Adsorption of rare bases on transition metal doped γ-graphyne nanosheets: a DFT study.

Detection of rare bases (RBs) is key to understanding biological complexity, rapidly diagnosing genetic diseases and advancing personalized medicine. Electrochemical sensors are one of the most promising methods for RB detection, but their low responsiveness limits their effectiveness. Therefore, enhancing selectivity and sensitivity is necessary. γ-Graphyne (γ-GY) has garnered significant attention due to its sp2 and sp hybrid carbon bonds and layered two-dimensional planar structure, as well as its extensive conjugated system, and sizable triangular hole. In this study, the structural characteristics, electronic properties, and sensing parameters of the adsorption involving RBs with both γ-GY and transition metal (Fe, Co, and Ni)-doped γ-graphyne (TM-GY) nanosheets are investigated using density functional theory calculations to evaluate the potential of nanosheets for sequencing RBs in DNA. The result shows that the adsorption interaction between RBs and γ-GY is weak physical adsorption, making it difficult to distinguish RBs. In contrast, the adsorption of RBs with TM-GY is stronger chemisorption and can be completely separated by translocation time and sensing response. Through translocation time calculations, we demonstrate the high selectivity of Ni-GY for RBs. Furthermore, sensitivity analysis reveals that Fe-GY exhibits excellent responsiveness to RBs. Our work reveals that the TM-GY nanosheets hold promise for detecting RBs compared with the γ-GY, and may provide valuable insights for the design of graphyne-based biosensors and catalysts.

Promoter of Cassava MeAHL31 Responds to Diverse Abiotic Stresses and Hormone Signals in Transgenic Arabidopsis.

The AT-hook motif nuclear-localized (AHL) family is pivotal for the abiotic stress response in plants. However, the function of the cassava AHL genes has not been elucidated. Promoters, as important regulatory elements of gene expression, play a crucial role in stress resistance. In this study, the promoter of the cassava MeAHL31 gene was cloned. The MeAHL31 protein was localized to the cytoplasm and the nucleus. qRT-PCR analysis revealed that the MeAHL31 gene was expressed in almost all tissues tested, and the expression in tuber roots was 321.3 times higher than that in petioles. Promoter analysis showed that the MeAHL31 promoter contains drought, methyl jasmonate (MeJA), abscisic acid (ABA), and gibberellin (GA) cis-acting elements. Expression analysis indicated that the MeAHL31 gene is dramatically affected by treatments with salt, drought, MeJA, ABA, and GA3. Histochemical staining in the proMeAHL31-GUS transgenic Arabidopsis corroborated that the GUS staining was found in most tissues and organs, excluding seeds. Beta-glucuronidase (GUS) activity assays showed that the activities in the proMeAHL31-GUS transgenic Arabidopsis were enhanced by different concentrations of NaCl, mannitol (for simulating drought), and MeJA treatments. The integrated findings suggest that the MeAHL31 promoter responds to the abiotic stresses of salt and drought, and its activity is regulated by the MeJA hormone signal.

Functional Characterization of the MeSSIII-1 Gene and Its Promoter from Cassava.

Soluble starch synthases (SSs) play important roles in the synthesis of cassava starch. However, the expression characteristics of the cassava SSs genes have not been elucidated. In this study, the MeSSIII-1 gene and its promoter, from SC8 cassava cultivars, were respectively isolated by PCR amplification. MeSSIII-1 protein was localized to the chloroplasts. qRT-PCR analysis revealed that the MeSSIII-1 gene was expressed in almost all tissues tested, and the expression in mature leaves was 18.9 times more than that in tuber roots. MeSSIII-1 expression was induced by methyljasmonate (MeJA), abscisic acid (ABA), and ethylene (ET) hormones in cassava. MeSSIII-1 expression patterns were further confirmed in proMeSSIII-1 transgenic cassava. The promoter deletion analysis showed that the -264 bp to -1 bp MeSSIII-1 promoter has basal activity. The range from -1228 bp to -987 bp and -488 bp to -264 bp significantly enhance promoter activity. The regions from -987 bp to -747 bp and -747 bp to -488 bp have repressive activity. These findings will provide an important reference for research on the potential function and transcriptional regulation mechanisms of the MeSSIII-1 gene and for further in-depth exploration of the regulatory network of its internal functional elements.

Integrated Analysis of Morphological, Physiological, Anatomical and Molecular Responses of Cassava Seedlings to Different Light Qualities.

Light quality is highly important for growth control of in vitro plant cultures. Here, we investigated the effect of blue light (BL), red light (RL) and combined red and blue light (RBL) on in vitro cassava growth. Our results indicate that RL facilitated radial elongation of cassava and increased stomatal conductance as well as glucose, sucrose, fructose and starch content in leaves and cellulose content in the stem. It also enhanced SOD and POD activities but decreased the stomatal density and chlorophyll and carotenoid content in leaves. In addition, RL leads to shorter palisade cells, denser chloroplasts and more starch granules. These phenotypic changes were inverted following BL treatment. The expression levels of photosynthesis-related genes MeLHCA1, MeLHCA3, MePSB27-2, MePSBY, MePETE1 and MePNSL2 in leaves were at their lowest following RL treatment, while the expression levels of MePSB27-2, MePSBY, MePETE1 and MePNSL2 were at their highest after BL treatment. The phenotypic changes after RBL treatment were between the values observed for the RL and BL treatments alone. Moreover, the responses of SC8 and SC9 cassava varieties to light quality were largely conserved. As such, we believe that the results of this study lay the foundation for controlling the in vitro growth of cassava seedlings by light quality.

Comparative Transcriptome Profiling of Cassava Tuberous Roots in Response to Postharvest Physiological Deterioration.

Cassava is one of the most versatile tuberous-root crops on Earth. However, the postharvest storage properties of cassava tuberous root mean that it is perishable through a process known as postharvest physiological deterioration (PPD), which seriously affects its starch quality. Therefore, a comprehensive understanding of the transcriptional regulatory activity of cassava against the PPD response is necessary in order to extract key molecular mechanisms related to PPD tolerance. In this study, we found that RYG1 tuberous roots showed delayed PPD compared to those of SC8. In addition, RYG1 roots maintained a more stable cell wall structure after storage than those of SC8. The transcriptome changes in tuberous roots were analyzed for both RYG1 and SC8 after 21 days of storage (SR and SS) compared to fresh (FR and FS) by the RNA-Seq method. The total number of differentially expressed genes (DEGs) in the various comparisons of these four samples ranged from 68 to 3847. Of these, a total of 2008 co-DEGs in SR vs. SS were shared by either SR vs. FR or SS vs. FS. GO and KEGG enrichment analysis revealed that upregulated co-DEGs in SR vs. SS were mainly enriched in photosynthesis, protein processing, hormone and cutin, suberine and wax biosynthesis. By contrast, the downregulated co-DEGs were mainly related to cell wall organization, starch and sucrose metabolism, galactose metabolism, phenylpropanoid biosynthesis, diterpenoid biosynthesis, cysteine and methionine metabolism and flavonoid biosynthesis. The protein-protein interaction (PPI) networks of the co-DEGs showed a complex interaction of genes in different pathways, and 16 hub genes were characterized to have a degree in excess of 15, among which eight genes were associated with photosynthesis. These results provide new information for the study of cassava resistance to PPD and lay a foundation for the further molecular breeding of storage-tolerant cassava varieties.

Genome-Wide Identification of Cassava Glyoxalase I Genes and the Potential Function of MeGLYâ -13 in Iron Toxicity Tolerance.

Glyoxalase I (GLYI) is a key enzyme in the pathway of the glyoxalase system that degrades the toxic substance methylglyoxal, which plays a crucial part in plant growth, development, and stress response. A total of 19 GLYI genes were identified from the cassava genome, which distributed randomly on 11 chromosomes. These genes were named MeGLYI-1-19 and were systematically characterized. Transcriptome data analysis showed that MeGLYIs gene expression is tissue-specific, and MeGLYI-13 is the dominant gene expressed in young tissues, while MeGLYI-19 is the dominant gene expressed in mature tissues and organs. qRT-PCR analysis showed that MeGLYI-13 is upregulated under 2 h excess iron stress, but downregulated under 6, 12, and 20 h iron stress. Overexpression of MeGLYI-13 enhanced the growth ability of transgenic yeast under iron stress. The root growth of transgenic Arabidopsis seedlings was less inhibited by iron toxicity than that of the wild type (WT). Potted transgenic Arabidopsis blossomed and podded under iron stress, but flowering of the WT was significantly delayed. The GLYI activity in transgenic Arabidopsis was improved under both non-iron stress and iron stress conditions compared to the WT. The SOD activity in transgenic plants was increased under iron stress, while the POD and CAT activity and MDA content were decreased compared to that in the WT. These results provide a basis for the selection of candidate genes for iron toxicity tolerance in cassava, and lay a theoretical foundation for further studies on the functions of these MeGLYI genes.

[Discovery and confirmation of protein action site AK1 of ginsenosides in brain based on DARTS technology].

This study aims to explore the targets of ginsenosides in brain based on drug affinity responsive target stability(DARTS) technology. Specifically, DARTS technology was combined with label-free liquid chromatography tandem mass spectrometry(LC-MS) to screen out the proteins in the brain that might interact with ginsenosides. Based on the screening results, adenylate kinase 1(AK1) was selected for further confirmation. First, the His-AK1 fusion protein was yielded successively through the construction of recombinant prokaryotic expression vector, expression of target protein, and purification of the fusion protein. Biolayer interferometry(BLI) was employed to detect the direct interaction of Rg_1, Re, Rb_1, Rd, Rh_2, F1, Rh_1, compound K(CK), 25-OH-PPD, protopanaxa-diol(PPD), and protopanaxatriol(PPT) with AK1, thereby screening the ginsenoside monomer or sapogenin that had strong direct interaction with the suspected target protein AK1. Then, the BLI was used to further determine the kinetic parameters for the binding of PPD(strongest interaction with AK1) to His-AK1 fusion protein. Finally, molecular docking technology was applied to analyze the binding properties between the two. With DARTS and LC-MS, multiple differential proteins were screened out, and AK1 was selected based on previous research for target verification. Fusion protein His-AK1 was obtained by prokaryotic expression, and the response(nm) of Re, Rg_1, Rd, Rb_1, Rh_1, Rh_2, F1, PPT, PPD, 25-OH-PPD, and CK with His-AK1 was respectively 0.003 1, 0.001 9, 0.042 8, 0.022 2, 0.013 4, 0.037 3, 0.013 9, 0.030 7, 0.140 2, 0.016 0, and 0.040 8. The K_(on), K_(off), and K_D values of PPD and His-AK1 were determined by the BLI as 1.22×10~2 mol~(-1)·L·s~(-1), 1.04×10~(-2) s~(-1), 8.52×10~(-5) mol·L~(-1). According to the molecular docking result, PPD bound to AK1 with the absolute value of the docking score of 3.438, and hydrogen bonds mainly formed between the two. Thus, AK1 is one of the protein action sites of ginsenosides in the brain. The direct interaction between ginsenoside metabolite PPD and AK1 is the strongest.

Character changes and Transcriptomic analysis of a cassava sexual Tetraploid.

BACKGROUND: Cassava (Manihot esculenta Crantz) is an important food crop known for its high starch content. Polyploid breeding is effective in its genetic improvement, and use of 2n gametes in sexual polyploid breeding is one of the potential methods for cassava breeding and improvement. In our study, the cassava sexual tetraploid (ST), which carries numerous valuable traits, was successfully generated by hybridizing 2n female gametes SC5 (♀) and 2n male gametes SC10 (♂). However, the molecular mechanisms remain unclear. To understand these underlying molecular mechanisms behind the phenotypic alterations and heterosis in ST plants, we investigated the differences in gene expression between polyploids and diploids by determining the transcriptomes of the ST plant and its parents during the tuber root enlargement period. We also compared the characters and transcriptomes of the ST plant with its parents. RESULTS: The ST plant was superior in plant height, stem diameter, leaf area, petiole length, plant weight, and root weight than the parent plants, except the leaf number, which was lower. The number of starch granules was higher in the roots of ST plants than those in the parent plants after five months (tuber root enlargement period), which could be due to a higher leaf net photosynthetic rate leading to early filling of starch granules. Based on transcriptome analysis, we identified 2934 and 3171 differentially expressed genes (DEGs) in the ST plant as compared to its female and male parents, respectively. Pathway enrichment analyses revealed that flavonoid biosynthesis and glycolysis/gluconeogenesis were significantly enriched in the ST plants, which might contribute to the colors of petiole (purple-red), root epidermis (dark brown), and tuber starch accumulation, respectively. CONCLUSIONS: After sexual polyploidization, the phenotype of ST has changed significantly in comparison to their diploid parents, mainly manifest as enlarged biomass, yield, early starch filling, deep colored petiole and root epidermis. The tetraploid plants were also mature early due to early starch grain filling. Owing to enriched flavonoid biosynthesis and glycolysis/gluconeogenesis, they are possibly resistant to adversity stresses and provide better yield, respectively.

Structure-activity relationship analysis of dammarane-type natural products as muscle-type creatine kinase activators.

Muscle-type creatine kinase (CK-MM) is the target protein of ginsenosides in skeletal muscle. 20(S)-protopanaxadiol [20(S)-PPD] is an activator of CK-MM and exerts an anti-fatigue effect. In this study, twelve dammarane-type compounds were used for structure-activity relationship analysis in terms of enzyme activity, intermolecular interaction, and molecular docking. Enzyme activity analysis showed that 20(S)-PPD, 20(R)-PPD, 20(S)-protopanaxatriol [20(S)-PPT], 25-OH-PPD, 24-COOH-PPD, panaxadiol (PD), and ginsenoside Rh2 significantly increased CK-MM activity. Panaxatriol (PT), ocotillol, ginsenoside Rg1, and ginsenoside Rd had no significant influence on CK-MM activity, while jujubogenin inhibited its activity. Biolayer Interferometry (BLI) assay produced the same results as those on enzyme activity. The interaction intensity between dammarane-type compounds and CK-MM was linearly related to the compounds' maximum increment rate of enzyme activity. Molecular docking showed the following sequence of docking scores: Rd > Rg1 > Rh2 > 24-COOH-PPD > 20(S)-PPD > 20(S)-PPT > 25-OH-PPD > 20(R)-PPD > ocotillol > PT > PD > jujubogenin. We demonstrated that 20(S)-PPD was the best activator of CK-MM among the 12 dammarane-type compounds. The cyclization of the dammarane side chain, the hydroxyl group at position C6, and the glycosylation of C3, C6, and C20 reduced the ability to activate CK-MM. These findings can help in the development of enhanced CK-MM activators through structural modification.

Identification and expression analysis of MinD gene involved in plastid division in cassava.

Cassava is a tropical crop known for its starchy root and excellent properties. Considering that starch biosynthesis in the amyloplast is affected by its division, it appears conceivable that the regulation of plastid division plays an important role in starch accumulation. As a member of the Min system genes, MinD participated in the spatial regulation of the position of the plastid division site.In our studies, sequence analysis and phylogenetic analysis showed that MeMinD has been highly conserved during the evolutionary process. Subcellular localisation indicated that MeMinD carries a chloroplast transit peptide and was localised in the chloroplast. Overexpression of MeMinD resulted in division site misplacement and filamentous formation in E. coli, indicating that MeMinD protein was functional across species. MeMinD exhibited different spatial and temporal expression patterns which was highly expressed in the source compared to that in the sink organ.

Structure, Expression, and Functional Analysis of the Hexokinase Gene Family in Cassava.

Hexokinase (HXK) proteins play important roles in catalyzing hexose phosphorylation and sugar sensing and signaling. To investigate the roles of HXKs in cassava tuber root development, seven HXK genes (MeHXK1-7) were isolated and analyzed. A phylogenetic analysis revealed that the MeHXK family can be divided into five subfamilies of plant HXKs. MeHXKs were clearly divided into type A (MeHXK1) and type B (MeHXK2-7) based on their N-terminal sequences. MeHXK1-5 all had typical conserved regions and similar protein structures to the HXKs of other plants; while MeHXK6-7 lacked some of the conserved regions. An expression analysis of the MeHXK genes in cassava organs or tissues demonstrated that MeHXK2 is the dominant HXK in all the examined tissues (leaves, stems, fruits, tuber phloems, and tuber xylems). Notably, the expression of MeHXK2 and the enzymatic activity of HXK were higher at the initial and expanding tuber stages, and lower at the mature tuber stage. Furthermore, the HXK activity of MeHXK2 was identified by functional complementation of the HXK-deficient yeast strain YSH7.4-3C (hxk1, hxk2, glk1). The gene expression and enzymatic activity of MeHXK2 suggest that it might be the main enzyme for hexose phosphorylation during cassava tuber root development, which is involved in sucrose metabolism to regulate the accumulation of starch.

Identification, Expression, and Functional Analysis of the Fructokinase Gene Family in Cassava.

Fructokinase (FRK) proteins play important roles in catalyzing fructose phosphorylation and participate in the carbohydrate metabolism of storage organs in plants. To investigate the roles of FRKs in cassava tuber root development, seven FRK genes (MeFRK1-7) were identified, and MeFRK1-6 were isolated. Phylogenetic analysis revealed that the MeFRK family genes can be divided into α (MeFRK1, 2, 6, 7) and ß (MeFRK3, 4, 5) groups. All the MeFRK proteins have typical conserved regions and substrate binding residues similar to those of the FRKs. The overall predicted three-dimensional structures of MeFRK1-6 were similar, folding into a catalytic domain and a ß-sheet ''lid" region, forming a substrate binding cleft, which contains many residues involved in the binding to fructose. The gene and the predicted three-dimensional structures of MeFRK3 and MeFRK4 were the most similar. MeFRK1-6 displayed different expression patterns across different tissues, including leaves, stems, tuber roots, flowers, and fruits. In tuber roots, the expressions of MeFRK3 and MeFRK4 were much higher compared to those of the other genes. Notably, the expression of MeFRK3 and MeFRK4 as well as the enzymatic activity of FRK were higher at the initial and early expanding tuber stages and were lower at the later expanding and mature tuber stages. The FRK activity of MeFRK3 and MeFRK4 was identified by the functional complementation of triple mutant yeast cells that were unable to phosphorylate either glucose or fructose. The gene expression and enzymatic activity of MeFRK3 and MeFRK4 suggest that they might be the main enzymes in fructose phosphorylation for regulating the formation of tuber roots and starch accumulation at the tuber root initial and expanding stages.

Extracellular UDP and P2Y6 function as a danger signal to protect mice from vesicular stomatitis virus infection through an increase in IFN-ß production.

Extracellular nucleotides that constitute a "danger signal" play an important role in the regulation of immune responses. However, the function and mechanism of extracellular UDP and P2Y6 in antiviral immunity remain unknown. In this study, we demonstrated the in vitro and in vivo protection of UDP/P2Y6 signaling in vesicular stomatitis virus (VSV) infection. First, we demonstrated that VSV-infected cells secrete UDP from the cytoplasm as a danger signal to arouse surrounding cells. Meanwhile, expression of the UDP-specific receptor P2Y6 also was enhanced by VSV. Consequently, UDP protects RAW 264.7 cells, murine embryonic fibroblasts, bone marrow-derived macrophages, and L929 cells from VSV and GFP lentivirus infection. This protection can be blocked by the P2Y6 selective antagonist MRS2578 or IFN-α/ß receptor-blocking Ab. VSV-induced cell death and virus replication were both enhanced significantly by knocking down and knocking out P2Y6 in different cells. Mechanistically, UDP facilitates IFN-ß secretion through the p38/JNK- and ATF-2/c-Jun-signaling pathways, which are crucial in promoting antiviral immunity. Interestingly, UDP was released through a caspase-cleaved pannexin-1 channel in VSV-induced apoptotic cells and protected cells from infection through P2Y6 receptor in an autocrine or paracrine manner. Furthermore, UDP also protected mice from VSV infection through P2Y6 receptors in an acute neurotropic infection mouse model. Taken together, these results demonstrate the important role of extracellular UDP and P2Y6 as a danger signal in antiviral immune responses and suggest a potential therapeutic role for UDP/P2Y6 in preventing and controlling viral diseases.

Lgr4/Gpr48 negatively regulates TLR2/4-associated pattern recognition and innate immunity by targeting CD14 expression.

The recognition of pathogen-associated molecular patterns by Toll-like receptors (TLRs) is pivotal in both innate and adaptive immune responses. Here we demonstrate that deletion of Lgr4/Gpr48 (G-protein-coupled receptor 48), a seven-transmembrane glycoprotein hormone receptor, potentiates TLR2/4-associated cytokine production and attenuates mouse resistance to septic shock. The expression of CD14, a co-receptor for TLR2/4-associated pathogen-associated molecular patterns, is increased significantly in Lgr4-deficient macrophages, which is consistent with the increased immune response, whereas the binding activity of cAMP-response element-binding protein is decreased significantly in Lgr4-deficient macrophages, which up-regulate the expression of CD14 at the transcriptional level. Together, our data demonstrate that Lgr4/Gpr48 plays a critical role in modulating the TLR2/4 signaling pathway and represents a useful therapeutic approach of targeting Lgr4/Gpr48 in TLR2/4-associated septic shock and autoimmune diseases.

Genome-wide identification, 3D modeling, expression and enzymatic activity analysis of cell wall invertase gene family from cassava (Manihot esculenta Crantz).

The cell wall invertases play a crucial role on the sucrose metabolism in plant source and sink organs. In this research, six cell wall invertase genes (MeCWINV1-6) were cloned from cassava. All the MeCWINVs contain a putative signal peptide with a predicted extracellular location. The overall predicted structures of the MeCWINV1-6 are similar to AtcwINV1. Their N-terminus domain forms a ß-propeller module and three conserved sequence domains (NDPNG, RDP and WECP(V)D), in which the catalytic residues are situated in these domains; while the C-terminus domain consists of a ß-sandwich module. The predicted structure of Pro residue from the WECPD (MeCWINV1, 2, 5, and 6), and Val residue from the WECVD (MeCWINV3 and 4) are different. The activity of MeCWINV1 and 3 were higher than other MeCWINVs in leaves and tubers, which suggested that sucrose was mainly catalyzed by the MeCWINV1 and 3 in the apoplastic space of cassava source and sink organs. The transcriptional levels of all the MeCWINVs and their enzymatic activity were lower in tubers than in leaves at all the stages during the cassava tuber development. It suggested that the major role of the MeCWINVs was on the regulation of carbon exportation from source leaves, and the ratio of sucrose to hexose in the apoplasts; the role of these enzymes on the sucrose unloading to tuber was weaker.

Cloning, 3D modeling and expression analysis of three vacuolar invertase genes from cassava (Manihot Esculenta Crantz).

Vacuolar invertase is one of the key enzymes in sucrose metabolism that irreversibly catalyzes the hydrolysis of sucrose to glucose and fructose in plants. In this research, three vacuolar invertase genes, named MeVINV1-3, and with 653, 660 and 639 amino acids, respectively, were cloned from cassava. The motifs of NDPNG (ß-fructosidase motif), RDP and WECVD, which are conserved and essential for catalytic activity in the vacuolar invertase family, were found in MeVINV1 and MeVINV2. Meanwhile, in MeVINV3, instead of NDPNG we found the motif NGPDG, in which the three amino acids GPD are different from those in other vacuolar invertases (DPN) that might result in MeVINV3 being an inactivated protein. The N-terminal leader sequence of MeVINVs contains a signal anchor, which is associated with the sorting of vacuolar invertase to vacuole. The overall predicted 3D structure of the MeVINVs consists of a five bladed ß-propeller module at N-terminus domain, and forms a ß-sandwich module at the C-terminus domain. The active site of the protein is situated in the ß-propeller module. MeVINVs are classified in two subfamilies, α and ß groups, in which α group members of MeVINV1 and 2 are highly expressed in reproductive organs and tuber roots (considered as sink organs), while ß group members of MeVINV3 are highly expressed in leaves (source organs). All MeVINVs are highly expressed in leaves, while only MeVINV1 and 2 are highly expressed in tubers at cassava tuber maturity stage. Thus, MeVINV1 and 2 play an important role in sucrose unloading and starch accumulation, as well in buffering the pools of sucrose, hexoses and sugar phosphates in leaves, specifically at later stages of plant development.

The relationship between cell wall and postharvest physiological deterioration of fresh produce.

Postharvest physiological deterioration (PPD) reduces the availability and economic value of fresh produces, resulting in the waste of agricultural products and becoming a worldwide problem. Therefore, many studies have been carried out at the anatomical structural, physiological and biochemical levels and molecular levels of PPD of fresh produces to seek ways to manage the postharvest quality of fresh produce. The cell wall is the outermost structure of a plant cell and as such represents the first barrier to prevent external microorganisms and other injuries. Many studies on postharvest quality of crop storage organs relate to changes in plant cell wall-related components. Indeed, these studies evidence the non-negligible role of the plant cell wall in postharvest storage ability. However, the relationship between cell wall metabolism and postharvest deterioration of fresh produces has not been well summarized. In this review, we summarize the structural changes of cell walls in different types of PPD, metabolic changes, and the possible molecular mechanism regulating cell wall metabolism in PPD of fresh produce. This review provides a basis for further research on delaying the occurrence of PPD of fresh produce.

Editing of the MeSWEET10a promoter yields bacterial blight resistance in cassava cultivar SC8.

Cassava starch is a widely used raw material for industrial production and food source for people. However, cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis (Xam) results in severe yield losses and is the most destructive bacterial disease in all worldwide cassava-growing regions. Xam11 is a highly pathogenic subspecies from China that infects the Chinese local cassava South China No. 8 (SC8) cultivar with marked symptoms. This study showed that the transcription activator-like effector TALE20Xam11 of Xam11 strain regulates the expression of disease-susceptibility gene MeSWEET10a by binding to the EBETALE20 region of the MeSWEET10a promoter in cassava cultivar SC8. CRISPR/Cas9-generated mutations of the EBETALE20 region resulted in a significant reduction in MeSWEET10a expression after infection by Xam11, correlating with reduced disease symptoms, smaller lesion sizes and decreased bacterial proliferation compared with the wild type. Importantly, the edited plants maintained normal growth, development and yield characteristics under greenhouse conditions. The results lay a research foundation for breeding resistant cassava cultivar SC8 to bacterial blight.

Integrated anatomical structure, physiological, and transcriptomic analyses to identify differential cold tolerance responses of Ziziphus jujuba mill. 'Yueguang' and its autotetraploid 'Hongguang'.

Cold stress is a limiting stress factor that limits plant distribution and development; however, polyploid plants have specific characteristics such as higher resistance to abiotic stress, especially cold stress, that allow them to overcome this challenge. The cultivated cultivar Ziziphus jujuba Mill. 'Yueguang' (YG) and its autotetraploid counterpart 'Hongguang' (HG) exhibit differential cold tolerance. However, the underlying molecular mechanism and methods to enhance their cold tolerance remain unknown. Anatomical structure and physiological analysis indicated YG had a higher wood bark ratio, and xylem ratio under cold treatment compared to HG. However, the half-lethal temperature (LT50), cortex ratio, and malondialdehyde (MDA) content were significantly decreased in YG than HG, which indicated YG was cold tolerant than HG. Transcriptome analysis showed that 2084, 1725, 2888, and 2934 differentially expressed genes (DEGs) were identified in HC vs YC, H20 vs Y20, Y20 vs YC, and H20 vs HC treatment, respectively. Meanwhile, KEGG enrichment analysis of DEGs showed that several metabolic pathways, primarily plant hormone signal transduction and the MAPK signaling pathway, were involved in the differential regulation of cold tolerance between YG and HG. Furthermore, exogenous abscisic acid (ABA) and brassinolide (BR) treatments could improve their cold tolerance through increased SOD and POD activities, decreased relative electrical conductivity, and MDA content. All of these findings suggested that plant hormone signal transduction, particularly ABA and BR, might have an important role in the regulation of differential cold tolerance between YG and HG, laying the foundation for further improving cold tolerance in jujube and examining the molecular mechanisms underlying differences in cold tolerance among different ploidy cultivars.

Evaluation of retinal structural and functional changes after silicone oil removal in patients with rhegmatogenous retinal detachment: a retrospective study.

BACKGROUND: To evaluate retinal structural and functional changes after silicone oil (SO) removal in eyes with macula-off rhegmatogenous retinal detachment (RRD). METHODS: Best-corrected visual acuity (BCVA) testing, microperimetry, and optical coherence tomography angiography were performed in 48 eyes with macula-off RRD before and 3 months after SO removal. The values of healthy contralateral eyes were used as control data. Correlations between retinal vessel density (VD), retinal nerve fiber layer thickness (RNFLT), the interval between retinal detachment and surgery, the duration of SO tamponade, the follow-up time after SO removal, and visual function were analyzed. RESULTS: Significant increases in 2˚ fixation rate (FR), 4˚ FR, 2˚ mean retinal sensitivity (MRS), 6˚ MRS, parafoveal superficial capillary plexus VD and RNFLT were observed after SO removal (all P < 0.05). The increase of 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade and the follow-up time after SO removal respectively (all P < 0.05). The last 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade, the interval between retinal detachment and surgery, and the follow-up time after SO removal (all P < 0.01). The last FR in RRD eyes was close to that of contralateral eyes (P > 0.05). CONCLUSION: Retinal structure and function improved to different degrees after SO removal. Fixation stability and retinal sensitivity increased more than BCVA postoperatively. Retinal sensitivity, which was affected by the interval between retinal detachment and surgery and the duration of SO tamponade, gradually recovered after SO removal.