown suppressed tumor growth and facilitated apoptosis in glioma mice model. CONCLUSION: NR5A2 affected glioma cell malignant behaviors and TMZ resistance via Notch signaling pathway and it might be a novel target in glioma therapy.

[Effects of foliar spraying DA-6 on the photosynthetic rate and plant growth of strawberry in autumn].

With strawberry ' French 3' (Fragaria x ananassa Duch cv. French 3) as test material, this paper studied the effects of foliar spraying DA-6 at the rates of 10, 20 and 30 mg x L(-1) in late autumn on its seedlings net photosynthetic rate, metabolism of reactive oxygen species, and plant growth. Compared with the control, foliar spraying DA-6 of 20 and 30 mg x L(-1) increased the net photosynthetic rate, chlorophyll a and b contents, and SOD and CAT activities significantly, and decreased the reactive oxygen and MDA contents. Moreover, foliar spraying DA-6 of 20 and 30 mg x L(-1) increased the average dry weight per leaf, and the dry mass of shoot and root significantly. The ratio of root to shoot after spraying DA-6 of 20 and 30 mg x L(-1) was 29.9% and 29.3% higher than the control, respectively. Foliar spraying appropriate concentration of DA-6 in late autumn could improve the plant growth of strawberry seedlings.