The Emerald ash borer （EAB, Agrilus planipennis Fairmaire） an exotic invasive insect pest has killed millions of ash trees （Fraxinus spp.） across North America and threatens billions more. We validated six A. plan...The Emerald ash borer （EAB, Agrilus planipennis Fairmaire） an exotic invasive insect pest has killed millions of ash trees （Fraxinus spp.） across North America and threatens billions more. We validated six A. planipennis reference genes （actin, ACT; beta tubulin, E-TUB; glyceraldehyde-3-phosphate dehydrogenase, GAPDH ; ribosomal protein, RPL7; translation elongation factor 1~, TEF-la; and ubiquitin, UBQ） using geNorm, Normfinder and BestKeeper for accurate determination of target messenger RNA levels in gene expression studies. The stability of the six reference genes was evaluated in different larval tissues, developmental stages and two treatments ofA. planipennis using quantitative real-time polymerase chain reaction. Although there was no consistent ranking observed among the reference genes across the samples, the overall analysis revealed TEF-la as the most stable reference gene. GAPDH and ACT showed least stability for all the samples studied. We conclude that TEF-I~ is the most appropriate reference gene for gene expression studies in A. planipennis. Results obtained can be applicable for transcript profiling in other invasive insect pests. Further, these validated reference genes could also serve as the basis for selection of candidate reference genes in any given insect system post-validation.展开更多
Pest preference and subsequent susceptibility of a host individual is likely related to previous growth patterns in that host.Emerald ash borer(Agrilus planipennis Fairmaire)is a pestiferous beetle introduced to North...Pest preference and subsequent susceptibility of a host individual is likely related to previous growth patterns in that host.Emerald ash borer(Agrilus planipennis Fairmaire)is a pestiferous beetle introduced to North America from Asia.While all species of ash are susceptible to attack,some individual trees appear to survive infestation.We selected ash trees in southeastern Michigan,collected cores and categorized trees as high tolerance to emerald ash borer attack(high overall health,low crown dieback),low tolerance(low overall health,high crown dieback)and intermediate tolerance(in-between the other categories).We artificially wounded trees and measured wound closure after 3 years.Ring width indices were not correlated between high and low tolerance trees.Regression slopes comparing growth and years were significantly different between the three tolerance categories,with high tolerance trees having the steepest slope.Wound closure was greatest in high tolerance trees.High tolerance trees demonstrating more rapid(steeper regression slope),consistent(lower variance),and effective(greater wound closure)growth.Those vigorously growing trees likely had more capacity to repair damage caused by emerald ash borer,leading to healthier trees in our categorization.Linking previous host growth patterns to health may have implications related to identifying individual trees potentially tolerant to attack.展开更多
Recent advances of Piwi-interacting RNAs （piRNAs） have enabled a better understanding of their putative roles in the protection of gerrn cells against selfish genetic elements. The germ plasm proteins namely, PIWI a...Recent advances of Piwi-interacting RNAs （piRNAs） have enabled a better understanding of their putative roles in the protection of gerrn cells against selfish genetic elements. The germ plasm proteins namely, PIWI and VASA, are key players in regulation of piRNAs. However, the biogenesis of piRNAs remains poorly understood. We report the characterization and the transcript profiles of a PIWI and VASA gene in various tissues and developmental stages of the emerald ash borer （Agrilusplanipennis）, an exotic invasive insect pest that has attained a high impact status worldwide. The deduced amino acid sequences of both these genes （herein referred to ＂ApPIWI and ApVASA＂） revealed homology with similar proteins from other insect and non-insect taxa. Peak transcript levels for ApPIWI and ApVASA were observed in the ovaries （compared to the other tissues assayed） and in adults （compared to the other developmental stages assayed）. To our knowledge this is the first report of profiling piRNA pathway genes in A. planipennis. These results provide new insights into the putative function of the PIWI and VASA proteins in insects.展开更多
Many natural enemies employ plant- and/or herbivore-derived signals for host/prey location. The larval parasitoid Tetrastichus planipennisi Yang （Hymenoptera： Eulophidae） is 1 of 3 biocontrol agents currently being...Many natural enemies employ plant- and/or herbivore-derived signals for host/prey location. The larval parasitoid Tetrastichus planipennisi Yang （Hymenoptera： Eulophidae） is 1 of 3 biocontrol agents currently being released in an effort to control the emerald ash borer （EAB）, Agrilus planipennis Fairmaire （Coloeptera： Burprestidae） in North America. To enhance its efficiency, allelochemicals that attract it need to be assessed. In this study, ash phloem volatile organic compounds （VOCs） of black, green, and white ash, and EAB larval frass were compared. Foraging behavior of T. planipennisi females in response to VOCs of white ash or frass from EAB larvae feeding on white ash phloem was tested using a Y-tube olfactometer. Results indicated that the 3 ash species had similar VOC profiles. EAB larval frass generally contained greater levels of VOCs than phloem. Factor analysis indicated that the 11 VOCs could be broadly divided into 2 groups, with c^-bisabolol, fl-caryophyllene, （E）-2-hexenal, （Z）-3-hexenal, limonene, methyl benzoate, methyl indole-3-acetic acid, methyl jasmonate, methyl salicylate as the first group and the rest （i.e., methyl linoleate and methyl linolenate） as a second. Abundance of VOCs in white ash phloem tissue and frass, nevertheless, did not attract T. planipennisi females. The concealed feeding of EAB larvae might explain the selection for detectable and reliable virbrational signals, instead of undetectable and relatively unreliable VOC cues from phloem and frass, in short-range foraging by T. planipennisi. Alternatively, it is possible that T. planipennisi is not amenable to the Y-tube olfactometer assay employed.展开更多
采用室内测定并结合林间实地调查的方法,研究了新发现的寄生于蛀干害虫白蜡窄吉丁的外寄生蜂——白蜡吉丁肿腿蜂Sclerodermus pupariae Yang et Yao的生物学特性及其人工繁殖技术。结果表明,白蜡吉丁肿腿蜂外寄生于白蜡窄吉丁的幼虫和...采用室内测定并结合林间实地调查的方法,研究了新发现的寄生于蛀干害虫白蜡窄吉丁的外寄生蜂——白蜡吉丁肿腿蜂Sclerodermus pupariae Yang et Yao的生物学特性及其人工繁殖技术。结果表明,白蜡吉丁肿腿蜂外寄生于白蜡窄吉丁的幼虫和蛹及预蛹,是自然控制该害虫的一种重要寄生蜂,自然寄生率为13.9%左右。该蜂在天津1年发生5代,世代重叠明显,寿命长。白蜡吉丁肿腿蜂的卵、幼虫、茧蛹期和全世代的发育起点温度分别为(16.89±0.79)℃,(17.03±1.42)℃,(16.90±1.68)℃和(15.31±0.47)℃。有效积温分别为(33.82±4.13)日.度、(49.11±7.93)日.度、(128.88±27.87)日.度和(277.00±14.15)日.度。雌性成蜂易于低温保存,对寄主有较强的搜索力和攻击力。繁蜂寄主容易大量获得,是生物防治白蜡窄吉丁的重要理想天敌之一。展开更多
为了解新疆野苹果（Malus sieversii）树皮厚度、径阶对苹小吉丁虫危害程度的影响,以具有不同抗苹小吉丁虫（Agrilus mali Matsumura）特性的新疆野苹果类型单株为试验材料,利用相关性回归法找出树皮厚度、径阶与总虫数之间的关系。结...为了解新疆野苹果（Malus sieversii）树皮厚度、径阶对苹小吉丁虫危害程度的影响,以具有不同抗苹小吉丁虫（Agrilus mali Matsumura）特性的新疆野苹果类型单株为试验材料,利用相关性回归法找出树皮厚度、径阶与总虫数之间的关系。结果表明：不同野苹果单株受苹小吉丁虫危害差异较大,其中XY-101单株羽化孔数最高11.2个,而XY-49单株最低为0个,总虫口平均数在0.3～11.2头之间,差异均极显著;径阶、树皮厚度分别与总虫数的回归方程为：Y=1.236＋0.119Z和Y=1.049＋2.071H,在P〈0.05显著水平下两个方程均通过了t检验,其中变量Z的回归系数为0.119,即径阶每增加1 mm,总虫数就增加0.119个。变量H的回归系数为2.071,即树皮厚度每增大1 mm,总虫数就相对应增加2.071个。因此,新疆野苹果的径阶、树皮厚度与总虫数在一定范围内呈正相关线性关系,随着树皮厚度、径阶的增大,总虫数也明显增大。展开更多
文摘The Emerald ash borer （EAB, Agrilus planipennis Fairmaire） an exotic invasive insect pest has killed millions of ash trees （Fraxinus spp.） across North America and threatens billions more. We validated six A. planipennis reference genes （actin, ACT; beta tubulin, E-TUB; glyceraldehyde-3-phosphate dehydrogenase, GAPDH ; ribosomal protein, RPL7; translation elongation factor 1~, TEF-la; and ubiquitin, UBQ） using geNorm, Normfinder and BestKeeper for accurate determination of target messenger RNA levels in gene expression studies. The stability of the six reference genes was evaluated in different larval tissues, developmental stages and two treatments ofA. planipennis using quantitative real-time polymerase chain reaction. Although there was no consistent ranking observed among the reference genes across the samples, the overall analysis revealed TEF-la as the most stable reference gene. GAPDH and ACT showed least stability for all the samples studied. We conclude that TEF-I~ is the most appropriate reference gene for gene expression studies in A. planipennis. Results obtained can be applicable for transcript profiling in other invasive insect pests. Further, these validated reference genes could also serve as the basis for selection of candidate reference genes in any given insect system post-validation.
基金supported in part by the Purdue University Fort Wayne Honors Programthe John Z.Duling Grant Program from the Tree Research and Education Fund
文摘Pest preference and subsequent susceptibility of a host individual is likely related to previous growth patterns in that host.Emerald ash borer(Agrilus planipennis Fairmaire)is a pestiferous beetle introduced to North America from Asia.While all species of ash are susceptible to attack,some individual trees appear to survive infestation.We selected ash trees in southeastern Michigan,collected cores and categorized trees as high tolerance to emerald ash borer attack(high overall health,low crown dieback),low tolerance(low overall health,high crown dieback)and intermediate tolerance(in-between the other categories).We artificially wounded trees and measured wound closure after 3 years.Ring width indices were not correlated between high and low tolerance trees.Regression slopes comparing growth and years were significantly different between the three tolerance categories,with high tolerance trees having the steepest slope.Wound closure was greatest in high tolerance trees.High tolerance trees demonstrating more rapid(steeper regression slope),consistent(lower variance),and effective(greater wound closure)growth.Those vigorously growing trees likely had more capacity to repair damage caused by emerald ash borer,leading to healthier trees in our categorization.Linking previous host growth patterns to health may have implications related to identifying individual trees potentially tolerant to attack.
文摘Recent advances of Piwi-interacting RNAs （piRNAs） have enabled a better understanding of their putative roles in the protection of gerrn cells against selfish genetic elements. The germ plasm proteins namely, PIWI and VASA, are key players in regulation of piRNAs. However, the biogenesis of piRNAs remains poorly understood. We report the characterization and the transcript profiles of a PIWI and VASA gene in various tissues and developmental stages of the emerald ash borer （Agrilusplanipennis）, an exotic invasive insect pest that has attained a high impact status worldwide. The deduced amino acid sequences of both these genes （herein referred to ＂ApPIWI and ApVASA＂） revealed homology with similar proteins from other insect and non-insect taxa. Peak transcript levels for ApPIWI and ApVASA were observed in the ovaries （compared to the other tissues assayed） and in adults （compared to the other developmental stages assayed）. To our knowledge this is the first report of profiling piRNA pathway genes in A. planipennis. These results provide new insights into the putative function of the PIWI and VASA proteins in insects.
文摘Many natural enemies employ plant- and/or herbivore-derived signals for host/prey location. The larval parasitoid Tetrastichus planipennisi Yang （Hymenoptera： Eulophidae） is 1 of 3 biocontrol agents currently being released in an effort to control the emerald ash borer （EAB）, Agrilus planipennis Fairmaire （Coloeptera： Burprestidae） in North America. To enhance its efficiency, allelochemicals that attract it need to be assessed. In this study, ash phloem volatile organic compounds （VOCs） of black, green, and white ash, and EAB larval frass were compared. Foraging behavior of T. planipennisi females in response to VOCs of white ash or frass from EAB larvae feeding on white ash phloem was tested using a Y-tube olfactometer. Results indicated that the 3 ash species had similar VOC profiles. EAB larval frass generally contained greater levels of VOCs than phloem. Factor analysis indicated that the 11 VOCs could be broadly divided into 2 groups, with c^-bisabolol, fl-caryophyllene, （E）-2-hexenal, （Z）-3-hexenal, limonene, methyl benzoate, methyl indole-3-acetic acid, methyl jasmonate, methyl salicylate as the first group and the rest （i.e., methyl linoleate and methyl linolenate） as a second. Abundance of VOCs in white ash phloem tissue and frass, nevertheless, did not attract T. planipennisi females. The concealed feeding of EAB larvae might explain the selection for detectable and reliable virbrational signals, instead of undetectable and relatively unreliable VOC cues from phloem and frass, in short-range foraging by T. planipennisi. Alternatively, it is possible that T. planipennisi is not amenable to the Y-tube olfactometer assay employed.
文摘采用室内测定并结合林间实地调查的方法,研究了新发现的寄生于蛀干害虫白蜡窄吉丁的外寄生蜂——白蜡吉丁肿腿蜂Sclerodermus pupariae Yang et Yao的生物学特性及其人工繁殖技术。结果表明,白蜡吉丁肿腿蜂外寄生于白蜡窄吉丁的幼虫和蛹及预蛹,是自然控制该害虫的一种重要寄生蜂,自然寄生率为13.9%左右。该蜂在天津1年发生5代,世代重叠明显,寿命长。白蜡吉丁肿腿蜂的卵、幼虫、茧蛹期和全世代的发育起点温度分别为(16.89±0.79)℃,(17.03±1.42)℃,(16.90±1.68)℃和(15.31±0.47)℃。有效积温分别为(33.82±4.13)日.度、(49.11±7.93)日.度、(128.88±27.87)日.度和(277.00±14.15)日.度。雌性成蜂易于低温保存,对寄主有较强的搜索力和攻击力。繁蜂寄主容易大量获得,是生物防治白蜡窄吉丁的重要理想天敌之一。
