Recent studies have shown that mating can alter starvation resistance in female D. melanogaster, but little is known about the behavioral and physiological mechanisms underlying such mating-mediated changes in starvation resistance. In the present study, we first investigated whether the effect of mating on starvation resistance is sex-specific in D. melanogaster. As indicated by a significant sex × mating status interaction, mating increased starvation resistance in females but not in males. In female D. melanogaster, post-mating increase in starvation resistance was mainly attributed to increases in food intake and in the level of lipid storage relative to lean body weight. We then performed quantitative genetic analysis to estimate the proportion of the total phenotypic variance attributable to genetic differences (i.e., heritability) for starvation resistance in mated male and female D. melanogaster. The narrow-sense heritability (h2) of starvation resistance was 0.235 and 0.155 for males and females, respectively. Mated females were generally more resistant to starvation than males, but the degree of such sexual dimorphism varied substantially among genotypes, as indicated by a significant sex × genotype interaction for starvation resistance. Cross-sex genetic correlation was greater than 0 but less than l for starvation resistance, implying that the genetic architecture of this trait was partially shared between the two sexes. For both sexes, starvation resistance was positively correlated with longevity and lipid storage at genetic level. The present study suggests that sex differences in starvation resistance depend on mating status and have a genetic basis in D. melanogaster.

Establishment of rapid resistance level detection system is essential step to adopt the adaptive management for the control of various kinds of resistant pest population. Here, we established acaricides resistance detection methods based on residual contact vial bioassay (RCV) and quantitative sequencing methods (QS), and applied to determine the resistance levels from several populations in two-spotted spider mite, Tetranychus urticae, which has been considered as major notorious pest in rose cultivation area in worldwide. 12 acaricides were applicable to the RCV among 19 representative acaricides by showing the dose-dependent mortality within 8 hr, suggesting the acaricide suitability for the RCV might be varied by toxicity mechanism in each acaricides. The QS regression was established for 10 point mutations associated with five number of acaricides resistance such as organophosphate, pyrethroid, abamectin, bifenazate and etoxazol. The 95% prediction level was ranged from 10.8±5.4∼92.2±3.2%. The resistance levels were determined by above two detection methods from a total 12 strains. The laboratory-reared populations were revealed high susceptibility with low resistance allele frequencies to some acaricides, suggesting the several acaricides would be chosen for the control of those populations. However, the field-collected populations were exhibited a severe cross resistance with low susceptibility and high resistance allele frequency to almost tested acaricides, suggesting the current acaricides resistance levels are serious in rose cultivation area in Korea. The RCV and QS methods would be useful for the rapid and accurate collection of valuable information associated with acaricide resistance.

The resistance levels to carbamate (CB) and organophosphate (OP) insecticides were determined by topical application in 14 field strains of Nilaparvata lugens. The resistance levels to CB and OP were 1.3~47.5-fold and 1.4~14.4-fold higher than a susceptible strain, respectively. A quantitative sequencing (QS) protocol was established to determine the allele frequencies of four acetylcholinesterase point mutations putatively associated with CB and OP resistance. The allele frequencies of the four mutations (G119A, F/Y330S, F331H and I332L) in field strains ranged from ca. 0.0~51.7%, 0.0~88.9%, 2.5~47.7%, 5.1~56.0% and 6.7~57.3%, respectively. The F331H and I332L were tightly linked each other, suggesting these mutations may occur simultaneously. In the correlation analysis, G119A was not well correlated with actual resistance levels (r2= < 0.232), whereas F331H and I332L showed a better correlation with the resistance levels of benzofuranyl methylcarbamates (r2= 0.595). This finding indicates that F331H and I332L mutation frequencies may be used as molecular markers for detecting carbamate resistance in N. lugens. A QS protocol detecting the F331H and I332L mutation frequencies would be employed as a supportive tool for rapid monitoring of CB insecticide resistance levels in N. lugens

The resistance levels against carbamates (CB) and organophosphates (OP) were determined through bioassay and quantitative sequencing (QS) methods in 16 field populations of Nilaparvata lugens. The resistance levels to CB and OP by bioassay were 1.3~47.5-fold and 1.4~14.4-fold higher than a susceptible strain, respectively. The QS protocol was established to determine the allele frequencies of eight point mutations on acetylcholinesterase putatively associated CB and OP resistance. The allele frequencies of four mutations in local populations (G119A, F/S330Y, F331H and I332L) ranged from ca. 0.0~51.7%, 1.0~44.3%, 8.5~57.3% and 7.12~56.6%, respectively. The average prediction limits were –9.6±5.1~7.7±2.9%. The F330Y, F331H and I332L were tightly linked each other, suggesting these mutations may occur simultaneously. In the correlation analysis, G119A was not well correlated with both insecticides (r2= less 0.25), whereas F/S330Y, F331H and I332L showed better correlation with the resistance levels of carbamate (r2=0.590) than organophosphate (r2=0.235). This finding indicates that F/S330Y, F331H and I332L mutation frequencies are suitable for detecting carbamate resistance in N. lugens. QS will be applicable for the rapid monitoring of resistance levels to CB insecticides in N. lugens.

A quantitative sequencing (QS) protocol was established for predicting the frequencies of the A298S and G324A mutations in the diamondback moth (Plutella xylostella) type-1 acetylcholinesterase locus, putatively involved with organophosphate and carbamate insecticideresistance. The nucleotide signal ratio at each mutation site was generated from sequencing chromatograms and plotted against the corresponding resistance allele frequency. Frequency prediction equations were generatedfrom the plots by linear regression, and the signal ratios were shown to highly correlated with resistance allele frequencies (r2>0.987). QS analysis of 15 representative regional field populations of DBM in Korea revealed that the allele frequencies of both A298S and G324A were over 70% in most field populations. As judged by inhibition assay, all populations showed resistance to paraoxon, DDVP, carbaryl, and carbofuran. In addition, different DBM strains exhibited differential sensitivities to both OPs and CBs depending on the structure of inhibitor, implying that the resistance of DBM against OPs and CBs is saturated and widespread in Korea.

Two point mutations (V419L and L925I) in the voltage-sensitive sodium channel (VSSC) α-subunit gene have been identified in deltamethrin-resistant bedbugs. To predict resistance allele frequencies of sodium channel mutations (V419L and L925I) in bedbugs at a population level, we developed quantitative sequencing (QS) protocol. The signal ratios between resistant and susceptible nucleotides were generated from sequencing chromatogram and plotted against the corresponding resistance allele frequencies. Linear regression coefficients of the plots were close to 1 (r2 = 0.9928 and 0.9998), suggesting that the signal ratios are reliable correlated with the resistance allele frequencies. To enable on-site monitoring of pyrethroid resistance in bed bugs, residual contact vial (RCV) bioassay method was established and used to determine median lethal concentration (LC50) values to deltamethrin for various bed bug strains. Resistance allele frequencies in these bedbug strains predicted by QS were correlated well with the RCV bioassay results, confirming the roles of two mutations in pyrethroid resistance. Taken together, employment of QS in conjunction with RCV bioassay should greatly facilitate resistance monitoring of bedbugs in the field.

A quantitative sequencing (QS) protocol that detects the frequencies of sodium channel mutations (M815I, T917I and L920F) responsible for knockdown resistance in permethrin-resistant head lice was tested as a population genotyping method. Genomic DNA fragments of the sodium channel α-subunit gene that encompass the three mutation sites were PCR-amplified from individual head lice with either resistant or susceptible genotypes, and combined together in various ratios to generate standard DNA template mixtures for QS. Following sequencing, the signal ratios between resistant and susceptible nucleotides were calculated and plotted against the corresponding resistance allele frequencies. Quadratic regression coefficients of the plots were close to 1, demonstrating that QS is highly reliable for the prediction of resistance allele frequencies. Prediction of resistance allele frequencies by QS in several globally collected lice samples including 12 Korean lice populations suggested that permethrin resistance varied substantially amongst different geographical regions. Three local populations of Korean lice were determined to have 9.8-36.7% resistance allele frequencies, indicating that an urgent resistance management is needed. QS should serve as a preliminary resistance monitoring tool for proper management strategies by allowing early resistance detection.

Radish, Raphanus sativus(2n = 18), belonging to the brassicaceae family, is herbaceous plant with 1-2 years life cycle. It is cultivated worldwide for producing leafy and root vegetables. Although an economically important crop, the genetics of yield and quality traits, disease resistance are not well-studies. The major purpose of this project is development of molecular breeding technology in radish. In this project, quantitative trait loci (QTL) for Fusarium wilt resistance of radish were analyzed. To identify QTL, genetic linkage map of radish was constructed using F2 mapping population derived from a cross between two inbred lines, “DB01” (resistant) and “DB05” (susceptible). A total 319 markers have been mapped into nine linkage groups, covering 639.3cM with an average distance of 2cM between loci. QTL mapping detected 2 loci conferring Fusarium wilt resistance. Two QTLs were located on LG3 and LG7, respectively. The QTL of LG3, flanked by EAGGMCT6 and WALK500 marker, exhibited a LOD value ranging from 2.3 to 8.7, and the R2 (Phenotypic variations) ranging from 28 to 48% in four tests. This QTL was named qYR1. The QTL of LG7, flanked by EACCMCAC-202 and DCJ14-390 marker, exhibited a LOD value ranging from 6.2 to 10.6, and the R2 ranging from 42 to 55% in four tests. This QTL was named qYR2. The results of the QTL analysis may be useful in marker-assisted selection (MAS) of Fusarium wilt resistant radish cultivars.

Bakanae disease incidence threat is an increasing trend in the top rice growing countries. Despite it is essential to identify the resistant genes and underlying mechanisms of bakanae disease to develop resistant varieties, there are very limited genetic studies on bakanae disease in rice. The indica rice variety Shingwang was selected as resistant donor to bakanae disease. One hundred sixty nine NILs, YR28297 (BC6F4) generated by five backcrosses of Shingwang with the genetic background of susceptible japonica variety, Ilpum were used for QTL analysis. Rice bakanae disease pathogen, CF283, was mainly used in this study and inoculation and evaluation of bakanae disease was performed with the method of the large-scale screening method developed by Kim et al. (2014). The proportion of healthy plants of Shingwang and Ilpum after inoculation was confirmed using bakanae disease pathogen, CF283. While inoculated Ilpum showed thin and yellowish-green phenotype which is typical symptom of Bakanae disease, Shingwang showed similar healthy phenotype with control plants. A major QTL for resistance against bakanae disease on chromosome 1 was identified using SSR marker, RM9, which explaining 65 % of the total phenotype variation. The major QTL designated as qBK1 and mapped to a 4.4 Mbp region between RM24 (19.30 Mb) and RM11295 (23.72 Mb). The information of qBK1 could be useful for improving rice bakanae disease resistance in marker-assisted breeding.

The whitebacked planthopper (WBPH) is one of the most serious insect pests of rice. The nymphs and adults suck the phloem sap which causes reduced plant vigor, stunting, yellowing of leaves. We employed a mapping population composed of 113 doubled haploid lines (DHLs), derived from a cross between resistant cultivar ‘Cheongcheong’ and susceptible cultivar ‘Nagdong’, to identify the quantitative trait loci (QTL) associated with WBPH resistance. The DH population was evaluated for resistance to WBPH using seed box screening test. The WBPH resistance of each lines or plants was estimated when susceptible check ‘Nagdong’ was killed using 1-9 scale according to Standard Evaluation System for Rice (IRRI, 1988). A linkage map was constructed with 119 polymorphic microsatellite markers using the Joinmap 4 software program to adjust for segregation distortion. Transgressive segregation was observed on WBPH resistance. Two significant QTLs conferring resistance to WBPH, qwbph6.1 and qwbph6.2, were detected in the regions of RM588-RM276 and RM527-RM528 on chromosome 6 with LOD scores of 3.7 and 2.4, respectively. They collectively explained 55% of phenotypic variation. These two QTLs have large effects on WBPH resistance and may be useful for establishment of marker assisted selection (MAS) in the rice breeding programs.

본 연구는 최근 우리나라에서 급격하게 발생되고 있는 콩 불마름병에 대한 저항성 중간모본을 육성하고자 할 때 marker-assisted selection에 적용할 수 있는 저항성 근접 분자표지를 개발하고자 수행하였다. 1. 불마름병에 이병성인 큰올콩과 저항성인 신팔달콩의 RIL 116 계통에 대하여 콩 불마름병 균주 8ra에 대한 저항성과 연관된 QTL을 탐색한 결과 포장에서는 연관군 B2, D2, I와 K에서, 온실에서는 연관군 D2, C1과 F에서

The elite rice cultivar, Suweon365, shows high level of leaf blast resistance. The number and chromosomal locations of genes conferring the resistance were detected by linkage analysis using DNA markers in the RILs from the cross between Suweon365 and Chu

콩 품종 Essex와 PI 437654간 교잡 후 F2 유래 F3 계통들을 재료로 하여 작성된 RAPD 유전자지도상에 cyst 선충 race 5에 대한 저항성 QTLs 분석을 실시한 바 결과를 요약하면 다음과 같다. 1. 회귀분석 결과 26개의 marker들(22 RAPD, 4 RFLP)에서 cyst 선충 race 5 저항성 반응에 대한 유의성이 인정되었다. 2. MAPMAKER /QTL 분석 결과2개의 저항성 QTL들이 탐색되었는데, 이 QTL들은 2개의 linkage groups(LGC-20와 Group 2)에 위치하였다. 3. 탐색된 2개의 QTL들 중 1개는 우성유전, ？고 나머지 하나는 열성유전양상을 나타내었다. 4. 콩 cyst 선충 race 5의 저항성에 대한 유의성이 인정되는 5개의 marker들간 상호작용을 알아보기 위한 다중회귀분석 결과 총 26개의 조합들 중 4개의 marker들(E023 , G101 , W03, pK418C)로 구성된 조합에서 가장 높은 표리적 변이의 값(35.2%)을 나타내었다.