Mechanisms underlying host plant selection by Holcocerus hippophaecolus adults

We determined the mechanisms underlying host selection by adults of the seabuckthorn carpenterworm, Holcocerus hippophaecolus Hua, Chou, Fang et Chen. Four sea buckthorn (Hippophae rhamnoides L.) subspecies (varieties) with different degrees of resistance to H. hippophaecolus were chosen for artificial insect infection in cages. The results showed that olfactory and visual cues are very important for the selection of host plants by H. hippophaecolus, but that olfactory stimuli play a more vital role in this process. The relative abundance of branches and leaves had no effect on the likelihood that adults landed on plants from four subspecies (varieties), but did influence landing rates within the same subspecies (varieties). When considering only the most resistant sea buckthorn subspecies (varieties), the presence of luxuriant branches and leaves led to lower landing rates. These results provide a theoretical basis for the understanding of H. hippophaecolus damage to sea buckthorn and the means to implement effective measures of control.     

沙棘主要蛀干害虫种群生态位

沙棘木蠹蛾(H olcocerus h ipp ophaecolusHua,Chou,F ang et Chen)是近几年在我国内蒙古、辽宁、山西、宁夏、陕西和甘肃等地大面积爆发的一种钻蛀性害虫,主要以幼虫危害沙棘(H ipp ophae rham noid ea)的根部和干部。在宁夏,沙棘除受到沙棘木蠹蛾的危害,还受到红缘天牛(A sias ha lod end ri Pa llas)的严重危害,该虫主要危害沙棘的干部。作者根据种群生态位理论,从时间、空间等资源利用上,定量地描述了沙棘木蠹蛾与红缘天牛种群之间的联系和竞争共存机制,结果表明:沙棘木蠹蛾幼虫主要分布在根部和干部80~120cm的范围内,不同时期,幼虫具有从干部向根部转移危害的习性;而红缘天牛主要分布在干部40~120cm的范围内,不同时期,幼虫没有转移危害的习性。沙棘木蠹蛾和红缘天牛的时间生态位和空间生态位宽度均较大,发生期较长,在沙棘上的活动范围较广,而不同时期内沙棘木蠹蛾的空间生态位宽度变动较红缘天牛大,其在沙棘上的活动范围在不同时期有较大的变动,而红缘天牛则较小。空间生态位重叠较小,在沙棘上的分布趋于分离,对空间资源的需求具有较大的差异,而时间生态位重叠较大,在沙棘的生长季节均能同时危害,危害期长但不具有明显的危害高峰期。两种害虫在空间生态位上的种间竞争强度较小,而在时间生态位上的种间竞争强度较大,在整个发生期内,两种害虫均能同时危害沙棘,但其位置有较大差异,在沙棘根部和干部40cm范围内,两种害虫几乎不能共存。     

不同土壤水分条件下中国沙棘雌雄株光合作用、蒸腾作用及水分利用效率特征

采用LI-6400便携式光合系统对野外不同生境(沟底、坡面)和田间不同土壤水分条件下中国沙棘雌雄株的净光合速率和蒸腾速率及水分利用效率特征进行了观测,结果表明,中国沙棘雌雄株在水分条件较好的生境中均表现较强的生活力,净光合速率和蒸腾速率主要受光照强度和大气温度的影响,雄株表现出更高的光合、蒸腾、水分利用效率;在水分条件较差的生境中,雌雄株均通过降低蒸腾和提高水分利用效率来适应逆境,净光合速率和蒸腾速率的影响因子增多,雄株的光合速率大幅度下降,雌株仍保持较高的光合速率,雌株的水分利用效率高于雄株.可见,在反映植物瞬时生理变化的性状方面,雌株对土壤水分减少表现出了更强的适应性,雄株对土壤水分变化表现出了更大的敏感性.     

祁连山两侧中国沙棘不同居群的遗传多样性研究

应用RAPD技术研究了祁连山中段中国沙棘(Hippophae rhamnoidoes ssp．sinensis)4个居群和1个对照居群的遗传多样性水平,探讨中国沙棘边缘居群的遗传变异以及天然屏障祁连山对中国沙棘居群遗传结构的影响。结果显示,祁连山地区中国沙棘居群水平的Nei’基因多样度(h)和Shannon多态信息指数(I)分别为0．2070和 0．297 4,基因分化系数(Gst)为0．319 3,均高于中国沙棘整个分布区的平均值,表明该地中国沙棘边缘居群遗传多样性水平及居群间的遗传分化都有增加的趋势;居群间每代迁移数(Nm=1．065 9)显著低于异交风媒植物(Nm= 5．380),表明祁连山的隔离对中国沙棘居群间的基因交流有限制作用,造成了该地中国沙棘边缘居群间较高的遗传分化。     

Plant wounding affects the oviposition of Hellula undalis(F.). The impact of leaf chemistry

Crucifer specialists, such as the tropical pest Hellula undalis (F.), developed a close association to their hosts and depend on characteristic secondary plant compounds, the glucosinolates (GS), in many cases. Following tissue damage, GS undergo hydrolysis catalyzed by the enzyme myrosinase to produce a complex array of products which include isothiocyantes, cyanides, and thiocyanates depending on reaction condition and the chemical nature of the side chain. We found that mechanical plant damage to the tropical crop plant Brassica campestris L. ssp. chinensis (pak-choi) leads to increased GS content, especially of indolyl GS and affected the oviposition behaviour of H. undalis negatively. GS were detected in methanolic leaf surface extracts from intact B chinensis and Sinapis alba (L.) plants, but no hydrolysis products of GS were found in leaf extracts with methylene chloride. Furthermore, the oviposition stimulant activity of GS extracts for H. undalis was greatly reduced after hydrolysis of GS by myrosinase. These results suggest the importance of GS for inducing oviposition, thus excluding hydrolysis products as active principle. Specific produced slightly volatile hydrolysis products of GS (3-indolylmethyl-cyanide and 5-vinyloxazolidine-2-thione) reduced oviposition, when applied to the host-plant. Leaf chemistry, including volatile and non-volatile compounds, may determine oviposition in H. undalis indicating a suitable host-plant.     

沙棘木蠹蛾蛹的空间分布

沙棘木蠹蛾（Holcocerus hippophaecolus Hua, Chou , Fang et Chen）是近几年在内蒙古、辽宁、山西、宁夏和陕西等地大面积爆发的一种钻蛀性害虫,该虫约4a完成1代,主要以幼虫危害沙棘（Hippophae rhamnoidea）的根部和干部,老熟幼虫在土壤中化蛹.为了解种群的空间结构,从而有效控制其危害,应用生物学统计方法和地质统计学（Geostatistics）方法对沙棘木蠹蛾蛹的空间分布特性进行了分析研究.结果表明：约90%的蛹在6月初到7月末之间羽化,而7月份羽化的数量占总数的一半之多.在调查样地中,雌雄蛹的比例基本为1：1.每株沙棘树周围,蛹的数量为0～4个,有蛹株率仅为24.3%.蛹在距离根基部周围1.3m的范围内均有分布,不同分布区间内蛹的数量变化没有一定的规律性,但90%的蛹分布在距根基部1m的范围内.沙棘木蠹蛾蛹的种群呈现较明显的空间聚集状态,空间依赖范围大小为11.1m,局部空间连续性强度为90.7%,呈现较明显的斑块状分布,在整个区域内有很多聚集点.对不同样方大小的变异曲线图进行比较得知：样方边长分别为5、6、7m时,变程、空间局部连续性强度和基台值的变化幅度均很小,几乎相等,而样方边长为5m时的决定系数较大,此样方为最适样方大小.     

Exploiting volatile organic compounds in crop protection: A systematic review of 1-octen-3-ol and 3-octanone

The 21st century has brought new challenges to the agri-food industry due to population growth, global warming, and greater public awareness of environmental issues. Ensuring global food security for future generations is crucial. However, pests, weeds, and diseases still significantly contribute to crop losses, and the availability of effective conventional synthetic pesticides is decreasing. To address this, new and diverse pest management tools are needed. One pest management tool showing potential for invertebrate pest management is the exploitation of volatile organic compounds (VOCs)—in particular, the compounds 1-octen-3-ol and 3-octanone. This review aims to explore the extent to which 1-octen-3-ol and 3-octanone show potential in the future management of invertebrate crop and animal pests. A significant increase in the rate of publication of literature on the use of 1-octen-3-ol and 3-octanone in crop protection since 2018 is identified by this review, therefore, showing the potential importance of these compounds for use in future pest management. This review also identifies key interactions between naturally occurring biosynthesised 1-octen-3-ol and 3-octanone, and a range of invertebrate targets. Many of these interactions with key crop pests are sourced from the taxonomic families Lamiaceae, Fabaceae, and Trichomaceae. However, analysis of the practical application of these sources in an integrated pest management programme identifies clear limitations with the use of naturally occurring biosynthesised 1-octen-3-ol and 3-octanone. Rather, future focus should be placed on the development and exploitation of synthesised nature identical 1-octen-3-ol and 3-octanone for use as a biopesticide product. Overall, 1-octen-3-ol and 3-octanone show potential for exploitation in future crop protection, being abundant in source and diversity of invertebrate interactions. However, their use as a naturally occurring biosynthesised chemical is likely not practical for direct implementation in crop protection. Rather, focus should be placed on the development and exploitation of synthesised nature identical variants of these compounds for use as a biopesticide.     

鸟类取食中国沙棘果实的方式及其对种子的传播作用

2003年9月～2004年3月,定期观察取食中国沙棘果实的鸟类及其取食方式。共记录取食中国沙棘果实的鸟类18种,其取食果实的方式主要有：1)直接在树冠上吞食果实,有时候在吞食后将种子呕出;2)将果实从树上衔走后,在栖息处吞食或啄食;3)将果实啄落至地面,然后取食果肉和种子,留下果皮;4)啄破果皮,吸食果肉,留下果皮及种子;5)从顶端将果皮啄破后,仅取食里面的种子。不同的取食方式决定了它们对沙棘种子的传播作用不同。收集鸟粪便中的种子与完整的干果实及人工剥离果肉和内果皮的种子做萌发对比实验,结果表明,鸟类消化道过程对种子的萌发有一定影响,但萌发率仍较高。沙棘为多种鸟类提供食物,而鸟类则为沙棘传播种子,它们之间形成一种互利关系。     

不同土壤水分条件下中国沙棘雌雄株叶片形态结构及生理生化特征

在不同土壤水分条件下,对中国沙棘雌雄株叶片的形态结构以及生理生化特征进行了研究.结果表明： 在土壤水分条件较差时,中国沙棘雌雄株的叶片结构旱化特征较明显,并且雌株的叶片厚度、上下表皮厚度、侧脉维管束距离均较小,而下表皮毛厚度、密度和栅栏组织与海绵组织的比值均较大,表现出较强的干旱适应性和生态可塑性;雌雄株叶片的游离脯氨酸、可溶性糖和丙二醛含量升高,其中雌株叶片的游离脯氨酸和可溶性糖含量上升幅度大于雄株,而雄株叶片的丙二醛含量上升幅度明显大于雌株.随着土壤水分条件的改变,雌雄株叶片的超氧化物歧化酶和过氧化氢酶活性变化较大.在干旱胁迫下,中国沙棘雌株的生理生化指标多元隶属度值大于雄株.雌株对干旱胁迫的适应性和生理调节能力更强.     

Genetic structure in the seabuckthorn carpenter moth (Holcocerus hippophaecolus) in China: the role of outbreak events, geographical and host factors

Understanding factors responsible for structuring genetic diversity is of fundamental importance in evolutionary biology. The seabuckthorn carpenter moth (Holcocerus hippophaecolus Hua) is a native species throughout the north of China and is considered the main threat to seabuckthorn, Hippophae rhamnoides L. We assessed the influence of outbreaks, environmental factors and host species in shaping the genetic variation and structure of H. hippophaecolus by using Amplified Fragment Length Polymorphism (AFLP) markers. We rejected the hypothesis that outbreak-associated genetic divergence exist, as evidenced by genetic clusters containing a combination of populations from historical outbreak areas, as well as non-outbreak areas. Although a small number of markers (4 of 933 loci) were identified as candidates under selection in response to population densities. H. hippophaecolus also did not follow an isolation-by-distance pattern. We rejected the hypothesis that outbreak and drought events were driving the genetic structure of H. hippophaecolus. Rather, the genetic structure appears to be influenced by various confounding bio-geographical factors. There were detectable genetic differences between H. hippophaecolus occupying different host trees from within the same geographic location. Host-associated genetic divergence should be confirmed by further investigation.     

黑河上游灌丛建群种中国沙棘自由授粉子代父本分析和花粉流

利用SSR分子标记对中国沙棘（Hippophae rhamnoides ssp. sinensis Rousi）自由授粉的种子进行父本分析,研究其子代的父本来源和花粉散布模式。结果显示：在80%的置信水平上,193个子代中有104个个体可以确定花粉来源;在20个确定的父本中,16个为中国沙棘,4个为肋果沙棘（H.neurocarpa S.W.Liu et T.N.He）。传粉格局分析结果显示,中国沙棘有效花粉散布范围为3~71 m,平均距离为20.4 m,2株母本分别有87.23%和78.95%的有效花粉来自距其30 m的范围之内,研究结果表明中国沙棘自然种群以近距离传粉为主。此外,在黑河上游沙棘杂交带中,中国沙棘子代中的肋果沙棘花粉平均贡献率达到14.84%,表明中国沙棘与肋果沙棘存在较高的种间当代花粉流。     

不同采收期栽培宽叶羌活挥发性成分的研究

采用水蒸气蒸馏法提取不同采收时间(5、6、7、8和9月)栽培宽叶羌活药材中的挥发油,测定其含量;通过GC-MS对挥发油成分进行了分析鉴定,并采用面积归一化法计算各组分的相对含量。实验结果表明,不同采收时间,栽培宽叶羌活挥发油含量存在差异,以8月份采收的药材挥发油含量最高;挥发油经GC-MS分析,共鉴定出39个化合物,有31种共有成分;对共有组分进行主成分分析显示,香桧烯、α-蒎烯、莰烯、β-蒎烯、γ-萜品烯、乙酸龙脑酯、α-红没药醇等15种成分可作为挥发油季节变化的特征组分。不同季节采集的羌活生药材,其挥发油含量和成分具有一定的差别,在一定程度上反映了其药用价值的微妙差异,可为羌活药材药理药用价值的进一步开发利用提供一定的参考。     

Identification of plant semiochemicals and evaluation of their interactions with early spring insect pests of asparagus

Information is lacking on the chemical ecology of asparagus, and knowledge about the effects of its volatile emissions on its associated early season pest species is completely absent. The current study aimed to (1) evaluate whether the asparagus miner responds to asparagus volatiles, (2) identify and compare the changes in asparagus host plant volatiles from mechanical and chewing damage by the black cutworm, a temporally co-occurring species with the asparagus miner, and (3) assess how asparagus volatiles affect asparagus miner populations in the field. Results indicated that asparagus miners were significantly attracted to healthy asparagus stems when compared to clean air. Damaged asparagus headspace volatiles were quantitatively and qualitatively different from healthy plants. Volatile baits elicited a range of responses, but their effects were inconsistent between sampling years and phenology-dependent. Overall, we demonstrated that the chemical ecology of asparagus may be altered by its pest community, and volatiles identified from asparagus may impact the behavior of the asparagus miner.     

Fatty acid ketodienes and fatty acid ketotrienes: Michael addition acceptors that accumulate in wounded and diseased Arabidopsis leaves

Physical damage and disease are known to lead to changes in the oxylipin signature of plants. We searched for oxylipins produced in response to both wounding and pathogenesis in Arabidopsis leaves. Linoleic acid 9- and 13-ketodienes (KODEs) were found to accumulate in wounded leaves as well as in leaves infected with the pathogen Pseudomonas syringae pv. tomato (Pst). Quantification of the compounds showed that they accumulated to higher levels during the hypersensitive response to Pst avrRpm1 than during infection with a Pst strain lacking an avirulence gene. KODEs are Michael addition acceptors, containing a chemically reactive alpha,beta-unsaturated carbonyl group. When infiltrated into leaves, KODEs were found to induce expression of the GST1 gene, but vital staining indicated that these compounds also damaged plant cells. Several molecules typical of lipid oxidation, including malonaldehyde, also contain the alpha,beta-unsaturated carbonyl reactivity feature, and, when delivered in a volatile form, powerfully induced the expression of GST1. The results draw attention to the potential physiological importance of naturally occurring Michael addition acceptors in plants. In particular, these compounds could act directly, or indirectly via cell damage, as powerful gene activators and might also contribute to host cell death.     

Fruits foraging patterns and seed dispersal effect of frugivorous birds on Hippophae rhamnoides sinensis

Behaviors of 18 species of birds eating fruits of Hippophae rhamnoides spp.sinensis were observed from September 2003 to March 2004.Their foraging patterns were found to be very different and Can be divided into five classes:(1)direct swallowing the fruits on crown of the shrubs and sometimes regurgitating seeds soon after;(2)carrying the fruits to their perching sites and swallowing;(3)pecking the fruits from the shrubs to the ground,eating pulp and seeds but leaving pericarp;(4)pecking through the pericarp,eating pulp and leaving pericarp and seeds;(5)pecking through the pericarp on the top of fruits,and only eating seeds.These foraging patterns have different effects on seed dispersal of H.rhamnoides spp.sinensis.The germination experiment of three groups of seeds(seeds from feces,dry fruits and extracted seeds from dry fruits)was carried out.Although ingestion processes of birds had some adverse effects on the seed germination of H.rhamnoides spp.sinensis,the seeds from feces still have a relatively higher germination ratio.H.rhamnoides spp.sinensis provides food to a variety of frugivorous birds.and the birds disperse its seeds.Thus,a mutually beneficial relationship between the bird and the seed is formed.     

Gypsy moth herbivory induced volatiles and reduced parasite attachment to cranberry hosts

Interactions between species can have cascading effects that shape subsequent interactions. For example, herbivory can induce plant defenses that affect subsequent interactions with herbivores, pathogens, mycorrhizae, and pollinators. Parasitic plants are present in most ecosystems, and play important roles in structuring communities. However, the effects of host herbivory on parasitic plants, and the potential mechanisms underlying such effects, are not well known. We conducted a greenhouse study to ask whether gypsy moth (Lymantria dispar) damage, host cultivar, and their interaction affected preference of the stem parasite dodder (Cuscuta spp.) on cranberry hosts (Vaccinium macrocarpum). We then assessed the mechanisms that could underlie such effects by measuring induced changes in phytohormones and secondary compounds. We found that damage by gypsy moths delayed dodder attachment by approximately 0.3 days when dodder stems were added 2 days after damage, and reduced attachment by more than 50% when dodder stems were added 1 week after host plant damage. Gypsy moth damage significantly increased jasmonic acid (JA) levels, total volatile emissions, and the flavonol, quercetin aglycone, suggesting possible mechanisms underlying variation in dodder ability to locate or attach to hosts. Dodder preference also differed between cranberry cultivars, with the highest attachment on the cultivar that had significantly lower levels of total volatile emissions and total phenolic acids, suggesting that volatile composition and phenolics may mediate dodder preference. Our results indicate that herbivory can reduce subsequent attachment by a highly damaging parasitic plant, demonstrating the potential importance of early damage for shaping subsequent species interactions.     

Genome sequence analysis and organization of the Hyphantria cunea granulovirus (HycuGV-Hc1) from Turkey

The fall webworm (Hyphantria cunea) impacts a wide variety of crops and cultivated broadleaf plant species. The pest is native to North America, was introduced to Europe and has since spread further as far as central Asia. Despite several attempts to control its distribution, the pest continues to spread causing damage all over the world. A naturally occurring baculovirus, Hyphantria cunea granulovirus (HycuGV-Hc1), isolated from the larvae of H. cunea in Turkey appears to have a potential as microbial control agent against this pest. In this report we describe the complete genome sequence and organization of the granulovirus isolate (HycuGV-Hc1) that infects the larval stages and compare it to other baculovirus genomes. The HycuGV-Hc1 genome is a circular double-stranded DNA of 114,825 bp in size with a nucleotide distribution of 39.3% G + C. Bioinformatics analysis predicted 132 putative open reading frames of (ORFs) ≥ 150 nucleotides. There are 24 ORFs with unknown function. Seven homologous repeated regions (hrs) and two bro genes (bro-1 and bro-2) were identified in the genome. Comparison to other baculovirus genomes, HycuGV-Hc1 revealed some differences in gene content and organization. Gene parity plots and phylogenetics confirmed that HycuGV-Hc1 is a Betabaculovirus and is closely related to Plutella xylostella granulovirus. This study expands our knowledge on the genetic variation of HycuGV isolates and provides further novel knowledge on the nature of granuloviruses.     

Effect of Chitinase on Resistance to Fungal Pathogens in Sea Buckthorn, Hippophae rhamnoides, and Cloning of Class I and III Chitinase Genes

Sea buckthorn (Hippophae rhamnoides L.) is naturally distributed from Asia to Europe. It has been widely planted as an ornamental shrub and is rich in nutritional and medicinal compounds. Fungal pathogens that cause diseases such as dried-shrink disease are threats to the production of this plant. In this study, we isolated the dried-shrink disease pathogen from bark and total chitinase protein from leaves of infected plants. The results of the Oxford Cup experiment suggested that chitinase protein inhibited the growth of this pathogen. To improve pathogen resistance, we cloned chitinase Class I and III genes in H. rhamnoides, designated Hrchi1 and Hrchi3. The full-length cDNA of the open reading frame region of Hrchi1 contained 903 bp encoding 300 amino acids and Hrchi3 contained 894 bp encoding 297 amino acids. Active domain analysis, protein types, and secondary and 3D structures were predicted using online software.     

黄足黄守瓜（Aulcophora femoralis chinensis）取食和机械损伤对南瓜子叶中葫芦素B的诱导作用

采用高效液相色谱分析方法，通过测定葫芦素B含量的变化，探讨黄足黄守瓜与南瓜之间在时间上的化学诱导关系。虫害和机械损伤均能引起南瓜子叶中的葫芦素B含量围绕着对照水平上、下波动的变化。但是，这两种因素所引起的葫芦素B含量变化的规律有较大的不同。黄足黄守瓜的为害相对于机械损伤诱导葫芦素B合成的差异主要表现在3个方面：首先，反应速度比较快。如叶部处理中，虫害株在虫害后1h葫芦素B含量已有了显著升高，而机械损伤株葫芦素B含量此时不仅没有升高，反而有下降趋势，在1．5h才有所升高。其次，反应程度比较大，即虫害株葫芦素B的最大诱导量显著大于机械损伤株的。最后，诱导反应持续的时间比较长，即是说虫害株结束诱导反应的时间要明显长于机械损伤株的。另外，即使被处理的是南瓜茎部，其子叶中葫芦素B含量也发生了变化，而且变化趋势与叶部被处理的具有相似性，证明虫害和机械损伤都能系统诱导被害南瓜合成葫芦素B。此外，实验结果还显示虫害株未被害叶葫芦素B的含量比被害叶的高。     

Starch biosynthesis,its regulation and biotechnological approaches to improve crop yields

Structurally composed of the glucose homopolymers amylose and amylopectin, starch is the main storage carbohydrate in vascular plants, and is synthesized in the plastids of both photosynthetic and non-photosynthetic cells. Its abundance as a naturally occurring organic compound is surpassed only by cellulose, and represents both a cornerstone for human and animal nutrition and a feedstock for many non-food industrial applications including production of adhesives, biodegradable materials, and first-generation bioethanol. This review provides an update on the different proposed pathways of starch biosynthesis occurring in both autotrophic and heterotrophic organs, and provides emerging information about the networks regulating them and their interactions with the environment. Special emphasis is given to recent findings showing that volatile compounds emitted by microorganisms promote both growth and the accumulation of exceptionally high levels of starch in mono- and dicotyledonous plants. We also review how plant biotechnologists have attempted to use basic knowledge on starch metabolism for the rational design of genetic engineering traits aimed at increasing starch in annual crop species. Finally we present some potential biotechnological strategies for enhancing starch content.