Two orthologs of late blight resistance gene R1 in wild and cultivated potato

2017 ◽  
Vol 64 (5) ◽  
pp. 718-727 ◽  
Author(s):  
M. P. Beketova ◽  
E. A. Sokolova ◽  
E. V. Rogozina ◽  
M. A. Kuznetsova ◽  
E. E. Khavkin
2009 ◽  
Vol 22 (4) ◽  
pp. 437-446 ◽  
Author(s):  
James M. Bradeen ◽  
Massimo Iorizzo ◽  
Dimitre S. Mollov ◽  
John Raasch ◽  
Lara Colton Kramer ◽  
...  

Late blight of potato ranks among the costliest of crop diseases worldwide. Host resistance offers the best means for controlling late blight, but previously deployed single resistance genes have been short-lived in their effectiveness. The foliar blight resistance gene RB, previously cloned from the wild potato Solanum bulbocastanum, has proven effective in greenhouse tests of transgenic cultivated potato. In this study, we examined the effects of the RB transgene on foliar late blight resistance in transgenic cultivated potato under field production conditions. In a two-year replicated trial, the RB transgene, under the control of its endogenous promoter, provided effective disease resistance in various genetic backgrounds, including commercially prominent potato cultivars, without fungicides. RB copy numbers and transcript levels were estimated with transgene-specific assays. Disease resistance was enhanced as copy numbers and transcript levels increased. The RB gene, like many other disease resistance genes, is constitutively transcribed at low levels. Transgenic potato lines with an estimated 15 copies of the RB transgene maintain high RB transcript levels and were ranked among the most resistant of 57 lines tested. We conclude that even in these ultra–high copy number lines, innate RNA silencing mechanisms have not been fully activated. Our findings suggest resistance-gene transcript levels may have to surpass a threshold before triggering RNA silencing. Strategies for the deployment of RB are discussed in light of the current research.


Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 339-343 ◽  
Author(s):  
Dennis A. Halterman ◽  
Lara Colton Kramer ◽  
Susan Wielgus ◽  
Jiming Jiang

Late blight of potato, caused by Phytophthora infestans, is one of the most devastating diseases of potato. A major late blight resistance gene, called RB, previously was identified in the wild potato species Solanum bulbocastanum through map-based cloning. The full-length gene coding sequence, including the open reading frame and promoter, has been integrated into cultivated potato (S. tuberosum) using Agrobacterium-mediated transformation. RB-containing transgenic plants were challenged with P. infestans under optimal late blight conditions in greenhouse experiments. All transgenic lines containing RB exhibited strong foliar resistance. Field-grown transgenic tubers also were tested for resistance to P. infestans. In contrast to the foliar resistance phenotype, RB-containing tubers did not exhibit increased resistance. Two years of field trials were used to ascertain whether the presence of RB had any effect on tuber yield. We were unable to detect any significant effect on tuber size or yield after addition of the resistance gene to several S. tuberosum cultivars.


2011 ◽  
Vol 130 (4) ◽  
pp. 464-468 ◽  
Author(s):  
Hilary Mayton ◽  
Gilda Rauscher ◽  
Ivan Simko ◽  
William E. Fry

2006 ◽  
Vol 112 (4) ◽  
pp. 674-687 ◽  
Author(s):  
G. M. Rauscher ◽  
C. D. Smart ◽  
I. Simko ◽  
M. Bonierbale ◽  
H. Mayton ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Saad Serfraz ◽  
Vikas Sharma ◽  
Florian Maumus ◽  
Xavier Aubriot ◽  
Andrew D. W. Geering ◽  
...  

Endogenous viral elements (EVEs) are widespread in plant genomes. They result from the random integration of viral sequences into host plant genomes by horizontal DNA transfer and have the potential to alter host gene expression. We performed a large-scale search for co-transcripts including caulimovirid and plant sequences in 1,678 plant and 230 algal species and characterized 50 co-transcripts in 45 distinct plant species belonging to lycophytes, ferns, gymnosperms and angiosperms. We found that insertion of badnavirus EVEs along with Ty-1 copia mobile elements occurred into a late blight resistance gene (R1) of brinjal eggplant (Solanum melongena) and wild relatives in genus Solanum and disrupted R1 orthologs. EVEs of two previously unreported badnaviruses were identified in the genome of S. melongena, whereas EVEs from an additional novel badnavirus were identified in the genome of S. aethiopicum, the cultivated scarlet eggplant. Insertion of these viruses in the ancestral lineages of the direct wild relatives of the eggplant would have occurred during the last 3 Myr, further supporting the distinctiveness of the group of the eggplant within the giant genus Solanum.


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