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Thaumatin-like protein (TLP) plays an important role in combating plant pathogen infection. Common root rot caused by Bipolaris sorokiniana and leaf rust caused by Puccinia triticina (Pt) are major fungal diseases in wheat. The disease responses of TaTLP1-overexpressing transgenic lines (TaTLP1-OE) were evaluated after inoculation with each pathogen. The TaTLP1-OE lines had no apparent differences in tiller number and 1000-kernel weight from the wild type Jinan Wheat No. 1 (JW1), whereas resistance to leaf rust and common root rot was improved, resulting from activated peroxidase and β-1,3-glucanase after B. sorokiniana infection, and reactive oxygen species-related genes were upregulated in TaTLP1-OE lines after Pt infection. These results indicated that stable expression of TaTLP1 increased resistance against both diseases.

Cyst nematodes are one of the most important pathogens worldwide. Most cyst nematode species have been reported recently in China. From 2016 to 2020, an extensive survey of cyst nematodes was conducted in the Bashang region of Hebei Province. A total of 158 soil samples were collected, and cyst-forming nematodes were isolated from five soil samples. Morphological and molecular characterization showed that four of the cyst-forming nematode populations were Heterodera glycines (SCN), named populations of ZM, KM, CB and FN, respectively. These SCN populations were collected from Zhangbei County, Kangbao County, Chabei Management Area of Zhangjiakou and Fengning Manchu Autonomous County of Chengde, respectively, where the corresponding cyst densities were 57, 41, 103 and 31 cysts/200 cc soil. Furthermore, the populations of ZM, KM and CB were identified as race 4, whereas the FN population was identified as race 3. The cyst-forming nematode population was collected from Zhangbei County of Zhangjiakou, which was confirmed to be Heterodera schachtii (SBCN), named population ZZ, and the cyst density was 94 cysts/200 cc soil. It is a new disease of Chinese cabbage caused by SBCN based on Koch’s postulates. Fourteen cultivars from five plant families were evaluated as hosts for SBCN. Chinese cabbage (cv. Linglonghuang012) and cabbage (cv. Chunwang) were suitable hosts, while celery (cv. Yuhuang), potato (cv. Helan 15) and eggplant (cv. Junlang) were nonhosts. The obtained results regarding the occurrence, distribution, races of SCN and hosts of SBCN in the Bashang region in this study provide a reference for SCN and SBCN management.

Wheat leaf rust, triggered by Puccinia triticina Eriks (Pt), is among the most important diseases of wheat worldwide. Deploying resistant varieties against leaf rust is the most effective, environmentally-friendly and economic way to control the disease. In the present study, 66 wheat varieties form China and foreign countries were tested with 17 Pt races for gene postulation during the seedling stage in the greenhouse. All the varieties were also planted to identify slow rusting responses to leaf rust at the adult plant stage in Baoding and Zhoukou field trials during the 2016/2017 to 2017/2018 cropping seasons. Moreover, 12 closely linked molecular markers to known leaf rust resistance (Lr) genes were used for assessing all the varieties. The results of both gene postulation and molecular marker identification showed that a total of eight Lr genes, Lr1, Lr10, Lr17, Lr20, Lr26, Lr34, Lr37 and Lr46, either singly or in combination were detected in 32 varieties. Known Lr genes were not identified in the remaining 34 varieties. Seventeen varieties were found to have slow rusting resistance. The resistance sources identified in this study can be used as resources for resistance against leaf rust in wheat breeding programs in China and the respective foreign countries.

Wheat (Triticum aestivum) common root rot (CRR) caused by predominant fungal pathogen Bipolaris sorokiniana occurs in all wheat-growing regions worldwide and is difficult to control. In this study, the efficacy of eight fungicides against Bipolaris sorokiniana was examined in in vitro assays, and we determined that the combined application of two fungicides significantly inhibits the growth of fungal mycelium. Half of the maximal effective concentration of a mixture containing fludioxonil and difenoconazole in the ratio 1:4 was 0.0372 mg/liter, and the cotoxicity coefficient was 160.14. Under an environmentally controlled pot assay, seed treatment with the mixture of fludioxonil and difenoconazole in the 1:4 ratio demonstrated the best control efficiency at seedling and adult stages, respectively. The best synergistic mixture on seed treatment was assessed in a 2-year field experiment at Hebei, China. The best control efficacy achieved at the seedling and adult stages was 82.65% and 68.48%, respectively. Overall, the in vitro mycelial growth inhibition assay and controlled-environment and field studies indicated that the synergistic action of a mixture of fludioxonil and difenoconazole provides effective control against wheat CRR. These findings highlight the potential application of the fungicide combination for controlling CRR and reducing the selection pressure on fungal pathogens by lessening the use of various fungicides in the field.

A genome-wide association analysis identified diverse loci for seedling and adult plant resistance to leaf rust and stripe rust. KASP markers were developed and validated for marker-assisted selection. Wheat leaf rust and stripe rust cause significant losses in many wheat producing regions worldwide. The objective of this study was to identify chromosome regions conferring resistance to both leaf rust and stripe rust at the seedling and adult plant stages. A diversity panel of 268 wheat lines, including 207 accessions from different wheat growing regions in China, and 61 accessions from foreign countries, were evaluated for leaf rust response at seedling stage using eight Chinese Puccinia triticina pathotypes, and also tested for leaf rust and stripe rust at adult plant stage in multiple field environments. The panel was genotyped with the Wheat 90 K Illumina iSelect SNP array. Genome-wide association mapping (GWAS) was performed using the mixed linear model (MLM). Twenty-two resistance loci including the known Lr genes, Lr1, Lr26, Lr3ka, LrZH22, and 18 potentially new loci were identified associated with seedling resistance, explaining 4.6 to 25.2% of the phenotypic variance. Twenty-two and 23 adult plant resistance (APR) QTL associated with leaf and stripe rust, respectively, were identified at adult stage, explaining 4.2–11.5% and 4.4–9.7% of the phenotypic variance. Among them, QLr-2BS was the potentially most valuable all-stage resistance gene. Seven and six consistent APR QTL were identified in multiple environments including best linear unbiased prediction (BLUP) data, respectively. Comparison with previously mapped resistance loci indicated that three of the seven leaf rust resistance APR QTL, and two of the six stripe rust resistance APR QTL were new. Four potentially pleiotropic APR QTL, including Lr46/Yr29, QLr-2AL.1/QYr-2AL.1, QLr-2AL.2/QYr-2AL.2, and QLr-5BL/QYr-5BL.1, were identified. Twelve associated SNPs were converted into kompetitive allele-specific PCR (KASP) markers and verified in bi-parental populations. The study reports genetic loci conferring resistance to both diseases, and the closely linked markers should be applicable for marker-assisted wheat breeding.

Leaf rust is an important wheat disease that is a significant hindrance for wheat production in most areas of the world. Breeding resistant cultivars can effectively and economically control the disease. In the present study, a wheat collection consisting of 100 cultivars from China and 18 improved germplasms from global landrace donors together with 36 known single Lr gene lines were tested with 20 strains of Puccinia triticina Eriks. in the seedling stage to postulate the Lr gene in the cultivars and germplasms. In addition, 12 diagnostic molecular markers specific to 10 Lr genes were used to detect the presence of the Lr genes in the wheat collection. Resistance to leaf rust of these cultivars at the adult plant stage was tested in fields under natural infection during the 2016 to 2018 cropping seasons in Baoding, Hebei Province. The gene postulation combined with molecular marker detection showed that six Lr genes (Lr1, Lr26, Lr33, Lr34, Lr45, and Lr46) were identified in 44 wheat accessions, including 37 cultivars and seven improved germplasms. Among the 44 wheat accessions postulated with Lr genes, Lr1 was present in four accessions, Lr26 in 12 accessions, Lr33 in two accessions, Lr34 in 14 accessions, Lr45 in three accessions, and Lr46 in 16 accessions. In the collection of 118 cultivars/germplasms, 34 wheat lines displayed adult-plant resistance carrying Lr34, Lr46, and/or underdetermined genes. Therefore, a high level of leaf rust resistance can be achieved through the combination of all-stage resistance and adult-plant resistance genes together in wheat cultivars.

Wheat leaf rust, caused by Puccinia triticina (Pt), is a widespread disease of bread wheat worldwide. In the present study, 50 wheat cultivars from Ethiopia and 34 differential lines, mostly near-isogenic lines (NILs) in the background of Thatcher with known resistance genes to leaf rust (Lr), were tested with 14 Pt races in the greenhouse to postulate Lr genes at the seedling stage. Field experiments were also conducted to identify adult plant responses to leaf rust in Baoding in the 2017–2018 and 2018–2019 growing seasons and in Zhoukou in the 2018–2019 growing season. Thirteen Lr genes (Lr1, Lr18, Lr3ka, Lr15, Lr26, Lr20, Lr14a, Lr30, Lr2a, Lr11, Lr34, Lr46, and Lr68) either singly or in combination were found in 39 cultivars. Known Lr genes were not present in the remaining 11 cultivars. Lr1 and Lr46, each in 13 cultivars, and Lr34 in 12 cultivars were the most commonly identified resistance genes. Less frequently identified genes included Lr26 (five cultivars); Lr30 and Lr18 (each present in four cultivars); Lr15, Lr3ka, and Lr2a (each identified in three cultivars); and Lr68 (two cultivars). Evidence for the existence of Lr11, Lr20, and Lr14a (each in one cultivar) was also obtained. Twenty-one cultivars were found to have slow rusting resistance to leaf rust in the field tests. The results should be valuable for cultivar selection with combinations of effective Lr genes and used in breeding new cultivars with improved resistance to leaf rust in Ethiopia and China.

Stripe or yellow rust (YR) and leaf rust (LR) cause large losses in wheat production worldwide. Resistant cultivars curtail the levels of losses. The present study aimed to identify quantitative trait loci (QTL) for YR and LR resistance in 147 F2:6 recombinant inbred lines (RIL) derived from the cross Fuyu 3/Zhengzhou 5389. The RIL population and parents were genotyped with the Wheat55K single nucleotide polymorphism (SNP) array and simple sequence repeat (SSR) markers. All materials were also phenotyped for YR severity at Mianyang in Sichuan province and Baoding in Hebei province in the 2015/2016, 2016/2017, and 2017/2018 cropping seasons, and LR severity at Zhoukou in Henan province and at Baoding in 2017/2018. Eleven QTL for YR resistance and five for LR resistance were detected using inclusive composite interval mapping (IciMapping). Four of these QTL on chromosomes 1BL, 2BS, 3AL, and 5AL conferred resistance to both YR and LR. The QTL on 1BL was Lr46/Yr29, and that on 7BL might be Lr68. The QTL on chromosome 2BS was detected at a similar position to previously detected loci. QYr.hebau-3AL/QLr.hebau-3AL, QYr.hebau-5AL/QLr.hebau-5AL, QYr.hebau-7DL, QYr.hebau-4BS, QYr.hebau-6DL, and QYr.hebau-2AS are likely to be new. An SSR marker for QYr.hebau-7DL was developed and validated in a diverse wheat panel from China, suggesting effectiveness in different genetic backgrounds. These QTL with closely linked SNP and SSR markers could be useful for marker-assisted selection in wheat breeding programs targeting durable resistance to both diseases.

Wheat leaf rust, caused by Puccinia triticina, is a common fungal disease of wheat in China. In order to identify races and determine the individual virulence of isolates in different wheat-growing regions in China, leaf rust samples collected from 18 provinces in 2011 to 2013 were tested on 37 Thatcher near-isogenic lines each carrying a different single leaf rust resistance gene. A total of 158 races were identified. Races THTT (19.5%), THTS (16.9%), PHTT (7.7%), THJS (5.0%), THJT (4.2%), and PHTS (4.0%) were the most predominant races in 2011 to 2013. All of these races were avirulent to resistance genes Lr9 and Lr24. The two most frequent races, THTT and THTS, were widely distributed. The frequencies of the isolates with virulence to Lr1, Lr2c, Lr3, Lr16, Lr26, Lr17, LrB, Lr10, Lr14a, Lr3bg, Lr14b, Lr33, Lr37, and Lr50 exceeded 90%. Frequencies of virulence to Lr2a, Lr3ka, Lr11, Lr30, Lr2b, and Lr32 exceeded 70% but were less than 90%. Frequencies of virulence to Lr18, Lr21, Lr15, Lr23, Lr33+34, Lr36, Lr39, and Lr44 were below 70%, whereas the frequency of virulence to Lr25 was less than 1%. All isolates were avirulent to Lr9, Lr19, Lr24, Lr28, Lr42, Lr29, Lr38, and Lr47. The identified races and individual virulence frequencies provide a basis for selection of effective leaf rust resistance genes for use in breeding programs and can also provide information for the study of race evolution of P. triticina.

Stripe rust and leaf rust cause wheat yield losses of up to 70% worldwide. The employment of resistant cultivars is the major method to reduce losses from these diseases. The objective of this study was to detect quantitative trait loci (QTL) for stripe rust and leaf rust resistance in 150 F6 recombinant inbred lines (RIL) derived from a cross between Mianyang351-15 and Zhengzhou 5389. Both parents and the RIL population were genotyped with the Wheat55K single nucleotide polymorphism (SNP) array and simple sequence repeat markers, and phenotyped for stripe rust severity at Mianyang in Sichuan Province and Baoding in Hebei Province, and for leaf rust severity at Zhoukou in Henan Province and at Baoding in 2014 to 2017 cropping seasons. Seven and four QTL all contributed from Mianyang351-15 were identified for resistance to stripe rust and leaf rust, respectively. Four of these QTL on chromosomes 1BL, 2AS, 2DS, and 7BL conferred resistance to both stripe rust and leaf rust. The QTL on 1BL, 2AS, and 7BL were identified as Lr46/Yr29, Lr37/Yr17, and Lr68, respectively. QYr.hbau-2DS/QLr.hbau-2DS was detected at similar positions to previously reported loci. QYr.hbau-1DL, QYr.hbau-3AS, and QYr.hbau-3DL are likely to be new. Combined effects of QTL in the RIL population indicated RIL combining all QTL had the highest resistance level compared with those of lower numbers or no QTL. These QTL, with their closely linked SNP markers, are applicable for marker-assisted breeding and candidate gene discovery.

In Arabidopsis, both pathogen invasion and benzothiadiazole (BTH) treatment activate the nonexpresser of pathogenesis-related genes 1 (NPR1)-mediated systemic acquired resistance, which provides broad-spectrum disease resistance to secondary pathogen infection. However, the BTH-induced resistance in Triticeae crops of wheat and barley seems to be accomplished through an NPR1-independent pathway. In the current investigation, we applied transcriptome analysis on barley transgenic lines overexpressing wheat wNPR1 (wNPR1-OE) and knocking down barley HvNPR1 (HvNPR1-Kd) to reveal the role of NPR1 during the BTH-induced resistance. Most of the previously designated barley chemical-induced (BCI) genes were upregulated in an NPR1-independent manner, whereas the expression levels of several pathogenesis-related (PR) genes were elevated upon BTH treatment only in wNPR1-OE. Two barley WRKY transcription factors, HvWRKY6 and HvWRKY70, were predicted and further validated as key regulators shared by the BTH-induced resistance and the NPR1-mediated acquired resistance. Wheat transgenic lines overexpressing HvWRKY6 and HvWRKY70 showed different degrees of enhanced resistance to Puccinia striiformis f. sp. tritici pathotype CYR32 and Blumeria graminis f. sp. tritici pathotype E20. In conclusion, the transcriptional changes of BTH-induced resistance in barley were initially profiled, and the identified key regulators would be valuable resources for the genetic improvement of broad-spectrum disease resistance in wheat. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Wheat leaf rust, caused by Puccinia triticina, is an important fungal disease of wheat in China. To study races of the pathogen in China, leaf rust samples were collected from 14 provinces in 2014 and 15 provinces in 2015. From the samples, 494 single-uredinial isolates were derived from the 2014 collection and 649 from the 2015 collection. These isolates were tested on 40 near-isogenic lines of Thatcher carrying single leaf rust resistance genes. From the isolates, 84 races were identified in 2014 and 65 races in 2015. Races THTT (22.1%), THTS (19.6%), THJT (8.7%), PHTT (4.9%), and PHJT (3.6%) were the most common races in 2014, and THTT (28.4%), THTS (12.8%), THJT (11.6%), THJS (9.9%), and PHTT (9.7%) were the most frequent in 2015. All of these races were avirulent to resistance genes Lr9 and Lr24. THTT and THTS, the most frequent races in both years, were widely distributed throughout the country. The frequencies of isolates with virulence to Lr1, Lr2a, Lr2c, Lr3, Lr16, Lr26, Lr11, Lr17, LrB, Lr10, Lr14a, Lr2b, Lr3bg, Lr14b, Lr32, Lr33, and Lr50 were over 80%, whereas the frequencies of virulence to Lr9, Lr19, Lr25, Lr28, Lr29, and Lr47 were less than 3.5%. In the present study, all isolates were avirulent to Lr24 and Lr38. The race analysis and individual virulence frequencies provide guidance to breeders in choosing leaf rust resistance genes for use in breeding programs.

Peach (Prunus persica [L.] Batsch) as an economically important fruit tree is widely cultivated in Shenzhou, China. In September 2021, peach rust was observed in the peach tree in Shenzhou City, Hebei Province (lat. 38°02'56'' N, long. 115°54'57'' E, altitude 22 m). We investigated a peach orchard with a planting area of 1334 m2, where a total of 162 peach trees were planted, and found that about 10% of peach trees exhibited severe disease symptoms. The leaves of infected plant developed 100% disease symptoms, in which 50% of the infected leaves showed about 10 small pale-yellow spots on the front of leaves and reddish-brown pustules on the corresponding abaxial surface of leaves. Urediniospores varied from obovoid to clavate in shape, sometimes in irregular shape. They were orange-brown, echinulate near base with spines smaller towards apex and often smooth at apex, with germ pores 3-4 at equator, size ranging from 25.4 to 38.6 × 10.1 to 18.7 µm (n=100), and with wall 1 to 1.5μm thick at sides and 5-7 μm thick at apex. Golden capitate paraphyses were present, ranging from 25 to 40 µm in length, with a head in diameter of 12 to 14 µm and a tail in width of 5.2 to 6.5 µm. Based on the rust morphological characters, this pathogen was primarily identified as Tranzschelia discolor (Fuckel) TranzschelLitv. (Hiratsuka et al. 1992). For molecular identification, total DNA was extracted from 2 isolates, respectively, and the internal transcribed spacer (ITS) region was PCR-amplified using the primer set ITS5-u and ITS4-u (Pfunder et al. 2001). Obtained sequences were compared with sequences in the GenBank repository using BLAST algorithm. BLAST showed a 100% sequence identify to T. discolor (accession nos. AB097449、MT786217、KU712078、KY764179、MH599069). The sequence has been deposited in GenBank with (accession NO. ON950745 and ON950747). Thus, combining morphological observations and molecular identification, the isolate was identified as T. discolor. The pathogenicity was verified by inoculating the abaxial surface of peach leaves with a suspension of 1 × 106 urediniospores/ml. Peach leaves sprayed with sterile water were used as controls. The inoculated peach trees were placed in a greenhouse at 20°C under dark for 24 hours and maintained at 100% relative humidity to promote disease development. Next, the peach trees were grown in a greenhouse at 20°C with a 12 h day length and symptoms were observed on the leaves 14 days after inoculation. In contrast, the control leaves were asymptomatic. Previous studies reported that peach rust occurred in Oman, Korea and Brazil was caused by T. discolor. (Deadman M L, et al.2007, Shin, H D, et al. 2019, Vidal G S, et al. 2021). To our knowledge, this is the first report of T. discolor as a causal agent causing peach leaf rust in Northern China, which will enable us to rapidly diagnose this disease, identify the occurrence of this disease and develop adequate management strategies to control it in China.

Wheat leaf rust (caused by Puccinia triticina) and stripe rust (caused by Puccinia striiformis f. sp. tritici) cause large production losses in many regions of the world. The objective of this study was to identify quantitative trait loci (QTL) for resistance to leaf rust and stripe rust in a recombinant inbred line population derived from a cross between wheat cultivars SW 8588 and Thatcher. The population and parents were genotyped with the Wheat 55K SNP Array and SSR markers and phenotyped for leaf rust severity at Zhoukou in Henan Province and Baoding in Hebei Province. Stripe rust responses were also evaluated at Chengdu in Sichuan Province, and at Baoding. Seven and six QTL were detected for resistance to leaf rust and stripe rust, respectively. Four QTL on chromosomes 1BL, 2AS, 5AL, and 7BL conferred resistance to both rusts. The QTL on 1BL and 2AS were identified as Lr46/Yr29 and Lr37/Yr17, respectively. QLr.hebau-2DS from Thatcher, identified as Lr22b that was previously thought to be ineffective in China, contributed a large effect for leaf rust resistance. QLr.hebau-5AL/QYr.hebau-5AL, QLr.hebau-3BL, QLr.hebau-6DS, QYr.hebau-4BS, and QYr.hebau-6DS are likely to be new QTL, but require further validation. Kompetitive allele-specific PCR (KASP) markers for QLr.hebau-2DS and QLr.hebau-5AL/QYr.hebau-5AL were successfully developed and validated in a diverse wheat panel from Sichuan Province, indicating their usefulness under different genetic backgrounds. These QTL and their closely linked SNP and SSR markers will be useful for fine mapping, candidate gene discovery, and marker-assisted selection in breeding for durable resistance to both leaf and stripe rusts.

Wheat leaf rust, caused by Puccinia triticina (Pt), is an important foliar disease that has an important influence on wheat yield. The most economic, safe and effective way to control the disease is growing resistant cultivars. In the present study, a total of 46 wheat landraces and 34 wheat lines with known Lr (leaf rust resistance) genes were inoculated with 16 Pt pathotypes for postulating seedling resistance gene(s) in the greenhouse. These cultivars and five wheat differential lines with adult plant resistance (APR) genes (Lr12, Lr22b, Lr34, Lr35 and Lr37) were also evaluated for identification of slow rusting resistance in the field trials in Baoding, Hebei Province of China in the 2014–2015 and 2015–2016 cropping seasons. Furthermore, 10 functional molecular markers closely linked to 10 known Lr genes were used to detect all the wheat genotypes. Results showed that most of the landraces were susceptible to most of the Pt pathotypes at seedling stage. Nonetheless, Lr1 was detected only in Hongtangliangmai. The field experimental test of the two environments showed that 38 landraces showed slow rusting resistance. Seven cultivars possessed Lr34 but none of the landraces contained Lr37 and Lr46. Lr genes namely, Lr9, Lr19, Lr24, Lr28, Lr29, Lr47, Lr51 and Lr53 were effective at the whole plant stage. Lr18, Lr36 and Lr45 had lost resistance to part of pathotypes at the seedling stage but showed high resistance at the adult plant stage. Lr34 as a slowing rusting gene showed good resistance in the field. Four race-specific APR genes Lr12, Lr13, Lr35 and Lr37 conferred good resistance in the field experiments. Seven race-specific genes, Lr2b, Lr2c, Lr11, Lr16, Lr26, Lr33 and LrB had lost resistance. The 38 landraces showed slow rusting resistance to wheat leaf rust can be used as resistance resources for wheat resistance breeding in China.

Ginger (Zingiber officinale Rosc.) is an important economic crop and its rhizome can be used as seasoning agent and traditional medicine in China. During July 2018 and 2019, decay symptoms occurred in the ginger planting area of Tangshan City, Hebei Province, with incidence rates of 15%～20%. The pathogen infected the rhizomes and leaves. The symptoms included leaves chlorosis and gradually wilting, even the whole plant wilted, the rhizome became soft and presented light brown maceration. In serious cases, the interior of rhizome was completely eroded, gray-white juice overflowing the epidermis, and with foul smell. The rhizome surfaces of ginger plants were disinfected with 1% NaOCl, and colonies were isolated and purified on nutrient agar (NA) solid medium by streaking. Eight isolates were obtained from 15 diseased tissue samples. Further morphological, physiological and biochemical identification of the pure cultured bacteria were carried out. Three strains of bacteria were picked for further analysis. All of the three strains were gram-negative, short rod-shaped，nonmotile bacillus. Colonies were round and milky yellow, smooth raised, and moist after incubation at 28°C for 24h on NA. Physiological and biochemical test results showed that strains were facultatively anaerobic, negative for indole, methyl red, the Voges-Prauskauer test (V-P) and urease; positive for glucose, sucrose, sorbitol, inositol, mannitol, citrate utilization and hydrogen sulfide production; gelatin liquefaction. A typical hypersensitive reaction was induced on 12-week-old tobacco (Nicotiana benthamiana) leaves, which were inoculated by injecting suspensions of the isolated strain (108 CFU/mL) at 25 ℃ after 24h. These characteristics were consistent with Citrobacter freundii (Werkman and Gillen 1932). To further assess the identity of the strains, the genomic DNA was extracted from one bacterium（JXJ4）. The partial 16S rRNA region (Lane 1991) and specific rpoB and gyrB genes (Mollet et al. 1997, Brady et al. 2013) were amplified and sequenced with primers 27F/1492R, CM7/CM31b and UP1f/UP2r, respectively. The obtained 16S, rpoB and gyrB sequences (GenBank accession MN148645, MN158728 and MW199734) of the isolate showed 99.93%, 99.51% and 99.82% identity to the corresponding sequences of C. freundii in GenBank (CP024679.1, CP024677.1 and KM509081.1). Maximum likelihood analysis was performed, and the phylogenetic tree clustered with C. freundii (MEGAX, Bootstrap n=1000). The pathogenicity of the isolates was tested on ginger plants and rhizomes tissue. The bacterial suspensions (108 CFU/mL) of three isolates were injected into the basal stem and rhizomes center of 9 healthy ginger seedlings respectively, and Control groups were treated with sterile water. The inoculated plants were kept in a moist chamber (28°C, 16-h light and 8-h dark period) and ginger rhizomes were placed in the incubator (30°C, 16-h light and 8-h dark period). Seven days after inoculation, the ginger tubers showed symptoms of decay, and 20 to 25 days later, the ginger plant leaves browned and died. The pathogenicity test was repeated 4 times and all controls were healthy. Pathogens were reisolated from symptomatic plants and rhizomes and identified as C. freundii based on the morphological, biochemical and molecular methods described previously, fulfilling Koch's hypothesis. To our knowledge, this is the first report of ginger rot caused by C. freundii in China.

Naked oats (Avena nuda L.) is rich in protein, fat, vitamin, mineral elements and so on, and is one of the world's recognized cereal crops with the highest nutritional and healthcare value. In July 2019, leaf spot was detected on A. nuda in Zhangbei experimental station of Hebei Agricultural University. The incidence of disease is 10% to 20%. The symptoms were similar to anthracnose disease, the infected leaves had fusiform or nearly fusiform yellowish-brown spots, yellow halo around the spots. Numerous acervuli with black setae diagnostic of fungi in the genus Colletotrichum were present on necrotic lesions. To identify the pathogen, ten symptomatic leaves were collected, and only one disease spot was isolated from each leaf. Small square leaf pieces (3 to 5 mm) were excised from the junction of diseased and healthy tissues with a sterile scalpel and surface disinfested with 75% alcohol for 30s, 0.1% corrosive sublimate for 1 min, rinsed three times in sterile water. Plant tissues were then transferred on potato dextrose agar (PDA), and incubated at 25°C for 7 days. Two fungal isolates were obtained and purified by single-spore isolation method. All fungi have the same morphology and no other fungi were isolated. The aerial mycelium was gray black. The conidia were colorless and transparent, falcate, slightly curved, tapered toward the tips, and produced in acervuli with brown setae. The length and width of 100 conidia were measured and size ranged from 1.86 to 3.84 × 8.62 to 29.81 μm. These morphological characteristics were consistent with the description of Colletotrichum cereale (Crouch et al. 2006). To further assess the identity of the species, the genomic DNA of two fungal isolates (LYM19-4 and LYM19-10) was extracted by a CTAB protocol. The ribosomal DNA internal transcribed spacer (ITS) region as well as, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), and the beta-tubulin 2 (Tub2) partial genes were amplified and sequenced with primers ITS4/5, GDF/GDR, ACT-512F/ACT-783R, and T1/Bt2b, respectively (Carbone et al. 1999; Templeton et al. 1992; O'Donnell et al. 1997; Glass et al. 1995). The sequences of the ITS-rDNA region (MW040121, MW040122), the GAPDH sequences (MW052554, MW052555), the ACT sequences (MW052556, MW052551) and the Tub2 sequences (MW052552, MW052553) of the two single-spore isolates were more than 99% identical to C. cereale isolate CGMCC3.15110 (JX625159, KC843517, KC843534 and JX625186). Maximum likelihood tree based on concatenated sequences of the four genes were constructed using MEGA7. The results showed the strains isolated from A. nuda were closely related to C. cereale, as supported by high bootstrap values. A pathogenicity test of the C. cereale isolates was performed on first unfolding leaves of A. nuda. Koch's postulates were carried out with isolates by spraying a conidial suspension of 106 conidia/mL on leaves of healthy A. nuda. Four replicated pots were inoculated at a time, 10 leaves each pot, while sterile distilled water was used as the control. All treated plants were placed in a moist chamber (25°C, 16-h light and 8-h dark period). Anthracnose symptoms developed on the inoculated plants 7 days post inoculation while all control plants remained healthy. Microscopic examination showed the surface of infected leaves had the same acervuli, setae, and conidia as the original isolate. The pathogenicity test was repeated three times. C. cereale was previously reported as the causal agent of anthracnose on feather reed grass in US (Crouch et al. 2009). To our knowledge, this is the first report of C. cereale as the causal agent of A. nuda anthracnose in China.

Naked oats (Avena nuda L.) is an independent species of Avena, which can be used as both food and forage for rich nutritional value. In August 2019, leaf spot was observed at a naked oats planting base in Zhangbei County, Zhangjiakou City, Hebei Province. The incidence of disease was 40% to 50%. The symptoms of the lesions were chlorosis and gradually developing light brown spots with light yellow halos. The spots were irregular, enlarged and even coalesced to form large areas of necrosis on leaves. To identify the pathogen, twenty symptomatic leaves were collected, and one disease spot was isolated from each samples. Small square leaf pieces (3 to 5 mm) were excised from the junction of diseased and healthy tissues with a sterile scalpel and were sterilized with 75% alcohol for 30s, 0.1% mercuric chloride solution for 1 min, and then rinsed three times with sterile water, then transferred cultured on potato dextrose agar (PDA) at 25°C for 7 days. Four fungal isolates were obtained and purified by single-spore isolation method. All fungi have the same morphology and no other fungi were isolated. Colonies of the isolates had round margins, and thick fluffy aerial mycelia with brown coloration after 7 days on PDA. Conidiophores were brown, straight or flexuous, septate, single or in clusters. Conidia were obclavate or oval, dark brown, and size ranging from 4.61 to 15.68 × 6.61 to 35.49μm (n=100), with longitudinal and transverse septa varying from 1 to 3 and 1 to 7, respectively. The transverse median septum of the central section was especially thick. On the basis of morphological characteristics, the isolates were identified as Alternaria spp. (Simmons 2007). To further assess the identity of the species, the genomic DNA of pathogenic isolate (YM3) was extracted by CTAB protocol. The ribosomal DNA internal transcribed spacer (ITS) region, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the RNA polymerase II second largest subunit (RPB2), and the plasma membrane ATPase genes were amplified and sequenced with primers ITS1/4, gpd1/2, RPB2-6F/7cR and ATPDF1/ATPDR1 respectively (Nishikawa and Nakashima 2015; Woudenberg et al. 2015). Sequences of ITS, GAPDH, RPB2 and ATPase (MN646900, MT233043, MT233042, MN640794) of the isolate was 99.82%, 99.68%, 100% and 99.51% similar to the fungus A. alternata (MK461082.1, MK451978, KP124770.1, MK804115). A neighbor-joining phylogenetic tree was constructed by combining all sequenced loci in MEGA7. The isolate YM3 clustered in the A. alternata clade with 100% bootstrap support. Therefore, the pathogen was identified as A. alternata based on the morphological characteristics and molecular identification. A pathogenicity test of the A. alternata isolates was performed by placing mycelial disks (5 mm) with conidia on the surface of the first unfolding leaves of naked oats. Each leaf was inoculated with three disks. The pathogenicity test was repeated four times, and 10 leaves were inoculated in each repetition, while sterile PDA was used as the control. All treated plants were placed in a moist chamber (25°C, 16-h light and 8-h dark period). Leaf spot symptoms developed on the inoculated plants about 10 days post inoculation while all control plants remained healthy. The similar isolates were re-isolated from the inoculated and infected leaves and identified as A. alternata by DNA sequencing, fulfilling Koch's postulates. It has been reported that A. alternata can cause leaf spots on A. Sativa(Chen et al. 2020). However, to our knowledge, this is the first report of A. alternata causing leaf spots on A. nuda in China. It can be concluded that A. alternata can cause leaf spot disease of oats (A. Sativa and A. nuda). The spots disease is worthy of our attention for its harm to the production of oats.

Leaf rust, caused by Puccinia triticina (Pt), is one of the most important wheat diseases of common wheat (Triticum aestivum L.). Using resistant cultivars is the most economical and efficient way to control the disease. A total of 86 wheat cultivars from Sichuan province in China were inoculated with 14 Pt races for postulating seedling leaf rust resistance (Lr) gene(s) in the greenhouse. Meanwhile, these cultivars were also planted in Baoding and Zhoukou trial fields for identifying slow leaf rusting genes during the 2014–2015 and 2015–2016 cropping seasons. Twelve specific markers for ten known Lr genes (Lr1, Lr9, Lr10, Lr19, Lr20, Lr24, Lr26, Lr34, Lr37 and Lr46) were also used for molecular marker detection. Based on the results from the gene postulation and molecular marker detection, nine Lr genes (Lr1, Lr2a, Lr26, Lr3ka, Lr30, Lr36, Lr15, Lr37, and Lr46) were identified in 45 cultivars either singly or in combination. Most frequently identified Lr genes were Lr26 in 25 cultivars and Lr37 in 21 cultivars. Less frequently detected genes were Lr1 and Lr46 each in nine cultivars, Lr3ka in five cultivars, Lr30 in three cultivars and Lr36 in two cultivars. Lr2a and Lr15 were found in Chuannong 16 and Chuanmai 1, respectively. Twenty-nine cultivars were found to have slow rusting resistance during the two growing seasons. The results should be useful for selecting cultivars with combinations of genes for effective resistance to grow and in breeding new cultivars with improved resistance to leaf rust.

Ginger (Zingiber officinale ROSC.) is an important economic crop in China, especially the rhizome tissue has a high medicinal value. In July 2019, the symptom of ginger rhizome rot appeared in Tang...

In Arabidopsis, systemic acquired resistance (SAR) is established beyond the initial infection by a pathogen or is directly induced by treatment with salicylic acid (SA) or its functional analogs, 2,6-dichloroisonicotinic acid (INA) and benzothiadiazole (BTH). NPR1 protein is considered the master regulator of SAR in both SA signal sensing and transduction. In wheat (Triticum aestivum) and barley (Hordeum vulgare), both pathogen infection and BTH treatment can induce broad-spectrum resistance to various diseases, including powdery mildew, leaf rust, Fusarium head blight, etc. However, three different types of SAR-like responses including acquired resistance (AR), systemic immunity (SI), and BTH-induced resistance (BIR) seem to be achieved by activating different gene pathways. Recent research on wheat and barley NPR1 homologs in AR and SI has provided the initial clue for understanding the mechanism of SAR in these two plant species. In this review, the specific features of AR, SI, and BIR in wheat and barley were summarized and compared with that of SAR in model plants of Arabidopsis and rice. Research updates on downstream genes of SAR, including pathogenesis-related (PR) and BTH-induced genes, were highlighted.

Wheat leaf rust, caused by Puccinia triticina, is a commonly occurring disease in wheat growing areas of the world. Research on the virulence and genetic diversity of P. triticina will be helpful for a better understanding of the evolution tendencies and subsequently for controlling this disease. In this study, 59 isolates of P. triticina collected from Hebei Province of China in 2008 and 2010 were analyzed for virulence diversity based on 37 near-isogenic Thatcher wheat lines at seedling stage, and genetic diversity using 21 pairs of EST-SSR primers. The predominant virulence phenotypes were PHTT, THTT, and THJT in 2008, while THTS, THSS, THTT, and THST were most common in Hebei province in 2010. Clustering analysis based on the virulence and EST-SSR data revealed a high diversity of P. triticina, and differences between the populations of 2008 and 2010. There was no significant correlation between the molecular and virulence data. Genetic parameters analysis also showed high diversity of the P. triticina population in Hebei province. Nei’s gene diversity index (H) and Shannon’s information index (I) showed that the genetic diversity of population 2008 was higher than 2010. The AMOVA analysis suggested that genetic variation mainly from intra-population (61.11%).

Wheat leaf rust caused by Puccinia triticina (Pt) is one of the most severe fungal diseases threatening the global wheat production. The use of leaf rust resistance (Lr) genes in wheat breeding programs is the major solution to solve this issue. Wheat isogenic line carrying the Lr39/41 gene has shown a moderate to high resistance to most of the Pt pathotypes detected in China. In the present study, a typical hypersensitive response (HR) was observed using microscopy in leaves of the Lr39/41 isogenic line inoculated with the avirulent Pt pathotype THTT from 48 h-post inoculation. Two Lr39/41 resistance-associated suppression subtractive hybridization (SSH) libraries with a total of 6000 clones were established. Microarray hybridizations were performed on all obtained SSH clones using RNAs extracted from leaves of the Pt-inoculated and non-inoculated Lr39/41 isogenic lines, and leaves of the Pt-inoculated and non-inoculated Thatcher susceptible lines. Differentially expressed clones were analyzed by significance analysis of microarrays (SAM), followed by further sequencing. A total of 36 Lr39/41-resistance-related differentially expressed genes (DEGs) were identified, many of which had been previously reported to be involved in the plant defense response. The expression levels of eight selected DEGs during different stages of the Lr39/41-mediated resistance were further quantified by a qRT-PCR assay. Several pathogenesis-related (PR) and HR-related genes seem to be crucial for the Lr39/41-mediated resistance. In general, a brief profile of DEGs associated with the Lr39/41-mediated wheat resistance to Pt was drafted.

One hundred thirty-five single-spore isolates were collected from grape vineyards from 15 provinces or autonomous regions belonging to five viticulture climatic zones in China. All the isolates were identified as Botrytis cinerea based on their morphological and molecular characters. The 135 isolates were all heterothallic isolates. Seventy-one isolates belonged to the MAT1-1 type and 64 were characterized to MAT1-2 type. All the isolates studied belonged to Group II based on PCR-RFLP of the Bc-hch locus. The four TE genotypes, transposa, Boty-only, Flipper-only, and vacuma, comprised 51.9%, 33.3%, 10.4%, and 4.5%, respectively, of the total population. The frequency of transposa was highest in the total population and the most of any subpopulation (each viticulture climatic zone), and Boty-only was highest in warm areas (46.2%). Vacuma was mainly distributed in northern China, although in small amounts, and Flipper-only was mainly was distributed in humid tropical areas (42.9%). A microsatellite analysis of B. cinerea populations was performed to assess the genetic population structure. A total of 127 different MLGs were identified among 135 B. cinerea isolates, with a genotypic diversity of 0.9991. The transposa population isolates showed higher genetic diversity than other populations. Pairwise tests of genetic differentiation among four TE-type populations yielded generally low to high Gst values. All isolates belonged to two genetic clusters. The population microsatellite diversity and genetic structure had a certain correlation with the TE type and geographic origin. This is the first report of the genotypic diversity of B. cinerea isolates from grape vineyards across China.

Leaf rust (LR) is a destructive foliar disease of common wheat (Triticum aestivum L.) worldwide. Growing resistant cultivars with adult plant resistance (APR) are the ideal way to control the disease. The aim of the present study was to map quantitative trait loci (QTL) for leaf rust resistance using 137 doubled-haploid (DH) lines derived from the Pingyuan 50 × Mingxian 169 cross. The same population was previously tested for stripe rust (YR) and powdery mildew (PM) response, and the data were reassessed to determine the presence of QTL with pleiotropic effects. Phenotyping for leaf rust response was conducted in six environments at Baoding in Hebei province and Zhoukou in Henan province. The DH lines were genotyped using the wheat 55K SNP array and additional SSR markers. Eight QTLs for LR resistance were identified in the present study using the inclusive composite interval mapping (ICIM). The flanking sequences of all the SNP probes were subjected to BLAST against the Chinese Spring reference sequence to determine physical positions. Six LR resistance loci were contributed by Pingyuan 50, but QLr.hebau-2DS2 and QLr.hebau-3AL were from Mingxian 169. QLr.hebau-3DS, a new and stable QTL detected in all environments, explained 4.2–20.0% of the phenotypic variation. Another new QTL, QLr.hebau-3AL detected in four environments had a PVE (phenotypic variance explained) of 5.7–10.1%. QLr.hebau-1BL, QLr.hebau-2DS2, and QLr.hebau-7DL are new loci. Two QTLs showed potential pleiotropic effects on disease response. QTL on chromosome 7DL might be pleiotropic to LR and PM, and the QTL on 5DL might confer pleiotropic resistance to LR and YR. Kompetitive allele-specific PCR (KASP) markers for QLr.hebau-3AL and QLr.hebau-3DS were successfully developed and validated. The QTL identified with their flanking markers and in the present study could be useful for fine mapping, candidate gene mining, and marker-assisted selection (MAS).

Cercospora leaf blotch disease of potato (Solanum tuberosum L.) caused by Cercospora concors (Casp.) Sacc (synonym Mycovellosiella concors (Casp.) Deighton) occurs worldwide but mainly has been reported in the cool and temperate climates of Europe, Asia, North America, and eastern Africa. Cercospora leaf blotch is usually a minor disease and may go unnoticed since it commonly occurs simultaneously with other potato leaf diseases such as late blight (caused by Phytophthora infestans) and early blight (caused by Alternaria solani) (2). Symptoms of Cercospora leaf blotch first appear on lower leaves as small, yellowish green, irregular blotches and later may appear on middle and upper leaves. As the leaves expand, the blotches enlarge and become purplish brown or black. Conidiophores and conidia form on the underside of the lesions, giving the lesions a mildewed appearance similar to late blight. Necrotic lesions are distinguished from those caused by the early blight pathogen A. solani by the lack of concentric rings (1). In more severe epidemics of Cercospora leaf blotch, potato leaves may be killed, stem lesions become dark and entire plants die, but no resulting yield loss from the disease has been documented. Potato tubers are not infected. From August to September of 2005, yellow-brown lesions appeared on the upper side of potato leaves (cv. Zihuabai, certified virus free) and gray mildew developed on the underside of leaves in potato field trials conducted in Jining County, 41°N, 113°E of Inner Mongolia, North China. The infections were observed mostly on lower and middle leaves of plants; 20 to 30% of plants were infected. In the laboratory, the mildew was scraped with a sterile scalpel and examined microscopically. The conidiophores were irregular in width, grayish, and highly branched. The conidia were numerous, light to dark, straight or slightly bent, cylindrical or obclavate, with conspicuous scars, and zero to six septa. The mature spores were from 16 to 59 μm long and 4 to 6 μm wide. The teleomorph of the fungus was not found. On the basis of the morphological characters, the causal agent was identified as C. concors. C. concors has been previously identified from potato leaves in the Engshi District of Hubei Province, China (3), but to our knowledge, this is the first report of the fungus causing Cercospora leaf blotch of potato in Inner Mongolia, North China. References: (1) G. D. Franc and B. I. Christ. Page 22 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson et al., eds. American Phytopathological Society, St. Paul, MN, 2001. (2) E. R. French. Page 19 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson et al., eds. American Phytopathological Society, St. Paul, MN, 2001. (3) S. M. Tian et al. China Potato J. 1:13, 1997.

Identification of resistance genes is important for developing leaf rust resistant wheat (Triticum aestivum) cultivars. A total of 102 Chinese winter wheat cultivars and advanced lines were inoculated with 24 pathotypes of Puccinia triticina for postulation of leaf rust resistance genes effective at the seedling stage. These genotypes were also planted in the field for characterization of slow rusting responses to leaf rust in the 2006–07 and 2007–08 cropping seasons. Fourteen leaf rust resistance genes—Lr1, Lr2a, Lr3bg, Lr3ka, Lr14a, Lr16, Lr17a, Lr18, Lr20, Lr23, Lr24, Lr26, Lr34, and LrZH84—either singly or in combinations, were postulated in 65 genotypes, whereas known resistance genes were not identified in the other 37 accessions. Resistance gene Lr26 was present in 44 accessions. Genes Lr14a and Lr34 were each detected in seven entries. Lr1 and Lr3ka were each found in six cultivars, and five lines possessed Lr16. Lr17a and Lr18 were each identified in four lines. Three cultivars were postulated to possess Lr3bg. Genes Lr20, Lr24, and LrZH84 were each present in two cultivars. Each of the genes Lr2a and Lr23 may exist in one line. Fourteen genotypes showed slow leaf rusting resistance in two cropping seasons.

Since 2009, brown leaf spot and panicle blight of Zanthoxylum piperitum (L.) DC. (“liujin,” commonly known as Japanese pepper and Japanese pricklyash) has been observed on 40% of the plants in the test field of Foresty Academy of Science in Hebei Province of China. When symptoms formed on leaves, a thick yellow spot appeared, which then turned brown. When on the spikes, brown lesions were observed initially on the grain, which then spread down to fruit stem, and finally the whole spike wilted and dried up. Yield and quality losses were considerable. A fungus was isolated consistently from the diseased tissues using potato dextrose agar (PDA) (1). Three representative isolates were chosen for further characterization. All the isolates grew at 28°C on PDA and potato carrot agar (PCA) medium. Fungal colonies were initially white, then became olivaceous with some white mycelium on the top of the colony, and turned brown with age. When observed with the microscope, crineous septate hypha appeared, and conidiophore peduncles were upright or slightly curved, with a few branches, 33.0 to 75.0 μm long and 4.0 to 5.5 μm wide. Conidia were crineous short clubs or near oval in shape, 22.5 to 40.0 μm long and 8.0 to 13.5 μm wide, with a short conical beak, and had one to four longitudinal cross walls. On PCA, condia had three to seven transepta and one to five longisepta, and were produced in a branched, long chain with more than five conidia. The pathogen was identified based on morphological characteristics as Alternaria alternata (Fr.:Fr.) Keissl. (3). DNA was extracted from mycelium and PCR was performed on the internal transcribed spacer (ITS) region with primers ITS1 and ITS4. A 570-bp fragment was amplified and sequenced (GenBank Accession No. JQ973810). BLASTn analysis revealed there was 100% sequence identity with A. alternata strains (GU566303 and GQ121322). To further identify the fungus, A. alternata species-specific primers AAF2/AAR3 (2) were used to generate an amplicon which was then sequenced (JX308287). Sequence comparison showed there was 100% sequence identity with A. alternata (JQ927300 and JQ907485). Pathogenicity tests were performed by spraying with a cultured suspension (106 spores/ml) of approximately 100 μl onto healthy leaves in 15-cm-diameter glass dishes containing sterilized filter paper soaked with sterilized water at room temperature. Control plants were inoculated with sterile distilled water. Ten days after inoculation, symptoms were observed in all inoculated leaves and appeared to be identical to those observed in the field. No symptoms were noted on the control leaves. Identical results were also obtained when spikes were inoculated. The fungi reisolated from symptomatic plants were A. alternata. To our knowledge, this is the first report of A. alternata causing leaf spots and panicle blight of Z. piperitum in China. References: (1) O. D. Dhingra and J. B. Sinclair. Basic Plant Pathology Methods. CRC Press, Boca Raton, FL, 1995. (2) P. Konstantinova. et al. Mycol. Res. 106:23, 2002. (3) T. Y. Zhang. China fungi records (Alternaria) (Volume 16) (in Chinese). Beijing: Science Press, 2003.

β-1,3-glucanases represent a group of pathogenesis-related proteins (PRs) that have been extensively reported to be involved in plant defense response towards fungal pathogens infection. However, it remains unknown how these genes are involved in wheat against leaf rust pathogen Puccinia triticina. Here, we present the cloning and expression analysis of a full length β-1,3-glucanase gene, TcLr19Glu, from the near isogenic wheat line TcLr19 infected by leaf rust pathogen. TcLr19Glu encodes a 342 amino acid protein with deduced molecular weight of 34.86 kDa that contains a conserved glycoside hydrolase family 17 domain widely existing in β-1,3-glucanases family. The expression profile of TcLr19Glu detected by quantitative real-time PCR showed that the transcript was induced by P. triticina both in the compatible and incompatible interactions, but the accumulation level of transcript was statistically significant in the incompatible interaction compared with that in the compatible interaction. Subsequently, we demonstrated that the accumulation of TcLr19Glu transcript significantly differentiates in tested wheat organs and TcLr19Glu was noticeably induced by the signaling molecules including abscisic acid (ABA) and salicylic acid (SA). Furthermore, induction and quantification of TcLr19Glu protein in compatible and incompatible interactions was measured and the amount of protein was higher in the incompatible interaction than compatible interaction. All these results allow us to conclude that TcLr19Glu is involved in the Lr19-mediated defense response against rust pathogen.

Wheat leaf rust is a destructive foliar disease of common wheat (Triticum aestivum L.) worldwide. The most effective, economical s to control the disease is growing resistant cultivars with adult plant resistance (APR). The Chinese wheat lines W014204 and Fuyu 3 showed high leaf rust resistance in the field. To identify leaf rust APR genes in the two lines, two mapping populations with 215 and 163 F2:3 lines from the crosses W014204/Zhengzhou 5389 and Fuyu 3/Zhengzhou 5389, respectively, were phenotyped for leaf rust severities during the 2010–2011, 2011–2012 and 2012–2013 cropping seasons in the field at Baoding, Hebei Province, China. A total of 1 215 SSR markers were used to identify the quantitative trait loci (QTLs) for leaf rust APR in the two populations. In the W014204/Zhengzhou 5389 population, three QTLs were detected and designated as QLr.hbu-1BL.1, QLr.hbu-2BS.1 and QLr.hbu-7DS, and explained 2.9–8.4, 11.5–38.3 and 8.5–44.5% of the phenotypic variance, respectively; all the resistance alleles at these loci were derived from W014204. In the Fuyu 3/Zhengzhou 5389 population, three QTLs, QLr.hbu-1BL.2, QLr.hbu-2BS.2 and QLr.hbu-7BL, explained 12.0–19.2, 22.3–38.9 and 4.1–4.3% of the phenotypic variance, respectively, and all resistance alleles were contributed by Fuyu 3. Based on chromosome positions of closely linked markers, both QLr.hbu-1BL.1 and QLr.hbu-1BL.2 are Lr46, and QLr.hbu-7DS is Lr34. QLr.hbu-7BL was mapped on chromosome 7BL near to Lr68 and they are likely the same gene. Based on chromosome positions, pedigree and field reactions, the two 2BS QTLs are different from all the known APR genes and are likely to be new APR QTL for leaf rust. These QTLs and their closely linked markers are potentially useful for improving leaf rust resistance in wheat breeding.

The Chinese wheat line Yu 356-9 exhibits a high level of resistance to leaf rust. In order to decipher the genetic base of resistance in Yu 356-9, gene postulation, inheritance analyses, and chromosome linkage mapping were carried out. Gene postulation completed using 15 leaf rust pathotypes and 36 isogenic lines indicated that Yu 356-9 was resistant to all pathotypes tested. F 1 and F 2 plants from the cross Yu 356-9 (resistant)/Zhengzhou 5389 (susceptible) were tested with leaf rust pathotype “FHNQ” in the greenhouse. Results indicated a 3:1 segregation ratio, indicative of the presence of a single dominant leaf rust resistance gene in Yu 356-9 which was temporarily designated as LrYu. Bulk segregant analysis and molecular marker assays were used to map LrYu. Five simple sequence repeat (SSR) markers on chromosome 2BS were found closely linked to LrYu. Among these markers, Xwmc770 is the most closely linked, with a genetic distance of 5.7 cM.

Leaf rust, caused by Puccinia triticina, is an important foliar disease of wheat (Triticum aestivum L.) worldwide. In the present study, CIMMYT line 19HRWSN-122 and 36 lines with known Lr (leaf rust resistance) genes were inoculated with 13 Chinese P. triticina pathotypes for postulation of Lr genes at the seedling stage. Line 19HRWSN-122 showed high resistance to all 13 P. triticina pathotypes in the greenhouse, indicating that it carries effective seedling resistance. This may be due to a resistance gene combination, an effective gene to all pathotypes present in China or a new resistance gene. With the objective of mapping the putatively new gene for resistance to leaf rust, 20 F1, 280 F2 plants and 254 F2:3 lines from the cross 19HRWSN-122 × Zhengzhou 5389 (susceptible) were inoculated with P. triticina pathotype THJP in the greenhouse. Results based on the F1, F2 and F2:3 lines indicated that a single dominant gene, temporarily designated LrHR122, was present in 19HRWSN-122. Bulked segregant analysis was performed on equal amounts of genomic DNA from ten resistant and ten susceptible F2:3 lines. Molecular markers polymorphic between the resistant and susceptible bulks were used to genotype F2:3 lines. LrHR122 was linked to one SSR marker, one STS marker, one SCAR marker and three EST markers on chromosome 3DL. Marker SCS1302 609 co-segregated with LrHR122, and the closest flanking markers were BE442875 and STS24-16 at genetic distances of 0.4 and 0.4 cM, respectively. Lr24 is known to be located on chromosome 3DL near LrHR122. In seedling tests, lines with both LrHR122 and Lr24 showed high resistance to all 13 Chinese P. triticina pathotypes. According to the pedigree and chromosome position LrHR122 should be Lr24. Lr24 was closely linked to one SSR marker and three EST markers in the terminal region of 3DL. These markers should be useful for marker assisted selection in breeding leaf rust resistant wheat cultivars.

Wheat leaf rust (Puccinia triticina) is one of the most important plant diseases in the world, and growing resistant cultivars is the most economical, effective and environmentally safe method for controlling this disease. With the aim of evaluating leaf rust resistance, 10 uncharacterized wheat genotypes, as well as 35 lines with known leaf rust resistance genes (Lr genes), were exposed to 12 Chinese P. triticina pathotypes at both seedling and adult stages. Two wheat genotypes, 09p205 and 09p200, showed high resistance to all the tested pathotypes at both seedling and adult stages. Three accessions, Xinmai 16, 00-225-2-1-2-2, and 21941-6, showed resistance at the adult stage. Four genotypes, 21898-3, 21924-4, 21915-3, and 21982-1, showed slow rusting resistance. In addition, 24 molecular markers were used to assess the presence of 20 known Lr genes. In the 10 genotypes analyzed Lr2c, Lr3ka, Lr9, Lr14a, Lr26, Lr34, and Lr37 were detected, either alone or in combination.

Leaf rust (LR), caused by Puccinia triticina , is one of the most widespread diseases of common wheat ( Triticum aestivum L.) worldwide. The LR resistance gene LrBi16 has been mapped on chromosome arm 7BL in Chinese wheat cultivar Bimai 16 and was closely linked to SSR loci Xcfa2257 and Xgwm344 with genetic distances of 2.8 cM and 2.9 cM, respectively. In the present study, a total of 304 AFLP primer pairs were used to screen Bimai 16 and Thatcher and resistant and susceptible DNA bulks. The polymorphic AFLP marker P-ATT/M-CGC 173 bp was used to genotype F 2 and F 3 populations to identify markers more closely linked to LrBi16 . Marker P-ATT/M-CGC 173 bp was tightly linked to LrBi16 with a genetic distance of 0.5 cM. As LrBi16 was mapped near the Lr14a locus, 809 F 2 plants from the Bimai 16/RL6013 ( Lr14a ) cross were inoculated with the Pt pathotype FHNQ to test the allelism of Lr14a and LrBi16 . All of the F 2 plants were resistant to FHNQ (IT between; and 2), suggesting that Lr14a and LrBi16 are allelic.

In this study we analysed the expression patterns of TaLr35PR2 and confirmed its role in Lr35-mediated adult resistance to leaf rust fungus. β-1,3-glucanase, a pathogenesis-related protein, has a critical function in plant defence response against fungal pathogens. We previously described the full-length gene TaLr35PR2, which encodes a protein exhibiting amino acid and structural similarity to β-1,3-glucanase, in the wheat near-isogenic line TcLr35 (GenBank accession number DQ294235.1). This work aimed to further assess TaLr35PR2 expression patterns and function in Lr35-mediated adult resistance to Puccinia triticina. Immunoblot was performed to demonstrate that TaLr35PR2 expression was triggered early by P. triticina, with expression levels markedly elevated in incompatible interaction compared with those in compatible one. Additionally, TaLr35PR2 accumulation steadily increased and overtly peaked after challenge with P. triticina through the various developmental stages of TcLr35 wheat, and remaining at similar levels after mock inoculation. Furthermore, TaLr35PR2 expression was significantly reduced in barley stripe mosaic virus (BSMV)-induced gene knockdown plants, in which pathological assessment revealed that TaLr35PR2-silenced plants was obviously susceptible to leaf rust fungus compared with wild-type TcLr35, indicating that Lr35-mediated resistance to leaf rust was diminished. These findings strongly suggest that TaLr35PR2 is involved in Lr35-mediated wheat defence against the leaf rust pathogen.

Leaf rust, caused by Puccinia triticina, is one of the major wheat diseases worldwide and poses a constant threat to common wheat (Triticum aestivum L.) production and food security. Results from the F2 and F2:3 populations derived from a cross between resistant line Fundulea 900 and susceptible cultivar Thatcher indicated that a single dominant gene, tentatively designated LrFun, conferred resistance to leaf rust. In order to identify other possible genes in Fundulea 900, nine P. triticina pathotypes avirulent on Fundulea 900 were used to inoculate F2:3 families. The results showed that at least two leaf rust resistance genes were present in Fundulea 900. A total of 1,706 pairs of simple sequence repeat (SSR) primers were used to test the parents and resistant and susceptible bulks. Eight polymorphic markers from chromosome 7BL were used for genotyping the F2 and F2:3 populations. LrFun was linked to eight SSR loci on chromosome 7BL. The two closest flanking SSR loci were Xgwm344 and Xwmc70, with genetic distances of 4.4 and 5.7 cM, respectively. At present four leaf rust resistance genes, Lr14a, Lr14b, Lr68 and LrBi16, are located on chromosome 7BL. In a seedling test with 12 P. triticina isolates, the reaction patterns of LrFun were different from those of lines carrying Lr14a, Lr14b and LrBi16. Lr68 is an adult plant resistance gene, and it is different from the seedling resistance gene LrFun. Therefore, we concluded that LrFun is a new leaf rust resistance gene.

To detect the leaf rust resistance genes in the 7 Chinese spring wheat clultivars Shenmian 99025, Shenmia 99042, Shenmian 85, Shenmian 91, Shenmian 96, Shenmian 1167 and Shenmian 962, Thatcher, Thatcher backgrounded near-isogenic lines and 15 pathotypes of P. triticina were used for gene postulate at the seedling stage, and 9 of the 15 pathotypes were used in the field tests. Molecular markers closely linked to, or co-segregated with resistance genes Lr1, Lr9, Lr10, Lr19, Lr20, Lr21, Lr24, Lr26, Lr28, Lr29, Lr32, Lr34, Lr35, Lr37, Lr38 , and Lr47 were screened to assist detection of the resistance genes. As results, 4 known resistance genes, including Lr1, Lr9, Lr26 , and Lr34 , and other unknown resistance genes were postulated singly or in combination in the tested cultivars. Shenmian 85, Shenmian 91, Shenmian 96, Shenmian 962, Shenmian 1167, and Shenmian 99042 are potentially useful for wheat production and breeding programs. The result suggested that combining gene postulation, molecular markers and pedigrees is effective and more accuracy method to know the resistance genes in cultivars.

Neijiang 977671 and 19 near-isogenic lines with known leaf rust resistance genes were inoculated with 12 pathotypes of Puccinia triticina for postulation of leaf rust resistance genes effective at the seedling stage. The reaction pattern of Neijiang 977671 differed from those of the lines with known leaf rust resistance genes used in the test, indicating that Neijiang 977671 may carry a new leaf rust resistance gene(s). With the objective of identifying and mapping the new gene for resistance to leaf rust, F1 and F2 plants, and F2:3 families, from Neijiang 977671 × Zhengzhou 5389 (susceptible) were inoculated with Chinese P. triticina pathotype FHNQ in the greenhouse. Results from the F2 and F2:3 populations indicated that a single dominant gene, temporarily designated LrNJ97, conferred resistance. In order to identify other possible genes in Neijiang 977671 other eight P. triticina pathotypes avirulent on Neijiang 977671 were used to inoculate 25 F2:3 families. The results showed that at least three leaf rust resistance genes were deduced in Neijiang 977671. Bulked segregant analysis was performed on equal amounts of genomic DNA from 20 resistant and 20 susceptible F2 plants. SSR markers polymorphic between the resistant and susceptible bulks were used to analyze the F2:3 families. LrNJ97 was linked to five SSR loci on chromosome 2BL. The two closest flanking SSR loci were Xwmc317 and Xbarc159 at genetic distances of 4.2 and 2.2 cM, respectively. At present two designated genes (Lr50 and Lr58) are located on chromosome 2BL. In the seedling tests, the reaction pattern of LrNJ97 was different from that of Lr50. Lr50 and Lr58 were derived from T. armeniacum and Ae. triuncialis, respectively, whereas according to the pedigree of Neijiang 977671 LrNJ97 is from common wheat. Although seeds of lines with Lr58 were not available, it was concluded that LrNJ97 is likely to be a new leaf rust resistance gene.

Leaf rust, caused by Puccinia triticina, is one of the most widespread diseases in common wheat globally. The Chinese wheat cultivar Zhoumai 22 is highly resistant to leaf rust at the seedling and adult stages. Seedlings of Zhoumai 22 and 36 lines with known leaf rust resistance genes were inoculated with 13 P. triticina races for gene postulation. The leaf rust response of Zhoumai 22 was different from those of the single gene lines. With the objective of identifying and mapping, the new gene(s) for resistance to leaf rust, F1, F2 plants and F2:3 lines from the cross Zhoumai 22/Chinese Spring were inoculated with Chinese P. triticina race FHDQ at the seedling stage. A single dominant gene, tentatively designated LrZH22, conferred resistance. To identify other possible genes in Zhoumai 22, ten P. triticina races avirulent on Zhoumai 22 were used to inoculate 24 F2:3 lines. The same gene conferred resistance to all ten avirulent races. A total of 1300 simple sequence repeat (SSR) markers and 36 EST markers on 2BS were used to test the parents, and resistant and susceptible bulks. Resistance gene LrZH22 was mapped in the chromosome bin 2BS1-0.53-0.75 and closely linked to six SSR markers (barc183, barc55, gwm148, gwm410, gwm374 and wmc474) and two EST markers (BF202681 and BE499478) on chromosome arm 2BS. The two closest flanking SSR loci were Xbarc55 and Xgwm374 with genetic distances of 2.4 and 4.8 cM from LrZH22, respectively. Six designated genes (Lr13, Lr16, Lr23, Lr35, Lr48 and Lr73) are located on chromosome arm 2BS. In seedling tests, LrZH22 was temperature sensitive, conferring resistance at high temperatures. The reaction pattern of Zhoumai 22 was different from that of RL 4031 (Lr13), RL 6005 (Lr16) and RL 6012 (Lr23), Lr35 and Lr48 are adult-plant resistance genes, and Lr73 is not sensitive to the temperature. Therefore, LrZH22 is likely to be a new leaf rust resistance gene or allele.

The invertebrate intestinal mucin is a major protein constituent of the peritrophic membrane. A SeIIM8 identified from Spodoptera exigua larvae contains a 16-amino acid signal leading sequence and six chitin-binding domains with one intervening mucin-like domain and one Aps-Lys-rich domain. Prediction of O-glycosylation indicated that the amino acid residues from 97 to 244 were potential O-glycosylation sites. Recombinant SeIIM8 expressed in baculorvirus-infected insect cell lines binds chitin in vitro.

An enhancin-like gene was cloned from Bacillus thuringiensis (Bt) strain GS8 isolated from soil samples in china. The sequence analysis revealed that an open reading frame (ORF) of 2202 nucleotides encoding a protein containing 733 amino acids with a molecular mass of 84 kDa. The enhancin-like protein showed 100% identity to Bel protein (FJ644935) and 23%–41% identity to viral enhancin proteins; in the 252 to 261 amino-acid sequence of enhancin-like protein, a conserved metal binding motif (HEIAH) similar to that in the reported bacterial enhancin-like proteins was found (HEXXH in viral enhancin protein), which indicated that the enhancin-like protein belongs to metalloprotease. The purified enhancin-like protein was fed together with Cry9Ea to Spodopera exigua and Trichoplusia ni larvae, but no significant increase in toxicity was observed.

This research was aimed to develop AFLP markers co-segregated with gene Lr24 and validate the using for marker assisted selection (MAS). An F2 population developed from the cross between the resistant line TcLr24 and the susceptible line Thatcher was tested for resistance to the Puccinia triticina races BGQQ and SHRT using for genetic analysis and molecular marker. A total of 224 AFLP primer combinations were used to test the resistant and susceptible parents, as well as the resistant bulk and the susceptible bulk. Four AFLP markers, P-AGA/M-CTT289 bp, P-AGC/M-CAC188 bp, P-AGC/M-CAC162 bp and P-ACG/M-CGC239 bp were co-segregated with Lr24. The AFLP fragment from the primer combination P-ACG/M-CGC was cloned, sequenced and converted into a STS marker named as ASTS212. Thatcher backgrounded NILs and 115 varieties were examined by using this STS marker and the marker SCS1302607 developed by Gupta. 5R615, 5R616, 1R13, and 1R17 were identified and validated to contain gene Lr24. The marker is dominant and may be useful in identification the resistance gene Lr24 in wheat and wheat breeding programs.

Virus-induced gene silencing (VIGS) offers a rapid and high throughout technology platform for the analysis of gene function in plants. The barley stripe mosaic virus (BSMV) VIGS system was optimized in studies silencing phytoene desaturase expression in wheat, and demonstrated that infection with BSMV construct carrying a 412 bp fragment of TaRAR1 caused conversion of incompatible to compatible interactions to Lr24-mediated resistance in wheat TcLr24 and cultivar 5R615 harboring Lr24 whereas infection with a control construct had no effect on resistance or susceptibility. RT-PCR analysis showed that BSMV-induced gene silencing could be detected at mRNA levels. These studies indicated that TaRAR1 was a required component for Lr24-mediated race-specific resistance and the BSMV-VIGS was a powerful tool for dissecting the genetic pathways of disease resistance in hexaploid wheat.

To clone the antibiotic biosynthesis gene cluster of Streptomyces roseoflavus Men-myco-93-63, we constructed a Fosmid genomic library. The genomic DNA of the strain Men-myco-93-63 was isolated by the modified CTAB procedure, and the size of most genomic DNA fragments was larger than 150 kb. Then, a Fosmid genomic library containing more than 6000 clones was constructed. The average size of the inserted DNA in recombinant plasmids was 38.1 kb, and the probability of harboring any gene in the genome of the strain Men-myco-93-63 was 99.99%. The library coverage was at least a 10-fold genome equivalent. Therefore, the constructed Fosmid library meets the requirements as a standard genomic library