scholarly journals Mechanisms of Phragmites australis invasion: feedbacks among genetic diversity, nutrients, and sexual reproduction

2011 ◽  
Vol 48 (5) ◽  
pp. 1305-1313 ◽  
Author(s):  
Karin M. Kettenring ◽  
Melissa K. McCormick ◽  
Heather M. Baron ◽  
Dennis F. Whigham
Genome ◽  
2004 ◽  
Vol 47 (5) ◽  
pp. 789-794 ◽  
Author(s):  
M Razavi ◽  
G R Hughes

This study examined the genetic structure of a Saskatchewan population of Mycosphaerella graminicola, cause of the foliar disease Septoria tritici blotch of wheat. Such knowledge is valuable for understanding the evolutionary potential of this pathogen and for developing control strategies based on host resistance. Nine pairs of single-locus microsatellite primers were used to analyze the genomic DNA of 90 isolates of M. graminicola that were collected using a hierarchical sampling procedure from different locations, leaves, and lesions within a wheat field near Saskatoon. Allelic series at eight different loci were detected. The number of alleles per locus ranged from one to five with an average of three alleles per locus. Genetic diversity values ranged from 0.04 to 0.67. Partitioning the total genetic variability into within- and among-location components revealed that 88% of the genetic variability occurred within locations, i.e., within areas of 1 m2, but relatively little variability occurred among locations. Low variability among locations and a high degree of variability within locations would result if the primary source of inoculum was airborne ascospores, which would be dispersed uniformly within the field. This finding was confirmed by gametic disequilibrium analysis and suggests that the sexual reproduction of M. graminicola occurs in Saskatchewan.Key words: Mycosphaerella graminicola, SSR markers, sexual reproduction, genetic diversity.


2021 ◽  
pp. 1168-1174
Author(s):  
A.A. Poroshina ◽  
◽  
D.Yu. Sherbakov ◽  

Abstract. Using a computer simulation model, we tried to investigate how the transition from sexual reproduction to asexual reproduction will affect the population of diploid organisms with a neutral character of molecular evolution. At the same time, special attention was paid to the specificity of microsatellite markers. In this paper, we develop fast and inexpensive methods for assessing the changes in populations that occur with a change in reproductive strategy.


2014 ◽  
Vol 7 (4) ◽  
pp. 433-441 ◽  
Author(s):  
Jeanne Ropars ◽  
Manuela López‐Villavicencio ◽  
Joëlle Dupont ◽  
Alodie Snirc ◽  
Guillaume Gillot ◽  
...  

2020 ◽  
Author(s):  
Raquel Pino-Bodas ◽  
Soili Stenroos

Abstract The diversity of lichen photobionts is not fully known. We studied here the diversity of the photobionts associated with Cladonia, a sub-cosmopolitan genus ecologically important, whose photobionts belong to the green algae genus Asterochloris. The genetic diversity of Asterochloris was screened by using the ITS rDNA and actin type I regions in 223 specimens and 135 species of Cladonia collected all over the world. These data, added to those available in GenBank, were compiled in a dataset of altogether 545 Asterochloris sequences occurring in 172 species of Cladonia. A high diversity of Asterochloris associated with Cladonia was found. The commonest photobiont lineages associated with this genus are A. glomerata, A. italiana, and A. mediterranea. Analyses of partitioned variation were carried out in order to elucidate the relative influence on the photobiont genetic variation of the following factors: mycobiont identity, geographic distribution, climate, and mycobiont phylogeny. The mycobiont identity and climate were found to be the main drivers for the genetic variation of Asterochloris. The geographical distribution of the different Asterochloris lineages was described. Some lineages showed a clear dominance in one or several climatic regions. In addition, the specificity and the selectivity were studied for 18 species of Cladonia. Potentially specialist and generalist species of Cladonia were identified. A correlation was found between the sexual reproduction frequency of the host and the frequency of certain Asterochloris OTUs. Some Asterochloris lineages co-occur with higher frequency than randomly expected in the Cladonia species.


2014 ◽  
Vol 15 (6) ◽  
pp. 1403-1415 ◽  
Author(s):  
Rodolphe L. Gigant ◽  
Alexandre De Bruyn ◽  
Brigitte Church ◽  
Laurence Humeau ◽  
Anne Gauvin-Bialecki ◽  
...  

2007 ◽  
Vol 94 (6) ◽  
pp. 957-964 ◽  
Author(s):  
J. L. Grimsby ◽  
D. Tsirelson ◽  
M. A. Gammon ◽  
R. Kesseli

Recent studies suggest that parasites (interpreted broadly to include viruses, bacteria, protozoans and helminths) may influence the numerical magnitude or geographical distribution of their host populations; most of such studies focus on the population biology and epidemiology of the host-parasite association, taking no explicit account of the genetics. Other researchers have explored the possibility that the coevolution of hosts and parasites may be responsible for much of the genetic diversity found in natural populations, and may even be the main reason for sexual reproduction; such genetic studies rarely take accurate account of the density- and frequency-dependent effects associated with the transmission and maintenance of parasitic infections. This paper aims to combine epidemiology and genetics, reviewing the way in which earlier studies fit into a wider scheme and offering some new ideas about host-parasite coevolution. One central conclusion is that ‘successful’ parasites need not necessarily evolve to be harmless: both theory and some empirical evidence (particularly from the myxoma-rabbit system) indicate that many coevolutionary paths are possible, depending on the relation between virulence and transmissibility of the parasite or pathogen.


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