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Solidago canadensis is native to North America, but has become a noxious invasive plant in China. We know only a little about its invasion history and the effects of introductions on its genetic composition. Here, we investigated genetic variation and structure between 15 North American and 13 Chinese populations of S. canadensis using AFLP makers. Four AFLP loci suggested relatively high genetic diversity of this weed and similar genetic variation between the invasive range and the native range. Most genetic variation was within populations across two ranges, but the Chinese range had a higher degree of among-population variation than the North American range. Multiple tests, including Bayesian assignment, UPGMA analysis, PCoA and analysis of 'isolation by distance', showed that the Chinese populations originated from at least two distinct native sources and that secondary introduction or dispersal should be common in China. Also, North American populations were possibly a single genetic group. Overall, S. canadensis in China was probably founded from multiple introductions and then spread through long-distance dispersal associated with human activities. Genetic variability in the species in the invaded range appears to have favoured establishment and spread and may well provide a challenge to successful control.

The dove tree, Davidia involucrata Baill. (Davidiaceae), is a relict species endemic to China. Human activities and the strict requirements for seedling recruitments have led to the decline in number of individuals in extant natural populations of this species. In order to provide information for the design of conservation management strategies for D. involucrata, we investigated the phylogeographical pattern of this relict tree. Our sampling included 256 individuals from 32 natural populations of D. involucrata in China and we sequenced six chloroplast DNA (cpDNA) non-coding regions. We distinguished a total of 13 different cpDNA haplotypes. From the cpDNA variation in D. involucrata, we found a very high level of regional differentiation (F ST = 0.812) and a strong phylogeographical pattern (N ST = 0.996 [ G ST = 0.981, P \ 0.05). Phylogenetic analysis reveals three main cpDNA haplotype lineages and four population groups. The split between these geographical groups can be dated back from the late Pliocene to early Pleistocene. Nonoverlapping distribution of chloroplast haplotypes and high genetic differentiation among four distinct geographical groups suggest that D. involucrata probably survives in four separate glacial refugia. Our findings have an important implication for conservation of its genetic diversity. The deduced glacial survival areas for D. involucrata should be recognized as four ''evolutionary significant units'' and be considered as separate targets in conserving its genetic diversity.

Adaptation to aquatic habitats is a formidable challenge for terrestrial angiosperms that has long intrigued scientists. As part of a suite of work to explore the molecular mechanism of adaptation to aquatic habitats, we here sequenced the transcriptome of the submerged aquatic plant Ranunculus bungei, and two terrestrial relatives R. cantoniensis and R. brotherusii, followed by comparative evolutionary analyses to determine candidate genes for adaption to aquatic habitats. We obtained 126,037, 140,218 and 114,753 contigs for R. bungei, R. cantoniensis and R. brotherusii respectively. Bidirectional Best Hit method and OrthoMCL method identified 11,362 and 8,174 1:1:1 orthologous genes (one ortholog is represented in each of the three species) respectively. Non-synonymous/synonymous (dN/dS) analyses were performed with a maximum likelihood method and an approximate method for the three species-pairs. In total, 14 genes of R. bungei potentially involved in the adaptive transition from terrestrial to aquatic habitats were identified. Some of the homologs to these genes in model plants are involved in vacuole protein formation, regulating ‘water transport process’ and ‘microtubule cytoskeleton organization’. Our study opens the door to understand the molecular mechanism of plant adaptation from terrestrial to aquatic habitats.

1. Linkage disequilibrium (LD), the non-random association of alleles at different loci, has been used as an important parameter to study the genetic diversity and evolutionary history of natural populations. A joint analysis of LD with the linkage of the same marker pair has proven to gain more insight into the genetic signature of population diversification than LD analysis alone. 2. We develop a unifying framework for simultaneously estimating the linkage and LD across pairs of multiallelic markers. The framework has particular power to construct the LD map from any markers with an arbitrary number of alleles per locus. We provide an efficient strategy to manipulate disequilibrium parameters whose number increases exponentially with the number of alleles. 3. The model was tested through extensive simulation studies and validated by analysing a real marker data set from a population genetic research project of euphrates poplar, a desert tree, distributed in the north-western China. For widespread undomesticated natural populations, compared with biallelic markers, multiallelic markers with a high level of polymorphism are more powerful to study their genetic structure and organization of an outcrossing population. 4. The model developed will potentially have an immediate implication for population and evolutionary genetic studies.

The giant lobelias in East African mountains are good models for studying molecular mechanisms of adaptation to different altitudes. In this study, we generated RNA-seq data of a middle-altitude species Lobelia aberdarica and a high-altitude species L. telekii, followed by selective pressure estimation of their orthologous genes. Our aim was to explore the important genes potentially involved in adaptation to different altitudes. About 9.3 Gb of clean nucleotides, 167,929-170,534 unigenes with total lengths of 159,762,099-171,138,936 bp for each of the two species were generated. OrthoMCL method identified 3,049 1:1 orthologous genes (each species was represented by one ortholog). Estimations of non-synonymous to synonymous rate were performed using an approximate method and a maximum likelihood method in PAML. Eightyfive orthologous genes were under positive selection. At least 8 of these genes are possibly involved in DNA repair, response to DNA damage and temperature stimulus, and regulation of gene expression, which hints on how giant lobelias adapt to high altitudinal environment that characterized by cold, low oxygen, and strong ultraviolet radiation. The negatively selected genes are over-represented in Gene Ontology terms of hydrolase, macromolecular complex assembly among others. This study sheds light on understanding the molecular mechanism of adaptation to different altitudes, and provides genomic resources for further studies of giant lobelias.

The quality and safety of agricultural products is a concern for the entire world. The main focus is pesticide residues, which is especially typical in process of tea production. The technology of Using Light to Trap is the best way to solve the problem, because it is to induce and kill pests with physical means of light, electricity, color and etc. Over the past decade, pilot demonstration and applications of insecticidal lamps applied in tea plantation have been conducted in more than a dozen provinces all over China, which achieved remarkable results. This article aims to conduct the work of conclusion and analysis on the basis of test results from fields over the years and the work of comprehensive analysis and accession with the consideration of current development status of the technology of Using Light to Trap, and thus provides scientific basis for ecological control of pests and diseases in tea plantation, reduction on volume of chemical pesticides, decrease of pesticide residues in tea, maintenance of ecological balance and protection for agricultural ecological environment.

Both historical (e.g., glaciations) and spatial (geological features) factors are considered to have had significant influences on the distribution and genetic structure of many plants. To understand the effects of such factors on the current genetic and geographical distributions of plant species in the Nanling and central regions in China, we examined genetic variation and phylogeographical patterns of Sagittaria lichuanensis J.K. Chen (Alismataceae), an endangered and endemic species in China, using chloroplast DNA atpB-rbcL intergenic spacer sequence variation. In this study, a total of 9 haplotypes from 47 individuals in 6 populations of S. lichuanensis were detected. The NST (0.193) was significantly higher than GST (0.082) (P < 0.05), indicating a significant phylogeographical structure. In the minimum spanning network (MSN) of the haplotypes, the distribution of haplotypes showed an east-west split. The results of the Mantel test analysis showed that there was no correlation between the genetic distance and geographical distance (r = 0.539, P > 0.05). The formation of barriers to dispersal might have played an important role in shaping the population genetic structure of S. lichuanensis. Within each region (east and west regions), high levels of gene flow between populations and low levels of population differentiation were found. Several conditions, such as co-ancestry due to recent common ancestry or short period of isolation, might have occurred among the populations studied. In the MSN, all tip haplotypes except for two (A and G) occurred in two or more populations, and the haplotype D in the interior node was widespread. The haplotype D is likely to be an ancestral haplotype and represents the relic, widely distributed haplotype before the populations were fragmented and isolated by mountain uplift. Résumé :On considère que les facteurs historiques (ex. glaciations) et spatiaux (caractères géologiques) exercent des influences significatives sur la distribution ainsi que la structure génétique de nombreuses plantes. Afin de comprendre les effets de tels facteurs sur la génétique actuelle et les distributions géographiques d'espèces végétales de la région de Nanling et du centre de la Chine, les auteurs ont examiné la variation génétique et les patrons phylogéographiques du Sagittaria lichuanensis J.K. Chen (Alismataceae), une espèce endémique menacée de la Chine, en utilisant la variation des séquences de l'espaceur intergénique atpB-rbcL de l'ADN chloroplastique. Dans cette étude, ils ont détecté un total de 9 haplotypes provenant de 47 individus issus de 6 populations du S. lichuanensis. Le N ST (0,193) étant significativement plus grand que le G ST (0,082) (P < 0,05) indique une structure phylogéographique robuste. Dans le réseau d'étalement minimum (MSN) des haplotypes, la distribution des haplotypes montre une fracture est-ouest. Les résultats d'analyse du test de Mantel montrent l'absence de corrélation entre la distance génétique et la distance géographique (r = 0,539, P > 0,05). La formation d...