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Hou Y.,Nanjing Agricultural University | Luo Q.,Nanjing Agricultural University | Luo Q.,Shanghai Institute of Landscape Gardening Science | Chen C.,Nanjing Agricultural University | Zhou M.,Nanjing Agricultural University
Pest Management Science | Year: 2011

Background: Resistance of Fusarium graminearum to the benzimidazole fungicide carbendazim is caused by point mutations in the β2-tubulin gene (FGSG-06611.3). The point mutation at codon 167 (TTT → TAT, F167Y) occurs in more than 90% of field isolates in China. It is important to find a suitable method for rapid detection and quantification of this point mutation in the F. graminearum populations. Results: A pair of primers, Codon167F/Codon167R, were designed to amplify a fragment containing the mutation site, and two cycling probes labelled with different fluorescent reporters were used to detect whether the mutation was present. A cycleave real-time PCR method was developed for rapid determination of the frequency of this point mutation in 282 F. graminearum perithecia collected from different fields in Jiangsu Province, China. The mutation frequency in ascospores from the perithecia to carbendazim by a spore germination assay was 6.0%, while the frequency of the point mutation at codon 167 by the cycleave real-time PCR assay was 3.9%. Conclusion: The cycleave real-time PCR method is suitable for accurate detection of the codon 167 point mutation. The frequency of this mutation in the β2-tubulin gene represents the resistance frequency in F. graminearum populations to carbendazim. © 2011 Society of Chemical Industry. Source


Hou Y.,Nanjing Agricultural University | Luo Q.,Shanghai Institute of Landscape Gardening Science | Chen C.,Nanjing Agricultural University | Zhou M.,Nanjing Agricultural University
Australasian Plant Pathology | Year: 2013

Tetra-primer ARMS-PCR (amplification refractory mutation system-PCR) was developed to detect isolates of Fusarium graminearum with resistance to carbendazim, a methyl benzimidazole carbamate-group fungicide. Resistance to carbendazim in F. graminearum is caused by point mutations at codon 167, 198, and 200 of the β 2-tubulin gene (FGSG-06611.3). According to single nucleotide polymorphisms on codon 167, 198, 200 of the resistance gene β 2-tubulin gene, two pairs of primer designed on each codon respectively, were used for amplification. SNP genotyping was made successfully based on the different patterns in agarose gels between point mutations and wild type strain. Tetra-primer ARMS-PCR protocol developed in this study is a simple and useful technique to identify genotypes and has a potential application in management of carbendazim resistance in F. graminearum. It will help researchers and growers select the best antifungal strategy to use in the field. © 2012 Australasian Plant Pathology Society Inc. Source


Ju R.-T.,Shanghai Institute of Landscape Gardening Science | Ju R.-T.,Fudan University | Chen G.-B.,Shanghai Institute of Landscape Gardening Science | Wang F.,Shanghai Institute of Landscape Gardening Science | Li B.,Fudan University
Entomologia Experimentalis et Applicata | Year: 2011

The sycamore lace bug, Corythucha ciliata (Say) (Hemiptera: Tingidae), is an invasive exotic pest on Platanus trees in China. This study assessed the thermotolerance of C. ciliata in the laboratory. Detailed experiments were conducted on the effects of high temperature (35, 37, 39, 41, 43, and 45°C), duration of exposure (0.5, 1, 2, 4, 6, and 8h), and developmental stage (egg, nymph, and adult) on survival of the bug. Meanwhile, the effects of heat hardening on survival at lethal temperature (exposure to 33, 35, 37, 39, and 41°C for 1h prior to transfer to 43°C for 2h) were also assessed for nymphs and adults. Survival of eggs, nymphs, and adults was not affected by temperatures between 35 and 39°C, but declined rapidly with increasing duration of exposure (from 0.5 to 8h) at temperatures ≥41°C. The lethal temperature that caused mortality of 50% (Ltemp 50) of all developmental stages decreased with increasing duration of exposure from 0.5 to 8h. The Ltemp 50 for nymphs was 44.3, 42.0, and 39.0°C after 0.5, 2, and 8h exposure, respectively. Thermotolerance was the highest in eggs, followed by adults and then nymphs. Thermotolerance was slightly greater for adult males than for adult females. The ability of nymphs, females, and males to survive exposure to 43°C for 2h significantly increased by heat hardening, i.e., by exposure to a non-lethal high temperature for 1h; the optimal heat-hardening temperature was 37°C. The results indicate that survival of C. ciliata at heat-shock temperatures depended on both the temperature and the duration of exposure, and the tolerance to heat shock was enhanced by heat hardening. The thermotolerance of C. ciliata may partially explain why C. ciliata has been rapidly spreading on Platanus trees in southern provinces of China. © 2011 The Authors. Entomologia Experimentalis et Applicata © 2011 The Netherlands Entomological Society. Source


Ju R.-T.,Fudan University | Ju R.-T.,Shanghai Institute of Landscape Gardening Science | Wang F.,Shanghai Institute of Landscape Gardening Science | Li B.,Fudan University
Journal of Insect Science | Year: 2011

The sycamore lace bug, Corythucha ciliata (Say) (Hemiptera: Tingidae), is an important invasive exotic pest of Platanus (Proteales: Platanaceae) trees in China. The objective of this study was to determine the effects of temperature on C. ciliata in the laboratory so that forecasting models based on heat accumulation units could be developed for the pest. Development and fecundity of C. ciliata reared on leaves of London plane tree (Platanus × acerifolia) were investigated at seven constant temperatures (16, 19, 22, 26, 30, 33, and 36!″#) and at a relative humidity of 80% with a photoperiod of 14:10 (L:D). The developmental time was found to significantly decrease with increasing temperature. The developmental time from egg hatching to adult emergence was respectively 47.6, 35.0, 24.1, 20.0, and 17.1 days at the temperatures of 19, 22, 26, 30, and 33!″#. C. ciliata could not complete full development at 16° and 36!″#. The developmental threshold temperature (C) estimated for egg-to-adult was 11.17!″#, with a thermal constant of (K) 370.57 degree-days. Longevity of females was found to be the shortest, 17.7 days at 33! C and the longest, 58.9 days at 16! C, and that of males was the shortest, 19.7 days at 33! C and the longest, 59.7 days at 16! C. Fecundity was the highest at 30!″#, being 286.8 eggs per female over an oviposition period of 8.9 days. Female lifetime fecundity was reduced at other temperatures, being the lowest (87.7 eggs per female) at 19!″#. The population trend index (I) of C. ciliata was the highest (130.1) at 30!″# and the lowest (24.9) at 19!″#. Therefore, the optimal developmental temperature for C. ciliata was determined to be 30!″#. Source


Ju R.-T.,Shanghai Institute of Landscape Gardening Science | Ju R.-T.,Fudan University | Xiao Y.-Y.,Shanghai Institute of Landscape Gardening Science | Li B.,Fudan University
Journal of Insect Physiology | Year: 2011

The sycamore lace bug, Corythucha ciliata is a new, invasive pest of Platanus trees in China. Although C. ciliata is often subjected to acute low temperatures in early winter and spring in northern and eastern China, the cold tolerance of C. ciliata has not been well studied. The objectives of this study were to determine whether adults of C. ciliata are capable of rapid cold hardening (RCH), and to compare the benefits of RCH vs. cold acclimation (ACC) in the laboratory. When the adult females incubated at 26°C were transferred directly to the discriminating temperature (-12°C) for 2h, survival was only 22%. However, exposure to 0°C for 4h before transfer to -12°C for 2h induced RCH, i.e., increased survival to 68%. RCH could also be induced by gradual cooling of the insects at rates between 0.1 and 0.25°Cmin -1. The protection against cold shock obtained through RCH at 0°C for 4h was lost within 1h if the adults were returned to 26°C before exposure to -12°C. Survival at both -12 and -5°C was greater for RCH-treated than for ACC-treated adults (for ACC, adults were kept at 15°C for 5days), and the lethal temperature (2h exposure) was lower for RCH-treated than for ACC-treated adults. The results suggest that RCH may help C. ciliata survive the acute low temperatures that often occur in early winter and early spring in northern and eastern China. © 2011 Elsevier Ltd. Source

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