Cuticular hydrocarbons of Cerambycidae species can function as signals for sex recognition. Little is known about the copulatory signals of the juniper bark borer Semanotus bifasciatus, a major economic threat to Platycladus orientalis Franco in China. Here, we investigated the cuticular hydrocarbons of both sexes of S. bifasciatus to determine the chemically mediated mating signals using the solid-phase microextraction (SPME) technique with carbowax/divinylbenzene fibers (CAR/DVB) and then analyzed by coupled gas chromatography-mass spectrometry (GC-MS). A series of aliphatic saturated straight-chain n-alkanes (n-C23 to n-C28), internally branched monomethylalkanes at carbons 3, 11, or 13, and dimethylalkanes were identified, which showed no qualitative differences in either sex and were similar in the samples with SPME fiber extraction and those with hexane extraction. The bioassay showed that 11-methylpentacosane (11-MeC25), 11-methylhexacosane (11-MeC26), and 11-methylheptacosane (11-MeC27) have sex-specific recognition functions that triggered more mating attempts at a female-specific ratio of 100:4:60 than at a male-specific ratio of 100:85:50. In addition, the female-specific ratio of 11-methylalkanes can elicit about 70% of male mating attempts within about 60 s, whereas live females elicit about 98% of male mating attempts within 25 s. The discrepancy in the initiation of mating attempts by synthetic mixtures and live females suggests that the methyl isomers 3-MeC25, 3-MeC27, and/or 11,15-diMeC27 may also be involved in the mating behavior of S. bifasciatus. These results suggest that 11-MeC25, 11-MeC26, and 11-MeC27 constitute the contact sex pheromone of S. bifasciatus, with the presence or absence of 11-MeC26 in particular playing an important role in mate recognition by males. 相似文献
Endemic species are important components of regional biodiversity and hold the key to understanding local adaptation and evolutionary processes that shape species distributions. This study investigated the biogeographic history of a relict conifer Pinus bungeana Zucc. ex Endl. confined to central China. We examined genetic diversity in P. bungeana using genotyping-by-sequencing and chloroplast and mitochondrial DNA markers. We performed spatial and temporal inference of recent genetic and demographic changes, and dissected the impacts of geography and environmental gradients on population differentiation. We then projected P. bungeana's risk of decline under future climates. We found extremely low nucleotide diversity (average π 0.0014), and strong population structure (global FST 0.234) even at regional scales, reflecting long-term isolation in small populations. The species experienced severe bottlenecks in the early Pliocene and continued to decline in the Pleistocene in the western distribution, whereas the east expanded recently. Local adaptation played a small (8%) but significant role in population diversity. Low genetic diversity in fragmented populations makes the species highly vulnerable to climate change, particularly in marginal and relict populations. We suggest that conservation efforts should focus on enhancing gene pool and population growth through assisted migration within each genetic cluster to reduce the risk of further genetic drift and extinction. 相似文献
Oresitrophe and Mukdenia (Saxifragaceae) are epilithic sister genera used in traditional Chinese medicine. The taxonomy of Mukdenia, especially of M. acanthifolia, has been controversial. To address this, we produced plastid and mitochondrial data using genome skimming for Mukdenia acanthifolia and Mukdenia rossii, including three individuals of each species. We assembled complete plastomes, mitochondrial CDS and nuclear ribosomal ETS/ITS sequences using these data. Comparative analysis shows that the plastomes of Mukdenia and Oresitrophe are relatively conservative in terms of genome size, structure, gene content, RNA editing sites and codon usage. Five plastid regions that represent hotspots of change (trnH-psbA, psbC-trnS, trnM-atpE, petA-psbJ and ccsA-ndhD) are identified within Mukdenia, and six regions (trnH-psbA, petN-psbM, trnM-atpE, rps16-trnQ, ycf1 and ndhF) contain a higher number of species-specific parsimony-informative sites that may serve as potential DNA barcodes for species identification. To infer phylogenetic relationships between Mukdenia and Oresitrophe, we combined our data with published data based on three different datasets. The monophyly of each species (Oresitrophe rupifraga, M. acanthifolia and M. rossii) and the inferred topology ((M. rossii, M. acanthifolia), O. rupifraga) are well supported in trees reconstructed using the complete plastome sequences, but M. acanthifolia and M. rossii did not form a separate clade in the trees based on ETS + ITS data, while the mitochondrial CDS trees are not well-resolved. We found low recovery of genes in the Angiosperms353 target enrichment panel from our unenriched genome skimming data. Hybridization or incomplete lineage sorting may be the cause of discordance between trees reconstructed from organellar and nuclear data. Considering its morphological distinctiveness and our molecular phylogenetic results, we strongly recommend that M. acanthifolia be treated as a distinct species. 相似文献
Vegetable crops provide a rich source of essential nutrients for humanity and represent critical economic values to global rural societies. However, genetic studies of vegetable crops have lagged behind major food crops, such as rice, wheat and maize, thereby limiting the application of molecular breeding. In the past decades, genome sequencing technologies have been increasingly applied in genetic studies and breeding of vegetables. In this review, we recapitulate recent progress on reference genome construction, population genomics and the exploitation of multi-omics datasets in vegetable crops. These advances have enabled an in-depth understanding of their domestication and evolution, and facilitated the genetic dissection of numerous agronomic traits, which jointly expedites the exploitation of state-of-the-art biotechnologies in vegetable breeding. We further provide perspectives of further directions for vegetable genomics and indicate how the ever-increasing omics data could accelerate genetic, biological studies and breeding in vegetable crops.
Chinese leymus (Leymus chinensis Trin.) is a perennial grass of the Gramineae, which is widely distributed in China, Mongolia and in Russian-Siberian. In order to explore the potential of biotechnology for genetic improvement of this forage grass, an efficient tissue culture system was established and the factors affecting plant regeneration were evaluated. Immature inflorescence segments 3–5 mm in length from eight accessions were cultured on N6 medium supplemented with 2.26–22.60 µM 2,4-D. The callus induction frequency ranged from 72.11 to 82.19%. Shoots were differentiated from the calli on N6 medium containing 4.65 µM kinetin and 4.44 µM BA. Viable regenerants were developed on hormone-free medium. Normal plants were obtained after natural vernalization in the field. The plant regeneration frequency in Chinese leymus was associated with different genotypes and different combinations of growth regulators in medium. The concentration of 2,4-D in the callus induction medium had a strong effect on successive plant regeneration. Relatively higher concentrations of 2,4-D (i.e., 9.04 and 22.60 µM) were more favorable to the plant regeneration than lower ones (i.e., 2.26 and 4.52 µM). This is the first report on plant regeneration in vitro in L. chinensis. 相似文献
Suppression subtractive hybridization was carried out to enrich gene fragments over-expressed in rice leaves by subtraction to rice roots, from which two identical cDNA fragments were identified to encode putative phosphoenolpyruvate carboxylase. Then the corresponding full-length cDNA (Osppc) is isolated by RT-PCR and sequenced, which indicates an open reading frame of 2895bp is contained. Its deduced protein is encoded in 10 exons and shows high similarity to many other plant PEPCs. Comparing with maize and bacterial PEPCs, it is revealed that OSPPC shares many conserved domains and active sites that responsible for the structure, activity and regulation of this enzyme. Phylogenetic analysis demonstrates that OSPPC is grouped with C3 form PEPCs of wheat, maize and sorghum, which is consistent with the classification of rice. And a putative promoter element is predicted with DOF binding box, CAAT box and TATA box in the 5'-flanking sequence of Osppc gene. Moreover, Quantitative RT-PCR analyses are performed in hybrid rice and its parents, which show that Osppc is specifically expressed in leaf including leaf vein and sheath. 相似文献