Postharvest ASM or Harpin Treatment Induce Resistance of Muskmelons Against Trichothecium roseum

Induced resistance was studied in muskmelons （cv. Yindi） inoculated Trichothecium roseum with postharvest 1,2,3- benzothiadiazole-7-carbothioic acid S-methyl ester （ASM） （100 mg L^-1） or harpin （50 mg L^-1） treatment. Both ASM and harpin significantly reduced lesion diameter in inoculated fruit. Lesion diameter was limited in the treated and untreated halves of the same fruit, indicating that the local and systemic resistance was induced. Inhibiting efficacy of elicitors lasted 7 and 5 days in the treated and untreated halves. The resistance increased by the chemicals was associated with the activation of peroxidase （POD） and chitinase （CHT）. The elicitors induced a significantly and progressively increasing activity of POD and CHT in the treated and untreated halves, and the activation lasted at least 5 days. The activities of POD isoenzymes increased in the treated fruit. However, no new enzyme band was found in the treated and untreated halves.

2,3-Butanediol from the leachates of pine needles induces the resistance of Panax notoginseng to the leaf pathogen Alternaria panax

Compared with the use of monocultures in the field,cultivation of medicinal herbs in forests is an effective strategy to alleviate disease.Chemical interactions between herbs and trees play an important role in disease suppression in forests.We evaluated the ability of leachates from needles of Pinus armandii to induce resistance in Panax notoginseng leaves,identified the components via gas chromatography-mass spectrometry(GC-MS),and then deciphered the mechanism of 2,3-Butanediol as the main component in the leachates responsible for resistance induction via RNA sequencing(RNA-seq).Prespraying leachates and 2,3-Butanediol onto leaves could induce the resistance of P.notoginseng to Alternaria panax.The RNA-seq results showed that prespraying 2,3-Butanediol onto leaves with or without A.panax infection upregulated the expression of large number of genes,many of which are involved in transcription factor activity and the mitogen-activated protein kinase(MAPK) signaling pathway.Specifically,2,3-Butanediol spraying resulted in jasmonic acid(JA)-mediated induced systemic resistance(ISR) by activating MYC2 and ERF1.Moreover,2,3-Butanediol induced systemic acquired resistance(SAR) by upregulating pattern-triggered immunity(PTI)-and effector-triggered immunity(ETI)-related genes and activated camalexin biosynthesis through activation of WRKY33.Overall,2,3-Butanediol from the leachates of pine needles could activate the resistance of P.notoginseng to leaf disease infection through ISR,SAR and camalexin biosynthesis.Thus,2,3-Butanediol is worth developing as a chemical inducer for agricultural production.

Effects of β-Amino Butyric Acid Induced Rice Blast Resistance on Reactive Oxygen Metabolism

[Objective] This study was to understand the effects of β-Amino butyric acid(abbreviated as BABA) induced rice blast resistance on reactive oxygen metabolism. [Method] Using the cultivar Chaochan 2 that is highly susceptible to disease as experimental material, the changes of catalase(CAT), and superoxide dismutase(SOD) and MDA activities in rice treated by BABA were investigated. [Result] In rice plants treated by BABA, the activities of CAT and SOD increased, meanwhile the MDA content also rose to some extent, resulting in the disease resistance to rice blast. [Conclusion] By influencing reactive oxygen metabolism, BABA endows rice plants with resistance to rice blast. BABA is safe to environment and has highly resistance-inducing capacity, it could be generalized in production.

Tomato Resistance to Botrytis cinerea Induced by Chitosan

[Objective] The aim was to explore the effect of tomato＇s resistance to Botrytis cinerea induced by exogenous Chitosan.[Method] The leaf spraying method was used to determine the induced resistance effect of Chitosan to tomato B.cinerea and the chlorophyll content,soluble protein,soluble sugar,proline influence,the activities of peroxidase（POD）,malondialdehyde（MDA）and the Proline content in leaves of tomato.[Result] The induced resistance of Chitosan reached 58.26% at 14th d after treatment;Compared with the B.cinerea stress group,the chlorophyll content in leaves of tomato seedlings of B.cinerea stress ＋ Chitosan group had increased by 34.63%,while that of soluble protein content,soluble sugar content,Pro content and POD activity was 5.30%,10.83%,16.21% and 16.88%,respectively（except for the MDA content,which was decreased by 16.54%）.[Conclusion] Exogenous Chitosan could improve photosynthetic efficiency and protect enzymes activity to improve the resistance of tomato seedlings to B.cinerea.

Resistance -induced Effect of Several Chemical Reagents on Cucumber against Pseudoperonospora cubensis

[ Objectlve] The paper was to compare the induced resistance of several chemicals on cucumber against Pseudoperonospora cubensis [ Method ] When the cucumber seedlings grew to 4-leaf stage, the second true leaf was treated with salicylic acid, oxalate, chitosan, calcium nitrate and Na2HPO4, the activity of protective enzymes in the third leaf was determined after 7 d. At the same time, inoculation test was also conducted after induced treatment, and the disease condi- tion was coumed. [ Result ] These chemical treatments promoted protective enzyme activities （POD, SOD, PAL, PPO） in different degree, improved the ultra-weak luminescence, and reduced the disease index of cucumber leaves. [ Conclusion] Five chemical treatments expressed good effects on induced resistance. Among the treatments, oxalate had the best induced effect, followed by salicylic acid, chitosan, Na2 HPO4 and calcium nitrate.

Postharvest Chitosan Treatment Induces Resistance in Potato Against Fusarium sulphureum

The effects of chitosan treatment and inoculation on dry rot in tubers and slices of potato were studied. The results showed that chitosan treatment significantly reduced the lesion diameter of potato inoculated with Fusarium sulphureum. The treatment at 0.25% showed the best effect. Chitosan at 0.25% increased the activities of peroxidase and polyphenoloxidase, and the contents of flavonoid compounds and lignin in tissues. Increased activities of 13-1,3-glucanase, and phenylalanine ammonialyase were observed, but there were no significant differences between the treated and the control. These findings suggested that the effects of chitosan could be associated with the induced resistance against Fusarium dry rot in potato.

Induced Resistance by the Toxin Filtrate of Bipolaris maydis Race T Cultivation

Resistance to maize southern leaf spot disease was induced by the low-concentration filtrate of Bipolaris maydis race T cultivation in an experiment. The nuclear neterogeny corn C103 was used as the test material. The lesion area on the leaves was significant difference by connalysis. The lesion areas on pretreated leaves were （0.3±0.05）- （0.9±0.5） mm^2, but those on the control were （23.1±8.7） mm^2. At the same time, the changes in peroxidase, phenylalanine, ammonialyase, and malondialdehvde activities were determined. During 0-96 h of inspection, phenylalanine and ammonialyase （PAL） activities increased by 64.2%, peroxidase （POD） activities increased by 41.2%, but the malondialdenvde （MDA） content decreased by 29.7% compared with the control. It seems that the low-concentration filtrate of Bipolaris maydis race T cultivation itself can be used as an elicitor to enhance the induced resistance.

Postharvest Treatment with β-Aminobutyric Acid Induces Resistance Against Dry Rot Caused by Fusarium sulphureum in Potato Tuber

The effectiveness ofpostharvest β-aminobutyric acid （BABA） treatment was studied for inducing resistance against dry rot caused by Fusarium sulphureum in tubers and slices of two potato cultivars （resistant cultivar Shepody and susceptible cultivar Xindaping）. The results showed that BABA at 100 mmol L-1 significantly reduced lesion diameter in inoculated both tubers and slices. The chemical at 100 mmol L-1 showed an effective reduction in infection ability ofF. sulphureum inoculated 48 and 72 h after treatment in slices of resistant cultivar, and 72 and 96 h in susceptible ones. BABA increased the activitives of peroxidase （POD）, polyphenoloxidase （PPO） and phenylalanine ammonialyase （PAL）, and accumulated the contents of lignin, flavonoids and phenolics in slices. The resistant cultivar had a stronger resistant response than the susceptible one. These findings suggest that the BABA treatment can induce the resistance in potato tubers, however, the inducing degree depends on the original level of resistance present in each cultivar.

Induces Resistance Against Fusarium and Pink Rots by Acibenzolar-S-Methyl in Harvested Muskmelon (cv.Yindi)

Acibenzolar-S-methyl （ASM） is a chemical activator of systematic resistance in many plants. The effect of preharvest and postharvest application of ASM was evaluated for its ability to induce resistance in muskmelon fruit. The results indicated that 50 and 100 mg L^-1 ASM or 1 mL L^-1 imazalil at 1 week or 1 day before harvest were effective in reducing the lesion area with 100 mg L^-1 ASM the most effective. No treatment inhibited the infection rate. The postharvest results showed that 50 and 100 mg L^-1 ASM, and 0.1 mL L^-1 imazalil were effective in reducing the lesion area with 100 mg L^-1 ASM the most effective. No treatment inhibited the infection rate. There was a clear time-dependent response of the fruit to postharvest ASM treatment, in which treatments applied 1, 3, and 5 day before inoculation provided the best results. ASM did not demonstrate any fungicide effect in vitro and suppressed lesion area in treated muskmelons, indicating that disease resistance was induced. The protection of ASM was associated with the activation of peroxidase （POD） in treated muskmelons.

Hot air treatment activates defense responses and induces resistance against Botrytis cinerea in strawberry fruit

The effect of hot air（HA, 45°C, 3.5 h） treatment on reducing gray mold caused by Botrytis cinerea in strawberry fruit and the possible mechanisms were investigated. The results showed that HA treatment significantly reduced lesion diameter and enhanced activities of chitinase（CHI）, β-1,3-glucanase and phenylalanine ammonia-lyase（PAL） in strawberry fruit. Total phenolic contents were also increased by HA treatment. The activities of antioxidant enzymes including superoxide dismutase（SOD）, catalase（CAT） and ascorbate peroxidase（APX） were higher in HA treated strawberry fruit than those in control. Expression of three defense related genes such as CAT, CCR-1 allele and PLA6 was greatly induced in HA treated strawberry fruit with or without inoculation by B. cinerea. In addition, the in vitro experiment showed that HA treatment inhibited spore germination and tube growth of B. cinerea. These results suggested that HA treatment directly activated disease resistance against B. cinerea in strawberry fruit without priming response and directly inhibiting growth of B. cinerea.

Potassium sulphate induces resistance of rice against the rootknot nematode Meloidogyne graminicola

Potassium(K),an important nutrient element,can improve the stress resistance/tolerance of crops.The application of K in resisting plant-parasitic nematodes shows that the K treatment can reduce the occurrence of nematode diseases and increase crop yield.However,data on K_(2)SO_(4)induced rice resistance against the root-knot nematode Meloidogyne graminicola are still lacking.In this work,K_(2)SO_(4)treatment reduced galls and nematodes in rice plants and delayed the development of nematodes.Rather than affecting the attractiveness of roots to nematodes and the morphological phenotype of giant cells at feeding sites,such an effect is achieved by rapidly priming hydrogen peroxide(H_(2)O_(2))accumulation and increasing callose deposition.Meanwhile,galls and nematodes in rice roots were more in the potassium channel OsAKT11 and transporter OsHAK5 gene-deficient plants than in wild-type,while the K_(2)SO_(4)-induced resistance showed weaker in the defective plants.In addition,during the process of nematode infection,the expression of jasmonic acid(JA)/ethylene(ET)/brassinolide(BR)signaling pathway-related genes and pathogenesis-related(PR)genes OsPR1 a/OsPR1 b was up-regulated in rice after K_(2)SO_(4)treatment.In conclusion,K_(2)SO_(4)induced rice resistance against M.graminicola.The mechanism of inducing resistance was to prime the basal defense and required the participation of the K^(+)channel and transporter in rice.These laid a foundation for further study on the mechanism of rice defense against nematodes and the rational use of potassium fertilizer on improving rice resistance against nematodes in the field.

Genetic improvement of Trichoderma ability to induce systemic resistance

The beneficial applications of Trichoderma spp. in agriculture include not only the control of plant pathogens, but also the improvement of plant growth, micronutrient availability, and plant tolerance to abiotic stress. In addition, it has been suggested that these fungi are able to increase plant disease resistance by activating induced systemic resistance (ISR) . The mode of action of these beneficial fungi in the Trichoderma -plant-pathogen interaction are many, complex and not completely understood. Numerous lytic enzymes have been characterized, the encoding genes (ech42 gluc78, nag1 from T. atroviride strain P1) cloned, and their role in biocontrol demonstrated. The corresponding biocontrol-related inducible promoters have been used in a reporter system based on the Aspergillus niger glucose oxidase gene (goxA) to monitor biocontrol activity. Glucose oxidase catalyzes the oxygen-dependent oxidation of D-glucose to D-glucono-1,5-lactone and hydrogen peroxide; this latter compound is known to have an antifungal effect and activate the plant defence cascade, thus increasing resistance to pathogen attack. T. atroviride P1 transformants with various promoters gox were tested as seed coating treatments on bean seeds planted in soil infested with a soilborne fungal pathogen. Successively, the emergent leaves were inoculated with a foliar pathogen to determine the effect of the GOX transformants on biocontrol and resistance to pathogen attack. Inoculations with the P1-GOX transformants not only reduced disease symptoms caused by a soil pathogen, but also the lesions of various foliar pathogens applied far from the Trichoderma colonization, thus activating ISR. A similar approach is being use to genetically improve T. harzianum T22, a rhizosphere competent and commercially marketed strain not transformed yet, by using four different gox gene constructs under the control of constitutive and inducible promoters. Plasmids have been introduced in Trichoderma by protoplasts co-transformation. hygromicin resistant progeny selected, and mitotically stable transformants analysed to confirm the presence of the novel enzyme activity. Progenies are being tested for biocontrol ISR inducing activity.

A Triterpenoid Inhibited Hormone-Induced Adipocyte Differentiation and Alleviated Dexamethasone-Induced Insulin Resistance in 3T3-L1 adipocytes

6a-Hydroxylup-20(29)-en-3-on-28-oic acid(1),a natural triterpenoid,was found to possess the ability in a dose-dependent manner inhibiting hormone-induced adipocyte differentiation in 3T3-L1 preadipocytes,and restoring glucose consuming ability in dexamethasone(DXM)-induced insulin resistant 3T3-L1 adipocytes.Compound 1 was also found to ameliorate DXM-induced adipocyte dysfunction in lipolysis and adipokine secretion.Mechanistic studies revealed that 1 inhibited adipocyte differentiation in 3T3-L1 preadipocytes via down-regulating hormone-stimulated gene transcription of peroxisome proliferator-activated receptor c and CCAAT-enhancer-binding protein alpha which are key factors in lipogenesis,and restored DXM-impaired glucose consuming ability in differentiated 3T3-L1 adipocytes via repairing insulin signaling pathway and activating down-stream signaling transduction by phosphorylation of signaling molecules PI3K/p85,Akt2 and AS160,thus leading to increased translocation of glucose transporter type 4 and transportation of glucose.

Induced Resistance of Tomato against Gray Mold (Botrytis cinerea) by Salicylic Acid (SA)

[ Objective ] The paper was to explore the induced resistance of tomato against gray mold （Botrytis cinerea） by salicylic acid. [ Method ] SA was used as an inducer to treat tomato seedlings, the effects of SA on mycelial diameter and spore germination of B. cinerea were studied, and the changes of 4 defense enzyme activities containing catalase （CAT）, peroxidase （POD）, polyphenol oxidase （PPO） and phenylalanine ammonia lyase （PAL）, as well as malondialdehyde （MDA） content during the production process of induced resistance were also measured. [ Result] SA had no inhibitory effect against spore germination and myce- lial growth of B. cinerea within the concentration range, and the relative induced effect had different degrees of improvement after treatment. The induced effect was the best as B. cinerea was challenged to inoculate at the third day after using 150 mg/L SA in tomato plants, and the duration of resistance was 10 -15 d. After treated by SA, CAT, POD, PPO and PAL first increased and then decreased in systemic induced resistance against B. cinerea, which were significantly higher than control. Meanwhile, MDA content showed ascendant trend in wavy line form. [ Conclusion ] The use of SA within a certain concentration range is safe; CAT, POD, PPO and PAL activities have positive correlation with induced resistance against B. cinerea, the increase of MDA content also has close relationship with the imvrovement of disease resistance.

Blast Resistance of Rice Induced by Ag-antibiotic 702

To explore rice blast resistance induced by Ag-antibiotic 702, different concentrations of Ag-antibiotic 702 were spayed on susceptible variety Luliangyou 996 at three-leaf and one-heart stage, to screen the optimal concentration for inducing rice blast resistance. Ag-antibiotic 702 was sprayed at seven different growth stages of rice, to determine the best growth stage for induced blast resistance and duration of blast resistance. Various treatments were inoculated with spore fluid of Magnaporthe grisea at 4 d post spraying, and disease index and incidence rate as well as induction effect of different treatments were investigated after 7 d. The results showed that six concentrations of Ag-antibiotic 702 could induce rice resistance against blast, and 15 μg/mL led to the highest blast resistance; spraying 15 μg/mL Ag-antibiotic 702 at seven different growth stages could induce rice resistance against blast ; the three-leaf and one-heart stage was the best growth stage for inducing rice blast resistance, and the relative induction effect reached 56.56% ; rice blast resistance was the highest at 48 -96 h post spraying, and duration of induced rice blast resistance exceeded 144 h. The study will provide useful experimental data for further development of Ag-antibiotic 702 and application of pre- vention and control methods against rice blast.

Study on Exogenous Ethylene Induced Rice Resistance to Rhizoctonia solani

Rice sheath blight is one of the main diseases in rice production in China,which can make rice unable to absorb and utilize nutrients,and has a serious impact on rice yield and quality.In this study,exogenous ethylene was used to induce rice resistance against rice sheath blight,aiming at exploring a new environment-friendly control method of rice sheath blight.The results showed that within a range of certain concentrations,ethylene had no significant effects on mycelium growth,but it could induce resistance to sheath blight in rice.The optimum concentration was 0.2 mmol•L^(-1) and the relative control was 86.17%.It was found that ethylene could effectively increase the activities of peroxidase(POD),phenylalanine ammonia-lyase(PAL),β-1,3-glucanase and reduce the contents of malondialdehyde(MDA),which could enhance the resistance of rice against Rhizoctonia solani.In addition,qRT-PCR detected the expressions of rice defense genes,which indicated that the expressions of the POX,PAL and OsPR1b genes were up-regulated.

Evaluation of Selected Chemical,Biological Fungicides,and Induced Resistance to Control White Rot(Sclerotium rolfsii Sacc.)on Tomato

Tomato(Solanum lycopersicum)is one of the most widely grown and consumed as fresh vegetable in the world.Sclerotium rolfsii Sacc.is one of the most destructive diseases and affects more than 500 plant species.This study was conducted for“Evaluation of Selected Chemical,Biological Fungicides,and Induced Resistant to Control White Rot(Sclerotium rolfsii Sacc.)on Tomato”.The experiment was conducted at the Royal University of Agriculture and divided into two sections.The first section conducted under in vitro condition consists of four treatments T1 control treatment,T2 copper hydroxide,T3 azoxystrobin+difenoconazole,T4 metalaxyl+mancozeb in Nagoya Laboratory,and had been starting from 11st May to 15th May 2020.Section two was conducted in a pot in net-house which started from 1st January 2019 to 19th February 2019 and 1st January to 19th February 2020 and arranged in RCBD(Randomized Completely Block Design)with six replications and nine treatments.T0 negative control,T1 inoculate but not treatment,T2 metalaxyl+mancozeb,T3 azoxystrobin+difenoconazole,T4 copper hydroxide,T5 acibenzolar-S-methyl,T6 chicken dung+Trichoderma harzianum,T7 acibenzolar-S-methyl+chicken dung+Trichoderma harzianum,T8 acibenzolar-S-methyl+metalaxyl+mancozeb.Data were collected on colonizing diameter in vitro.For pot experiment collected on disease incidence,incubation period Based on the result under in vitro condition metalaxyl+mancozeb highly inhibited germination of Sclerotium rolfsii when compared with another treatment.However,the application of copper hydroxide seems less effective compared with control.For in pot experiment,when treated after symptom of southern blight appeared to seem less effective on the severity of southern blight.In contrast,when applied as a protectant and curative when symptoms appeared only systemic fungicide azoxystrobin+difenoconazole significantly reduced the severity of Sclerotium rolfsii and delayed incubation period while compared with other treatments(p<0.05)and was followed by metalaxyl+mancozeb,whereas,copper hydroxide,acibenzolar-S-methyl,chicken dung+Trichoderma harzianum,acibenzolar-S-methyl+chicken dung+Trichoderma harzianum,acibenzolar-S-methyl+metalaxyl+mancozeb were less effective(p>0.05).Based on the three experiments we can assume that fungicide is more effective in reducing the growth of the pathogen and delaying the incubation period of fungal colonization when compared with biological control and induced resistance.

Resistance and Reactance of Monopole Fields Induced by a Test Charge Drifting Off-Axis in a Cold and Collisional Cylindrical Plasma

We study the interaction of a uniform, cold and collisional plasma with a test charged particle moving off-axis at a constant speed down a cylindrical tube with a resistive thick metallic wall. Upon matching the electromagnetic field components at all interfaces, the induced monopole electromagnetic fields in the plasma are obtained in the frequency domain. An expression for the plasma electric resistance and reactance is derived and analyzed numerically for some representative parameters. Near the plasma resonant frequency, the plasma resistance evolves with frequency like a parallel RLC resonator with peak resistance at the plasma frequency pe, while the plasma reactance can be capacitive or inductive in nature depending on the frequency under consideration.

Preliminary Studies on Induced Resistance of Cucumber to Downy Mildew

1 mL of sporangial suspensions (5 x 10 5spporangia per milliliter) of Pseudoperonospora cubensis was droplet-inoculated on the surface of the second leaf of the plant grown in greenhouse ( inducing inoculatoin), then the lower surfaces of the third, the forth and the fifth leaves were uniformly sprayed with inoculum of the same fungi (5 x 10 4sporangia per milliliter, about 5 mL per plant) every 3 days interval (challenge inoculation). Plants were moistened at 18- 22 C for 18 h, then kept at room temperature (24 - 28 C) and supplemented with cool-white fluorescent lights. All three challenge leaves were collected after 7 days of challenge to measure the amount of sporulation and area of necrosis. Plants prior inoculated with P. cubensis were protected 38% (based on the area of necrosis) against disaesc caused by subsequent foliar challenge with the pathogen. Protective action was about 12% after 3 days, and maintained this level until 9 days, suddenly reached 34% after 12 days, and came to a maximum after 15 days, then dropped down slowly.

A change of phenolic acids content in poplar leaves induced by methyl sali-cylate and methyl jasmonate

The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramibalis c.v and Populus deltoids） suffocated by Methyl jasmonate （MeJA） and Methyl salicylate （MeSA） were monitored for analyzing their functions in interplant communications by using high-pressure liquid chromatography （HPLC）.The results showed that the contents of phenolic acids had obviously difference in leaves exposed to either MeSA or MeJA.When P.deltoides leaves exposed to MeJA or MeSA, the level of gallic acid, coumaric acid, caffeic acid, ferulic acid and benzoic acid was increased, gallic acid in leaves treated with MeJA comes to a peak at 24 h while to a peak at 12-d having leaves treated with MeSA.When P.Simonii ×P.Pyramibalis c.v leaves were exposed to MeJA or MeSA, the level of gallic acid, pyrocatechol and ferulic acid was increased; The catechinic acid and benzoic acid had a little drop; The caffeic acid and coumaric acid were undetected in both suffocated and control leaves.This changed pattern indicated that MeJA and MeSA can act as airborne signals to induce defense response of plants.