Aspects of brown planthopper adaptation to resistant rice varieties with the Bph3 gene

Despite over 30 years of deployment, varieties with the Bph3 gene for resistance to the brown planthopper (BPH), Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), are still effective in much of the Philippines. In the present study, we determined the effects of adaptation to one resistant variety, IR62 – assumed to possess the Bph3 gene – on (1) resistance against a series of varieties with similar biotypical responses (presumed to contain the same major resistance genes), and (2) a differential variety with the bph4 gene that occurs at the same chromosome position as Bph3. We also examined the effects of high soil nitrogen on the effectiveness of Bph3. Feeding, planthopper biomass, and development times were reduced in a wild BPH population when reared on IR62 compared with the susceptible standard variety TN1. However, nitrogen application increased the susceptibility of IR62. After 13 generations on IR62, BPH had adapted to the plant’s resistance. Virulence of the adapted BPH against the variety ‘Rathu Heenati’ supports the idea that Bph3 is present in IR62. Across similar IR varieties (IR60, IR66, IR68, IR70, IR72, and IR74), feeding, planthopper biomass, and development rates were generally higher for IR62‐adapted than for non‐adapted BPH; however, contrary to expectations, many of these varieties were already susceptible to wild BPH. Fitness was also higher for IR62‐adapted BPH on the variety ‘Babawee’ indicating a close relation between Bph3 and bph4. The results indicate that the conventional understanding of the genetics behind resistance in IR varieties needs to be readdressed to develop and improve deployment strategies for resistance management.     

云南野生稻抗褐飞虱评价及其抗性基因鉴定

褐飞虱是水稻生产中最严重的害虫之一,从野生稻中发掘抗虫基因,有利于培育具有抗虫能力强的水稻新品种。该研究通过对云南野生稻进行温室和大田抗虫鉴定以及9个已知抗褐飞虱基因的PCR鉴定,发现云南野生稻对褐飞虱表现出不同程度的抗性,尤其疣粒野生稻和药用野生稻对褐飞虱表现出高抗,可作为抗虫基因发掘的优良抗源材料;不同褐飞虱抗性的云南野生稻中含有的抗褐飞虱基因差异很大,3种野生稻中均不含Bph1和Bph18(t)抗病基因,景洪普通野生稻和元江普通野生稻可能含bph2基因,东乡普通野生稻可能含bph2、Bph15和Bph27(t)基因,疣粒野生稻中可能含bph2和bph19(t)基因,药用野生稻和药用野生稻(宽叶型)中可能含bph2和Bph6基因,药用野生稻F1中可能含bph2、Bph14和bph20(t)基因,药用野生稻F2中可能含bph2和Bph27(t)基因或者其同源基因。该研究为快速发掘利用云南野生稻中的抗虫基因奠定了理论基础。     

Survival rate and stylet penetration behavior of current Korean populations of the brown planthopper,Nilaparvata lugens,on resistant rice varieties

To understand the development of host plant resistance-breaking ability of the current BPH populations in Korea, we conducted nymphal survivorship tests and electrical penetration graph (EPG) studies on susceptible and resistant rice varieties with four different BPH populations, which were collected in the early 1980s (S-BPH) and in 2005, 2006, and 2007. The S-BPH had low survival rates on resistant rice varieties carrying either Bph1 or bph2. However, the current BPH populations have high resistance-breaking ability on the varieties with their elevated survival rates, whereas their survival rates were still low on the other resistant varieties, Gayabyeo (Bph1  the other unknown gene) and Rathu Heenati (Bph3). The EPG analysis also revealed that the ratio of BPH that could reach the phloem sap ingestion waveform (N4-b) within 15 h on the resistant rice varieties containing Bph1 or bph2 was higher in the current BPH populations (16.7–50%) than in the S-BPH population (0-4.2%). However, the pre-reaching time from the penetration start to the first N4-b waveform in the current BPH populations was significantly longer on resistant varieties (Bph1 or bph2) than on susceptible varieties. Furthermore, the total duration of N4-b waveform was significantly shorter on the resistant varieties.From these results, we suggest that, although the current BPHs collected in Korea have a high resistance-breaking ability through the increase of survival rate on resistant rice varieties carrying either Bph1 or bph2, they still have some difficulties feeding on the phloem sap of the resistant rice varieties.     

Feeding‐induced changes in defence enzymes and PR proteins and their implications in host resistance to Nilaparvata lugens

Six rice genotypes showing susceptible and resistant reactions to brown planthopper (BPH), Nilaparvata lugens were studied for feeding‐induced changes in defence enzymes and pathogenesis‐related (PR) proteins. The high resistant genotypes PTB 33, ADT 45 and ASD 7 and moderately resistant genotypes CO 43 and KAU 1661 recorded the greater expression of defence enzymes peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, total phenol and β‐1,3 glucanase in response to N. lugens feeding at 1 day after infestation (DAI) compared with susceptible genotype TN1. The greater activity of chitinase was observed in resistant cultivars at 3 DAI and the activity was sustained for more than 1 week compared with susceptible TN1. In conclusion, the current study revealed that these defence enzymes and PR proteins might attribute to the resistance mechanisms in rice plants against BPH infestation.     

Electrical penetration graphs indicate that tricin is a key secondary metabolite of rice,inhibiting phloem feeding of brown planthopper,Nilaparvata lugens

Tricin (5,7,4′‐trihydroxy‐3′,5′‐dimethoxyflavone) is a valuable secondary metabolite which is widely present in gramineous plants, including cultivated rice (Oryza sativa L.) (Poaceae). It can defend the rice plant against damage by the brown planthopper (BPH), Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), one of the most important pests of rice. This study was conducted to elucidate the mechanisms of action of tricin on BPH feeding behavior. BPH feeding behavior in resistant (Rathu Heenati, RHT) and susceptible (Taichuang native 1, TN1) rice varieties and artificial diets was monitored using the electrical penetration graph (EPG) technique. Tricin concentrations in leaves of varieties RHT and TN1 were quantitatively analyzed by liquid chromatography, coupled to tandem mass spectrometric techniques. Six (NP and N1‐5) and four (NP, N1, N2, and N4) types of waveforms occurred during feeding on rice plants and artificial diets, respectively. The tricin concentration of rice varieties was correlated with total and average durations of N4. Moreover, EPG data indicated that tricin significantly increased the duration of non‐probing and pathway periods and strongly inhibited phloem ingestion (N4). The inhibition was strongly dose dependent, resulting in complete suppression of activity in the phloem region when the tricin concentration was increased to 1 g l^?1. This study revealed that tricin disturbed the feeding behavior of BPH mainly by increasing the non‐probe period and inhibiting phloem ingestion. We confirmed the hypothesis that tricin is a ‘stylet probing stimulant’ of rice planthoppers as proposed in previous studies. The information on the ecological effect of tricin from this study may be useful to clarify the resistance mechanism against BPH of RHT and other tricin‐containing rice varieties.     

Differential expression of vitellogenin mRNA and protein in response to rice resistance genes in two strains of <Emphasis Type="Italic">Nilaparvata</Emphasis><Emphasis Type="Italic">lugens</Emphasis> (Hemiptera: Delphacidae) with different levels of virulence

Controlling the brown planthopper (BPH), Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), is a difficult task in rice (Oryza sativa L.) production. We focused on vitellogenins (Vg), which are the major yolk protein precursors of vitellins and play an important role in the reproduction of oviparous species, including insects. We studied the accumulation of Vg mRNA and protein in a virulent BPH strain, Nagasaki-03, and a nonvirulent strain, Hatano-66, after rearing them on four rice lines. The rice lines used were two single resistance gene introgression lines, Norin-PL3 (Bph1 carrier) and Norin-PL4 (bph2 carrier), a pyramided line in which both genes were combined, and a susceptible japonica recurrent parent Tsukushibare. RT-PCR and quantitative RT-PCR analyses showed that the Vg mRNA level decreased greatly in Hatano-66 on the resistant lines. In contrast, the level of reduction on the resistant lines was much less in Nagasaki-03. Immunoblot analysis showed that Nagasaki-03 retained comparable levels of 175 kDa Vg protein on both the susceptible and resistant lines, whereas in Hatano-66, no Vg protein was detected on the resistant lines. Our results showed that BPH resistance genes caused differential reduction in the accumulation of Vg mRNA and protein, leading to the retardation of BPH reproduction on the resistant host rice plants.     

Genetic mapping of the rice resistance-breaking gene of the brown planthopper Nilaparvata lugens

Host plant resistance has been widely used for controlling the major rice pest brown planthopper (BPH, Nilaparvata lugens). However, adaptation of the wild BPH population to resistance limits the effective use of resistant rice varieties. Quantitative trait locus (QTL) analysis was conducted to identify resistance-breaking genes against the anti-feeding mechanism mediated by the rice resistance gene Bph1. QTL analysis in iso-female BPH lines with single-nucleotide polymorphism (SNP) markers detected a single region on the 10th linkage group responsible for the virulence. The QTL explained from 57 to 84% of the total phenotypic variation. Bulked segregant analysis with next-generation sequencing in F₂ progenies identified five SNPs genetically linked to the virulence. These analyses showed that virulence to Bph1 was controlled by a single recessive gene. In contrast to previous studies, the gene-for-gene relationship between the major resistance gene Bph1 and virulence gene of BPH was confirmed. Identified markers are available for map-based cloning of the major gene controlling BPH virulence to rice resistance.     

High-resolution genetic mapping at the <Emphasis Type="Italic">Bph15</Emphasis> locus for brown planthopper resistance in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Resistance to the brown planthopper (BPH), Nilaparvata lugens Stål, a devastating sucking insect pest of rice, is an important breeding objective in rice improvement programs. Bph15, one of the 17 major BPH resistance genes so far identified in both cultivated and wild rice, has been identified in an introgression line, B5, and mapped on chromosome 4 flanked by restriction fragment length polymorphism markers C820 and S11182. In order to pave the way for positional cloning of this gene, we have developed a high-resolution genetic map of Bph15 by positioning 21 DNA markers in the target chromosomal region. Mapping was based on a PCR-based screening of 9,472 F₂ individuals derived from a cross between RI93, a selected recombinant inbred line of B5 bearing the resistance gene Bph15, and a susceptible variety, Taichung Native 1, in order to identify recombinant plants within the Bph15 region. Recombinant F₂ individuals with the Bph15 genotype were determined by phenotype evaluation. Analysis of recombination events in the Bph15 region delimited the gene locus to an interval between markers RG1 and RG2 that co-segregated with the M1 marker. A genomic library of B5 was screened using these markers, and bacterial artificial chromosome clones spanning the Bph15 chromosome region were obtained. An assay of the recombinants using the sub-clones of these clones in combination with sequence analysis delimited the Bph15 gene to a genomic segment of approximately 47 kb. This result should serve as the basis for eventual isolation of the Bph15 resistance gene.     

Study of the relationship between the content of the rare earth element Eu in rice plants and in Nilaparvata lugens (Hemiptera: Delphacidae)

Abstract The current study investigated changes in the content of the rare earth element Europium (Eu) in roots, shoots and leaves of rice plants and in Nilaparvata lugens Stål (Hemiptera: Delphacidae) using an Eu marker and hydroponic culture. The results showed that N. lugens infestation significantly reduced Eu content in roots, shoots and leaves of two rice varieties, Shenyou 1 and Xieyou 963. The Eu content in roots, shoots and leaves of the susceptible variety, Shenyou 1, was significantly higher than that in the resistant variety, Xieyou 963. The Eu content of N. lugens fed on Shenyou 1 was significantly higher than of those fed on Xieyou 963. In addition, the Eu level was elevated at a higher density of N. lugens infestation. Eu content in the bodies of N. lugens was related to their weight and honeydew excretion, with a significant positive correlation. Thus, Eu content in the bodies of N. lugens can be considered an index of the amount of phloem sap taken in by N. lugens because the amount of honeydew excretion is proportional to the amount of phloem sap consumed. The ratios of Eu content in N. lugens to that in roots, shoots and leaves of rice plants were elevated at a higher N. lugens infestation density. That ratio was maximal in leaves, was intermediate in shoots and was minimal in roots. There was no significant difference in ratios between the two plant varieties. An Eu marker may be useful in the screening of resistant varieties and in the study of the mechanisms of resistance.     

Insights into the structure–function relationship of brown plant hopper resistance protein,Bph14 of rice plant: a computational structural biology approach

Brown plant hopper (BPH) is one of the major destructive insect pests of rice, causing severe yield loss. Thirty-two BPH resistance genes have been identified in cultivated and wild species of rice Although, molecular mechanism of rice plant resistance against BPH studied through map-based cloning, due to non-existence of NMR/crystal structures of Bph14 protein, recognition of leucine-rich repeat (LRR) domain and its interaction with different ligands are poorly understood. Thus, in the present study, in silico approach was adopted to predict three-dimensional structure of LRR domain of Bph14 using comparative modelling approach followed by interaction study with jasmonic and salicylic acids. LRR domain along with LRR-jasmonic and salicylic acid complexes were subjected to dynamic simulation using GROMACS, individually, for energy minimisation and refinement of the structure. Final binding energy of jasmonic and salicylic acid with LRR domain was calculated using MM/PBSA. Free-energy landscape analysis revealed that overall stability of LRR domain of Bph14 is not much affected after forming complex with jasmonic and salicylic acid. MM/PBSA analysis revealed that binding affinities of LRR domain towards salicylic acid is higher as compared to jasmonic acid. Interaction study of LRR domain with salicylic acid and jasmonic acid reveals that THR987 of LRR form hydrogen bond with both complexes. Thus, THR987 plays active role in the Bph14 and phytochemical interaction for inducing resistance in rice plant against BPH. In future, Bph14 gene and phytochemicals could be used in BPH management and development of novel resistant varieties for increasing rice yield.     

Responses by the brown planthopper,Nilaparvata lugens,to conspecific density on resistant and susceptible rice varieties

This study examines the nature of intraspecific interactions among Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) planthoppers feeding on resistant and susceptible rice varieties. Planthopper nymphs produced less honeydew and gained less weight when feeding on rice variety IR62 (resistant) compared to susceptible rice varieties. A series of bioassays was conducted that varied N. lugens nymph densities on IR62 and IR22 (susceptible). Increasing nymph density facilitated feeding by conspecifics; however, intraspecific competition increased mortality of nymphs on IR62 (but rarely on IR22). Furthermore, nymph weights declined with increasing conspecific density on IR22, and the effects were weak on IR62. More female nymphs than males survived on IR62 but this was not affected by density. Nitrogenous fertilizer increased competition among N. lugens on young plants of IR22, but not on IR62. Results indicate that nymphs have a low efficiency in accessing resources when feeding on IR62, even where the plants have received fertilizer. Female‐biased survival and biomass compensation for mortality may promote population recovery after development on the resistant plant and accelerate adaptation to the resistant variety.     

Behavioral and physiological responses of rice leaffolder Cnaphalocrocis medinalis to selected wild rices

Of four wild rices evaluated, Oryza perennis and O. punctata showed resistance to rice leaffolder, Cnaphalocrocis medinalis (Guenée), whereas O. australiensis and O. nivara were moderately resistant. C. medinalis larvae showed a strong nonpreference for settling and feeding on Oryza australiensis, O. perennis and O. nivara as compared to susceptible IR36 rice variety. Among wild rices tested, however, only O. australiensis, was more preferred for larval settling and feeding than resistant TKM6 plants. The growth index of C. medinalis on all wild rices, except O. punctata was significantly lower than on IR36 and TKM6 plants. First-instar larvae caged on O. perennis showed significantly lower larval and pupal weights than those on other wild rices. Incorporation of dry leaf powder of O. punctata and O. perennis wild rices in an artificial diet caused high larval mortality. Ovipositing gravid females showed less preference for wild rices than for IR36 and TKM6 plants.Based at the International Rice Research Institute (IRRI), P.O. Box 933, Manila, Philippines     

水稻OsLecRK1基因介导的抗褐飞虱功能分析

褐飞虱Nilaparvata lugens St(a)l是对水稻最具破坏性的害虫之一,OsLecRK1是水稻Bph3基因簇中对褐飞虱抗性贡献最大的基因.本文对RHTd(含Bph3)等材料进行了褐飞虱抗性评价,克隆并构建了OsLecRK1过量表达突变体水稻,利用该突变体分析了OsLecRK1基因对褐飞虱若虫存活率、若虫发育历期等生物学参数的影响.结果 表明,含Bph3基因水稻RHTd对褐飞虱的抗性明显地强于含Bph1基因水稻Mudgo和bph2基因水稻ASD7,RHTd水稻的褐飞虱受害指数仅为Mudgo和ASD7水稻的53.5％和24.1％.过量表达OsLecRK1基因能显著地增加水稻对褐飞虱的驱避性和抗生性,褐飞虱雌成虫偏好于在野生型水稻上产卵;突变体水稻上的褐飞虱若虫存活率显著地降低,仅为野生型水稻上若虫存活率的75.2％ ～81.8％,且若虫发育历期显著地延长,羽化率和初羽化雌成虫体重均显著地降低;此外,褐飞虱在突变体水稻上取食分泌的蜜露量只有野生型上的40.3％ ～ 60.9％,褐飞虱单雌产卵量只为野生型51％ ～61.2％,卵孵化率只有野生型的52.2％～56.7％,均显著地减少.结果 表明,含Bph3基因水稻RHTd对褐飞虱的抗性明显地高于分别含Bph1、bph2的水稻Mudgo和ASD7;水稻Bph3基因座的OsLecRK1单个基因过量表达即可显著增加水稻对褐飞虱的抗性,OsLecRK1协同影响褐飞虱的多个生物学参数降低褐飞虱的适合度.     

寄主经历对稻褐飞虱致害特性的影响

对寄主经历不同的稻褐飞虱Nilaparvata lugens 3龄若虫致害特性的研究结果表明：在抗虫品种Mudgo上的生活经历显著提高试虫在含Bphl基因的Mudeo、IR26、IR28、IR34上的蜜露排泄量、存活率及试虫对Mudgo的选择性：而ASD7上的经历仅显著提高试虫在ASD7上的蜜露量和存活率。不同品种上的经历对试虫的影响有所不同。同时,各经历试虫 在抗虫品种上的蜜露排泄量显著小于在TNl上的排泄量。     

THE VIRULENCE CHANGE AND DAMAGE CHARACTERISTICS OF VARIOUS GEOGRAPHIC POPULATIONS OF BROWN PLANTHOPPER*

Abstract The virulence change and damage characteristics of brown planthopper (BPH), Nilaparvata lugens Stal, populations collected from Guangxi, Yunnan and Zhejiang Provinces were studied by using various resistant rice varieties. The results indicated that the Zhejiang population could successfully infest varieties IR26 and Mudgo, showing the characters of BPH biotype 2 after 1989. The Guangxi population, however, could adapt the resistant varieties IR26, Mudgo and ASD7 after 1991. In 1997, the nymphal survival indices of Guangxi and Yunnan populations on Rathu Heenati (Bph3) were up to 70. 9 and 66. 7 respectively. This may imply that the BPH populations in Guangxi and Yunnan have shifted into a new biotype. In free-choice test, there was obvious difference in the feeding preference of nymphs and adults of Zhejiang population, the adult preferred to feeding on resistant variety IR26 and the nymphs chose the hosts randomly. Under 26 C and L12: D12, the nymphal duration of Zhejiang population was the longest in the three tested populations. For Guangxi population, the nymphal duration on ASD7 was significantly longer than on TN1, although it could infest resistant variety ASD7. The nymphal survival rate of Zhejiang population fed on IR26 was higher than those fed on TN1 and ASD7. On varieties IR26 and ASD7, an obviously higher nymphal survival rate was observed in Yunnan population as compared to those of Zhejiang and Guangxi populations. These results indicate that difference in virulence and damage characteristics could be found in different geographical populations of BPH.     

Mapping of a broad-spectrum brown planthopper resistance gene, <Emphasis Type="Italic">Bph3</Emphasis>, on rice chromosome 6

The brown planthopper (BPH) is one of the most destructive insect pests of rice in Thailand. We performed a cluster analysis that revealed the existence of four groups corresponding to the variation of virulence against BPH resistance genes in 45 BPH populations collected in Thailand. Rice cultivars Rathu Heenati and PTB33, which carry Bph3, showed a broad-spectrum resistance against all BPH populations used in this study. The resistant gene Bph3 has been extensively studied and used in rice breeding programs against BPH; however, the chromosomal location of Bph3 in the rice genome has not yet been determined. In this study, a simple sequence repeat (SSR) analysis was performed to identify and localize the Bph3 gene derived from cvs. Rathu Heenati and PTB33. For mapping of the Bph3 locus, we developed two backcross populations, BC₁F₂ and BC₃F₂, from crosses of PTB33 × RD6 and Rathu Heenati × KDML105, respectively, and evaluated these for BPH resistance. Thirty-six polymorphic SSR markers on chromosomes 4, 6 and 10 were used to survey 15 resistant (R) and 15 susceptible (S) individuals from the backcross populations. One SSR marker, RM190, on chromosome 6 was associated with resistance and susceptibility in both backcross populations. Additional SSR markers surrounding the RM190 locus were also examined to define the location of Bph3. Based on the linkage analysis of 208 BC₁F₂ and 333 BC₃F₂ individuals, we were able to map the Bph3 locus between two flanking SSR markers, RM589 and RM588, on the short arm of chromosome 6 within 0.9 and 1.4 cM, respectively. This study confirms both the location of Bph3 and the allelic relationship between Bph3 and bph4 on chromosome 6 that have been previously reported. The tightly linked SSR markers will facilitate marker-assisted gene pyramiding and provide the basis for map-based cloning of the resistant gene.     

Evaluation of resistance of wild rices,Oryza spp., to the whitebacked planthopper,Sogatella furcifera (Horvath) (Homoptera: Delphacidae)

Evaluation of wild rice species for resistance against major insect pests of rice was carried out in both field and greenhouse conditions. A total of 219 wild rice lines were evaluated under field conditions against yellow stem borer, Scirpophaga incertulas (Walker) and leaf folder, Cnaphalocrocis medinalis (Guenee). Of the selected 185 lines tested by “standard seed box screening technique” against whitebacked planthopper, Sogatella furcifera (Horvath), 20 were found to be resistant, 54 moderately resistant, 88 moderately susceptible, and 23 susceptible. Out of the 185 wild rice lines tested against all the three major pests, 17 lines had multiple resistance. Out of these 17 lines, 14 lines were evaluated for mechanisms of resistance against S. furcifera; they showed antixenosis for feeding, as fewer nymphs settled on them compared to the susceptible O. sativa cultivar TN1. However, the eggs were observed to be randomly distributed on them. Antibiosis was exhibited as the nymphal period was prolonged, while there was a decrease in survival and growth index. Thus, besides possessing multiple resistance against all the three major pests during the present investigation, all these 14 wild rice lines belonging to different Oryza spp. exhibited good antixenotic and antibiotic effects.     

共生菌在褐飞虱致害性变化中的作用

研究了不同虫源和致害性褐飞虱Nilaparvata lugens种群体内共生菌数量动态及其对褐飞虱在抗虫品种上的取食选择、生长发育、繁殖以及氨基酸转移酶活性的影响。结果表明,褐飞虱田间种群的致害性与其体内共生菌数量有关。广西南宁种群雌成虫体内的共生菌数量显著地高于浙江杭州和龙游两个虫源的雌成虫体内共生菌数量,而已纯化的3个不同致害性生物型体内的共生菌数量无显著差异。取食抗性品种能显著减少生物型Ⅰ雌成虫体内的共生菌数量。缺乏共生菌时,生物型Ⅰ、Ⅱ若虫对水稻品种TN1和ASD7的选择性增大,而对Mudgo的取食选择性下降。尽管缺共生菌的3个生物型在已适应的和不适应的感虫和抗虫品种上的若虫存活率和雌成虫产卵量均下降,若虫历期明显延长,但在已适应品种上的变化程度明显小于在不适应的抗虫品种上的变化程度。共生菌还明显影响成虫体内丙氨酸氨基转移酶和天门冬氨酸氨基转移酶的活性。这些结果证明体内共生菌的数量和质量在褐飞虱对水稻致害性的变化中发挥了重要作用。     

the differentiation of amino acid requirements in three host‐related populations of the brown planthopper,nilaparvata lugens (stål)*

Abstract In order to understand the differentiation of amino acid requirments in host‐related populations of the brown planthopper (BPH), Nilaparvata lugens (Stål), we established three BPH populations by separately maintaining them on three rice varieties, i.e. TN1 (common susceptible control), Mudgo (containing resistant gene Bph 1) and ASD7 (containing resistant gene bph2) for over 30 generations, and then reared them on 20 holidic diets, each with distinct overall amino acids and ratio of essential amino acid (EAA) to nonessential amino acid (NEAA). The emergence rate, brachypter rate, nymphal duration and weight of newly molted adults were evaluated and compared. The results showed significant difference among the three populations in the effect of amino acid variation on BPH performance, ascending in an order of Mudgo population ASD7 population > TN1 pupulation. The results also indicated that the required optimum concentrations of overall amino acids by BPH populations on Mudgo and ASD7 were 4.0% ‐4.8% and 4.0%, respectively, higher than that of TN1 population (2.4% ‐ 3.2%). In addition, it was found that Mudgo and ASD7 populations were more sensitive to the concentration of EAAs than TN1 population. We propose that there is substantial differentiation in responses to dietary amino acid conditions among different host‐associated BPH populations and that such differentiation may be closely related to the induced virulence shift on resistant rice varieties.     

褐飞虱致害性变异过程及其体内酶的变化

在室内连续用具不同抗虫基因的水稻品种TNl、IR26、Mudg。和ASD7、单管饲养褐飞虱(Nilaparvata lugens)种群,研究它对抗虫水稻品种的适应过程及其体内酶的变化规律。 结果表明：褐飞虱在抗虫品种上取食2代的若虫存活率、若虫历期和短翅成虫体重均明显比取食感虫品种TNl的低,第3代以后与取食TNl者基本相同。第2代是褐飞虱适应抗虫品种的关键期。天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)和丁-谷氨酰基转移 酶(GGT)的活性在关键的第2代最低,而超氧物歧化酶(SOD)和过氧化氢酶(CAT)的含量增加。褐飞虱在适应抗虫品种以后体内天冬氨酸氨基转移酶活性明显提高。