不同地理种群褐飞虱的致害性变异和为害特征(英文)

本文对采自广西、云南和浙江的不同地理种群的褐飞虱致害性变异和为害特性进行了比较研究。致害性测定结果表明,１９８９年后浙江种群褐飞虱仍表现为生物型２的致害特性;而广西种群在１９９１年后不仅能致害含 ＢＰｈ１基因的ＩＲ２６和 ＭＵｄｇｏ而且还能致害含 ｂｐｈ２基因的ＡＳＤ７,１９９７年广西和云南种群均能致害抗虫品种ＩＲ２６、Ｍｕｄｇｏ、ＡＳＤ７和Ｒ．Ｈ,表明这两个种群产生了不同与生物型１、２和３的致害性更强的新的生物型。自由选择试验结果表明,浙江种群的若虫和成虫对不同抗虫品种的取食选择性有明显的差异,成虫嗜食ＩＲ２６品种而若虫对不同品种的选择性无显著差别。云南种群若虫嗜食ＡＳＤ７,而成虫则嗜食ＴＮ１。室内试验表明,浙江种群的若虫历期最长,而在广西种群中取食ＡＳＤ７的若虫历期明显比取食ＴＮ１的长。取食ＩＲ２６的浙江种群的若虫存活率比取食ＴＮ１和ＡＳＤ７的高,而在抗虫品种ＡＳＤ７和ＩＲ２６上云南种群的若虫存活率明显高于浙江和广西种群。研究表明不同地理种群的褐飞虱的致害性与其为害特性并不完全一致。     

不同虫源和致害性的褐飞虱体内共生菌的种群动态

通过对不同地理种群和致害性的褐飞虱体内共生菌,在高温和抗性水稻品种作用下的种群动态研究表明,在正常湿度下褐飞虱体内共生菌的数量随若虫的生长发育而增加,5龄若虫期是共生菌增长的关键期;同一种群的褐飞虱秋季共生菌数量明显高于夏季。广西田间种群的短翅雌虫体内的共生菌数量显高于浙江省的杭州和龙游种群,经高温处理后,3个生物开共生菌数量均显减少,但其子代共生菌的数量在正常温度下马上恢复,与未经高温处理的褐飞虱共生菌数量基本相同,取食抗性品种的生物型1和田间种群的褐飞虱体内的共生菌数量均明显减少,取食抗性品种的第2代的共生菌又均比第1代少。这说明高温对共生菌的影响是暂的,而抗性品种的对共生菌的作用与褐飞虱种群对品种的适应性有关。     

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。     

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。     

稻褐飞虱生物型的研究

在浙江,如温州地区虽然大面积推广抗褐飞虱的杂交稻汕优6号已经5年,但是田间种群仍以生物型1占优势。 我们把田间褐飞虱罩在具有Bphl抗虫基因的品种 Mudgo 上连续饲养 11代,即可育成褐飞虱生物型2,既可以适应 Mudgo,也可适应具有 bph2基因的品种 ASD7和 IR36。在台湾省用同样方法育成的生物型 2也可以适应ASD7,因此我们的生物型 2与台湾省的生物型 2相类似;但是后者不适应 CR94-13(IR36的亲本),故两者又有所不同。菲律宾的生物型2对 ASD7和IR36均不能适应,故与我们的不同。 把田间褐飞虱在抗虫品种ASD7上连续饲养,结果很容易育成褐飞虱生物型3。甚至在 ASD7上所饲养的第1代5龄若虫即能为害具有bph2抗虫基因的品种 ASD7,甚至 IR36。这表明本地田间种群由生物型1能很快向生物型3转变。 由于褐飞虱在浙江基本上不能越冬,并根据本地自然种群的生物型鉴定结果,推测本省南部的虫源可能由台湾和福建迁入,而中部和北部虫源可能主要来自两广以至中印半岛。故本地自然种群可能混杂有生物型1、2甚至3的个体。     

水稻品种对褐飞虱的田间抗性及其生态学机制

评价了7个水稻品种(浙粳22、宜香845、中组14、秀水123、二优倍九、感虫对照品种TN1和抗虫对照品种IR36)在田间成株期对褐飞虱Nilaparvata lugens(Stl)的抗性表现,并初步分析了它们的抗性机制。结果表明,在田间网室人工诱发条件下,浙粳22、宜香845、秀水123和中组14等4个品种的抗性水平与抗虫品种IR36相同,均小于3级,表现为抗虫,而二优培九则与感虫品种TN1相同,表现为感虫。在自然发生条件下的水稻分蘖期至乳熟期,宜香845和中组14上褐飞虱数量仅为TN1上的7.84%～24.44%,秀水123和浙粳22则为TN1上的30.19%～60.27%。在4个抗性品种上褐飞虱的产卵量和卵孵化率明显减少,而若虫存活率仅为TN1上的20%～30%。与IR36相同,4个抗性品种上褐飞虱的若虫存活率和种群增长倍数均显著低于TN1上,说明他们对褐飞虱的抗性主要表现为抗生性。     

中国南宁和越南褐飞虱不同地理种群比较

比较了我国南宁、越南河内、河静、顺化、胡志明市、九龙江6个褐飞虱地理种群的差异.结果表明:南宁、河内、河静、顺化的褐飞虱种群能致害含Bph1和bph2抗虫基因的水稻品种,而越南胡志明市、九龙江褐飞虱种群的致害能力更强,对含Bph1、bph2、Bph3、bph4抗虫基因的水稻品种均表现为致害或强致害;南宁、河内、河静、顺化褐飞虱若虫在水稻品种TN1、Mudgo、ASD7上的存活率均在52％以上,在Rathu Heenati、Babawee、Ptb33上的存活率均低于44％;胡志明市、九龙江褐飞虱若虫除了在Rathu Heenati上的存活率低于50％外,在其他品种上的存活率都在50％以上.南宁、河内、顺化褐飞虱若虫在TN1、Mudgo、ASD7上的发育历期显著短于在Rathu Heenati、Babawee、Ptb33上的发育历期;河静褐飞虱若虫在TN1、Mudgo、ASD7上的发育历期与在Rathu Heenati、Ptb33上的发育历期差异不显著.胡志明市褐飞虱若虫在TN1、ASD7上的发育历期显著短于在Rathu Heenati、Babawee、Ptb33上的发育历期;九龙江褐飞虱若虫在TN1、Mudgo、ASD7、Rathu Heenati、Babawee、Ptb33上的发育历期差异不显著.选择性试验表明,接虫192 h后,南宁、河内褐飞虱若虫在Rathu Heenati、Babawee、Ptb33上的虫口密度显著低于在TN1、Mudgo和ASD7上的虫口密度;河静褐飞虱若虫在Babawee上的虫口密度显著低于在TN1、Mudgo上的虫口密度;顺化、胡志明市褐飞虱若虫在Babawee上的虫口密度显著低于在TN1、Mudgo、ASD7、Rathu Heenati上的虫口密度;九龙江褐飞虱若虫在Babawee、Ptb33上的虫口密度显著低于在TN1、ASD7上的虫口密度.本研究发现,我国南宁褐飞虱田间种群与越南河内、顺化、河静(属于越南中部及北部地区)的褐飞虱田间种群致害性相似,从而为“越南中北部是褐飞虱迁入我国的虫源地”提供了新的证据.     

褐飞虱对五种杀虫剂抗性的快速检测技术

【目的】建立褐飞虱Nilaparvata lugens对常用杀虫剂抗性的快速检测技术,实时掌握田间褐飞虱种群的抗药性水平,以指导褐飞虱防控合理用药。【方法】基于玻璃瓶药膜法,研制褐飞虱3龄若虫对吡虫啉、啶虫脒、醚菊酯、毒死蜱和异丙威5种杀虫剂抗性的快速检测试剂盒;利用试剂盒测定的死亡率与稻苗浸渍法测得的抗性倍数进行相关性分析,并验证利用试剂盒快速测定褐飞虱田间种群对5种杀虫剂 抗性水平的准确性。【结果】处理1 h时吡虫啉、啶虫脒、醚菊酯、毒死蜱和异丙威对褐飞虱室内敏感种群3龄若虫的LD₉₀分别为：30.96, 92.05, 117.24, 514.21和1.24 ng/cm²。在吡虫啉、啶虫脒、醚菊酯、毒死蜱和异丙威相应诊断剂量下,贵州省不同田间种群褐飞虱3龄若虫的校正死亡率分别在23.75%~78.75%, 25.00%~78.75%, 43.75%~88.75%, 36.25%~85.00%和18.75%~67.50%之间。相关性分析表明,上述田间种群褐飞虱3龄若虫的死亡率与稻苗浸渍法测定的抗性倍数呈显著负相关,相关系数在0.8751~0.9754之间。通过快速检测试剂盒获得的死亡率及相关性方程计算得到贵州安龙地区(AL)褐飞虱种群对吡虫啉、啶虫脒、醚菊酯、毒死蜱和异丙威的推测抗性倍数分别为7.23, 3.68, 4.14, 4.12和31.18,采用稻苗浸渍法测得上述5种杀虫剂的实测抗性倍数分别为6.33, 5.24, 3.71, 4.50和26.56,表明推测抗性倍数与实测的抗性倍数结果表现一致。【结论】该快速检测试剂盒可以通过测定褐飞虱田间种群的死亡率,快速评估褐飞虱田间种群对杀虫剂的抗性水平。     

稻株含氮量和密度对褐飞虱存活、发育和生殖特性的影响

对褐飞虱种群在不同含氮量稻株和若虫密度条件下的反应进行了研究。结果表明,若虫密度对褐飞虱存活的抑制作用随若虫密度提高而增强,但随寄主含氮量的增加而显著下降,表现为低含量的寄主植物可以增强对种群调节的负反馈作用。在低氮稻株上的饲养代数也明显影响若虫存活率,而在高氮稻株上饲养的不同代别褐飞虱之间则无显著差异。若虫率与稻株含氮量呈极显著的负相关,即在高若虫密度下寄主含氮量的增加可显著缩短褐飞虱若虫的发育历期。与高含氮量稻株上的褐飞虱种群相比,饲养在低含氮量稻株上的褐飞虱种群的若虫发育时间在高若虫密度下显著延长。在每盆40头褐飞虱若虫的密度下,成虫性比与稻株含氮量呈极显著的正相关,而在不同若虫密度下,随着若虫密度的增加雌性成虫比例显著下降。在每盆160头的若虫密度时低氮稻株上褐飞虱种群的性比低于0.3,显著低于在高氮稻株上的褐飞虱种群的性比0.85。在含氮量低的稻株上的雌成虫体重随若虫密度的增加极显著减少,连续取食第2代的雌成虫又比取食第1代时的轻。在所研究的所有若虫密度下,取食高含氮量稻株的褐飞虱种群的雌成虫寿命均为取食低含氮量稻株褐飞虱种群雌成虫寿命的3倍左右,差异极为显著。稻株含氮量和若虫密度对褐飞虱生殖力的作用最大,特别是在低氮稻株上若虫密度对褐飞虱生殖力的作用更为突出。在高含氮量稻株上的卵孵化率均随若虫密度的增加而有所下降,但在相同含氮量稻株上卵孵化率的差异均不显著。结果推测由于施用氮肥较多的水稻可以承受高密度的褐飞虱,提高了它们的迁出临界密度,减少了褐飞虱在克服逆境过程中的种群损失,从而造成更高的密度和更重的田间危害程度。     

我国褐飞虱若干地理种群致害性的研究

褐飞虱致害性变异是水稻品种抗性利用的一个重要障碍,监测田间种群的致害性对水稻抗虫品种的培育和利用有重要意义。本文采用蜜露量法对采集自云南勐海、贵州遵义和旧州、广西南宁、湖南衡阳以及浙江富阳等6个褐飞虱田间种群对IR26(含Bph1)和IR42(含bph2)的致害性进行了研究,发现勐海种群对IR26、IR42均有较强的致害性,遵义、旧州、南宁和衡阳种群仅对IR26致害性较强,而对IR42相对较弱;富阳种群对IR26、IR42的致害能力均相对较弱。采用SSST法进一步比较了西南稻区云南勐海、贵州遵义和旧州褐飞虱种群对TN1、IR26、Mudgo、ASD7、IR36、IR42、IR56、Rathu Heenati、Ptb33和Babawee等10个水稻品种的致害性,结果表明:勐海种群的致害性最强,主要体现在对Rathu Heenati、IR56、Ptb33等含Bph3基因的致害性显著强于旧州种群和遵义种群;后两者间,除旧州种群对IR36致害性显著较强外,对其他品种的致害性均无显著差异。总体上,处于东南季风带之外、云南西南部的勐海褐飞虱种群致害性明显强于来源于东南季风带之内的5个褐飞虱种群,进一步为我国西南稻区西部与云贵高原东缘及以东地区分属不同的褐飞虱迁飞场提供了重要依据。     

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.     

褐飞虱的迁人和翅型分化规律的研究

褐飞虱Nilaparvata lugens(Stal)属迁飞性水稻害虫,其成虫有短翅和长翅两种翅型。 褐飞虱迁入雌虫均未经过交配,其短翅型由一对显性等位基因控制。翅型分化同时受到遗传和内分泌系统的协调控制,外界条件如密度和寄主等因子通过内分泌系统来影响翅型的分化。褐飞虱翅型分化的敏感龄期雌虫为1～3龄,而雄虫为1-5龄;不同若虫蜜度处理对褐飞虱成虫的前翅形成有一定的影响。分蘖期水稻饲养的褐飞虱短翅型比例明显高于孕穗期水稻饲养的褐飞虱。不同密度下各生物型间的翅型分化差异不显著。迁入地的浙江各种群属温带型,其雌虫短翅率低且与密度呈显著负相关;菲律宾热带种群雌虫在不同密度下均为短翅型,而雄虫的短翅率随密度增加而上升。广西种群接近热带型,其雌虫短翅率高但不随密度而变化。试验各种群的雄虫在中等密度甚至高密度时其短翅率出现最高。     

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.     

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.     

中国与越南褐飞虱和白背飞虱生物型研究

【目的】监测我国与越南褐飞虱Nilaparvata lugens St?l和白背飞虱Sogatella furcifera Horvath生物型,为抗虫育种工作提供指导。【方法】应用群体集团检测法和蜜露量检测法研究了中国广西、云南、河南、湖南、重庆、贵州和越南河内、河静、顺化、胡志明市和九龙江田间褐飞虱和白背飞虱的致害特性和生物型组成结构。【结果】我国主要稻区(除云南思茅外)和越南中北部的田间褐飞虱以Ⅱ型的比例多,对含Bph1、bph2基因的鉴别品种表现为致害;云南思茅的田间褐飞虱以Ⅱ+Ⅱ型的比例多,对含Bph1、bph2和bph4基因的鉴别品种表现为致害或强致害;越南胡志明市、九龙江的田间褐飞虱以Ⅱ+Ⅱ型的比例多,对含Bph1、bph2、Bph3、bph4基因的鉴别品种主要表现为致害或强致害。我国白背飞虱以Ⅰ型比例较多;越南顺化和河内以Ⅱ型比例多;所有监测点白背飞虱的致害特性总体表现为对含Wph1、Wbph2基因的鉴别品种的致害能力较强,对Wbph3的致害能力表现不一,对含Wph5基因的鉴别品种表现为中等致害。【结论】抗虫育种选择抗源时,不要选含Bph1、bph2基因的水稻品种作为褐飞虱抗源,不要选含基因Wbph1或Wbph2的水稻品种作为白背飞虱抗源。     

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。     

High-resolution mapping of the brown planthopper resistance gene Bph6 in rice and characterizing its resistance in the 9311 and Nipponbare near isogenic backgrounds

Brown planthopper (Nilaparvata lugens Stål, BPH) is one of the most destructive insect pests of rice. Exploring resistance genes from diverse germplasms and incorporating them into cultivated varieties are critical for controlling this insect. The rice variety Swarnalata was reported to carry a resistance gene (designated Bph6), which has not yet been assigned to a chromosome location and the resistance mechanism is still unknown. In this study, we identified and mapped this gene using the F₂ and backcrossing populations and characterized its resistance in indica 9311 and japonica Nipponbare using near isogenic lines (NILs). In analysis of 9311/Swarnalata F₂ population, the Bph6 gene was located on the long arm of chromosome 4 between the SSR markers RM6997 and RM5742. The gene was further mapped precisely to a 25-kb region delimited between the STS markers Y19 and Y9; and the distance between these markers is 25-kb in Nipponbare genome. The Bph6 explained 77.5% of the phenotypic variance of BPH resistance in F₂ population and 84.9% in BC₂F₂ population. Allele from Swarnalata significantly increased resistance to the BPH, resulted in a reduced damage score. In characterization of Bph6-mediated resistance, the BPH insects showed significant preference between NIL-9311 and 9311 in 3 h and between NIL-NIP and Nipponbare in 120 h after release. BPH growth and development were inhibited, and the insect’s survival rates were lower on Bph6-NIL plants, compared with the parents 9311 and Nipponbare. The results indicate that the Bph6 exerted prolonged antixenotic and antibiotic effects in Bph6-NIL plants, and NIL-9311 plants showed a quicker and stronger effect toward BPH than NIL-NIP 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.     

不同地理种群褐飞虱体内共生酵母菌的个体大小及数量差异

褐飞虱腹部脂肪体内普遍存在共生酵母菌,该类共生菌在褐飞虱的生理代谢和营养利用等方面起着重要作用。采用冷冻切片技术结合显微摄像系统观察法测定不同地理种群褐飞虱体内共生酵母菌的个体大小和数量。试验结果表明,不同地理种群褐飞虱雌(雄)成虫体内共生菌的个体大小和数量差异显著,依次为:对照种群>广西种群>浙江种群>福建种群。结合虫体内脂肪和糖元含量的分析得出,褐飞虱体内共生酵母菌的长、宽度和数量与脂肪和糖元含量显著正相关。文章从共生酵母菌的角度解释了不同地理种群褐飞虱致害性变异的内在原因,并推测,迁飞过程所导致的褐飞虱体内脂肪和糖元的消耗影响了该类共生菌的数量和质量,并最终导致褐飞虱对抗性品种水稻的致害性减弱。