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Plant speciation

Nilam Borah, Emad Albarouki, Jan Schirawski
Many plant-pathogenic fungi are highly host-specific. In most cases, host-specific interactions evolved at the time of speciation of the respective host plants. However, host jumps have occurred quite frequently, and still today the greatest threat for the emergence of new fungal diseases is the acquisition of infection capability of a new host by an existing plant pathogen. Understanding the mechanisms underlying host-switching events requires knowledge of the factors determining host-specificity. In this review, we highlight molecular methods that use a comparative approach for the identification of host-specificity factors...
March 15, 2018: International Journal of Molecular Sciences
Alain Manceau, Jianxu Wang, Mauro Rovezzi, Pieter Glatzel, Xinbin Feng
Plant leaves serve both as a sink for gaseous elemental mercury (Hg) from the atmosphere and a source of toxic mercury to terrestrial ecosystems. Litterfall is the primary deposition pathway of atmospheric Hg to vegetated soils, yet the chemical form of this major Hg input remains elusive. We report the first observation of in vivo formation of mercury sulfur nanoparticles in intact leaves of 22 native plants from six different species across two sampling areas from China. The plants grew naturally in soils from a mercury sulfide mining and retorting region at ambient-air gaseous-Hg concentrations ranging from 131 ± 19 to 636 ± 186 ng m-3 and had foliar Hg concentration between 1...
March 14, 2018: Environmental Science & Technology
Koji Takayama, Daniel J Crawford, Patricio López-Sepúlveda, Josef Greimler, Tod F Stuessy
Adaptive radiation is a common evolutionary phenomenon in oceanic islands. From one successful immigrant population, dispersal into different island environments and directional selection can rapidly yield a series of morphologically distinct species, each adapted to its own particular environment. Not all island immigrants, however, follow this evolutionary pathway. Others successfully arrive and establish viable populations, but they remain in the same ecological zone and only slowly diverge over millions of years...
March 13, 2018: Journal of Plant Research
Vittorio Filippo Nicolis, Eduard Venter
Plants respond in a similar manner to aphid feeding as to pathogen attack. Diuraphis noxia is a specialist aphid, feeding only on selected grasses that include wheat, barley, and oats. The wheat-Diuraphis noxia interaction is characterized by very similar responses as seen in wheat-pathogen interactions with none of the underlying resistance pathways and genes characterized yet. From wheat harboring the Dn1 resistance gene, we have identified a nucleotide-binding leucine-rich repeat (NLR) gene containing two integrated domains (IDs)...
March 13, 2018: Molecular Plant-microbe Interactions: MPMI
Monika Janišová, Katarína Skokanová, Tomáš Hlásny
Tephroseris longifolia agg. is a complex group of outcrossing perennials distributed throughout Central Europe. Recent morphological study revealed six morphotypes corresponding to five previously distinguished subspecies, together with Alpine and Pannonian morphotypes of T. longifolia subsp. longifolia . The delimited morphotypes differ in relative DNA content, geographical range, and rarity. We compared ecological niches of the six morphotypes in order to assess the impact of ecological differentiation on the speciation processes within the T...
March 2018: Ecology and Evolution
Ha-Na Jang, Seung-Ki Back, Jin-Ho Sung, Youn-Suk Kang, Jongsoo Jurng, Yong-Chil Seo
The hybrid filter (HF) was newly designed and operated with powder activated carbon (PAC) injection to capture mercury and fine particulate matter in the coal power plant. With PAC injection in HF operation, the capture efficiency of elemental mercury was clearly enhanced. When the injection rate of PAC increased from 0 to 20 mg/m3 , the speciation fraction of elemental mercury significantly decreased from 85.19% to 3.76% at the inlet of the hybrid filter. The speciation fraction of oxidized mercury did not vary greatly, whereas the particulate mercury increased from 1...
March 7, 2018: Environmental Pollution
Haiyan Zeng, Jumei Zhang, Qingping Wu, Wenjing He, Haoming Wu, Yingwang Ye, Chengsi Li, Na Ling, Moutong Chen, Juan Wang, Shuzhen Cai, Tao Lei, Yu Ding, Liang Xue
Cronobacter strains harboring the CRISPR-Cas system are important foodborne pathogens causing serious neonatal infections. However, the specific role of the CRISPR-Cas system in bacterial evolution remains relatively unexplored. In this study, we investigated the impact of CRISPR-Cas in Cronobacter evolution and obtained 137 new whole-genome sequences of Cronobacter by next-generation sequencing technology. Among the strains examined (n=240), 90.6% (193/213) of prevalent species Cronobacter sakazakii , Cronobacter malonaticus , and Cronobacter dublinensis strains had intact CRISPR-Cas systems...
March 9, 2018: Applied and Environmental Microbiology
Wenjuan Zhang, Yang Wang, Zhufeng Geng, Shanshan Guo, Juqin Cao, Zhe Zhang, Xue Pang, Zhenyang Chen, Shushan Du, Zhiwei Deng
The speciation of a methanolic extract of Zanthoxylum armatum stem bark has enabled the isolation and characterization of 11 known lignans. Among them, five compounds ( 6 , 8 - 11 ) are reported in this plant for the first time. All of the chemical structures were elucidated on the basis of NMR spectral analysis. Additionally, their antifeedant activities against Tribolium castaneum were evaluated scientifically. Among them, asarinin ( 1 ), with an EC50 of 25.64 ppm, exhibited a much stronger antifeedant activity than the positive control, toosendanin (EC50 = 71...
March 9, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Lila Fishman, Andrea L Sweigart
Hybrids between flowering plant species often exhibit reduced fitness, including sterility and inviability. Such hybrid incompatibilities create barriers to genetic exchange that can promote reproductive isolation between diverging populations and, ultimately, speciation. Additionally, hybrid breakdown opens a window into hidden molecular and evolutionary processes occurring within species. Here, we review recent work on the mechanisms and origins of hybrid incompatibility in flowering plants, including both diverse genic interactions and chromosomal incompatibilities...
March 5, 2018: Annual Review of Plant Biology
Rebecca L Stubbs, Ryan A Folk, Chun-Lei Xiang, Douglas E Soltis, Nico Cellinese
Disjunct distributions have intrigued biologists for centuries. Investigating these biogeographic patterns provides insight into speciation and biodiversity at multiple spatial and phylogenetic scales. Some disjunctions have been intensively studied, yet others have been largely overlooked and remain poorly understood. Among the lesser-known disjunction patterns is that between the mountain ranges of western North America. Flora and fauna endemic to the mountains of this region provide important systems for investigating causes and results of disjunctions, given the relatively recent geological formation of this area and the intense climatic fluctuations that have occurred since its formation...
February 26, 2018: Molecular Phylogenetics and Evolution
Jana C Vamosi, Susana Magallón, Itay Mayrose, Sarah P Otto, Hervé Sauquet
Species diversity is remarkably unevenly distributed among flowering plant lineages. Despite a growing toolbox of research methods, the reasons underlying this patchy pattern have continued to perplex plant biologists for the past two decades. In this review, we examine the present understanding of transitions in flowering plant evolution that have been proposed to influence speciation and extinction. In particular, ploidy changes, transitions between tropical and nontropical biomes, and shifts in floral form have received attention and have offered some surprises in terms of which factors influence speciation and extinction rates...
February 28, 2018: Annual Review of Plant Biology
Ying Ji, Adrien Mestrot, Rainer Schulin, Susan Tandy
Used as a hardening agent in lead bullets, antimony (Sb) has become a major contaminant in shooting range soils of some countries including Switzerland. Soil contamination by Sb is also an environmental problem in countries with Sb-mining activities such as China and Bolivia. Because of its toxicity and relatively high mobility, there is concern over the risk of Sb transfer from contaminated soils into plants, and thus into the food chain. In particular there is very little information on the environmental behavior of methylated antimony, which can be produced by microbial biomethylation of inorganic Sb in contaminated soils...
2018: Frontiers in Plant Science
Pierre Gladieux, Bradford Condon, Sebastien Ravel, Darren Soanes, Joao Leodato Nunes Maciel, Antonio Nhani, Li Chen, Ryohei Terauchi, Marc-Henri Lebrun, Didier Tharreau, Thomas Mitchell, Kerry F Pedley, Barbara Valent, Nicholas J Talbot, Mark Farman, Elisabeth Fournier
Delineating species and epidemic lineages in fungal plant pathogens is critical to our understanding of disease emergence and the structure of fungal biodiversity and also informs international regulatory decisions. Pyricularia oryzae (syn. Magnaporthe oryzae ) is a multihost pathogen that infects multiple grasses and cereals, is responsible for the most damaging rice disease (rice blast), and is of growing concern due to the recent introduction of wheat blast to Bangladesh from South America. However, the genetic structure and evolutionary history of M...
February 27, 2018: MBio
Tatiana V Danilova, Bernd Friebe, Bikram S Gill, Jesse Poland, Eric Jackson
Interspecific or introgressive hybridization is one of the driving forces in plant speciation, producing allopolyploids or diploids with rearranged genomes. The process of karyotype reshaping following homoploid interspecific hybridization has not been studied experimentally. Interspecific hybridization is widely used in plant breeding to increase genetic diversity and introgress new traits. Numerous introgression stocks were developed for hexaploid wheat Triticum aestivum L. (2n = 6x = 42, genome AABBDD). Double monosomic lines, containing one alien chromosome from the tertiary gene pool of wheat and one homoeologous wheat chromosome, represent a simplified model for studying chromosome rearrangements caused by interspecific hybridization...
February 28, 2018: Cytogenetic and Genome Research
Alan J Martin, Colin Fraser, Stephanie Simpson, Nelson Belzile, Y-W Chen, Jacqueline London, Dirk Wallschläger
Controls governing the speciation and accumulation of Se in a 3.7 ha marsh influenced by mine drainage were assessed through examination of water balance, water quality, sediment, and plant tissue components. Over the eight month study period, mean monthly flows ranged from 1,600 to 2,300 m3 •d-1 (hydraulic retention time of 1 to 3 days). Total Se concentrations in the marsh outflow were lower than the inflow by 0.4 to 6.2 µg•L-1 (mean difference = 3.3 µg•L-1 ), illustrating Se removal. Se accumulation pathways are illustrated by elevated concentrations of Se in sediments (3 to 35 mg•kg-1 dw) as well as in below ground (2 to 41 mg•kg-1 dw; mean = 10 mg•kg-1 dw) and above ground (0...
February 26, 2018: Environmental Toxicology and Chemistry
Watanabe Yoichi, Izumi Kawamata, Yu Matsuki, Yoshihisa Suyama, Koichi Uehara, Motomi Ito
Ecological speciation is an important factor in the diversification of plants. The distribution of the woody species Rhododendron indicum, which grows along rivers and is able to withstand water flow when rivers flood (i.e. it is a rheophyte), is disjunct, in contrast to the widespread distribution of its relative, Rhododendron kaempferi. This study aimed to elucidate the phylogenetic relationships between R. indicum and R. kaempferi and the evolutionary processes that gave rise to them. The sequences of three non-coding chloroplast DNA regions (total length 1977 bp) were obtained from 21 populations covering the ranges of the two species...
February 26, 2018: Heredity
Ying Wu, Yue Sun, Shuai Sun, Guo Li, Jie Wang, Bin Wang, Xiuyun Lin, Meng Huang, Zhiyun Gong, Karen A Sanguinet, Zhiwu Zhang, Bao Liu
We report a repertoire of diverse aneuploids harbored by a newly synthesized segmental allotetraploid rice population with fully sequenced sub-genomes and demonstrate their retention features and phenotypic consequences. Aneuploidy, defined as unequal numbers of different chromosomes, is a large-effect genetic variant and may produce diverse cellular and organismal phenotypes. Polyploids are more permissive to chromosomal content imbalance than their diploid and haploid counterparts, and therefore, may enable more in-depth investigation of the phenotypic consequences of aneuploidy...
February 24, 2018: TAG. Theoretical and Applied Genetics. Theoretische und Angewandte Genetik
Yanlong Jia, Tangfu Xiao, Jialong Sun, Fei Yang, Philippe C Baveye
Thallium (Tl) is a toxic trace metal, whose geochemical behavior and biological effects are closely controlled by its chemical speciation in the environment. However, little tends to be known about this speciation of Tl in soil and plant systems that directly affect the safety of food supplies. In this context, the objective of the present study was to elaborate an efficient method to separate and detect Tl(I) and Tl(III) species for soil and plant samples. This method involves the selective adsorption of Tl(I) on microcolumns filled with immobilized oxine, in the presence of DTPA (diethylenetriaminepentaacetic acid), followed by DTPA-enhanced ultrasonic and heating-induced extraction, coupled with ICP-MS detection...
February 21, 2018: Science of the Total Environment
Tobias Otte, Monika Hilker, Sven Geiselhardt
The insect integument is covered by cuticular hydrocarbons (CHCs) which provide protection against environmental stresses, but are also used for communication. Here we review current knowledge on environmental and insect-internal factors which shape phenotypic plasticity of solitary living insects, especially herbivorous ones. We address the dynamics of changes which may occur within minutes, but may also last weeks, depending on the species and conditions. Two different modes of changes are suggested, i.e...
February 22, 2018: Journal of Chemical Ecology
Andrea Boghi, Tiina Roose, Guy Jd Kirk
We develop a model with which to study the poorly-understood mechanisms of uranium (U) uptake by plants. The model is based on equations for transport and reaction of U and acids and bases in the rhizosphere around cylindrical plant roots. It allows for the speciation of U with hydroxyl, carbonate and organic ligands in the soil solution; the nature and kinetics of sorption reactions with the soil solid; and the effects of root-induced changes in rhizosphere pH. A sensitivity analysis showed the importance of soil sorption and speciation parameters as influenced by pH and CO2 pressure; and of root geometry and root-induced acid-base changes linked to the form of nitrogen taken up by the root...
February 21, 2018: Environmental Science & Technology
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