Complete Genome Sequence of a Novel Wild tomato mosaic virus Isolate Infecting Nicotiana tabacum in China

Virus particles of approximately 740–760 nm in length and 13 nm in diameter were observed from a diseased Nicotiana tabacum (tobacco) plant in Sichuan Province, China. The complete genomic sequence of the virus isolate XC1 was determined to contain 9659 nucleotides without 3′ terminal poly(A) tail. XC1 has a genome typical of members of the genus Potyvirus, encoding a large polyprotein of 3075 amino acids. Putative proteolytic cleavage sites and a number of well characterized functional motifs were identified by sequence comparisons with those of known potyviruses. Sequence comparison revealed that XC1 shared the highest level of nucleotide sequence identity (76.5%) with Wild tomato mosaic virus (WTMV). Phylogenetic analysis showed that XC1 was closely related to the WTMV Guangdong isolate with an identity of 94.3% between CP gene sequence of the two viruses. We thus named XC1 WTMV‐XC‐1 as a novel isolate of WTMV. The full sequence of WTMV‐XC‐1 may serve as a basis for future investigations on the gene diversity of WTMV.     

Dietary resveratrol impairs body weight gain due to reduction of feed intake without affecting fatty acid composition in Atlantic salmon

Recent studies suggest that the use of vegetable oils at expense of fish oil in aquaculture feeds might have potential negative effects on fish redox homeostasis and adiposity. Resveratrol (RESV) is a lipid-soluble phytoalexin present in fruits and vegetables with proven in vivo antioxidant function in animals. The present study aims to assess the potential use of RESV in Atlantic salmon feeds. To this end, post-smolt salmons with an initial BW of 148±3 g were fed four experimental diets for 15 weeks. A diet low in fish oil served as a control and was supplemented with 0, 0.5, 1.5 and 2.5 g/kg of RESV, respectively. The effect of the experimental diets on animal performance, tissue fatty acid composition, and the expression of genes encoding proteins involved in antioxidant signalling, lipid peroxidation, and metabolism were studied. Resveratrol significantly reduced feed intake and final BW of the salmon. Feeding RESV did not affect the sum of saturated and monounsaturated fatty acids or total lipids in the fillet. While the content of total polyunsaturated fatty acids was not affected, the percentages of some fatty acids in the liver and fillet were changed by RESV. Furthermore, in liver, the relative expression of glutathione peroxidase 4b, nuclear factor-like 2, and arachidonate 5-lipoxygenase remained unchanged across treatment groups. In conclusion, the negative impact of dietary RESV on FI and hence reduction of the BW discourages its inclusion in low fish oil diets for Atlantic salmon.     

Alteration of selection regime resulting from harvest of American ginseng, <Emphasis Type="Italic">Panax quinquefolius</Emphasis>

Replicate harvest simulations were conducted in a large natural population of Panax quinquefolius L.␣(Araliaceae) to determine the selective effects of harvest. We investigated how minimum size requirements and the influence of size on apparency to human harvesters could result in preferential removal of large plants. To determine which plants were encountered in the large population, harvesters were tracked using GPS as they searched for every legally harvestable, adult plant they could find. Plants were assigned stage-specific fitness measures based on their contributions to population growth rate (λ) under three demographically based harvest regimes: no harvest, harvest and harvest removing seeds. Plant size was codified into a size-index equal to the product of total leaf area and stem height. Heterogeneity of slopes was tested to determine if the selection gradients (β) describing the relationship between fitness and size varied among the three harvest regimes. Harvest differentially reduced the fitness of larger plants in one of four individual harvest simulations. The combined harvest simulation significantly altered the selection regime for size in the population of juvenile and adult (harvestable) plants. Seed removal by harvesters intensified fitness declines for larger plants. Because larger plants contribute most to population growth, the selective effects of harvest could result in a shift in the evolutionary dynamics of this species with significant conservation implications.     

云南省爬行动物名录和地理区划更新

云南省作为中国生物多样性最高的省份, 其详实的物种本底资料对我国生物多样性研究和保护具有重要意义。本文在前期研究的基础上, 结合实体标本, 汇总编制了云南省现生、原生爬行动物更新名录。截至2021年12月31日, 云南省记录爬行动物25科82属235种, 其中龟鳖目4科12属16种, 有鳞目蜥蜴亚目6科20属72种, 蛇亚目15科50属147种。较《云南两栖爬行动物》确认新增82种, 存疑收录21种, 移除23种。基于先前云南省爬行动物区划和更新后的物种分布信息, 将云南省爬行动物地理分为6个动物地理区, 即滇西北横断山区、滇西山地区、滇南山地区、滇东南山地区、滇中高原区以及滇东北山地区; 其中滇西北横断山区、滇西山地区、滇中高原区和滇东南山地区的范围与先前研究相比有所调整。结合调整后的爬行动物地理区划, 对物种分布、物种特有性、受威胁状况等给出了统计结果。云南省爬行动物特有物种、国内仅见于云南的非特有物种数量较多, 受威胁等级高。建议今后继续加大分类学研究投入, 对滇西北、滇中特有爬行动物分布集中的区域积极开展栖息地保护工作, 同时在最新调整的《国家重点保护野生动物名录》基础上, 定期组织专家研讨, 对《云南省省级重点保护动物名录》提出更新建议。     

烟粉虱对几种常见蔬菜寄主的取食选择性

在多种蔬菜寄主同时存在的情况下,烟粉虱对寄主的选择性和嗜好性排序为:黄瓜>节瓜,番茄,菜豆>芥蓝,茄子>甘蓝,苦瓜。     

Quantitative and qualitative differences in morphological traits revealed between diploid Fragaria species

BACKGROUND AND AIMS: The aims of this investigation were to highlight the qualitative and quantitative diversity apparent between nine diploid Fragaria species and produce interspecific populations segregating for a large number of morphological characters suitable for quantitative trait loci analysis. METHODS: A qualitative comparison of eight described diploid Fragaria species was performed and measurements were taken of 23 morphological traits from 19 accessions including eight described species and one previously undescribed species. A principal components analysis was performed on 14 mathematically unrelated traits from these accessions, which partitioned the species accessions into distinct morphological groups. Interspecific crosses were performed with accessions of species that displayed significant quantitative divergence and, from these, populations that should segregate for a range of quantitative traits were raised. KEY RESULTS: Significant differences between species were observed for all 23 morphological traits quantified and three distinct groups of species accessions were observed after the principal components analysis. Interspecific crosses were performed between these groups, and F2 and backcross populations were raised that should segregate for a range of morphological characters. In addition, the study highlighted a number of distinctive morphological characters in many of the species studied. CONCLUSIONS: Diploid Fragaria species are morphologically diverse, yet remain highly interfertile, making the group an ideal model for the study of the genetic basis of phenotypic differences between species through map-based investigation using quantitative trait loci. The segregating interspecific populations raised will be ideal for such investigations and could also provide insights into the nature and extent of genome evolution within this group.     

Four thousand years of plant exploitation in the Lake Chad Basin (Nigeria), part III: plant impressions in potsherds from the Final Stone Age Gajiganna Culture*

Late Holocene climatic changes caused a large scale regression of the Lake Chad shoreline followed by an expansion of settlements into previously unexplored territories. Numerous Final Stone Age sites of the Gajiganna Culture (1,800 to 800 b.c.) in the Lake Chad Basin (northeast Nigeria) yielded plant impressions in potsherds. The ceramics of Phase I (1,800–1,400 b.c.) were mineral tempered, and plant impressions, mainly of Paniceae, were caused only by incidental inclusion. In contrast, a considerable number of the sherds from Phase II (1,500–800 b.c.) were intentionally tempered with chaff derived from domesticated pearl millet (Pennisetum glaucum), wild Paniceae and wild rice species (Oryza cf. barthii and O. cf. longistaminata). This plant spectrum suggests the exploitation of the wet wild areas, and also the cultivation of pearl millet on sandy soils. The evidence suggests that agricultural practices were established late and were introduced from elsewhere. During the time of seasonally occupied sites in Phase I, the subsistence strategy was based on herding, fishing, and gathering, while in Phase II there are signs of permanent settlements and agriculture. The evidence from the plant impressions indicates that in the Final Stone Age Gajiganna Culture around 1,000–800 b.c., pearl millet became well established while the gathering of wild millets and rice was still practised.*Klee et al. (2000), Zach and Klee (2003)     

Microsatellite polymorphism in natural populations of wild emmer wheat,Triticum dicoccoides,in Israel

Diversity in 20 microsatellite loci of wild emmer wheat, Triticum dicoccoides, was examined in 15 populations (135 genotypes) representing a wide range of ecological conditions of soil, temperature, and water availability, in Israel and Turkey. An extensive amount of diversity at microsatellite loci was observed despite the predominantly selfing nature of this plant species. The 20 Gatersleben wheat microsatellites (GWM), representing 13 chromosomes of genomes A and B of wheat, revealed a total of 364 alleles, with an average of 18 alleles per GWM marker (range: 5–26). The proportion of polymorphic loci per population averaged 0.90 (range: 0.45– 1.00); genic diversity, He, averaged 0.50 (range 0.094– 0.736); and Shannon’s information index averaged 0.84 (range 0.166–1.307). The coefficients of genetic distance between populations were high and averaged D=1.862 (range 0.876–3.320), an indication of sharp genetic divergence over short distances. Interpopulation genetic distances showed no association with geographic distance between the population sites of origin, which ruled out a simple isolation by distance model. Genetic dissimilarity values between genotypes were used to produce a dendrogram of the relationships among wild wheat populations by the unweighted pair-group method with arithmetic averages (UPGMA). The results showed that all the wild emmer wheat populations could be distinguished. Microsatellite analysis was found to be highly effective in distinguishing genotypes of T. dicoccoides, originating from diverse ecogeographical sites in Israel and Turkey, with 88% of the 135 genotypes correctly classified into sites of origin by discriminant analysis. Our present microsatellite results are non-random and in agreement with the previously obtained allozyme and RAPD patterns, although the genetic-diversity values obtained with microsatellites are much higher. Significant correlates of microsatellite markers with various climatic and soil factors suggest that, as in allozymes and RAPDs, natural selection causes adaptive microsatellite ecogeographical differentiation, not only in coding, but most importantly in non-coding genomic regions. Hence, the concept of ”junk DNA” needs to be replaced by at least partly regulatory DNA. The obtained results suggest that microsatellite markers are useful for the estimation of genetic diversity in natural populations of T. dicoccoides and for the tagging of agronomically important traits derived from wild emmer wheat. Received: 27 February 2001 / Accepted: 22 March 2001