POD Enzyme Activities Research Articles

Biological Control of Verticillium Wilt and Growth Promotion in Tomato by Rhizospheric Soil-Derived Bacillus amyloliquefaciens Oj-2.16

Verticillium wilt disease caused by Verticillium dahliae seriously affects tomato quality and yield. In this work, strain Oj-2.16 was isolated from rhizosphere soil of the medicinal plant Ophiopogon japonicas and identified as Bacillus amyloliquefaciens on the basis of morphological, physiological, and biochemical characteristics and 16S rDNA sequencing. Strain Oj-2.16 exhibited a high inhibition rate against V. dahliae, and the hyphae inhibited by Oj-2.16 were found to be destroyed on scanning electron microscopy. Lipopeptide and dipeptide genes were detected in the Oj-2.16 genome by PCR amplification involved in surfactin, iturin, fengycin, and bacilysin biosynthesis. In pot experiments, the biocontrol efficacy of strain Oj-2.16 against Verticillium wilt in tomato was 89.26%, which was slightly higher than the efficacy of the chemical fungicide carbendazim. Strain Oj-2.16 can produce indole acetic acid, siderophores, assimilate various carbon sources, and significantly promoted the growth of tomato seedlings by increasing plant height, root length, stem width, fresh weight, and dry weight by 44.44%, 122.22%, 80.19%, 57.65%, 64.00%, respectively. Furthermore, defense-related antioxidant CAT, SOD, POD, and PAL enzyme activities significantly increased and MDA contents significantly decreased in tomato seedlings treated with strain Oj-2.16 upon inoculation of V. dahliae compared with the pathogen-inoculated control. In summary, we concluded that B. amyloliquefaciens Oj-2.16 could be used as a promising candidate for the biocontrol of Verticillium wilt and as plant growth stimulator of tomato.

Cold Hardiness of Prunus mume ‘Xiang Ruibai’ and Its Parents Based on Biological Indexes and Physical Parameters

Low temperature is a primary factor limiting the distribution of Prunus mume. In order to produce a variety that has both cold tolerance and the characteristic fragrance of true mume, previous researchers crossbred a strong-tolerance variety apricot mei, P. mume ‘DF’ (‘Dan Fenghou’) and the weak-tolerance variety of true mume, P. mume ‘BY’ (‘Beijing Yudie’). They gained an offspring variety named P. mume ‘XR’ (‘Xiang Ruibai’), but its cold tolerance is unknown at this point. Here, three varieties (XR, BY, and DF) were selected as the materials, and different low-temperature treatments were used, with temperature as the only variable. Conventional biological methods, such as ion leakage rate, different tissues, and plant viability statistics, were used, as well as an innovative use of infrared engineering and moisture monitoring for dynamic observation of the water-to-ice process in tissues. The results were as follows: DF cold tolerance was the highest, followed by XR and then BY. The LT50 of XR was increased by 6 °C after five days of cold priming at 4 °C, which indicated a stronger cold acclimation ability than the parent varieties. The XR variety enhanced the antioxidant capacity by increasing SOD and POD enzyme activities during low temperature treatment, thus enhancing the cold tolerance. The antioxidant enzyme genes PmSOD3, PmPOD2, PmPOD19, and PmPOD22 had important regulatory roles in XR’s cold acclimation process.

POD, CAT and SOD enzyme activity of corn kernels as affected by low plasma pretreatment

ABSTRACT In this study, low-temperature plasma was used as an efficient pretreatment method of corn kernels (XY335), which developed and optimized a process of enzyme activity. The effects of plasma pretreatment power (300, 400, 500 W), plasma pretreatment time (30, 40, 50 s) and air flow rate (100, 150, 200 mL min−1) on enzyme activity during this process were investigated. Regression equations were established through a three-factor and three-level Box-Behnken design and used to evaluate the optimal conditions for the process. The optimal pretreatment conditions of POD enzyme activity were plasma pretreatment power of 500 W, plasma pretreatment time of 30 s and air flow rate of 150 mL min−1. The optimal pretreatment conditions of CAT enzyme activity were plasma pretreatment power of 350 W, plasma pretreatment time of 30 s and air flow rate of 150 mL min−1. The optimal pretreatment conditions of SOD enzyme activity were plasma pretreatment power of 400 W, plasma pretreatment time of 30 s and air flow rate of 200 mL min−1. Results showed that low-temperature plasma can be used effectively to increase the enzyme activity of corn kernels.

The Poplar (Populus trichocarpa) Dehydrin Gene PtrDHN-3 Enhances Tolerance to Salt Stress in Arabidopsis.

Dehydrin (DHN), a member of the late embryogenesis abundant protein (LEA) family, was recently found to play a role in physiological responses to salt and drought stress. In this study, we identified and cloned the PtrDHN-3 gene from Populus trichocarpa. The PtrDHN-3 protein encoded 226 amino acids, having a molecular weight of 25.78 KDa and an isoelectric point of 5.18. It was identified as a SKn-type DHN and was clustered with other resistance-related DHN proteins. Real-time fluorescent quantitative PCR showed that transcription levels of PtrDHN-3 were induced by mannitol stress, and more significantly by salt stress. Meanwhile, in a yeast transgenic assay, salt tolerance increased in the PtrDHN-3 transgenic yeast, while the germination rate, fresh weight and chlorophyll content increased in PtrDHN-3-overexpressing transgenic Arabidopsis plants (OE) under salt stress. Significant increases in expression levels of six antioxidant enzymes genes, and SOD and POD enzyme activity was also observed in the OE lines, resulting in a decrease in O2- and H2O2 accumulation. The proline content also increased significantly compared with the wild-type, along with expression of proline synthesis-related genes P5CS1 and P5CS2. These findings suggest that PtrDHN-3 plays an important role in salt resistance in plants.

Physiological and Growth Responses of Castor (Ricinus Communis L) Under Cadmium Stressed Environment

Cadmium (Cd) is considered as phytotoxic in nature, its toxicity on the plant development decrease the antioxidative enzymes activities under stress environment. Castor (Ricinus Communis L.) is a metal tolerant plant and its ability to survive in highly polluted soils. Castor plant exhibited the high level of the Cd stress in the soil and buildup the antioxidants i.e., super oxide dismutase (SOD), peroxidase (POD) and malondialdehyde (MAD) on the top of the ground parts under Cd stress. Castor plant grown in the treated soil for 30 days in various levels of Cd 0, 10, 25 and 50 mg kg-1 soil treatments. Stress caused by heavy metal toxicity effects on reduced the plant growth, biomass, of castor plant respectively under 25- 50 mg kg-1 stress as against to control treatment. Our results indicated that castor significantly enhanced the Cd contents in root, stem and leaves. The POD and SOD enzyme activities were significantly increased 215.30 µmol/g-1 and 53.20 U/g respectively under 50 mg kg-1 stress as against control. While, MAD and chlorophyll content 3.11% and 0.48%, proline content 2.23 to 1.75 µg-1 were decreased under 25 and 50 mg kg-1 Cd stress as against control. According to Pearson’s correlation the our research work exposed strongly positive relationship with root, shoot, proline and malionaldihyde. Although the destructive relationship was demonstrated by PoD and SOD enzyme activities. Hence, this study recommended that castor can grow in highly polluted soils for phytoremediation

Application of 2,4-Epibrassinolide Improves Drought Tolerance in Tobacco through Physiological and Biochemical Mechanisms.

Simple SummaryDrought stress is one of the most serious abiotic stresses and negatively affects crop growth and development. Given global climate change, it is important to identify effective methods of alleviating drought stress effects. Brassinosteroids (2,4-epibrassinolide-EBR) play an important role in mitigating the negative effects of drought stress on plants. Therefore, this study evaluated the role of EBR in improving drought tolerance. The results demonstrated that EBR application improved drought tolerance by strengthening the enzymatic antioxidant defense system and osmoregulation to scavenge reactive oxygen species. EBR application improved BR and IAA phytohormone content and improved drought tolerance by upregulating genes related to their respective signaling pathways. Therefore, EBR application is an effective strategy for improving drought tolerance in crop plants.Drought stress is a major abiotic stress that hinders plant growth and development. Brassinosteroids (BR), including 2,4-epibrassinolide (EBR), play important roles in plant growth, development, and responses to abiotic stresses, including drought stress. This work investigates exogenous EBR application roles in improving drought tolerance in tobacco. Tobacco plants were divided into three groups: WW (well-watered), DS (drought stress), and DSB (drought stress + 0.05 mM EBR). The results revealed that DS decreased the leaf thickness (LT), whereas EBR application upregulated genes related to cell expansion, which were induced by the BR (DWF4, HERK2, and BZR1) and IAA (ARF9, ARF6, PIN1, SAUR19, and ABP1) signaling pathway. This promoted LT by 28%, increasing plant adaptation. Furthermore, EBR application improved SOD (22%), POD (11%), and CAT (5%) enzyme activities and their related genes expression (FeSOD, POD, and CAT) along with a higher accumulation of osmoregulatory substances such as proline (29%) and soluble sugars (14%) under DS and conferred drought tolerance. Finally, EBR application augmented the auxin (IAA) (21%) and brassinolide (131%) contents and upregulated genes related to drought tolerance induced by the BR (BRL3 and BZR2) and IAA (YUCCA6, SAUR32, and IAA26) signaling pathways. These results suggest that it could play an important role in improving mechanisms of drought tolerance in tobacco.

Remediation Potential of Taraxacum kok-saghyz Rodin on Lead and Cadmium Contaminated Farmland Soil

Taraxacum kok-saghyz Rodin (TSK) is an energy plant that can be used as a raw material for natural rubber. The aim of this study was to examine the remediation potential of TSK to lead (Pb)- and cadmium (Cd)-contaminated farmland soil. In this study, a pot experiment was conducted, and the "Soil Environmental Quality and Agricultural Land Soil Pollution Risk Control Standard (GB 15618-2018)" was used as reference. We set up four different concentrations of Pb and Cd pollution treatment to study the characteristics of the accumulation and tolerance of TSK to Pb and Cd. The results showed that as the content of Pb and Cd in the soil increased, the chlorophyll content and biomass of TSK gradually decreased, and the SOD, POD, and CAT enzyme activities gradually increased. The BCF and TF of Cd were between 1.20 and 1.50, indicating that TSK presented some characteristics of a Cd hyperaccumulator. The BCF and TF of Pb were between 0.71 and 1.11. Thus, TSK was a good Pb enrichment plant and possessed the potential to repair soil with ω(Pb) below 400 mg·kg-1. The accumulation of Pb and Cd gradually increased, and the maximum accumulation of Cd and Pb in the shoots was 9.832 μg·plant-1 and 1091.185 μg·plant-1, respectively. However, in lower concentrations of Pb- and Cd-contaminated soil, the removal rate was greater, and the remediation efficiency was better. Overall, using TSK to repair Pb- and Cd-contaminated farmland soil has good application prospects and economic value.

Physio-biochemical, anatomical and functional responses of Helianthus annuus L. and Brassica juncea (Linn) to cypermethrin pesticide exposure

Pesticides are applied all over the world to protect plants from pests. However, their application also causes toxicity to plants, which negatively affects the growth and development of plants.This study compared the physiological, biochemical and anatomical modifications of two oil seed crops viz., Helianthus annuus L. and Brassica juncea under different levels of pesticides. The present research was aimed to assess responses at the biochemical, physiological and anatomical levels to Cypermethrin (CYP) pesticide to discriminate the effects of osmotic stress and micronutrients availability. The two different concentrations of CYP-pesticide (20 mg /kg and 40 mg /kg) were examined. The obtained results showed that as the concentration of cypermethrin increased in soil, the fresh and dry weight of growing plants gradually decreased. The application of 40 mg /kg −1 soil of cypermethrin reduced the fresh weight of root in both H. annuus and B. juncea (up to 33 % and 29.4 % %, respectively) decreased root length (up to 2.3 % and 11 %, respectively). While shoot length was increased in both plant species at both levels of CYP relative to control. Shoot fresh weight decreased at 20 mg /kg CYP-treatment in H. annuus whereas in B. juncea at same level of cypermethrin increased fresh weight of shoot was found relative to un-treated seedlings. Reactive oxygen species viz., H2O2 and MDA contents in roots increased by 40 mg/kg-1 CYP in B. juncea followed by H. annuus (upto 50.27 % and 19.79 %; 36.33 % and 35.21 %, respectively). Furthermore, pesticide increased the activities of antioxidant enzymes in H. annuus followed by B. juncea. SOD, POD and CAT enzyme activities significantly decreased in B. juncea under 40 mg/kg-1 CYP by 38.8 %, 44.78 % and 36.83 %, respectively. In 20 mg /kg cypermethrin treatment declined antioxidant enzyme activities were found in H. annuus shoot compared to B. juncea shoot. In case of B. juncea increased APX enzyme activity was observed at 20 mg /kg-1 cypermethrin treatment. While significantly decreased activities of an antioxidant enzymes were found to be at 40 mg /kg CYP-treatment. The main aimed of this study to determine the anatomical responses of H. annuus and B. juncea roots to the cypermethrin exposure. Cypermethrin stress (40 mg /kg-1) change the root diameter (smaller), damaged epidermis layer, irregular form of epidermal cells of both species. The area of vascular bundle is decreasing when increasing the cypermethrin pesticide. Moreover, in stem, epidermis thickness was observed only in B. juncea xylem thickness increased in H. annuus at 20 mg /kg treatment, while in B. juncea non-significant difference was observed at this trait relative to un-treated plants. Phloem thickness raises and pith area in both species at lower concentration of cypermethrin. Leaf collenchymatous cell area was increased at both plant species at 20 mg /kg. Epidermis, spongy mesophyll and palisade mesophyll thickness increased when increased cypermethrin. Mineral uptake by H. annuus and B. juncea from cypermethrin treated soil was measured and also Pearson correlation was measured between all analyzed traits of plants. PCA clearly differentiated all treatments and growth parameters of both plant species. Thus, findings of present study confirmed that overdose of pesticides exhibited toxic effects on different growth, physiological and biochemical attributes of tested plants and pesticide also alter structural changes in plant tissues.

Acid-Modified Biochar Impacts on Soil Properties and Biochemical Characteristics of Crops Grown in Saline-Sodic Soils

Soil salinity and sodicity is a potential soil risk and a major reason for reduced soil productivity in many areas of the world. This study was conducted to investigate the effect of different biochar raw materials and the effects of acid-modified biochar on alleviating abiotic stresses from saline-sodic soil and its effect on biochemical properties of maize and wheat productivity. A field experiment was conducted as a randomized complete block design during the seasons of 2019/2020, with five treatments and three replicates: untreated soil (CK), rice straw biochar (RSB), cotton stalk biochar (CSB), rice straw-modified biochar (RSMB), and cotton stalk-modified biochar (CSMB). FTIR and X-ray diffraction patterns indicated that acid modification of biochar has potential effects for improving its properties via porous functions, surface functional groups and mineral compositions. The CSMB treatment enhanced the soil’s physical and chemical properties and porosity via EC, ESP, CEC, SOC and BD by 28.79%, 20.95%, 11.49%, 9.09%, 11.51% and 12.68% in the upper 0–20 cm, respectively, compared to the initial properties after the second season. Soil-available N, P and K increased with modified biochar treatments compared to original biochar types. Data showed increases in grain/straw yield with CSMB amendments by 34.15% and 29.82% for maize and 25.11% and 15.03% for wheat plants, respectively, compared to the control. Total N, P and K contents in both maize and wheat plants increased significantly with biochar application. CSMB recorded the highest accumulations of proline contents and SOD, POD and CAT antioxidant enzyme activity. These results suggest that the acid-modified biochar can be considered an eco-friendly, cheaper and effective choice in alleviating abiotic stresses from saline-sodic soil and positively effects maize and wheat productivity.

Potassium application promote cotton acclimation to soil waterlogging stress by regulating endogenous protective enzymes activities and hormones contents

To investigate the effect of potassium application on cotton damage mitigation after waterlogging stress, experiments were conducted under two potassium application levels (0 and 150 kg K2O hm−2) with three types of soil waterlogging treatments (0d, 3d and 6d) during cotton flowering stage. The results showed that: (a) under simple soil waterlogging stress, the increments of endogenous hormones contents of IAA, GA3 and ZR in cotton leaves were decreased as days of soil waterlogging. On the contrary, the soluble protein, MDA and ABA contents were significantly increased, while ZR/ABA, IAA/ABA and GA3/ABA were decreased. CAT and POD enzyme activities were increased although SOD activity decreased with the duration of soil waterlogging. (b) Potassium application combined with soil waterlogging significantly affected the antioxidant enzymes activity and endogenous hormones balance compared with soil waterlogging alone, leading to a significant increase in soluble protein and a pronounced decrease in H2O2 content, O2− generation rate, and MDA content, a significant increase in IAA, GA3 and ZR contents while a decrease in ABA content. Besides, it also kept higher SOD, CAT activities and slowly increased POD activity. (c) There was an obvious compensatory effect in cotton after 3d soil waterlogging under potassium application, which promoted rapidly recovery of physiological enzymes activities and ABA content. However, 6d soil waterlogging required a longer time for recovery. These findings were expected to provide a scientific and theoretical basis for reducing flood damage and improving cotton yield.

Proteomics Analysis of Zygosaccharomyces mellis in Response to Sugar Stress

The high-osmotic-pressure environment of honey is not suitable for the survival of microorganisms, except for osmotic-tolerant fungal and bacterial spores. In this study, shotgun metagenomic sequencing technology was used to identify yeast species present in honey samples. As a result, Zygosaccharomyces spp. yeast, including Zygosaccharomyces rouxii, Z. mellis and Z. siamensis, were isolated. The intracellular trehalose and glycerin concentrations of yeast, as well as the antioxidant-related CAT, SOD and POD enzyme activities, increased under a high-glucose environment (60%, w/v). To learn more about the osmotic resistance of Z. mellis, iTRAQ-based proteomic technology was used to investigate the related molecular mechanism at the protein level, yielding 522 differentially expressed proteins, of which 303 (58.05%) were upregulated and 219 (41.95%) were downregulated. The iTRAQ data showed that the proteins involved in the pathway of the cell membrane and cell-wall synthesis, as well as those related to trehalose and glycerin degradation, were all downregulated, while the proteins in the respiratory chain and TCA cycle were upregulated. In addition, formate dehydrogenase 1 (FDH1), which is involved in NADH generation, displayed a great difference in response to a high-sugar environment. Furthermore, the engineered Saccharomyces cerevisiae strains BY4741△scFDH1 with a knocked-out FDH1 gene were constructed using the CRISPR/Cas9 method. In addition, the FDH1 from Z. mellis was expressed in BY4741△scFDH1 to construct the mutant strain BY4717zmFDH1. The CAT, SOD and POD enzyme activities, as well as the content of trehalose, glycerin, ATP and NADH, were decreased in BY4741△scFDH1. However, those were all increased in BY4717zmFDH1. This study revealed that Z. mellis could increase the contents of trehalose and glycerin and promote energy metabolism to improve hypertonic tolerance. In addition, FDH1 had a significant effect on yeast hypertonic tolerance.

Morphological, physiological and biochemical responses to combined cadmium and drought stress in radish (Raphanus sativus L.)

Drought and heavy metal stress are among the most important stress factors that negatively affect plant growth. This study was carried out to determine the individual and combined effects of cadmium (Cd) and drought stress on growth (plant leaf area, stem and root diameter, shoot and root fresh weight, shoot and root dry weight), physiological [electrolyte leakage (EL), leaf relative water content (LRWC)] and biochemical [antioxidant enzyme activity, hydrogen peroxide (H2O2), malondialdehyde (MDA), proline, sucrose and mineral element content] parameters of radish. In the study, four Cd concentrations (0 mg kg−1, 100 mg kg−1, 150 mg kg−1 and 200 mg kg−1), three irrigation levels (100%, 75% and 50% of field capacity—FC) were used. Leaf area, stem and root diameter, shoot and root fresh weight, shoot and root dry weight, LRWC, chlorophyll a, chlorophyll b and total chlorophyll content decreased with increased level of drought and Cd stress, but EL has increased. The effect of water deficit on these parameters was more detrimental than heavy metal stress; however, the stress-related damage was greater under combined stress conditions. In addition, H2O2, MDA, proline and sucrose content of radish leaves increased with increased water deficit and Cd stress levels. POD, CAT and SOD enzyme activities of radish leaves under combined stresses increased more than individual stress conditions. There was a significant increase in the content of Cd in the plant leaves and roots under Cd stress compared to the control. This increase in leaves was more pronounced than roots. Although individual drought and Cd stress negatively influenced radish growth and development, the damage was greater with the simultaneous occurrence of these two stress factors.

Change in the Physiological and Biochemical Aspects of Tomato Caused by Infestation by Cryptic Species of Bemisia tabaci MED and MEAM1.

Simple SummaryBemisia tabaci is a polyphagous pest with cryptic species that infest various agricultural crops worldwide. Among the cryptic species, MED and MEAM1 are the most invasive, causing large production losses due to the feeding and transmission of the virus. We aimed to analyze the influence of these insects on the physiology and biochemistry of tomato. We found that the cryptic species MED caused considerable reduction in CO2 assimilation rates, stomatal conductance, and instantaneous carboxylation efficiency. Furthermore, plants infested with MED showed high activity of the enzymes peroxidase and polyphenol oxidase, which are considered expressions of plant defense. In contrast, plants infested with MEAM1 showed low peroxidase activity, which may result in a less lignified feeding place.Infestation by Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes damage to tomatoes with production losses of up to 100%, affecting the physiological and biochemical aspects of host plants. The objective of this study was to analyze the influence of infestation of cryptic species of B. tabaci MED and MEAM1 on the physiological and biochemical aspects of tomato. Tomato plants ‘Santa Adélia Super’ infested with B. tabaci (MED and MEAM1), and non-infested plants were evaluated for differences in gas exchange, chlorophyll - a fluorescence of photosystem II (PSII), and biochemical factors (total phenols, total flavonoids, superoxide dismutase—SOD, peroxidase—POD, and polyphenol oxidase—PPO). Plants infested with B. tabaci MED showed low rates of CO2 assimilation and stomatal conductance of 55% and 52%, respectively. The instantaneous carboxylation efficiency was reduced by 40% in MED and by 60% in MEAM1 compared to the control. Regarding biochemical aspects, plants infested by MED cryptic species showed high activity of POD and PPO enzymes and total phenol content during the second and third instars when compared to control plants. Our results indicate that B. tabaci MED infestation in tomato plants had a greater influence than B. tabaci MEAM1 infestation on physiological parameters (CO2 assimilation rate (A), stomatal conductance (gs), and apparent carboxylation efficiency (A/Ci)) and caused increased activity of POD and PPO enzymes, indicating plant resistance to attack. In contrast, B. tabaci MEAM1 caused a reduction in POD enzyme activity, favoring offspring performance.

High Pressure Processing vs. Thermal Pasteurization of Whole Concord Grape Puree: Effect on Nutritional Value, Quality Parameters and Refrigerated Shelf Life.

High-pressure processing (HPP) is utilized for food preservation as it can ensure product safety at low temperatures, meeting consumers’ demand for fresh-like and minimally processed products. The purpose of this study was to determine the effects of HPP (600 MPa, 3 min, 5 °C) and pasteurization by heat treatment (HT, 63 °C, 3 min) on the production of a novel whole Concord grape puree product (with skin and seeds, no waste), and the shelf-life of the puree under refrigerated storage (4 °C). Microbial load, physicochemical properties, phenolic content and antioxidant activity, composition and sensorial attributes of puree samples were evaluated. HPP- and HT-treated purees were microbiologically stable for at least 4 months under refrigeration, with less microbial growth and longer shelf life for HPP samples. HPP and HT samples had similar levels of phenolic contents and antioxidant activities throughout the 4-month refrigerated storage period, even though HPP retained >75% PPO and POD enzyme activities while those of HT were less than 25%. Inclusion of seeds in the puree product significantly increased the fiber, protein, total fatty acid, and linoleic acid contents. Sensory results showed that HPP-treated puree retained more fresh-like grape attributes, had better consistency, and showed significantly higher ratings in consumer overall liking, product ranking, and purchase intent than the HT puree (p < 0.05).

Comparison of Antioxidant and Antibacterial Activities of Camellia Oil From Hainan With Camellia Oil From Guangxi, Olive Oil, and Peanut Oil.

Background/Aim: Camellia oil from Hainan (SY) is a unique vegetable oil in Hainan, China, due to the geographical environment and oil extraction only through simple physical treatments. To compare SY with camellia oil from Guangxi (SC), olive oil (GL), and peanut oil (HS), this study analyzed the antioxidant and antibacterial activity of four vegetable oils.Methods: Using Gallic acid, BHT as the control, Saccharomyces cerevisiae as the model organism, the antioxidant activities of vegetable oils were measured in vitro and in vivo, and the antibacterial activity was measured with the minimum inhibitory concentration (MIC) method.Results: The major contents of SY, SC, and HS were oleic Acid; the major content of GL was squalene. The highest total flavonoids content of SY was 39.50 ± 0.41 mg RE/g DW; and the highest total phenolic content of SC was 47.05 ± 0.72 mg GAE/g DW. SY exhibited the strongest scavenging activity of hydroxyl radical (HO·) and superoxide anions (), the IC50 value were 2.06 mg/mL, 0.62 mg/mL, respectively; and SC showed the strongest DPPH· and ABTS· scavenging activity and the reducing abilities. SY showed excellent effect on survival rate, protection rate, flavonoids uptake of S. cerevisiae cells, decreased MDA content and ROS level, inhibited CAT, POD, and GR enzyme activity. The absorption of SC total phenols was the highest by cells. The activity showed GL had a broad-spectrum antibacterial activity.Conclusion: Thus, SY shows potential antioxidant activity and provides an important reference value for people to choose edible vegetable oils.

Effects of Superparamagnetic Nanomaterials on Soil Microorganisms and Enzymes in Cadmium-Contaminated Paddy Fields

Using Fe3O4 and hydroxyapatite as raw materials, superparamagnetic nanometer-sized Fe3O4-phosphate functionalized materials (MFH) were prepared. Soil was subsequently magnetically repaired by adding MFH to cadmium-contaminated paddy field soil. Two kinds of rice with high (Yuzhenxiang) and low (Xiangwanxian-13) cadmium enrichment were selected for conduct pot experiments to study the effect of MFH magnetic separation on soil microorganisms and enzymes, and explore the possibility of application in the remediation of cadmium-polluted farmland. The results showed that MFH application improved the soil remediation effect, with significantly reduced total Cd (38.9%) and available Cd (27.3%) contents. In addition, the Cd content of the two kinds of rice grain was significantly reduced. After MFH magnetic separation, soil microbial community diversity and richness were decreased during the jointing, heading, and maturing stages of the two rice varieties. Treatment of cultivated Yuzhenxiang rice with high concentrations of Cd significantly increased the abundance of dominant Firmicute bacteria in the rice field during the jointing and heading stages. With the use of MFH in the magnetic separation, urease, catalase, and soil peroxidase activity were improved during the jointing, heading, and maturing stages of the two rice soils. The POD enzyme activity in the soil planted with Yuzhenxiang was slightly higher than that planted with Xiangwanxian-13, while urease activity showed the opposite trend.

Optimization of Blanching Process of hawthorn using central composite design and response surface method

Response surface method (RSM) was used to optimize hawthorn blanching process based on single-factor experiments. There were two numerical (time and temperature) and one categorical variable (POD enzyme activity) that was used for the evaluation of the hawthorn blanching quality. The changes in POD enzyme activity, procyanidin content, and total flavonoid content were also analyzed. The regression model (P< 0. 05) was obtained through Central-Composite experimental design, indicating that the model could evaluate the residual POD enzyme activity in the blanching process under different parameters. The results show that time 103s and temperature 92.5°C were the best blanching conditions. Under these optimized conditions, the residual POD enzyme activity of hawthorn was within a reasonable range, which was 0.7731 U⋅g-1⋅min-1. The calculated results were basically consistent with the model predicted values (0.7989 U⋅g-1⋅min-1).

Preparation of antimicrobial peptides from Bacillus subtilis and effect on fresh-cut vegetables

In order to extend the shelf life of fresh-cut vegetables, the principle of preservation of Bacillus subtilis antimicrobial peptides was discussed. Fresh potatoes, yam and lotus root were used as test materials, and the prepared Bacillus subtilis antimicrobial peptides were used for soaking treatment, soaked in clean water as a control, and stored at 4°C. The sensory quality changes during storage were analyzed and their physiological and biochemical indexes were determined. The results show: compared with the control group, the group treated with Bacillus subtilis antimicrobial peptides had the best sensory quality during storage, significantly inhibited the increase in electrical conductivity, reduced cell membrane damage, and had significant POD and PPO enzyme activities (P < 0.05). The reduction effectively inhibits the proliferation of microorganisms during the storage of fresh-cut vegetables, thereby better maintaining the quality of fresh-cut vegetables and effectively extending their shelf life.

COMPARATIVE GROWTH PERFORMANCE AND ACTIVITY OF DEFENSE RELATED ENZYMES AND GENE EXPRESSION IN RUBBER CLONES AGAINST RIGIDOPORUS MICROPORUS INFECTION

Rigidoporus microporus is the causal agent of rubber white root disease (WRD). Control of this is commonly carried out by chemical treatment. The use of tolerant rootstocks may present an effective method to lessen its impact. The screening of rubber rootstocks for tolerance of WRD was investigated by both defense-related enzymes and gene expression, and assessment of disease symptoms.Two recommended clones in Thailand (RRIT251 and RRIT408) and RRIM623 (Malaysian clone) were screened and compared with susceptible clones (RRIM600 and BPM24) and tolerant clone (PB5/51) by inoculating young rubber seedling with R. microporus. The expression of PRs and PAL were analyzed at 0, 1, 3, 5, and 7 days post inoculation (dpi) along with the defense-related enzyme activities. Based on observed transcriptional level of PRs and PAL genes, CHI, PAL, and POD enzyme activities, and also evidence from WRD symptom assessment in the field, we concluded that PB 5/51 had the best tolerance with the lowest disease incidence, high PAL and POD enzyme activities, with the next best being RRIM 623 and RRIT 251, respectively. Meanwhile, BPM 24, RRIM 600, and RRIT 408 clones are moderately susceptible to WRD. The study introduces new possibilities for the control of WRD using alternative rubber rootstock clones.

Physiological and transcriptional response to heat stress in heat-resistant and heat-sensitive maize (Zea mays L.) inbred lines at seedling stage.

To understand the molecular and physiological mechanism underlying the heat stress in maize, transcriptional and physiological response to heat stress in the heat-resistant Huangzaosi (HZS) and heat-sensitive Lv-9-Kuan (L9K) inbred lines at seedling stage were analyzed and compared at seedling stage. Our results indicated that MDA content of the two inbred lines increased significantly under heat stress; the values of MDA in L9K was significantly higher than that in HZS. The level of SOD, CAT, and POD enzyme activities in HZS was higher than those in L9K for both the heat-treated group and controls. The values of Fv/Fm, qP, and ФPSII reduced by heat stress in L9K were higher than the respective values in HZS. RNA-seq data showed that heat stress induced more heat stress-related genes in HZS (257 heat stress-related genes) than in L9K (224 heat stress-related genes). GO and KEGG enrichment analyses indicated that HZS and L9K changed their physiological and biochemical mechanisms in response to heat stress through different molecular mechanisms. Weighted Gene Co-expression Network Analysis showed that HZS might obtain stronger heat resistance than L9K through a unique transcriptional regulatory network. Our findings provide insights into the molecular networks that mediate the tolerance of maize heat stress and also help us to mine key heat stress-related genes.