Sulfation on polysaccharides from Zizania latifolia extracted using ultrasound: Characterization, antioxidant and anti-non-small cell lung cancer activities

Zizania latifolia is a highly nutritious vegetable being praised as "Ginseng in Water". Polysaccharides are the main bioactive ingredients in Z. latifolia, but there have been no reports on the yield- and activity-guided ultrasonic-assisted extraction (UAE), sulfation and anti-non-small cell lung cancer (NSCLC) activity. In this study, Z. latifolia polysaccharides (ZLP) were extracted using UAE under an optimized power, followed by sulfation to give three derivatives (SZLP-1 ∼ 3). After characterization, the antioxidant and anti-NSCLC activities were evaluated. The optimal ultrasonic power for ZLP extraction was screened out to be 300 W, under which the yield was 16.9 ± 2.10 %, and the scavenging rate against 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical was 63.3 ± 5.71 %, significantly higher than those of other powers and hot-water extraction. A series of characterizations fully confirmed the sulfated modification of ZLP. Sulfation improved the antioxidation of ZLP and was positively proportional to the degree of substitution (DS), of which SZLP-2 with a DS of 15.1 ± 2.50 elicited strong hydroxyl and DPPH radicals-scavenging capacities. Meanwhile, SZLP-2 also exerted promising anti-NSCLC potency via inhibiting A549 cell proliferation, with a median inhibition concentration (IC50) of 0.57 ± 0.01 mg/mL at 72 h, markedly smaller than that of unmodified ZLP (0.78 ± 0.04 mg/mL). In summary, the yield- and activity-guided UAE led to the ZLP with high yield and strong antioxidation. Further sulfation enhanced the bioactivities and produced the promising SZLP-2, which showed great potential in the development of novel antioxidant and anti-NSCLC drug.

Isolation, structural characterization, and bioactivities of neutral polysaccharides from Zizania latifolia

The swollen culm (also known as Jiaobai) of Zizania latifolia is formed by the smut Ustilago esculenta invades the Z. latifolia. The new tissue formed due to the symbiotic relationship has entices the attention of researchers to study its polysaccharide structure along with biological evaluation. Five fractions of polysaccharides were obtained owing to hot water extraction, alcoholic precipitation, and chromatographic purification. Bioactivity assays showed that ZLPs have good antioxidant, hypoglycemic activities and protective activity against oxidative damage. The ZLP-1 and ZLP-2 were determined to be neutral polysaccharides with high purity, exhibiting propitious bioactivity, consequently they were subjected to indispensable structural characterization. These results showed that ZLP-1 has molecular weight (Mw) of 103 kDa and glucose (Glc) (76.68 %) as the primary monosaccharide; the ZLP-2 has Mw of 122 kDa and galactose (Gal) (41.04 %) and arabinose (Ara) (27.12 %). Structural elucidation by methylation and nuclear magnetic resonance (NMR) analysis suggested ZLP-1 is a glucan, with →3)-β-Glcp-(1→3)-β-Glcp-(1→4)-β-Glcp-(1→4)-β-Glcp-(1→3,6)-β-Galp-(1→3)-β-Glcp-(1→ as the mainchain and the terminal Araf and Glcp; the ZLP-2 is a Galactoxylan, with →3,4)-β-xylp-(1→3)-β-Galp-(1→3,6)-β-Galp-(1→3,6)-β-Galp-(1→ as the mainchain and the terminal Araf and Glcp. The structural arrangements provide a chemical basis for understanding the nutritional and pharmacological activities of polysaccharides from Zizania latifolia.

Tricin-enriched Zizania latifolia ameliorates non-alcoholic fatty liver disease through AMPK-dependent pathways

This study aimed to identify and elucidate the mechanism underlying the protective effect of tricin-enriched Zizania latifolia (Z. latifolia) extract (ETZL) against free fatty acid (FFA)-induced lipid accumulation in vitro and non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet and fructose diet (HFD/F) in vivo. ETZL treatment significantly lowered body weight gain and decreased adipose tissue, lipid, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels in HFD/F-fed mice. ETZL acted on phosphorylated acetyl-CoA carboxylase (ACC) and anti-peroxisome proliferator-activated receptor α (PPARα) by activating the adenosine monophosphate-activated protein kinase (AMPK) pathway and inhibiting sterol regulatory element-binding proteins-1 (SREBP)/fatty acid synthase (FAS) signaling to inhibit de novo adipogenesis and increase fatty acid oxidation. In addition, treatment with ETZL increased nuclear factor erythroid-2-related factor 2 (Nrf2) levels to activate the antioxidant pathway. FFA-induced oxidative stress and fatty acid accumulation in HepG2 cells confirmed the improvement in fat accumulation through the AMPK and Nrf2 pathway activities of ETZL. These results suggest that ETZL ameliorates NAFLD by regulating lipid metabolism and defending against oxidative stress via AMPK-dependent pathways.

The Difference in Diversity between Endophytic Microorganisms in White and Grey Zizania latifolia

The Zizania latifolia is usually infected by the obligate parasitic fungus Ustilago esculenta to form an edible fleshy stem which is an aquatic vegetable called Jiaobai in China. The infection by the teliospore (T) strain of U. esculenta induces Z. latifolia forming gray fleshy stems, while the mycelia-teliospore (MT) strain of U. esculenta induces white fleshy stems which are more suitable for edibility than gray fleshy stems. The mechanism of this phenomenon is still largely unknown. One of the possible causes is the diversity of endophytic microbial communities between these two fleshy stems. Therefore, we utilized fungal ITS1 and bacterial 16S rDNA amplicon sequencing to investigate the diversity of endophytic microbial communities in the two different fleshy stems of Z. latifolia. The results revealed that the α diversity and richness of endophytic fungi in white Z. latifolia were significantly greater than in gray Z. latifolia. The dominant fungal genus in both fleshy stems was U. esculenta, which accounted for over 90% of the endophytic fungi. The community composition of endophytic fungi in gray and white Z. latifolia was different except for U. esculenta, and a negative correlation was observed between U. esculenta and other endophytic fungi. In addition, the dominant bacterial genus in gray Z. latifolia was Alcaligenaceae which is also negatively correlated with other bacterium communities. Additionally, the co-occurrence network of white Z. latifolia was found to have a stronger scale, connectivity, and complexity compared to that of gray Z. latifolia. And the detected beneficial bacteria and pathogens in the stems of Z. latifolia potentially compete for resources. Furthermore, the function of endophytic bacteria is more abundant than endophytic fungi in Z. latifolia. This research investigated the correlation between the development of Z. latifolia fleshy stems and endophytic microbial communities. Our findings indicate that the composition of endophytic microbial communities is closely related to the type of Z. latifolia fleshy stems. This research also suggests the potential utilization of specific microbial communities to enhance the growth and development of Z. latifolia, thereby contributing to the breeding of Z. latifolia.

Aboveground biomass estimation of wetland vegetation at the species level using unoccupied aerial vehicle RGB imagery

Wetland vegetation biomass is an essential indicator of wetland health, and its estimation has become an active area of research. Zizania latifolia (Z. latifolia) is the dominant species of emergent vegetation in Honghu Wetland, and monitoring its aboveground biomass (AGB) can provide a scientific basis for the protection and restoration of this and other wetlands along the Yangtze River. This study aimed to develop a method for the AGB estimation of Z. latifolia in Honghu Wetland using high-resolution RGB imagery acquired from an unoccupied aerial vehicle (UAV). The spatial distribution of Z. latifolia was first extracted through an object-based classification method using the field survey data and UAV RGB imagery. Linear, quadratic, exponential and back propagation neural network (BPNN) models were constructed based on 17 vegetation indices calculated from RGB images to invert the AGB. The results showed that: (1) The visible vegetation indices were significantly correlated with the AGB of Z. latifolia. The absolute value of the correlation coefficient between the AGB and CIVE was 0.87, followed by ExG (0.866) and COM2 (0.837). (2) Among the linear, quadratic, and exponential models, the quadric model based on CIVE had the highest inversion accuracy, with a validation R² of 0.37, RMSE and MAE of 853.76 g/m² and 671.28 g/m², respectively. (3) The BPNN model constructed with eight factors correlated with the AGB had the best inversion effect, with a validation R² of 0.68, RMSE and MAE of 732.88 g/m² and 583.18 g/m², respectively. ​Compared to the quadratic model constructed by CIVE, the BPNN model achieved better results, with a reduction of 120.88 g/m² in RMSE and 88.10 g/m² in MAE. This study indicates that using UAV-based RGB images and the BPNN model provides an effective and accurate technique for the AGB estimation of dominant wetland species, making it possible to efficiently and dynamically monitor wetland vegetation cost-effectively.

Dissipation, uptake, translocation and accumulation of five phthalic acid esters in sediment-Zizania latifolia system

The dissipation, uptake, translocation and accumulation of phthalic acid esters (PAEs) including diallyl phthalate (DAP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP) and di-(2-ethylhexyl) phthalate (DEHP) in sediment-Zizania latifolia system were investigated by gas chromatography-flame ionization detector after a QuEChERS pretreatment method. The dissipation rates of PAEs in sediment were positively correlated with exposure time, and more than 68.12% of PAEs in sediment were decreased after 28 d even when the spiked contents were extremely high. All the five PAEs could be taken up by roots from contaminated sediment and subsequently be transported into stems and leaves. There were significant linear correlations between the sediment content and the content in each tissue. DEHP was most readily transported from sediment to roots and stems, followed by BBP, DBP, DIBP and DAP, whereas the order of transportation from roots to leaves was reversed. During 28 d of exposure, the average concentration of each PAE in stems was the highest, followed by roots, leaves and edible parts. DEHP and BBP were the major contaminants in edible parts but could not pose a risk to human health. The accumulation of PAEs in edible parts was influenced by the species and concentration of PAEs as well as the survival time and harvest time of edible parts. The differences in uptake and translocation behaviors among PAEs in plant tissues were significantly correlated to their physicochemical properties, such as alkyl chain length and octanol/water partition coefficient (logK_ow). The results reveal that Zizania latifolia is not only a kind of safe food, but also a potential plant to remediate contaminated sediment by accumulating and degrading PAEs from the habitats.

Mating Types of Ustilago esculenta Infecting Zizania latifolia Cultivars in Japan Are Biased towards MAT-2 and MAT-3

Zizania latifolia cultivars infected by the endophytic fungus Ustilago esculenta develop an edible stem gall. Stem gall development varies among cultivars and individuals and may be affected by the strain of U. esculenta. To isolate haploids from two Z. latifolia cultivars in our paddy fields, Shirakawa and Ittenkou, we herein performed the sporadic isolation of U. esculenta strains from stem gall tissue, a PCR-based assessment of the mating type, and in vitro mating experiments. As a result, we obtained heterogametic strains of MAT-2 and MAT-3 as well as MAT-2, but not MAT-3, haploid strains. Another isolation method, in which we examined poorly growing small clusters of sporidia derived from teliospores, succeeded in isolating a MAT-3 haploid strain. We also identified the mating types of 10 U. esculenta strains collected as genetic resources from different areas in Japan. All strains, except for one MAT-1 haploid strain, were classified as MAT-2 haploid strains or heterogametic strains of MAT-2 and MAT-3. The isolated strains of MAT-1, MAT-2, and MAT-3 mated with each other to produce hyphae. Collectively, these results indicate that the mating types of U. esculenta infecting Z. latifolia cultivars in Japan are biased towards MAT-2 and MAT-3 and that U. esculenta populations in these Japanese cultivars may be characterized by the low isolation efficiency of the MAT-3 haploid.

Transcriptome Comparison between Two Strains of Ustilago esculenta during the Mating

Ustilago esculenta is a smut fungus that obligately infects Zizania latifolia and stimulates tissue swelling to form galls. Unlike T-type, MT-type U. esculenta can only proliferate within plant tissues and infect the offspring of their host. Production of telispores, haploid life, and plant cuticle penetration are not essential for it, which may lead to the degeneration in these processes. Transcriptome changes during the mating of T- and MT-type U. esculenta were studied. The functions of several secreted proteins were further confirmed by knock-out mutants. Our results showed that MT-type U. esculenta can receive environmental signals in mating and circumstance sensing as T-type does. However, MT-type U. esculenta takes a longer time for conjunction tube formation and cytoplasmic fusion. A large number of genes encoding secreted proteins are enriched in the purple co-expression module. They are significantly up-regulated in the late stage of mating in T-type U. esculenta, indicating their relationship with infecting. The knock-out of g6161 (xylanase) resulted in an attenuated symptom. The knock-out of g943 or g4344 (function unidentified) completely blocked the infection at an early stage. This study provides a comprehensive comparison between T- and MT-type during mating and identifies two candidate effectors for further study.

A comparative study on adsorption of cadmium and lead by hydrochars and biochars derived from rice husk and Zizania latifolia straw

In this study, hydrochars and biochars were prepared from rice husk (RH) and Zizania latifolia straw (ZL) at various pyrolysis temperatures as absorbents, for removing toxic ions from single and competitive solutions of cadmium (Cd) and/or lead (Pb). The adsorption efficiencies of Cd and Pb in both hydrochars and biochars were lower in the competitive solution than in the single solution, and the absorbents had a stronger affinity for Pb than for Cd. Compared to hydrochars, biochars showed more favorable Cd and Pb adsorption capacities in the single or competitive solutions, and the ZL biochars had the maximum adsorption capacity among them. The SEM and FTIR analyses suggest that the predominant adsorption mechanisms of biochars and hydrochars are surfaces monolayer adsorption, precipitation, complexation, and coordination with π electrons. However, hydrochars derived from ZL exhibited an optimal additional Pb adsorption capacity in the high-level (5 ~ 10 mg L^-1 Cd and Pb) competitive solution. This extra Pb adsorption of hydrochars was likely attributed to the Si-O-Si groups and more bumpy structure. Zizania latifolia straw biochar had a huge potential removal of Cd or/and Pb, and applying hydrochars as absorbents was beneficial to the removal of Cd and Pb in polluted solutions.

Germicide Fenaminosulf Promots Gall Formation of Zizania latifolia without directly affecting the growth of endophytic fungus Ustilago esculenta

Zizania latifolia is a popular aquatic vegetable in China because of its enlarged edible stems resulting from persistent infection by a fungal endophyte, Ustilago esculenta. Fenaminosulf (FM) is a germicide that can be used to improve agricultural crop yields. In Z. latifolia fields, appropriate spraying of FM not just controls diseases, but also promotes an earlier harvest of Z. latifolia. In this study, we show that the timing of gall formation was advanced and the plant's yield was increased significantly under a high concentration treatment of FM. Yet FM had a strong inhibitory effect on the growth of U. esculenta in vitro, while the transcript levels of mating-type alleles, cell metabolism-related genes and chitin synthase genes were all substantially downregulated. Through a transcriptome analysis, we investigated changes in gene expression of the host Z. latifolia and fungal endophyte U. esculenta in response to FM. FM directly affected the growth of Z. latifolia by altering the expression level of genes involved in plant-pathogen interactions, plant hormone signal transduction and some metabolism pathways. By contrast, FM had little effect on U. esculenta growing inside of Z. latifolia. Collectively, our results provide a more in-depth understanding of the molecular processes that promote gall formation in Z. latifolia, while also identifying potential targets for genetic manipulation to improve the yield and quality of Z. latifolia, in a safer and more effective way.

Phytolith-occluded carbon in residues and economic benefits under rice/single-season Zizania latifolia rotation

Zizania latifolia is a wild rice that contains phytoliths (Phyt) that have considerable potential for carbon sequestration. We hypothesized that the capacity of phytolith-occluded carbon (PhytOC) sequestration in residues might increase by 20%, and economic profit would be twice as high under a rice/single-season Z. latifolia rotation as under rice monoculture. To test this hypothesis, we collected rice and Z. latifolia plants and their corresponding soil samples from Zhejiang Province to determine the ability of both crops to fix carbon in the phytoliths. We showed that the soil concentrations of available Si, total carbon (Ctot) and total nitrogen (N_tot) were highly positively correlated with the concentrations of phytoliths and phytolith-occluded carbon in the residues of both crops. The cold waterlogged paddy fields in China have low productivity but their environmental conditions are suitable for planting Z. latifolia. Our model scenario, built on secondary data, demonstrated that, on a national basis, if the cold waterlogged paddy fields (occupying approximately 15% of the total paddy fields) were under rice/single-season Z. latifolia rotation, the contents of phytoliths and PhytOC in rice and Z. latifolia residues would be up to 19.46 × 10⁶ t yr^-1 and 8.82 × 10⁴ t yr^-1 (0.32 Tg CO₂ yr^-1), respectively. As a result, the economic benefit would be increased by 1.12 × 10¹¹ USD per year compared to rice monoculture. Therefore, adopting rotational cropping of rice with single-season Z. latifolia will not only increase the content of PhytOC sequestration in residues and improve cold waterlogged paddy fields but also bring economic benefits to farmers.

Toxicological assessment of enzyme-treated Zizania latifolia extract: Oral toxicology and genotoxicity in rats

Zizania latifolia Turcz. has long been used as a food source in Southeast Asia. The grains, stems, and leaves of Z. latifolia and its major component, tricin, have also been studied to determine their biological activities. Previously, we hydrolyzed the aerial part of Z. latifolia using an enzyme mixture to maximize the tricin content of the Z. latifolia extract. However, the safety of enzyme-treated Z. latifolia extract (ETZL; DermaNiA™) has not yet been determined. In this study, we performed an in vivo 90-day repeated-dose evaluation and genotoxicity study to assess the toxicological potential of ETZL. EZTL did not exhibit genotoxicity in the bacterial reverse mutation test, in vitro chromosomal aberration assay, or in vivo micronucleus test. Moreover, no changes in body weight or hematological and serum biological parameters were observed in male or female rats under high-dose EZTL treatment (5000 mg/kg body weight (bw)/day) for 90 days with a 4-week recovery period. Significant changes were noted in the forestomach, kidneys, and adrenal glands in the test groups, but these changes, or tendency for recovery, were not observed in the recovery group. Based on these data, the no adverse effect level was determined to be 1250 mg/kg bw/day in rats.

Shoot rot of Zizania latifolia and the first record of its pathogen Pantoea ananatis in China

The aquatic grass Zizania latifolia grows symbiotically with the fungus Ustilago esculenta producing swollen structures called Jiaobai, widely cultivated in China. A new disease of Z. latifolia was found in Zhejiang Province, China. Initial lesions appeared on the leaf sheaths or sometimes on the leaves near the leaf sheaths. The lesions extended along the axis of the leaf shoots and formed long brown to dark brown streaks from the leaf sheath to the leaf, causing sheath rot and death of entire leaves on young plants. The pathogen was isolated and identified as the bacterium Pantoea ananatis, based on 16S ribosomal RNA (rRNA) gene sequencing, multilocus sequence analysis (atpD (β-subunit of ATP synthase F1), gyrB (DNA gyrase subunit B), infB (translation initiation factor 2), and rpoB (β‍-subunit of RNA polymerase) genes), and pathogenicity tests. Ultrastructural observations using scanning electron microscopy revealed that the bacterial cells colonized the vascular tissues in leaf sheaths, forming biofilms on the inner surface of vessel walls, and extended between vessel elements via the perforated plates. To achieve efficient detection and diagnosis of P. ananatis, species-specific primer pairs were designed and validated by testing closely related and unrelated species and diseased tissues of Z. latifolia. This is the first report of bacterial sheath rot disease of Z. latifolia caused by P. ananatis in China.

Mixed Transcriptome Analysis Revealed the Possible Interaction Mechanisms between Zizania latifolia and Ustilago esculenta Inducing Jiaobai Stem-Gall Formation

The smut fungus Ustilago esculenta infects Zizania latifolia and induces stem expansion to form a unique vegetable named Jiaobai. Although previous studies have demonstrated that hormonal control is essential for triggering stem swelling, the role of hormones synthesized by Z. latifolia and U. esculenta and the underlying molecular mechanism are not yet clear. To study the mechanism that triggers swollen stem formation, we analyzed the gene expression pattern of both interacting organisms during the initial trigger of culm gall formation, at which time the infective hyphae also propagated extensively and penetrated host stem cells. Transcriptional analysis indicated that abundant genes involving fungal pathogenicity and plant resistance were reprogrammed to maintain the subtle balance between the parasite and host. In addition, the expression of genes involved in auxin biosynthesis of U. esculenta obviously decreased during stem swelling, while a large number of genes related to the synthesis, metabolism and signal transduction of hormones of the host plant were stimulated and showed specific expression patterns, particularly, the expression of ZlYUCCA9 (a flavin monooxygenase, the key enzyme in indole-3-acetic acid (IAA) biosynthesis pathway) increased significantly. Simultaneously, the content of IAA increased significantly, while the contents of cytokinin and gibberellin showed the opposite trend. We speculated that auxin produced by the host plant, rather than the fungus, triggers stem swelling. Furthermore, from the differently expressed genes, two candidate Cys2-His2 (C2H2) zinc finger proteins, GME3058_g and GME5963_g, were identified from U. esculenta, which may conduct fungus growth and infection at the initial stage of stem-gall formation.

Enzyme-Treated Zizania latifolia Extract Protects against Alcohol-Induced Liver Injury by Regulating the NRF2 Pathway

Binge drinking patterns easily produce a state of oxidative stress that disturbs liver function. Eventually, this leads to alcoholic liver disease. A safe and effective therapy for alcoholic liver disease remains elusive. Enzyme-treated Z. latifolia extract (ETZL) was studied as a potential agent for treating alcohol-induced liver disease. In addition, its underlying mechanisms were elucidated. In the binge model, ETZL was pretreated with alcohol (5 g/kg) three times at 12-h intervals. Our results showed that ETZL pretreatment decreased the serum levels of ALT, AST, ALP, and TG. ETZL treatment appeared to prevent an increase in hepatic TG and MDA levels, and there was a decrease in total GSH following alcohol treatment. Histopathological examination showed that lipid droplets were significantly reduced in the ETZL group compared to the control group. ETZL also exhibited radical scavenging activity. It significantly reduced t-BHP-induced cytotoxicity and the production of reactive oxygen species (ROS) in HepG2 cells. ETZL also enhanced NRF2 nuclear translocation and increased expression of the downstream target genes HO-1, NQO1, and GCLC as an antioxidant defense. Finally, ETZL treatment significantly reduced cell death. Our study suggests that ETZL ameliorates binge ethanol-induced liver injury by upregulating the antioxidant defense mechanism.

Role of Long Noncoding RNAs ZlMSTRG.11348 and UeMSTRG.02678 in Temperature-Dependent Culm Swelling in Zizania latifolia

Temperature influences the physiological processes and ecology of both hosts and endophytes; however, it remains unclear how long noncoding RNAs (lncRNAs) modulate the consequences of temperature-dependent changes in host-pathogen interactions. To explore the role of lncRNAs in culm gall formation induced by the smut fungus Ustilago esculenta in Zizania latifolia, we employed RNA sequencing to identify lncRNAs and their potential cis-targets in Z. latifolia and U. esculenta under different temperatures. In Z. latifolia and U. esculenta, we identified 3194 and 173 lncRNAs as well as 126 and four potential target genes for differentially expressed lncRNAs, respectively. Further function and expression analysis revealed that lncRNA ZlMSTRG.11348 regulates amino acid metabolism in Z. latifolia and lncRNA UeMSTRG.02678 regulates amino acid transport in U. esculenta. The plant defence response was also found to be regulated by lncRNAs and suppressed in Z. latifolia infected with U. esculenta grown at 25 °C, which may result from the expression of effector genes in U. esculenta. Moreover, in Z. latifolia infected with U. esculenta, the expression of genes related to phytohormones was altered under different temperatures. Our results demonstrate that lncRNAs are important components of the regulatory networks in plant-microbe-environment interactions, and may play a part in regulating culm swelling in Z. latifolia plants.

Transcriptome Analysis Reveals the Symbiotic Mechanism of Ustilago esculenta-Induced Gall Formation of Zizania latifolia

Zizania latifolia is a perennial aquatic vegetable, whose symbiosis with the fungus Ustilago esculenta (member of Basidiomycota, class Ustilaginaceae) results in the establishment of swollen gall formations. Here, we analyzed symbiotic relations of Z. latifolia and U. esculenta, using a triadimefon (TDF) treatment and transcriptome sequencing (RNA-seq). Specifically, accurately identify the whole growth cycle of Z. latifolia. Microstructure observations showed that the presence of U. esculenta could be clearly observed after gall formation but was absent after the TDF treatment. A total of 17,541 differentially expressed genes (DEGs) were identified, based on the transcriptome. According to gene ontology term and Kyoto Encyclopedia of Genes and Genomes pathway results, plant hormone signal transduction, and cell wall-loosening factors were all significantly enriched due to U. esculenta infecting Z. latifolia; relative expression levels of hormone-related genes were identified, of which downregulation of indole 3-acetic acid (IAA)-related DEGs was most pronounced in JB_D versus JB_B. The ultra-high performance liquid chromatography analysis revealed that IAA, zeatin+trans zeatin riboside, and gibberellin 3 were increased under U. esculenta infection. Based on our results, we proposed a hormone-cell wall loosening model to study the symbiotic mechanism of gall formation after U. esculenta infects Z. latifolia. Our study thus provides a new perspective for studying the physiological and molecular mechanisms of U. esculenta infection of Z. latifolia causing swollen gall formations as well as a theoretical basis for enhancing future yields of cultivated Z. latifolia.[Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. 2021.

Enzyme-Treated Zizania latifolia Ethanol Extract Protects from UVA Irradiation-Induced Wrinkle Formation via Inhibition of Lysosome Exocytosis and Reactive Oxygen Species Generation

Ultraviolet A (UVA) is a risk factor for photoaging and wrinkle formation. Zizania latifolia is an herbaceous perennial plant. It contains many bioactive compounds such as tricin that show antioxidative and anti-inflammatory effects. The aim of this study was to investigate the antiwrinkle effect of a mixture of hydrolytic enzyme (cellulase, hemicellulase and pectinase)-treated Z. latifolia extract (ZLE) and tricin on UVA-irradiated human dermal fibroblasts (HDFs) and SKH-1 hairless mice. Treatment of UVA-irradiated HDF cells with ZLE and tricin significantly decreased UVA induced-plasma membrane rupture, generation of ROS, expression levels of total and secreted lysosomal associated membrane protein (LAMP-1), cathepsin B and metalloproteinases (MMPs) and inhibited NF-κB activation. In the animal study, UVA-damaged epidermal and dermal tissues were repaired by the ZLE and tricin treatments. Administration of ZLE or tricin to UVA-irradiated animals recovered skin surface moisture and collagen fiber in dermal tissue. Treatment of ZLE or tricin decreased wrinkle formation, secretion of MMPs and expression levels of vascular endothelial growth factor (VEGF) and cathepsin B, and increased the expression level of collagen-1 in UVA-irradiated animals. Overall, the ZLE and tricin treatments decreased the skin damage induced by UVA irradiation via inhibition of lysosomal exocytosis and ROS generation. Therefore, ZLE and tricin are promising as antiwrinkle and antiphotoaging agents.

Gene expression in the smut fungus Ustilago esculenta governs swollen gall metamorphosis in Zizania latifolia

Ustilago esculenta, a smut fungus, can induce the formation of culm galls in Zizania latifolia, a vegetable consumed in many Asian countries. Specifically, the mycelia-teliospore (M-T) strain of U. esculenta induces the Jiaobai (JB) type of gall, while the teliospore (T) strain induces the Huijiao (HJ) type. The underlying molecular mechanism responsible for the formation of the two distinct types of gall remains unclear. Our results showed that most differentially expressed genes relevant to effector proteins were up-regulated in the T strain compared to those in the M-T strain during gall formation, and the expression of teliospore formation-related genes was higher in the T strain than the M-T strain. Melanin biosynthesis was also clearly induced in the T strain. The T strain exhibited stronger pathogenicity and greater teliospore production than the M-T strain. We evaluated the implications of the gene regulatory networks in the development of these two type of culm gall in Z. latifolia infected with U. esculenta and suggested potential targets for genetic manipulation to modify the gall type for this crop.

Inhibition of lignification of Zizania latifolia with radio frequency treatments during postharvest

Zizania latifolia is easily lignified after harvesting, leading to the degradation of food quality and commercial value. Thus, this study evaluated the effect of radio frequency (RF) treatments on lignification inhibition of Zizania latifolia. The results showed that the lignin content of Zizania latifolia treated with RF decreased significantly compared with the control group. At the 7th day of storage, the phenylalanine ammonia lyase activity of the 90 W RF treatment group decreased by 52.9% compared with the initial value. The activities of peroxidase and polyphenol oxidase in the stems of Zizania latifolia were significantly (p < 0.05) decreased after RF treatments. Besides, a decrease in conversion rate of O₂⁻ and H₂O₂ to downstream products was observed, indicating that the related invertases were inhibited by RF treatment. All of these showed that RF treatments contribute to inhibit or delay the lignification of Zizania latifolia, providing a better taste and quality for products.

Release of taste and odour compounds during Zizania latifolia decay: A microcosm system study

Organic matter-induced black bloom frequently occurs in a number of large eutrophic shallow lakes; this can result in the release of malodorous compounds and has a negative impact on water quality. In the study, a microcosm system containing Zizania latifolia (Z. latifolia), a common aquatic plant, was established and the release of seven taste and odour compounds, dimethyl sulphide (DMS), dimethyl disulphide (DMDS), dimethyl trisulphide (DMTS), 2-methylisoborneol (MIB), geosmin (GSM), β-cyclocitral, and β-ionone, was investigated. The results showed that these compounds were all detected during Z. latifolia decay, and that volatile organic sulphur compounds (VOSCs), such as DMS, DMDS, and DMTS, were the main factors responsible for the strong foul odour (the maximum reached 5.0 μg L^-1). The release of odorous compounds was stronger during the initial seven days, and then progressively decreased in the middle stage of the experiment. Furthermore, large amounts of nutrients were released into the overlying water; nutrient concentration increased with increasing plant biomass. A positive correlation was observed between the odorant concentration and plant biomass. These results indicate that the density of aquatic plants should be controlled as part of future management of aquatic ecosystems.

iTRAQ-based mitochondrial proteome analysis of the molecular mechanisms underlying postharvest senescence of Zizania latifolia

To explore the molecular mechanisms underlying postharvest senescence of Zizania latifolia, the changes in the mitochondrial proteome of plants treated with or without (control) 1-methyleyelopropene and ethylene during storage at room temperature for 0, 3 and 6 days were investigated using isobaric tags for relative and absolute quantitation (iTRAQ) labeling combined with two-dimensional liquid chromatography-tandem mass spectrometry. A total of 1,390 proteins with two or more peptides were identified, of which 211 showed a significant (p < .05) change (at least twofold) in relative abundance. Monitoring the parallel reaction validated the reliability and accuracy of the iTRAQ results. Bioinformatics and functional analysis of these differentially expressed proteins (DEPs) revealed that postharvest senescence of Z. latifolia could be attributed to (a) strengthened pentose phosphate pathway, (b) imbalanced protein, amino acid, organic acid, and fatty acid metabolism, (c) disordered energy homeostasis, (d) exacerbated oxidative damage, (e) RNA degradation, (f) activation of the Ca²⁺ , mitogen-activated protein kinase, and jasmonic acid signaling pathways, (g) programed cell death, (h) excessive biosynthesis of secondary metabolites, or (i) degradation of cell structure. Our findings provide integrated insight into the molecular mechanisms of postharvest senescence during storage as well as the DEPs that show promise as targets for controlling senescence-induced quality deterioration of Z. latifolia. PRACTICAL APPLICATIONS: Postharvest senescence is the most important factor that causes fast quality deterioration of Zizania latifolia. The understanding of the processes leading to postharvest senescence of Z. latifolia is essential in enhancing the commercial value and extending the shelf life of the product. It is currently believed that the mitochondrial metabolism is closely related to postharvest senescence. For this, the changes of proteome in Z. latifolia mitochondria treated with or without (control) 1-MCP and ETH during storage at room temperature were investigated. Results showed that a variety of physiobiochemical responses occur during postharvest senescence of Z. latifolia. 1-MCP treatment significantly inhibited the changes of these physiobiochemical processes, finally, retarding the postharvest senescence of Z. latifolia. ETH treatment had opposite effects on proteome changes compared with 1-MCP treatment. Taken together, these results enrich the understanding of the molecular mechanisms of postharvest senescence of Z. latifolia.

Extraction of Proanthocyanidins from Chinese Wild Rice (Zizania latifolia) and Analyses of Structural Composition and Potential Bioactivities of Different Fractions

Due to the importance of proanthocyanidin bioactivity and its relationship with chemical structure, ultrasound-assisted extraction and purification schemes were proposed to evaluate the proanthocyanidin content and analyze the structural composition and potential bioactivities of different proanthocyanidin fractions from Chinese wild rice (Zizanialatifolia). Following an optimized extraction procedure, the crude wild rice proanthocyanidins (WRPs) were purified using n-butanol extraction, chromatography on macroporous resins, and further fractionation on Sephadex LH-20 to yield six specific fractions (WRPs-1–WRPs-6) containing proanthocyanidin levels exceeding 524.19 ± 3.56 mg/g extract. Structurally, (+)-catechin, (−)-epicatechin, and (−)-epigallocatechin were present as both terminal and extension units, and (−)-epicatechin was the major extension unit, in each fraction. This is the first preparation of WRP fractions with a different mean degree of polymerization (mDP), ranging from 2.66 ± 0.04 to 10.30 ± 0.46. A comparison of the bioactivities of these fractions revealed that fractions WRPs-1−WRPs-5 had significant DPPH radical scavenging activities, whereas fraction WRPs-6 with a high mDP showed better α-glucosidase and pancreatic lipase inhibitory effects. These findings should help define possible applications of WRPs to functional foods or nutraceuticals.

The smut fungus Ustilago esculenta has a bipolar mating system with three idiomorphs larger than 500 kb

Zizania latifolia Turcz., which is mainly distributed in Asia, has had a long cultivation history as a cereal and vegetable crop. On infection with the smut fungus Ustilago esculenta, Z. latifolia becomes an edible vegetable, water bamboo. Two main cultivars, with a green shell and red shell, are cultivated for commercial production in Taiwan. Previous studies indicated that cultivars of Z. latifolia may be related to the infected U. esculenta isolates. However, related research is limited. The infection process of the corn smut fungus Ustilago maydis is coupled with sexual development and under control of the mating type locus. Thus, we aimed to use the knowledge of U. maydis to reveal the mating system of U. esculenta. We collected water bamboo samples and isolated 145 U. esculenta strains from Taiwan's major production areas. By using PCR and idiomorph screening among meiotic offspring and field isolates, we identified three idiomorphs of the mating type locus and found no sequence recombination between them. Whole-genome sequencing (Illumina and PacBio) suggested that the mating system of U. esculenta was bipolar. Mating type locus 1 (MAT-1) was 552,895 bp and contained 44% repeated sequences. Sequence comparison revealed that U. esculenta MAT-1 shared high gene synteny with Sporisorium reilianum and many repeats with Ustilago hordei MAT-1. These results can be utilized to further explore the genomic diversity of U. esculenta isolates and their application for water bamboo breeding.

Inferring the Origin of Cultivated Zizania latifolia, an Aquatic Vegetable of a Plant-Fungus Complex in the Yangtze River Basin

Crop domestication is one of the essential topics in evolutionary biology. Cultivated Zizania latifolia, domesticated as the special form of a plant-fungus (the host Zizania latifolia and the endophyte Ustilago esculenta) complex, is a popular aquatic vegetable endemic in East Asia. The rapid domestication of cultivated Z. latifolia can be traced in the historical literature but still need more evidence. This study focused on deciphering the genetic relationship between wild and cultivated Z. latifolia, as well as the corresponding parasitic U. esculenta. Twelve microsatellites markers were used to study the genetic variations of 32 wild populations and 135 landraces of Z. latifolia. Model simulations based on approximate Bayesian computation (ABC) were then performed to hierarchically infer the population history. We also analyzed the ITS sequences of the smut fungus U. esculenta to reveal its genetic structure. Our results indicated a significant genetic divergence between cultivated Z. latifolia and its wild ancestors. The wild Z. latifolia populations showed significant hierarchical genetic subdivisions, which may be attributed to the joint effect of isolation by distance and hydrological unconnectedness between watersheds. Cultivated Z. latifolia was supposedly domesticated once in the low reaches of the Yangtze River. The genetic structure of U. esculenta also indicated a single domestication event, and the genetic variations in this fungus might be associated with the diversification of cultivars. These findings provided molecular evidence in accordance with the historical literature that addressed the domestication of cultivated Z. latifolia involved adaptive evolution driven by artificial selection in both the plant and fungus.

Seed characteristic variations and genetic structure of wild Zizania latifolia along a latitudinal gradient in China: implications for neo-domestication as a grain crop

Crop wild relatives are not only important genetic resources for crop improvement, but also domestication candidates for selecting new crops. As a close relative of American wild rice Zizania palustris, Z. latifolia is a perennial aquatic grass widely distributed in China. Although Z. latifolia has been domesticated and cultivated as an aquatic vegetable for >1000 years, a neo-domestication for grain production needs to be soundly evaluated. In this study, we investigated the seed characteristic variations and genetic structure of 15 Z. latifolia wild populations along a latitudinal gradient in China. Our results showed that Z. latifolia tended to produce relatively larger seeds with lower moisture content and lower investments in seed pericarp at lower latitudes. The width, size, shape, seed-pericarp ratio and relative water content of seeds were significantly associated with climatic variables. The seeds of Z. latifolia showed a relatively low germination percentage and strong dormancy, which might hinder the neo-domestication. In addition, high genetic differentiation had been found among Z. latifolia populations, which could be attributed to isolation by distance. This study offered preliminary information for the utilization and conservation of wild Z. latifolia. It suggested that the wild populations in the middle and lower reaches of the Yangtze River could be good candidates for grain crop domestication due to appropriate seed traits and high genetic diversity. The neo-domestication of wild Z. latifolia requires further researches on the genetic mechanism of the Domestication Syndrome and more works on artificial breeding.

Water-based extracts of Zizania latifolia inhibit Staphylococcus aureus infection through the induction of human beta-defensin 2 expression in HaCaT cells

Zizania latifolia is a perennial herb belonging to the family Gramineae that has been used as a health food in Asian countries. In this study, we investigated the antimicrobial effect of Z. latifolia, which increased human beta-defensin 2 (hBD2) expression in HaCaT cells. hBD2 expression was further increased in cells treated with Z. latifolia extracts and subsequently infected with Staphylococcus aureus. Inversely, S. aureus infection decreased after treatment. The induction of hBD2 in HaCaT cells was mediated by the Toll-like receptor 2 (TLR2) signaling pathway, including the activation of extracellular signal-regulated kinase (ERK) and activator protein 1 (AP-1). Further study using siRNA revealed that hBD2 played an important role in the inhibition of S. aureus infection in HaCaT cells. Our data suggest that Z. latifolia extracts can be used as an antimicrobial ingredient for skin treatment formulas.

Protection against UVB-Induced Wrinkle Formation in SKH-1 Hairless Mice: Efficacy of Tricin Isolated from Enzyme-Treated Zizania latifolia Extract

Tricin, a flavone found mainly in rice bran and sugarcane, has various beneficial effects. It has proven to be a clinically safe and selective potent inhibitor of different cancer cell lines. In this study, we evaluated the efficacy of enzyme-treated Zizania latifolia (ETZL) and its major active compound tricin on skin photoaging in SKH-1 hairless mice. Tricin (0.3 mg/kg) and ETZL (50, 150, and 300 mg/kg) were orally administrated to mice for 14 weeks; no cytotoxicity was observed during the entire experimental period. After UVB exposure, we observed significant increases in keratinization, coarse wrinkles, loss of moisture, thickened epidermis, and collagen fiber degradation in the dorsal skin. These features of photoaging were significantly suppressed after oral administration of tricin or ETZL. In addition, the protein expression of collagen effectively increased in ETZL (150 and 300 mg/kg)-treated mice, while the increased metalloproteinase (MMP)-1 and MMP-3 expressions were reduced after exposure to tricin or ETZL, although the effects were not dose-dependent. These data indicate that ETZL may be effective for attenuation of UVB-induced skin damage and photoaging in hairless mice, possibly by inhibiting MMPs expression.

Comparative whole-genome analysis reveals artificial selection effects on Ustilago esculenta genome

Ustilago esculenta, infects Zizania latifolia, and induced host stem swollen to be a popular vegetable called Jiaobai in China. It is the long-standing artificial selection that maximizes the occurrence of favourable Jiaobai, and thus maintaining the plant-fungi interaction and modulating the fungus evolving from plant pathogen to entophyte. In this study, whole genome of U. esculenta was sequenced and transcriptomes of the fungi and its host were analysed. The 20.2 Mb U. esculenta draft genome of 6,654 predicted genes including mating, primary metabolism, secreted proteins, shared a high similarity to related Smut fungi. But U. esculenta prefers RNA silencing not repeat-induced point in defence and has more introns per gene, indicating relatively slow evolution rate. The fungus also lacks some genes in amino acid biosynthesis pathway which were filled by up-regulated host genes and developed distinct amino acid response mechanism to balance the infection-resistance interaction. Besides, U. esculenta lost some surface sensors, important virulence factors and host range-related effectors to maintain the economic endophytic life. The elucidation of the U. esculenta genomic information as well as expression profiles can not only contribute to more comprehensive insights into the molecular mechanism underlying artificial selection but also into smut fungi-host interactions.

Morphological Characteristics, Nutrients, and Bioactive Compounds of Zizania latifolia, and Health Benefits of Its Seeds

Zizania latifolia (tribe Oryzeae Dum., subfamily Oryzoideae Care, family Gramineae) is native to East Asian countries. The seeds of Z. latifolia (Chinese wild rice) have been consumed as a cereal in China for >3000 years. Z. latifolia forms swollen culms when infected with Ustilago esculenta, which is the second most-cultivated aquatic vegetable in China. The current review summarizes the nutrients and bioactive compounds of Z. latifolia, and health benefits of its seeds. The seeds of Z. latifolia contain proteins, minerals, vitamins, and bioactive compounds, the activities of which—for example, antioxidant activity—have been characterized. Various health benefits are associated with their consumption, such as alleviation of insulin resistance and lipotoxicity, and protection against cardiovascular disease. Chinese wild rice may be used to prevent and treat metabolic disease, such as diabetes, obesity, and cardiovascular diseases. Various compounds were isolated from the swollen culm, and aerial parts of Z. latifolia. The former suppresses osteoclast formation, inhibits growth of rat glioma cells, and may act as antioxidants and immunomodulators in drugs or foods. The latter exerts anti-fatigue, anti-inflammatory, and anti-allergic effects. Thus, Z. latifolia may be used to produce nutraceuticals and functional foods.

Transfer kinetics of phosphorus (P) in macrophyte rhizosphere and phytoremoval performance for lake sediments using DGT technique

DGT (diffusive gradients in thin films) technique and DIFS (DGT induced fluxes in sediment) model are firstly designed for macrophyte-rhizobox system and in-situ macrophytes in Lake Erhai. Dynamics of phosphorus (P) transfer in Zizania latifolia (ZL) and Myriophyllum verticiilatur (MV) rhizosphere is revealed and phytoremediation performance for P in sediment is evaluated. Dynamic transfer process of P at DGT/sediment interface includes (i) diffusion flux and concentration gradients at DGT(root)/porewater interface leading to porewater concentration (C₀) depletion and (ii) P desorption from labile P pool in sediment solid to resupply C₀ depletion. Fe-redox controlled P release from Fe-bound P (BD-P2) and then NH₄Cl-P1 in rhizosphere sediment resupplies porewater depletion due to DGT (root) sink. K_d (labile P pool size in solid phase), r (resupply ratio) and kinetic exchange (Tc and k_-1) lead to change characters of DIFS curves of (1) r against deployment time and (2) C_solu (dissolved concentration) against distance at 24 h. They include two opposite types of "fast" and "slow" rate of resupplies. Sediment properties and DIFS parameters control P diffusion and resupply in rhizosphere sediment. Phytoremoval ability for sediment P in lake is estimated to be 23.4 (ZL) or 15.0 t a^-1 (MV) by "DGT-flux" method.

Effect of dilute acid pretreatment of wild rice grass (Zizania latifolia) from Loktak Lake for enzymatic hydrolysis

Zizania latifolia commonly known as wild rice grass which is available in huge quantities in Loktak Lake is a major concern as it occupies a large area of the Lake and causing a several environmental problems. The investigation of present study was to evaluate possibilities of using Zizania latifolia as feed stock for bioethanol production. The method involved the pretreatment with dilute acid or alkali followed by enzymatic hydrolysis with commercial cellulase. Acid pretreatment was performed with 10% biomass loading with different concentration of acids (0.4-2% w/v) and alkali (0.25-1.5% w/v). Maximum sugar release of 457 mg/g was obtained from 10% biomass loading and 2% w/v of acids. Alkali pretreatment is not effective for this grass. Physicochemical characterization of untreated and treated biomass was carried out by XRD, FTIR, SEM and corresponding alterations in the chemical composition were also monitored. Results showed the feasibility of this grass as biofuel (bioethanol) feed stock and can be potential approach to address the sustainable utilization phumdis grasses of Loktak Lake for the production of value added product.

Investigation on the differentiation of two Ustilago esculenta strains - implications of a relationship with the host phenotypes appearing in the fields

BACKGROUND

Ustilago esculenta, a pathogenic basidiomycete fungus, infects Zizania latifolia to form edible galls named Jiaobai in China. The distinct growth conditions of U. esculenta induced Z. latifolia to form three different phenotypes, named male Jiaobai, grey Jiaobai and white Jiaobai. The aim of this study is to characterize the genetic and morphological differences that distinguish the two U. esculenta strains.

RESULTS

In this study, sexually compatible haploid sporidia UeT14/UeT55 from grey Jiaobai (T strains) and UeMT10/UeMT46 from white Jiaobai (MT strains) were isolated. Meanwhile, we successfully established mating and inoculation assays. Great differences were observed between the T and MT strains. First, the MT strains had a defect in development, including lower teliospore formation frequency and germination rate, a slower growth rate and a lower growth mass. Second, they differed in the assimilation of nitrogen sources in that the T strains preferred urea and the MT strains preferred arginine. In addition, the MT strains were more sensitive to external signals, including pH and oxidative stress. Third, the MT strains showed an infection defect, resulting in an endophytic life in the host. This was in accordance with multiple mutated pathogenic genes discovered in the MT strains by the non-synonymous mutation analysis of the genome re-sequencing data between the MT and T strains (GenBank accession numbers of the genome re-sequencing data: JTLW00000000 for MT strains and SRR5889164 for T strains).

CONCLUSION

The MT strains appeared to have defects in growth and infection and were more sensitive to external signals compared to the T strains. They displayed an absolutely stable endophytic life in the host without an infection cycle. Accordingly, they had multiple gene mutations occurring, especially in pathogenicity. In contrast, the T strains, as phytopathogens, had a complete survival life cycle, in which the formation of teliospores is important for adaption and infection, leading to the appearance of the grey phenotype. Further studies elucidating the molecular differences between the U. esculenta strains causing differential host phenotypes will help to improve the production and formation of edible white galls.

Purification, characterization and immunomodulatory activity of water extractable polysaccharides from the swollen culms of Zizania latifolia

The swollen culms of Zizania latifolia is a popular vegetable and traditional herbal medicine mainly consumed in some Asian countries. In our previous study, water extractable polysaccharide (ZLPs-W) and alkali extractable polysaccharide (ZLPs-A) was sequentially prepared from the swollen culms of Zizania latifolia. In vitro cell assay revealed that ZLPs-W without cytotoxicity had higher immunomodulatory activity than ZLPs-A. Therefore, in this study, ZLPs-W was further separated to three purified polysaccharides of ZLPs-W1, ZLPs-W2, and ZLPs-W3 by anion exchange chromatography and size exclusive chromatography in sequence. They were found to be homogeneous polysaccharides in β-type glycosidic linkage. ZLPs-W1 and ZLPs-W2 without triple helix conformation mainly contained Glc in molar percentage of 96.47% and 85.1%, respectively. ZLPs-W3 with triple helix conformation mainly consisted of Man, Rha, GalA, Glc, Gal and Ara in the molar ratio of 10.23:14.14:37.44:17.14:16.54:4.51. In addition, all the three purified polysaccharides could effectively enhanced the proliferation, phagocytosis, and nitric oxide production of murine macrophage RAW 264.7, suggesting that they possessed a potent immunostimulatory activity and could be developed as immunomodulator in medicine or functional food areas.

Inhibitory effect of Zizania latifolia chloroform fraction on allergy-related mediator production in RBL-2H3 cells

Zizania latifolia exhibits anti-inflammatory and anti-allergic effects; however, the mechanisms behind these effects are unknown. Here the ethanol extract of Z. latifolia was partitioned using hexane, chloroform, ethyl acetate, butanol, and water. Subsequently, the anti-allergic effects of these fractions were evaluated in vitro. The results showed that the chloroform fraction of Z. latifolia inhibited the release of β-hexosaminidase and tumor necrosis factor (TNF-α) from RBL-2H3 cells stimulated with dinitrophenyl-bovine serum albumin (DNP-BSA). In addition, this fraction suppressed the expression of cyclooxygenase-2 (COX-2) and inhibited the activation of mitogen-activated protein kinases (MAPKs). The results obtained suggest that the chloroform fraction of Z. latifolia inhibited mast cell-mediated allergic inflammatory responses.

An efficient genetic manipulation protocol for Ustilago esculenta

Ustilago esculenta grows within the flowering stem of the aquatic grass Zizania latifolia, resembling a fungal endophyte. The fungus colonizes Z. latifolia and induces swelling which results in the formation of galls near the base of the plant. Due to their unique flavor and textures these galls are considered as a delicacy in southern China. Efficient genetic manipulation is required to determine the relationship between U. esculenta and Z. latifolia. In this study, we report a protoplast-based transformation system for this unique fungal species. We have explored various factors (enzyme digesting conditions, osmotic pressure stabilizers, vectors and selection agents) that might impact protoplast yield and high frequencies of transformation. A haploid strain (UeT55) of U. esculenta was found to produce higher yields of protoplasts when treating with 15 mg mL(-1) lywallzyme in a sucrose-containing solution at 30°C for 3 h. The transformation frequencies were higher when fungal strain was transformed with a linear plasmid harboring hygromycin or carboxin resistance gene and regenerated on a sucrose-containing medium. A UeICL gene (coding isocitrate lyase) was disrupted and an EGFP (coding enhanced green fluorescent protein) gene was overexpressed successfully in the UeT55 strain using the developed conditions. The genetic manipulation system reported in this study will open up new opportunities for forward and reverse genetics in U. esculenta.

Tricin derivatives as anti-inflammatory and anti-allergic constituents from the aerial part of Zizania latifolia

Methanol extract of Zizania latifolia was partitioned with EtOAc, n-BuOH, and H2O. From the EtOAc layers, a new flavonolignan along with a known flavone and three known flavonolignans, tricin (1), salcolin A (2), salcolin B (3), and salcolin C (4), were isolated through repeated silica gel and ODS column chromatography. The chemical structure of the new flavonolignan was determined to be tricin-4'-O-[erythro-β-guaiacyl-(7″-O-methyl)-glyceryl] ether and was named salcolin D (5) based on physicochemical and spectroscopic data, including FT-NMR and ESI-MS. All compounds were isolated for the first time from this plant. Compounds 2-5, tricin derivatives, all exhibited higher anti-inflammatory and anti-allergy activities than tricin. In particular, salcolin D (5) was shown to have the strongest inhibitory activity against LPS-induced NO production in RAW 264.7 cells as well as β-hexosaminidase release in IgE-sensitized RBL-2H3 cells. These results suggest that the presence of tricin derivatives conveys allergy and inflammation treatment ability to Z. latifolia.

Regulation of photosynthetic performance and antioxidant capacity by ⁶⁰Co γ-irradiation in Zizania latifolia plants

The aim of the present work was to investigate the photosynthetic performance and antioxidant enzyme activities in response to γ-irradiation of an aquatic plant Zizania latifolia. The Z. latifolia seedlings at 6-leaf stage were exposed to 25, 50 and 100 Gy of γ rays from a (60)Co source. The growth parameters, chlorophyll contents, photosynthetic gas exchange, chlorophyll fluorescence, malondialdehyde (MDA) content, antioxidant enzyme activities and antioxidant contents were examined at 1-5 weeks post-irradiation (WPI). The results showed that plant height, leaf number and tiller (branch close to ground) number were significantly suppressed by 50 and 100 Gy irradiation at 5, 3-5 and 4-5 WPI, respectively, but they were not significantly different from control by 25 Gy irradiation. Chlorophyll a, chlorophyll b, and total chlorophyll contents were also found to be significantly decreased by irradiation. The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) generally declined in a dose-dependent manner. As for the chlorophyll fluorescence parameters, maximum quantum efficiency of PSII photochemistry (Fv/Fm), actual photochemical efficiency of PSII (Φ(PSII)) and photochemical quenching (qP) were observed to be significantly decreased compared to the control at 3 WPI, while non-photochemical quenching (NPQ) significantly increased by 100 Gy. γ-irradiation induced substantial increase in MDA content, ascorbate peroxidase (APX) activity, reduced ascorbate (AsA) content and reduced glutathione (GSH) content, suggesting a protective mechanism of Z. latifolia plant against oxidative stress when exposed to γ-irradiation.