Integrated analysis of HSP20 genes in the developing flesh of peach: identification, expression profiling, and subcellular localization.

BACKGROUND: Plant HSP20s are not only synthesized in response to heat stress but are also involved in plant biotic and abiotic stress resistance, normal metabolism, development, differentiation, survival, ripening, and death. Thus, HSP20 family genes play very important and diverse roles in plants. To our knowledge, HSP20 family genes in peach have not yet been characterized in detail, and little is known about their possible function in the development of red flesh in peach. RESULTS: In total, 44 PpHSP20 members were identified in the peach genome in this study. Forty-four PpHSP20s were classified into 10 subfamilies, CI, CII, CIII, CV, CVI, CVII, MII, CP, ER, and Po, containing 18, 2, 2, 10, 5, 1, 1, 2, 1, and 2 proteins, respectively. Among the 44 PpHSP20 genes, 6, 4, 4, 3, 7, 11, 5, and 4 PpHSP20 genes were located on chromosomes 1 to 8, respectively. In particular, approximately 15 PpHSP20 genes were located at both termini or one terminus of each chromosome. A total of 15 tandem PpHSP20 genes were found in the peach genome, which belonged to five tandemly duplicated groups. Overall, among the three cultivars, the number of PpHSP20 genes with higher expression levels in red flesh was greater than that in yellow or white flesh. The expression profiling for most of the PpHSP20 genes in the red-fleshed 'BJ' was higher overall at the S3 stage than at the S2, S4-1, and S4-2 stages, with the S3 stage being a very important period of transformation from a white color to the gradual anthocyanin accumulation in the flesh of this cultivar. The subcellular localizations of 16 out of 19 selected PpHSP20 proteins were in accordance with the corresponding subfamily classification and naming. Additionally, to our knowledge, Prupe.3G034800.1 is the first HSP20 found in plants that has the dual targets of both the endoplasmic reticulum and nucleus. CONCLUSIONS: This study provides a comprehensive understanding of PpHSP20s, lays a foundation for future analyses of the unknown function of PpHSP20 family genes in red-fleshed peach fruit and advances our understanding of plant HSP20 genes.

Lactate Dehydrogenase-Inhibitors Isolated from Ethyl Acetate Extract of Selaginella doederleinii by Using a Rapid Screening Method with Enzyme-Immobilized Magnetic Nanoparticles.

BACKGROUND: Lactate dehydrogenase (LDH) is one of the important enzyme systems for glycolysis and gluconeogenesis. It can catalyze the reduction and oxidation reaction between propionic acid and L-lactic acid, which is usually overexpressed in cancer cells. Therefore, inhibiting the activity of LDH is a promising way for the treatment of cancer. In this study, an effective method based on ligand fishing and ultra performance liquid chromatography-mass spectrum (UPLC-MS) was established to screen and identify active ingredients from Selaginella doederleinii with potential inhibitory activity for LDH. METHODS: Firstly, LDH was immobilized on the magnetic nanoparticles (MNPs), three immobilization parameters including LDH concentration, immobilization time and pH were optimized by single factor and response surface methodology for maximum (max) immobilization yield. Then, a mixed model of galloflavin and chlorogenic acid (inhibitors and non-inhibitors of LDH) was used to verify the specificity of immobilized LDH ligand fishing, and the conditions of ligand fishing were further optimized. Finally, combined with UPLC-MS, immobilized LDH was used to simultaneously screen and identify potential LDH inhibitors from the ethyl acetate extract of Selaginella doederleinii. RESULTS: The prepared fishing material was comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and fourier transform infrared spectrometer (FT-IR). The optimal immobilization conditions were obtained as LDH concentration of 0.7 mg/mL, pH value of 4.5, and immobilization time of 3.5 h. Under these conditions, the max immobilization yield was (3.79 ± 0.08) × 103 U/g. The specificity analysis showed that immobilized LDH could recognize and capture ligands, and the optimal ligand fishing conditions included that the incubation time was 30 min, the elution time was 20 min, and the concentration of methanol as eluent was 80%. Finally, two LDH inhibitors, amentoflavone and robustaflavone, were screened by immobilized LDH from the ethyl acetate extract of Selaginella doederleinii. CONCLUSIONS: The study provided a meaningful evidence for discovering the bioactive constituents in ethyl acetate extract of Selaginella doederleinii related to cancer treatment, and this ligand fishing method was feasible for screening enzyme inhibitors from similar complex mixtures.

Melatonin treatment maintains the quality of cherry tomato by regulating endogenous melatonin and ascorbate-glutathione cycle during room temperature.

Changes in quality attributes, ascorbate-glutathione (AsA-GSH) cycle, and melatonin (MLT) synthesis were evaluated in cherry tomato fruit treated with MLT solution at 0.1 mM during storage at room temperature for 16 days. According to the results, the MLT treatment was beneficial to maintaining fruit quality as indicated by the declines in weight loss, fruit decay, and titratable acid (TA), accompanied by the maintenance of fruit firmness, total soluble solids (TSS) as well as TSS/TA ratio. Also, the MLT treatment not only effectively inhibited oxidative damage via reducing relative electrolyte leakage and malondialdehyde content, but also improved antioxidant capacity via stimulating AsA-GSH cycle. Moreover, the MLT treatment promoted endogenous MLT synthesis by upregulating the expressions of biosynthetic genes consisting of SlTDC, SlT5H, SlSNAT, and SlASMLT. Thus, our results suggested that the MLT treatment might be involved in maintaining quality in cherry tomato fruit during room temperature by promoting antioxidant capacity and enhancing endogenous MLT. PRACTICAL APPLICATIONS: As a typical climacteric fruit, cherry tomato fruit ripen rapidly and are easily infected by various pathogenic fungi during storage under ambient conditions, which leads to short storage life and a decrease in economic value. The results showed that the application of MLT maintained cherry tomato quality via improving antioxidant capacities and enhancing endogenous MLT. Therefore, MLT treatment could become a promising postharvest strategy for quality maintenance in cherry tomatoes during room storage.

Engineered Nanomaterials Suppress the Soft Rot Disease (Rhizopus stolonifer) and Slow Down the Loss of Nutrient in Sweet Potato.

About 45% of the world's fruit and vegetables are wasted, resulting in postharvest losses and contributing to economic losses ranging from $10 billion to $100 billion worldwide. Soft rot disease caused by Rhizopus stolonifer leads to postharvest storage losses of sweet potatoes. Nanoscience stands as a new tool in our arsenal against these mounting challenges that will restrict efforts to achieve and maintain global food security. In this study, three nanomaterials (NMs) namely C60, CuO, and TiO2 were evaluated for their potential application in the restriction of Rhizopus soft rot disease in two cultivars of sweet potato (Y25, J26). CuO NM exhibited a better antifungal effect than C60 and TiO2 NMs. The contents of three important hormones, indolepropionic acid (IPA), gibberellic acid 3 (GA-3), and indole-3-acetic acid (IAA) in the infected J26 sweet potato treated with 50 mg/L CuO NM were significantly higher than those of the control by 14.5%, 10.8%, and 24.1%. CuO and C60 NMs promoted antioxidants in both cultivars of sweet potato. Overall, CuO NM at 50 mg/L exhibited the best antifungal properties, followed by TiO2 NM and C60 NM, and these results were further confirmed through scanning electron microscope (SEM) analysis. The use of CuO NMs as an antifungal agent in the prevention of Rhizopus stolonifer infections in sweet potatoes could greatly reduce postharvest storage and delivery losses.

1-Methylcyclopropene treatment controls ethanol accumulation associated with regulation of mitochondrial energy metabolism in kiwifruit (Actinidia deliciosa) cv. "Bruno" during storage at room temperature.

In this paper, the effects of 1-methylcyclopropene (1-MCP) treatment on the ethanol accumulation and mitochondrial energy metabolism in kiwifruit (Actinidia deliciosa) cv. "Bruno" were investigated during storage at room temperature (24 ± 1°C). The results showed that 1-MCP treatment significantly reduced the ethanol accumulation, maintained higher levels of adenosine triphosphate (ATP) content and energy charge (EC), enhanced enzymes activities involved in mitochondrial energy metabolism, such as succinic dehydrogenase, cytochrome C oxidase, H+ -adenosine triphosphatase (H+ -ATPase), and Ca2+ -adenosine triphosphatase (Ca2+ -ATPase), and regulated the NADH/NAD+ ratio, and pyruvate to tricarboxylic acid cycle (TCA) by suppressing the glutamate-pyruvate transaminase and promoting the pyruvate dehydrogenase activity, and decarboxylation of citric acid in harvested kiwifruit. These shifts in mitochondrial energy metabolism and oxidative phosphorylation correlated the higher ATP yield and an elevated EC with lower ethanol accumulation (13.71% of those in the control fruit) under 1-MCP treatment, and reduced the susceptibility of ethanol related off-flavor disorder in kiwifruit during storage. PRACTICAL APPLICATIONS: A kiwifruit (Actinidia deliciosa) cv. "Bruno," a major cultivated kiwifruit in China, is prone to accumulate ethanol sharply after respiratory climacteric during storage. Ethanol has been accounted as a vital aroma volatile metabolite in various fruits. However, over accumulation of ethanol often leads to the development of alcohol off-flavor disorder, particularly in typical climacteric fruit such as kiwifruit. This work was aimed to maintain the flavor quality of kiwifruit cv. "Bruno" via improving the mitochondrial energy metabolism and functional TCA cycle, and limiting the ethanol accumulation under 1-MCP treatment. Thus, 1-MCP treatment could be beneficial to prevent the occurrence of alcohol off-flavor disorder along with sustainment of the flavor quality of kiwifruit cv. "Bruno" during storage at room temperature.

Effect of benzothiadiazole treatment on improving the mitochondrial energy metabolism involved in induced resistance of apple fruit during postharvest storage.

The effects of benzothiadiazole (BTH) on Penicillium expansum development, mitochondria energy metabolism, and changes in the number and structure of mitochondria in apple fruit were investigated after the fruit were immersed in 100 mg L-1 BTH for 10 min and then stored at 22 °C. The results indicated that BTH treatment significantly decreased the lesion diameter of fruit challenged with P. expansum; further, treatment enhanced the activities of mitochondrial respiratory metabolism-related enzymes, such as succinate dehydrogenase, cytochrome oxidase, H+-ATPase and Ca2+-ATPase, along with high ATP level and energy status in apple fruit during storage. Moreover, transmission electron microscopy results indicated that BTH treatment was beneficial for maintaining the number and structure of mitochondria during storage. The results suggested that BTH treatment enhanced ATP levels via mitochondrial energy metabolism, which might contribute to the induced resistance in apple fruit during storage.

Sodium silicate prime defense responses in harvested muskmelon by regulating mitochondrial energy metabolism and reactive oxygen species production.

The effects of postharvest treatment with sodium silicate (Si) (100 mM) on mitochondrial ROS production and energy metabolism of the muskmelon fruits (cv. Yujinxiang) on development of defense responses to Trichothecium roseum were studied. Si treatment decreased decay severity of inoculated muskmelons, enhanced the activities of energy metabolism of key enzymes and kept the intracellular ATP at a higher level; meanwhile, Si also induced the mtROS accumulation such as H2O2 and superoxide anion. TMT-based quantitative proteomics analysis revealed that a total of 24 proteins with significant differences in abundance involved in energy metabolism, defense and stress responses, glycolytic and TCA cycle, and oxidation-reduction process. It is suggested by our study that melon fruit mitochondria, when induced by Si treatments, play a key role in priming of host resistance against T. roseum infection through the regulation of energy metabolism and ROS production in the pathogen infected muskmelon fruits.

Early Defense Responses Involved in Mitochondrial Energy Metabolism and Reactive Oxygen Species Accumulation in Harvested Muskmelons Infected by Trichothecium roseum.

Mitochondria play an essential part in fighting against pathogen infection in the defense responses of fruits. In this study, we investigated the reactive oxygen species (ROS) production, energy metabolism, and changes of mitochondrial proteins in harvested muskmelon fruits ( Cucumis melo cv. Yujinxiang) inoculated with Trichothecium roseum. The results indicated that the fungal infection obviously induced the H2O2 accumulation in mitochondria. Enzyme activities were inhibited in the first 6 h postinoculation (hpi), including succinic dehydrogenase, cytochrome c oxidase, H+-ATPase, and Ca2+-ATPase. However, the activities of Ca2+-ATPase and H+-ATPase and the contents of intracellular adenosine triphosphate (ATP) were improved to a higher level at 12 hpi. A total of 42 differentially expressed proteins were identified through tandem mass tags-based proteomic analyses, which are mainly involved in energy metabolism, stress responses and redox homeostasis, glycolysis and tricarboxylic acid cycle, and transporter and mitochondria dysfunction. Taken together, our results suggest that mitochondria play crucial roles in the early defense responses of muskmelons against T. roseum infection through regulation of ROS production and energy metabolism.