Effects of Wheat Cultivar Mixtures on Population Genetic Structure of Puccinia striiformis f. sp. tritici

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive wheat diseases worldwide. Understanding the effects of cultivar mixture on disease control and population genetic structure of Pst could promote the effective application of cultivar mixtures. This study designed nine cultivar mixtures that composed of different component cultivars with field experiments in Zitong county, Sichuan province in two seasons from 2016 to 2018. Diseased leaves were collected in each plot of treatment in the spring, and a total of 835 and 568 isolates were obtained and genotyped with ten pairs of SSR markers in the two years, respectively. The observed and theoretical values of the area under the disease progress curve (AUDPC), wheat yield, Pst genotypic diversity and the frequency of Pst dominant genetic groups were compared among cultivar mixtures. With the two years’ experiments, there were three and two cultivar mixtures showing significant effect on the relative reduction of AUDPC, respectively; there were no significant effects on the relative yield increase in all mixtures in the two years. There were four and five cultivar mixtures showing positive effects on the relative increase of Pst genotypic diversity in the respective two years. Moreover, all cultivar mixtures could decrease the frequencies of Pst dominant genetic groups on highly susceptible component cultivar compared with their theoretical frequencies.

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Population Genetic Structure and the Migration of Puccinia striiformis f. sp. tritici Between the Gansu and Sichuan Basin Populations of China

Phytopathology ◽

10.1094/phyto-03-15-0081-r ◽

2016 ◽

Vol 106 (2) ◽

pp. 192-201 ◽

Cited By ~ 6

Author(s):

Junmin Liang ◽

Xiufeng Liu ◽

Yong Li ◽

Qiong Wan ◽

Zhanhong Ma ◽

...

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Sichuan Basin ◽

Population Genetic ◽

Puccinia Striiformis ◽

Gansu Province ◽

Molecular Evidence ◽

Long Distance ◽

The Sichuan Basin ◽

Basin Area

Puccinia striiformis f. sp. tritici is the causal pathogen of interregional epidemics of wheat stripe rust in China via long-distance migration. Gansu Province serves as putative inoculum center providing oversummering inoculum, while Sichuan Basin area serves as a region providing huge amounts of overwintering inoculum. Thus, the relationship between these two regions in population exchange and migration become important in prediction of interregional epidemics. In this study, we compared the population genetic structure and race composition between Gansu and Sichuan Basin populations to infer their migration relationships. A total of 526 isolates, spanning 3 years, were genotyped using eight pairs of amplified fragment length polymorphism markers, and a subset of 98 isolates were inoculated onto 19 Chinese differentials to perform the race analysis. Twenty-three common races and 26 shared genotypes supplied molecular evidence for migration between Gansu and Sichuan Basin populations. Bayesian assignment and principal component analysis revealed that the genetic group assignment of the Sichuan Basin populations (10SB and 11SB) changed in the spring to align with the fall Gansu populations in the prior seasons (09GS and 10GS), which indicated an asymmetric migration from Gansu Province to the Sichuan Basin area. The linkage disequilibrium and the parsimony tree length permutation test revealed a strong annual recombination signal in the Gansu populations and an inconsistent signal in the Sichuan Basin populations.

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Population genetic structure of Puccinia striiformis f. sp. tritici at the junction of Gansu, Sichuan and Shaanxi Provinces in China

Phytopathology Research ◽

10.1186/s42483-019-0032-8 ◽

2019 ◽

Vol 1 (1) ◽

Author(s):

Cuicui Wang ◽

Rui Zhang ◽

Bingyao Chu ◽

Bo Ming Wu ◽

Zhanhong Ma

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Puccinia Striiformis

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Population Genetic Structure of Clinical and Environmental Isolates of Blastomyces dermatitidis, Based on 27 Polymorphic Microsatellite Markers

Applied and Environmental Microbiology ◽

10.1128/aem.00258-11 ◽

2011 ◽

Vol 77 (15) ◽

pp. 5123-5131 ◽

Cited By ~ 20

Author(s):

Jennifer K. Meece ◽

Jennifer L. Anderson ◽

Matthew C. Fisher ◽

Daniel A. Henk ◽

Brian L. Sloss ◽

...

Keyword(s):

Genetic Structure ◽

Microsatellite Markers ◽

Mating Type ◽

Population Genetic Structure ◽

Population Genetic ◽

Blastomyces Dermatitidis ◽

Environmental Isolates ◽

Data Set ◽

Content Type ◽

Genetic Groups

ABSTRACTBlastomyces dermatitidis, a thermally dimorphic fungus, is the etiologic agent of North American blastomycosis. Clinical presentation is varied, ranging from silent infections to fulminant respiratory disease and dissemination to skin and other sites. Exploration of the population genetic structure ofB. dermatitidiswould improve our knowledge regarding variation in virulence phenotypes, geographic distribution, and difference in host specificity. The objective of this study was to develop and test a panel of microsatellite markers to delineate the population genetic structure within a group of clinical and environmental isolates ofB. dermatitidis. We developed 27 microsatellite markers and genotypedB. dermatitidisisolates from various hosts and environmental sources (n=112). Assembly of a neighbor-joining tree of allele-sharing distance revealed two genetically distinct groups, separated by a deep node. Bayesian admixture analysis showed that two populations were statistically supported. Principal coordinate analysis also reinforced support for two genetic groups, with the primary axis explaining 61.41% of the genetic variability. Group 1 isolates average 1.8 alleles/locus, whereas group 2 isolates are highly polymorphic, averaging 8.2 alleles/locus. In this data set, alleles at three loci are unshared between the two groups and appear diagnostic. The mating type of individual isolates was determined by PCR. Both mating type-specific genes, the HMG and α-box domains, were represented in each of the genetic groups, with slightly more isolates having the HMG allele. One interpretation of this study is that the species currently designatedB. dermatitidisincludes a cryptic subspecies or perhaps a separate species.

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Population Genetic Structure of Septoria passerinii in Northern Great Plains Barley

Phytopathology ◽

10.1094/phyto-97-8-0938 ◽

2007 ◽

Vol 97 (8) ◽

pp. 938-944 ◽

Cited By ~ 6

Author(s):

S. H. Lee ◽

S. M. Neate

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

North Dakota ◽

Population Genetic Structure ◽

Population Differentiation ◽

Population Genetic ◽

Genotypic Diversity ◽

Aflp Markers ◽

Northern Great Plains ◽

Geographical Regions

The genetic structure of Septoria passerinii from nine field populations was examined at several scales (within lesions, among lesions in a leaf, among leaves in a field, and among fields in North Dakota and western Minnesota) by using amplified fragment length polymorphism (AFLP) markers. A total of 390 isolates were sampled from seven barley fields located in North Dakota and two barley fields located nearby in western Minnesota in 2003 and 2004. Based on 57 polymorphic AFLP markers, AFLP DNA fingerprints identified 176 different genotypes among 390 (non-clone-corrected) isolates in nine different fields. In two intensively sampled sites, ND16 (Williston, ND) and ND17 (Langdon, ND), only one to four different genotypes were found within a lesion. A higher level of genetic and genotypic diversity was found within a leaf in which six to nine different genotypes were found from lesions on a leaf. The genetic diversity within a leaf was similar to the genetic diversity within a field. The average genetic diversity (H) within a field across all AFLP loci was approximately 0.3, except at site ND12 (Carrington, ND) where it was 0.16. Genotypic diversity was high in all populations, and with the exception of ND15 (Rothsay, MN), very low multilocus linkage disequilibrium values ( rd) were found in all populations. The population differentiation, GST, was relatively high (GST = 0.238) among the nine populations due to the high GST in ND12, ND14 (Twin Valley, MN), and ND15. Population differentiation without those three populations was 0.09. A lack of correlation between geographical distance and genetic distance was found, suggesting the potential for a high level of gene flow between different geographical regions. The population genetic structure described in this study for S. passerinii in North Dakota and western Minnesota is consistent with that of a sexually reproducing fungus.

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Comparative population genetic structure of two Ixodidae ticks (Ixodes ovatus and Haemaphysalis flava) in Niigata Prefecture, Japan

10.21203/rs.2.18669/v1 ◽

2019 ◽

Author(s):

Maria Angenica Fulo Regilme ◽

Megumi Sato ◽

Tsutomu Tamura ◽

Reiko Arai ◽

Marcello Otake Sato ◽

...

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Southern China ◽

Isolation By Distance ◽

Rrna Gene ◽

Data Set ◽

Genetic Groups ◽

Niigata Prefecture ◽

Haemaphysalis Flava

Abstract Background Ixodid tick species such as Ixodes ovatus and Haemaphysalis flava function as important vectors of tick-borne diseases in Japan. The study of the genetic patterns of tick populations can reveal information regarding the spread of tick-borne disease. We hypothesized that I. ovatus and H. flava have different population genetic structure because of their host mobility in different tick life stages despite sharing of hosts. Methods Samples (n = 1 to 77) were collected in 29 (I. ovatus) and 17 (H. flava) sampling locations across Niigata. In this study, we used genetic structure at two mitochondrial loci (cox1, 16S rRNA gene) to infer gene flow patterns of I. ovatus and H. flava from Niigata Prefecture, Japan. Results For I. ovatus, pairwise FST and analysis of molecular variance (AMOVA) analyses of cox1 sequences indicated significant among-population differentiation. This was in contrast to H. flava, for which there were only two cases of significant pairwise differentiation and no overall structure. A Mantel test revealed isolation by distance and there was positive spatial autocorrelation of haplotypes in I. ovatus cox1 and 16S sequences, but non-significant results were observed in H. flava in both markers. We found three genetic groups (China 1, China 2 and Japan) in the cox1 I. ovatus tree. Newly sampled I. ovatus grouped together with a published I. ovatus sequence from northern Japan and were distinct from two other I. ovatus groups that were reported from southern China. Conclusions The three genetic groups in our data set suggest the potential for cryptic species within the lineage. While many factors can potentially account for the observed differences in genetic structure, including population persistence and large-scale patterns of range expansion, we propose that differences in the mobility of hosts of tick immature stages (small mammals in I. ovatus; birds in H. flava) may be driving the observed patterns.

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