Comparison of hydroxyl radical-scavenging abilities between white rot fungus Lentinula edodes and five mildews on lignocellulose substance

The hydroxyl radical（-OH）-scavenging ability of culture filtrates from submerged culture of Lentinula edodes AX3 and five mildews on lignocellulose substance was analysed. Only L. edodes AX3 showed significant -OH-scavenging ability which reached 52.2% at about the 48th hour. All mildews could hardly scavenge -OH under the experimental conditions. -OH-scavenging ability is considered related to the mode and ability of lignocellulose degradation of a strain. The degradation or bioconversion products might be the substance base for.this effect.

Biological and molecular interplay between two viruses and powdery and downy mildews in two grapevine cultivars

Grapevine may be affected simultaneously by several pathogens whose complex interplay is largely unknown.We studied the effects of infection by two grapevine viruses on powdery mildew and downy mildew development and the molecular modifications induced in grapevines by their multiple interactions.Grapevine fanleaf virus(GFLV)and grapevine rupestris stem pitting-associated virus(GRSPaV)were transmitted by in vitro-grafting to Vitis vinifera cv Nebbiolo and Chardonnay virus-free plantlets regenerated by somatic embryogenesis.Grapevines were then artificially inoculated in the greenhouse with either Plasmopara viticola or Erysiphe necator spores.GFLV-infected plants showed a reduction in severity of the diseases caused by powdery and downy mildews in comparison to virus-free plants.GFLV induced the overexpression of stilbene synthase genes,pathogenesis-related proteins,and influenced the genes involved in carbohydrate metabolism in grapevine.These transcriptional changes suggest improved innate plant immunity,which makes the GFLV-infected grapevines less susceptible to other biotic attacks.This,however,cannot be extrapolated to GRSPaV as it was unable to promote protection against the fungal/oomycete pathogens.In these multiple interactions,the grapevine genotype seemed to have a crucial role:in‘Nebbiolo’,the virus-induced molecular changes were different from those observed in‘Chardonnay’,suggesting that different metabolic pathways may be involved in protection against fungal/oomycete pathogens.These results indicate that complex interactions do exist between grapevine and its different pathogens and represent the first study on a topic that still is largely unexplored.

Identif ication of a hypersensitive response core peptide of HrpZ and its role in increasing grape downy mildew resistance

Harpins play a key role in inducing disease resistance in crops,and identifying their core functional regions and establishing a system for their efficient expression would be very valuable.In this study,large amounts of soluble fusion proteins of harpin HrpZ and its subpeptides were obtained via the optimized induction conditions(28C with 0.5 mmol$L1 IPTG for 6 h)in Escherichia coli BL21(DE3).Hypersensitive response(HR)assays demonstrated that the C-terminal 66 aa of HrpZ(HrpZ_C_2_2)elicited a strong HR in tobacco(Nicotiana benthamiana)and grape(Flame Seedless)leaves.Additionally,treatment with HrpZ,and particularly HrpZ_C_2_2,significantly reduced the disease incidence and severity index of field vine leaves and those inoculated with downy mildew.The determination of the physiological parameters indicated that HrpZ,and especially HrpZ_C_2_2,improved the photosynthesis-and chlorophyll fluorescence-related parameters,enhanced the activity of defense-related enzymes,including SOD,POD,CAT and PAL,and increased the H_(2)O_(2)level.Collectively,we efficiently expressed a core peptide of HrpZ and elucidated its strong ability to elicit a HR and resistance to downy mildew.This research provides insight into understanding the structure and function of HrpZ and will advance the application of HrpZ_C_2_2 to increase the resistance of grapevine to downy mildew.

Development and identification of two novel wheat-rye 6R derivative lines with adult-plant resistance to powdery mildew and high-yielding potential

Powdery mildew,caused by Blumeria graminis f.sp.tritici(Bgt),is a devastating disease that seriously threatens wheat yield and quality.To control this disease,host resistance is the most effective measure.Compared with the resistance genes from common wheat,alien resistance genes can better withstand infection of this highly variable pathogen.Development of elite alien germplasm resources with powdery mildew resistance and other key breeding traits is an attractive strategy in wheat breeding.In this study,three wheat-rye germplasm lines YT4-1,YT4-2,and YT4-3 were developed through hybridization between octoploid triticale and common wheat,out of which the lines YT4-1 and YT4-2 conferred adult-plant resistance(APR)to powdery mildew while the line YT4-3 was susceptible to powdery mildew during all of its growth stages.Using genomic in situ hybridization,multi-color fluorescence in situ hybridization,multi-color GISH,and molecular marker analysis,YT4-1,YT4-2,and YT4-3 were shown to be cytogenetically stable wheat-rye 6R addition and T1RS.1BL translocation line,6RL ditelosomic addition and T1RS.1BL translocation line,and T1RS.1BL translocation line,respectively.Compared with previously reported wheat-rye derivative lines carrying chromosome 6R,YT4-1 and YT4-2 showed stable APR without undesirable pleiotropic effects on agronomic traits.Therefore,these novel wheat-rye 6R derivative lines are expected to be promising bridge resources in wheat disease breeding.

Fine mapping of the powdery mildew resistance gene PmXQ-0508 in bread wheat

In a wheat breeding line XQ-0508 showing consistent resistance to powdery mildew disease,a recessive gene,designated PmXQ-0508,was identified and mapped to a distal region on chromosome arm 2BS.Of three resistance-associated genes in this region,one encoding a protein kinase was selected as the primary candidate for PmXQ-0508.Ten closely linked DNA markers developed in the study could be used for marker-assisted selection for powdery-mildew resistance in breeding programs.

Molecular cytogenetic analyses of two new wheat-rye 6RL translocation lines with resistance to wheat powdery mildew

Rye(Secale cereale)is a valuable gene donor for wheat improvement,especially for its resistance to diseases.Developing rye-derived resistance sources is important for wheat breeding.In the present study,two wheat-rye derivatives,designated JS016 and JS110,were produced by crossing common wheat cultivar Yangmai 23 with Pakistani rye accession W2A.Using sequential genomic in situ hybridization(GISH)and multicolor fluorescence in situ hybridization(mc-FISH),JS016 and JS110 were identified as a T6BS.6RL translocation line and a T6BS.6BL6RL translocation line,respectively.Ten newly 6RL chromosome arm-specific markers were developed and used to confirm the 6RL translocation.The wheat 55K single-nucleotide polymorphism(SNP)array further verified the molecular cytogenetic identification results above and clarified their breakpoints at 430.9 and 523.0 Mb of chromosome 6B in JS016 and JS110,respectively.Resistance spectrum and allelism test demonstrated that JS016 and JS110 possessed novel powdery mildew resistance gene(s)that was derived from the 6RL translocation but differed from Pm20.Moreover,JS016 and JS110 had better agronomic traits than the previously reported 6RL translocation line carrying Pm20.To efficiently transfer and detect the 6RL translocation from JS016 and JS110,one 6RL-specific Kompetitive allele specific PCR(KASP)marker was developed and validated in high throughput marker-assisted selection(MAS).

Genetics,resistance mechanism,and breeding of powdery mildew resistance in cucumbers(Cucumis sativus L.)

Cucumber is an important vegetable worldwide,and powdery mildew(PM)is a common and serious disease of cucumbers.Breeding disease-resistant cucumber varieties is the most advantageous strategy to control this disease.In recent years,exploration and identification of cucumber PM resistance genes have achieved great advancement,and many genes have been cloned and verified using different methods.However,the resistance mechanism of cucumber PM is still unclear,and many ambiguities need to be elucidated urgently.In this review,we summarized the research advances in PM resistance in cucumbers,including genetic analysis,quantitative trait locus mapping,map-based cloning,transcriptomics,mlo-mediated PM resistance,and mining of noncoding RNAs involved in resistance.Finally,the research directions and the problems that need to be solved in the future were discussed.

Identification and fine mapping of PmNJ3946 for powdery mildew resistance in einkorn wheat

Powdery mildew caused by Blumeria graminis f.sp.tritici(Bgt)is a destructive wheat disease.Although it can be easily overcome by deployment of resistance genes,the resistance is often quickly compromised by pathogen virulence.Thus,exploration and characterization of new resistance genes is always ongoing.Line NJ3946 derived from a cross of einkorn wheat accessions TA2032 and M389 showed resistance to powdery mildew.Inheritance analysis of an F2 population derived from a cross of NJ3946 and M389 suggested that the resistance was conferred by a dominant allele.With polymorphic markers identified through bulked segregant analysis(BSA),this gene was mapped to a novel locus on chromosome 3A,and was designated as PmNJ3946.Bulked segregant RNA-seq analysis(BSR-seq)was conducted to obtain more closely linked markers,which allowed delimitation of the PMNJ3946 locus to a 0.9 cM interval covering a physical distance of less than 1 Mb.PMNJ3946 was flanked by Xwgrc5153 and SNP-derived marker CHS21_3A008915069,and co-segregated with SNP-derived markers CHS21_3A008939814 and CHS21_3A008943175.The PmNJ3946 discovery expands the diversity of powdery mildew resistance genes and is useful for wheat breeding.

Effect of powdery mildew on interleaf microbial communities and leaf antioxidant enzyme systems

Chinese peony(Paeonia lactiflora Pall.)is both medicinally and aesthetically beneficial.Powdery mildew is a common fungal disease that seriously jeopardizes the value of numerous species,including peonies as a crop.In order to provide a basis for the prevention and treatment of peony powdery mildew,we examined the microbial diversity,the malondialdehyde(MDA)concentrations and antioxidant enzyme activities of peony leaves infected with three levels of powdery mildew to determine any modifications to the leaf's antioxidant enzyme systems and microbial community structure following the onset of disease.The results show that the MDA content rose as the degree of infection became worse.Antioxidant enzyme activity rose and then declined.Following the initiation of powdery mildew,fungal community diversity decreased,whereas there was not any appreciable change in bacterial communities according to microbial diversity sequencing.The relative abundance of more than half of fungal species decreased,with the bacterial genera displaying both abundant and diminished communities with less pronounced alterations in their community structure after the disease spread.Significant different taxa that were critical to the organization of each microbiome were found.Correlation analysis showed that the relative abundance of powdery mildew pathogenic fungal genus Erysiphe was correlated with those of 11 fungal genera and one bacterial genus.Among them,Aureobasidium,Neosetophoma and Sclerostagonospora showed significant positive correlations with Erysiphe and MDA.

Ectopic Overexpression of EuCHIT30.7 Improves Nicotiana tabacum Resistance to Powdery Mildew

Various strains of powdery mildew(PM),a notorious plant fungal disease,are prevalent and pose a significant threat to plant health.To control PM,transgenic technology can be used to cultivate more resistant plant varieties.In the present study,we utilized the rapid amplification of cDNA ends(RACE)technique to clone the full-length cDNA sequence of the EuCHIT30.7 gene to explore plant genes with disease resistance functions.Bioinformatics analysis revealed that this gene belongs to the GH18 family and is classified as a class III chitinase.The EuCHIT30.7 gene is expressed throughout the Eucommia ulmoides plant,with the most abundant expression in male flowers.Subcellular localization analysis indicated that the protein encoded by this gene was detected within both the cell membrane and cytoplasm.Upon PM inoculation,overexpression of EuCHIT30.7 in tobacco plants led to a significantly reduced relative lesion area and a decreased spore count compared to both wild-type and empty vector control plants.Activities of the protective enzymes,namely,peroxidase(POD),superoxide dismutase(SOD),catalase(CAT),and phenylalaninammo-nialyase(PAL),in tobacco plants overexpressing EuCHIT30.7 were significantly greater than those in wild-type and empty vector tobacco plants.Furthermore,the rate of increase in malondialdehyde(MDA)content was significantly lower in tobacco plants expressing EuCHIT30.7 compared to control tobacco plants.In EuCHIT30.7 transgenic tobacco,the expression of pathogen-related protein genes,namely,PR2,PR5,PR1a,PDF1.2,and MLP423,along with the tobacco PM negative regulatory gene,MLO2,were significantly higher compared to control tobacco plants.These findings suggested that EuCHIT30.7 significantly enhances the resistance of tobacco to PM.

Diversity Analysis of Endophytes in Wheat Infected by Powdery Mildew

Common wheat (Triticum aestivum L.) is one of the most important food crops. Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most serious diseases on wheat. In this study, the changes of endogenous bacteria in root, stem and leaf tissues of wheat infected and uninfected with powdery mildew were measured based on 16S rDNA. Integration, OTU cluster analysis, taxonomic analysis, diversity index, Shannon-Index curve, Rank-Abundance curve and PCoA analysis were carried out for each sample, and the roots, stems and leaves of different tissue parts were classified and summarized. The results showed that the infection of wheat powdery mildew had a certain effect on endophytic bacteria in stem tissue. There are also differences in the control and treatment of leaf tissue and root tissue. This indicated that endophytic bacteria were distributed differently in different parts of wheat.

In-Silico Identification and Differential Analysis of Mitochondrial RNA Editing Events in Helianthus Genotypes/Species and Powdery Mildew Infected Variants

Sunflower is one of the most used commercial oilseed crops and suffers due to Powdery mildew. RNA sequence alteration occurs due to RNA editing which is a post transcriptional modification. It causes a deviation from the genomic DNA sequence resulting in RNA-DNA differences. Accurate study of RNA editing events in diverse species is possible by NGS based methods. Here, we performed RNA sequencing of 12 leaf transcriptomes, which include three genotypes of Helianthus annuus (2023B, TX16R and ID25), H. debilis, H. niveus, and H. praecox along with their respective powdery mildew pathogen infected variants and systematically analysed the mitochondrial RNA editing events using computational reference-based mapping approach. We discovered 687 editing sites, 220 editing events in the protein-coding regions, among all species and genotypes considered in this study. These included “C to U” and “U to C” RNA editing events. On further analysis, we observed that these editing events include 14 different types of amino acid changes that involve the creation of two stop codon events. The conserved editing sites identified were 247 accounting for ~36% of all the editing sites identified. This study provides a detailed picture of the Helianthus species’ mitochondrial RNA editing status. We have identified and characterized for the first time, genotype-specific, species-specific, and stress-specific RNA editing events which may be useful as a potential source for stress-responsive studies in the future.

The Relationship of Methyl Jasmonate Enhanced Powdery Mildew Resistance in Wheat and the Expressions of 9 Disease Resistance Related Genes

[Objective] This study was carried out to determine the induction effect of jasmonic acid（JA）on powdery mildew resistance in wheat,the activation effect on the expressions of plant disease resistance related genes,and to investigate the relationship between the induced resistance and the gene expression patterns.[Method] Three powdery mildew susceptible cultivars of ＂Chinese Spring＂,＂Pumai 9＂ and ＂Zhoumai 18＂ typically representing different phenotypes in the field were employed.The powdery mildew was assessed by detached leaf assay,and real time quantitative RT-PCR was used to determine the expression patterns of 9 disease resistance related genes of PR1（PR1.1）,PR2（β,1-3 glucanase）,PR3（chitinase）,PR4（wheatwin1）,PR5（thaumatin-like protein）,PR9（TaPERO,peroxidase）,PR10,TaGLP2a（germin-like）and Ta-JA2（jasmonate-induced protein）in leaf of the three cultivars.[Result] MeJA application enhanced the powdery mildew resistances of ＂Chinese Spring＂,＂Pumai 9＂ and ＂Zhoumai 18＂.The induced powdery mildew resistance could be detected from 12 h to 96 h after MeJA treatment,and the peak value was at 24 h.Though there were differences between the three cultivars,MeJA significantly effect on the expressions of the 8 disease resistance related genes except TaGLP2a,and the peak values were at 12 h,24 h or 48 h after treatments.The strongest activation of MeJA was on PR9 and PR1 that their expressions could reach more than 100 times of the untreated samples.MeJA strongly activated PR2、PR4、PR5、PR3、PR10 and Ta-JA2,their expression could reach 10 to 70 times,and there was almost no activation effect on TaGLP2a.The induced powdery mildew resistance positively correlated with the induced expressions of the 8 disease related genes.[Conclusion] The induced powdery mildew resistance positively correlated with the induced expressions of the disease related genes.Jasmonate signalling plays a role in defence against Blumeria graminis f.sp.tritici.and future manipulation of this pathway may improve powdery mildew resistance in wheat.

Molecular Cloning and Characterization of a Serine/Threonine Protein Kinase Gene from Triticum aestivum

To isolate genes related to resistance to Erysiphe graminis DC. ex Merat f. sp. tritici Em. Marchal in wheat (Triticum aestivum L.), differential display analysis was conducted for mRNA extracted from the seedlings of the wheat-Haynaldia villosa 6VS/6AL translocation line 92RI37 that contains the powdery mildew resistance gene Pm21. A full-length cDNA named TaPK1 was isolated. BLAST analysis revealed that it was significantly homologous to Glycine max (L.) Merr. protein kinase (GmPK6) cDNA. TaPK1 encodes a 416 amino acid long polypeptide, which belongs to serine/threonine protein kinase family, also has tyrosine kinase specificity. TaPK1 is a novel protein kinase from wheat.

Field Efficacy of Six Kinds of Fungicides for Control and Prevention of Apple Powdery Mildew(Podosphaera leucotricha)

[Objective] This study aimed to screen effective fungicide for prevention and control of apple powdery mildew. [Method] Field efficacy of six kinds of fungi- cides with 18 concentrations against apple powdery mildew was investigated. [Re- sult] 4 000-fold triflumizole WP exhibited the highest control efficacy of 82.96%, fol- lowed by 3 000-fold triflumizole WP with control efficacy of 77.75%, while 800-fold and 1 000-fold 70% thiophanate methyl WP exhibited relatively low control efficacy, which was both lower than 60%. [Conclusion] In actual production, 4 000-fold triflu- mizole WP and 3 000-fold triflumizole WP should be used alternately to control and prevent apple powdery mildew.

Toxicity Test and Field Control Effects of 4 Different Fungicides on Grape Downy Mildew

[Objective] This study was conducted to investigate the biocontrol activity of Streptomyces corchorusii strain NF0919 and Bacillus subtilis D J-6 WP to grape downy mildew. [Methed] We determined the indoor toxicity of the supernatant of S. corchorusii strain NF0919, 1.0×1011 cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph on Plasmopara viticola by the leaf disc method, respectively, and a field efficacy trial was conducted. [Result] The results showed that the ECso values of the supernatant of strain NF0919, 1.0×1011cfu/g B. subtilis D J-6 WP, mancozeb and dimethomorph were 96.285 9, 86.603 8, 69.947 2 and 7.263 6 μg/ml, respec- tively. The values of field efficacy in preventive experiments for grape downy mildew on the 7th day after 2 times of spraying 20 times diluent of the supernatant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 71.55% and 70.71%, respectively, and the values of field efficacy on the 14th day after the 2 times of fungicide application were 67.54% and 68.19%, respectively. The values of field efficacy in curative experiments on the 7th day after 2 times of spraying 20 times diluent of the supematant of strain NF0919 and 1 000 times diluent of 1.0×1011 cfu/g B. subtilis D J-6 WP were 59.72% and 56.07%, respectively, and the val- ues of field efficacy on the 14th day after the 2 times of fungicide application were 56.88% and 57.46%, respectively. The field efficacy values of the 2 tested biocon- trol agents were equivalent. The protective effect showed no significant difference between each of tested biocontrol agents and 300 times diluent of 50% mancozeb WP, but there was a significant difference in the efficacy between each of tested biocontrol agents and 200 times diluent of 40% dimethomorph SC. [Conclusion] The S. corchorusii strain NF0919 and B. subtilis D J-6 WP had certain biocontrol poten- tial to grape downy mildew and development value.

Molecular Detection of Resistance Genes to Stripe Rust and Powdery Mildew in Common Wheat Cultivar Yunmai52

Yunmai52, developed by crossing with common wheat-Haynaldia villosa6AL/6VS translocation line 92R149 as a resistant parent in 1992, was a common wheat cultivar approved and released in 2007 in Yunnan Province, China, which is characterized by high resistance to powdery mildew and stripe rust. In this study,an F_2 population derived from a cross K78S/Yunmai52 was constructed to investigate the resistance genes, where K78 S is a wheat male sterile line susceptible to powdery mildew and stripe rust. Phenotypic identification of the parents, F_1 and F_2 populations and chi-square analyses showed that F_1 population was immune to stripe rust and powdery mildew; the segregation ratio of resistance and susceptibility to powdery mildew（χ~2=1.10χ~2_（1,0.05）=3.84） and stripe rust（χ~2=0.15χ~2_（1,0.05）=3.84） fit to a 3：1 ratio in F_2 population, indicating that Yunmai52 harbors a dominant stripe rust resistance gene and a dominant powdery mildew resistance gene. The individuals were further detected with a marker co-segregated with Pm21（SCAR_（1400）） and two markers closely linked with Yr26（XWe173 and Xbarc181）. The results showed that polymorphic bands could be amplified between the parents and between resistance and susceptibility gene pools at the same locus. Randomly 96 individuals of F_2 population were selected for verification. The results showed that the phenotype was significantly correlated with the genotype. The detection accuracy of markers SCAR_（1400）, XWe173 and Xbarc181 was 100%, 97.91% and 92.70%, respectively.Yunmai52 harbored powdery mildew resistance gene Pm21 and stripe rust resistance gene Yr26, which were both derived from 6AL/6VS translocation line 92R149.In addition, the results also demonstrate that Pm21 and Yr26 are two genes conferring durable resistance to powdery mildew and stripe rust in wheat.

Irradiation Dose for the Insect Disinfestation and Mildew Control of Peanut

The bulk peanuts were used as the materials. After ）,-ray irradiation of different doses, the peanuts were stored up at room temperature, and the degree of pest infection and gradient of mould infection were observed regularly. The results showed that insects began to appear in the unirradiated peanuts in 2 months, while after 4 months, the pest infection rate increased with the prolonged storage time, and the pest infection rate reached up to 58%-100% after 6 months of storage. However, the irradiated peanuts did not suffer from the pest infection throughout the storage. The unirradiated peanuts were contaminated by moulds after three months of storage, while the peanuts with an irradiation dose of 0.3-0.5 kGy were mildewed after 6 months of storage, while those with an irradiation dose of 1.0, 4.0 kGy had no mould after 12 months of storage. Combined with relevant international and national standards as well as the findings of scholars at home and abroad, the minimum effective irradiation dose for insect disinfestations of peanuts was 0,3 kGy, and the minimum effective irradiation dose for mildew control was 1.0 kGy, while the maximum tolerance dose was 4.0 kGy.

Toxicity of 26 Fungicides against and Synergistic Effects of Binary Mixtures on Oidium heveae

[Objective] This study was conducted to determine the toxicity of 26 fungicides against Oidium heveae and the synergistic effects of their binary mixtures.[Method] The sensitivity of O.heveae to 26 fungicides was determined in vitro and in vivo by calculating EC50 values.Horsfall＇s toxicity rate was preliminarily employed to predict the type of joint action of 180 two-way mixtures,based on which the interaction level of the potentially synergistic mixtures was validated by Sun and Johnson＇s co-toxicity coefficient.[Result] Triflumizole,pyraoxystrobin,flufenoxystrobin,epoxiconazole,pyrametostrobin,flusilazole,pyraclostrobin and tetraconazole were the most potent inhibitors of both spore germination and mycelial growth.An ‘in vitro-in vivo＇ integrated strategy is proposed for screening the inhibitors of O.heveae,according to the fact that data obtained in germination experiment are able to reflect to some extent the effectiveness of fungicide confirmed by pot experiment.Results achieved by Horsfall＇s were in line with that validated by Sun and Johnson＇s,the Horsfall＇s seems to be a convenient means to assess rapidly the potential interaction type and level of fungicides in a binary mixture.Nineteen mixtures interact synergistically：epoxiconazole ＋ pyraclostrobin at the mixing ratio of 6：4,8：2;tetraconazole ＋ flufenoxystrobin at 1：9,2：8,3：7 and 4：6;triadimefon ＋ flufenoxystrobin at 9：1;triflumizole ＋ flufenoxystrobin at 8：2;flusilazole ＋pyrametostrobin at 7：3,8：2 and 9：1;tetraconazole ＋ pyrametostrobin at 6：4;triadimefon ＋ pyrametostrobin at 5：5,8：2;triflumizole ＋ pyrametostrobin at 7：3,8：2;tetraconazole ＋ pyraoxystrobin at 9：1;triflumizole ＋ pyraoxystrobin at 8：2,9：1.[Conclusion] The single fungicides and their binary mixtures are expected to serve as the alternatives to triadimefon and the alternate use of them could delay the buildup of resistant O.heveae isolate.

Construction of Cucumber Powdery Mildew Early Warning System in Solar Greenhouse Based on Internet of Things

ln order to explore the design and construction of cucumber powdery mildew warning system in solar greenhouse, internet of things technology was used to conduct the real-time dynamic monitoring of the incidence of cucumber powdery mildew and cucumber growth environment in solar greenhouse. The growth environ-ment included temperature and humidity of air and soil. Logistic regression model was used to construct cucumber powdery mildew warning model. The results showed that humidity characteristic variable （maximum air humidity） and temperature characteristic variable （maximum air temperature） had significant effects on the inci-dence probability of cucumber powdery mildew in solar greenhouse. And it was fea-sible to construct cucumber powdery mildew warning system in solar greenhouse with internet of things.