Inheritance of greenbug, Schizaphis graminum (Rondani), virulence to Gb2 and Gb3 resistance genes in wheat

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Gary J. Puterka ◽  
Don C. Peters
Keyword(s):  
Triticum Aestivum ◽  
Resistance Genes ◽  
Single Gene ◽  
Duplicate Gene ◽  
Modifier Gene ◽  
Schizaphis Graminum ◽  
Sexual Cycle ◽  
Duplicate Genes ◽  
Polygenic Inheritance ◽  
Gene For Gene

The inheritance of greenbug, Schizaphis graminum (Rondani), virulence to wheat, Triticum aestivum L., was investigated. Clones of greenbug biotypes C, E, and F were induced into the sexual cycle, reciprocally crossed, and inbred. The resulting progeny were cloned via parthenogenetic reproduction, so their virulence to resistance genes Gb2 ('Amigo') and Gb3 ('Largo') could be established using diagnostic feeding lesions. The data for both resistance sources fit a duplicate gene – modifier gene inheritance model where avirulence was dominant and virulence was recessive. Virulence to genes Gb2 and Gb3 was conditioned by duplicate genes and a dominant modifier gene epistatic to one of the duplicate genes. Linkage was definite among the genes conditioning virulence to Gb2 and Gb3 when heterozygous males were used in crosses, as a result of achiasmic spermatogenesis. When homozygous males were used in reciprocal crosses, 50% recombination occurred. This unique linkage affinity suggests that the multiple genes conditioning virulence to Gb2 and Gb3 reside on the same chromosomes but are ≥50 map units apart. Specific aphid–host genetic interactions did not fully conform to the gene-for-gene inheritance hypothesis normally associated with host–parasite relationships. Nevertheless, polygenic inheritance of greenbug virulence in wheat could easily be regarded as a gene-for-gene relationship because the duplicate gene – modifier gene mode of inheritance still influences a single gene product in the aphid.Key words: Schizaphis graminum, Triticum aestivum, insect resistance, insect virulence, insect biotypes.

Gene-for-gene interactions between the rye mildew fungus and wheat cultivars

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 758-762 ◽  
Author(s):  
Y. Tosa
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Chinese Spring ◽  
Single Gene ◽  
Erysiphe Graminis ◽  
Gene Interactions ◽  
Wheat Cultivars ◽  
Genetic Mechanisms ◽  
Host Parasite ◽  
Gene For Gene

Genetic mechanisms of the incompatibility between Erysiphe graminis f.sp. secalis and wheat cultivars were analyzed using F1 hybrids between E. graminis f.sp. secalis, Sk-1, and f.sp. tritici, Tk-1. The avirulence of Sk-1 on Triticum aestivum 'Norin 4', 'Chinese Spring', and 'Kokeshi-komugi' was controlled by a single gene. The resistance of the three cultivars to Sk-1 was also controlled by a single gene, Pm15, a gene for resistance to E. graminis f.sp. agropyri. Implications of these results were discussed in terms of host–parasite coevolution.Key words: powdery mildew, Erysiphe graminis, resistance, wheat.

GENE-FOR-GENE RELATIONSHIPS IN HOST: PARASITE SYSTEMS

1959 ◽  
Vol 37 (5) ◽  
pp. 1101-1130 ◽  
Author(s):  
Clayton Person
Keyword(s):  
Resistance Genes ◽  
Theoretical Consideration ◽  
Single Gene ◽  
General Rule ◽  
Published Data ◽  
Correct Analysis ◽  
Specific Locus ◽  
Differential Varieties ◽  
Host Parasite ◽  
Gene For Gene

Theoretical consideration of the origin of gene-for-gene relationships led to the conclusion that such relationships, postulated by Flor for the Linum:Melampsora system, should occur as a general rule in host:parasite systems. An ideal gene-for-gene system, with five related host and parasite loci, was designed to illustrate the properties inherent in gene-for-gene systems, and to illustrate a new method of analyzing for these properties. Analyses of published data of the Solanum:Phytopthora and Linum:Melampsora systems proved that gene-for-gene relationships are in fact operative in these systems and that Flor's hypothesis—that for each specific locus in the host determining resistance and susceptibility there is a specific and related locus in the parasite which determines virulence and avirulence—is correct. Analysis of Flor's data showed, however, that most of his "single-gene" differential varieties actually possess two or more genes for resistance, and that resistance genes in these varieties need not fall into allelic or closely linked groups.

scholarly journals DNA methylation signatures of duplicate gene evolution in angiosperms

2020 ◽  
Author(s):  
Sunil K. Kenchanmane Raju ◽  
S. Marshall Ledford ◽  
Chad E. Niederhuth
Keyword(s):  
Dna Methylation ◽  
Gene Evolution ◽  
Gene Dosage ◽  
Single Gene ◽  
Constitutive Expression ◽  
Duplicate Gene ◽  
Duplicate Genes ◽  
Whole Genome ◽  
Gene Duplicates ◽  
Methylation Patterns

ABSTRACTGene duplications have greatly shaped the gene content of plants. Multiple factors, such as the epigenome, can shape the subsequent evolution of duplicate genes and are the subject of ongoing study. We analyze genic DNA methylation patterns in 43 angiosperm species and 928 Arabidopsis thaliana ecotypes to finding differences in the association of whole-genome and single-gene duplicates with genic DNA methylation patterns. Whole-genome duplicates were enriched for patterns associated with higher gene expression and depleted for patterns of non-CG DNA methylation associated with gene silencing. Single-gene duplicates showed variation in DNA methylation patterns based on modes of duplication (tandem, proximal, transposed, and dispersed) and species. Age of gene duplication was a key factor in the DNA methylation of single-gene duplicates. In single-gene duplicates, non-CG DNA methylation patterns associated with silencing were younger, less conserved, and enriched for presence-absence variation. In comparison, DNA methylation patterns associated with constitutive expression were older and more highly conserved. Surprisingly, across the phylogeny, genes marked by non-CG DNA methylation were enriched for duplicate pairs with evidence of positive selection. We propose that DNA methylation has a role in maintaining gene-dosage balance and silencing by non-CG methylation and may facilitate the evolutionary fate of duplicate genes.

YIELD OF SPRING WHEAT IN RELATION TO LEVEL OF INFESTATION BY GREENBUGS (HOMOPTERA: APHIDIDAE)

1994 ◽  
Vol 126 (1) ◽  
pp. 61-66 ◽  
Author(s):  
R.W. Kieckhefer ◽  
N.C. Elliott ◽  
W.E. Riedell ◽  
B.W. Fuller
Keyword(s):  
Triticum Aestivum ◽  
Linear Regression ◽  
South Dakota ◽  
Spring Wheat ◽  
Yield Components ◽  
Seed Weight ◽  
Schizaphis Graminum ◽  
Boot Stage ◽  
Steady Decrease ◽  
Number Of Seeds

AbstractThe effect of greenbug, Schizaphis graminum (Rondani), infestations on yield components of early- and late-planted spring wheat, Triticum aestivum L., were measured in 2 successive years in eastern South Dakota. Greenbug populations in plots generally increased rapidly and peaked when wheat plants were in boot stage. Populations then began a steady decrease until anthesis, at which time they were near zero. The number of seeds per spikelet and the number of spikelets per square metre were consistently significantly negatively correlated with aphid-days, whereas average seed weight was significantly negatively correlated with aphid-days for only one planting. A linear regression model that included different intercepts for each spring wheat planting and a common slope relating yield to greenbug feeding days (aphid-days) provided a good fit to the data. Based on the model, a loss of 41 kg of grain per hectare is expected for each 100 aphid-days that accumulate per tiller.

Knockdown of duplicated zebrafishhoxb1genes reveals distinct roles in hindbrain patterning and a novel mechanism of duplicate gene retention

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2339-2354 ◽  
Author(s):  
James M. McClintock ◽  
Mazen A. Kheirbek ◽  
Victoria E. Prince
Keyword(s):  
Protein Function ◽  
Cranial Nerve ◽  
Duplicate Gene ◽  
Regulatory Elements ◽  
Duplicate Genes ◽  
Duplicated Genes ◽  
Gene Retention ◽  
Redundant Functions ◽  
Group 1 ◽  
Rhombomere 4

We have used a morpholino-based knockdown approach to investigate the functions of a pair of zebrafish Hox gene duplicates, hoxb1a and hoxb1b, which are expressed during development of the hindbrain. We find that the zebrafish hoxb1 duplicates have equivalent functions to mouse Hoxb1 and its paralogue Hoxa1. Thus, we have revealed a ‘function shuffling’ among genes of paralogue group 1 during the evolution of vertebrates. Like mouse Hoxb1, zebrafish hoxb1a is required for migration of the VIIth cranial nerve branchiomotor neurons from their point of origin in hindbrain rhombomere 4 towards the posterior. By contrast, zebrafish hoxb1b, like mouse Hoxa1, is required for proper segmental organization of rhombomere 4 and the posterior hindbrain. Double knockdown experiments demonstrate that the zebrafish hoxb1 duplicates have partially redundant functions. However, using an RNA rescue approach, we reveal that these duplicated genes do not have interchangeable biochemical functions: only hoxb1a can properly pattern the VIIth cranial nerve. Despite this difference in protein function, we provide evidence that the hoxb1 duplicate genes were initially maintained in the genome because of complementary degenerative mutations in defined cis-regulatory elements.

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