scholarly journals Chemical suppressors of mlo-mediated powdery mildew resistance

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
Hongpo Wu ◽  
Mark Kwaaitaal ◽  
Roxana Strugala ◽  
Ulrich Schaffrath ◽  
Paweł Bednarek ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Brefeldin A ◽  
Loss Of Function ◽  
Mildew Resistance ◽  
Inhibitor Analysis ◽  
Guanine Derivatives ◽  
Powdery Mildew Pathogen ◽  
Inhibitor Screen ◽  
Molecular Components

Loss-of-function of barley mildew locus o (Mlo) confers durable broad-spectrum penetration resistance to the barley powdery mildew pathogen, Blumeria graminis f. sp. hordei (Bgh). Given the importance of mlo mutants in agriculture, surprisingly few molecular components have been identified to be required for this type of resistance in barley. With the aim to identify novel cellular factors contributing to mlo-based resistance, we devised a pharmacological inhibitor screen. Of the 41 rationally chosen compounds tested, five caused a partial suppression of mlo resistance in barley, indicated by increased levels of Bgh host cell entry. These chemicals comprise brefeldin A (BFA), 2′,3′-dideoxyadenosine (DDA), 2-deoxy-d-glucose, spermidine, and 1-aminobenzotriazole. Further inhibitor analysis corroborated a key role for both anterograde and retrograde endomembrane trafficking in mlo resistance. In addition, all four ribonucleosides, some ribonucleoside derivatives, two of the five nucleobases (guanine and uracil), some guanine derivatives as well as various polyamines partially suppress mlo resistance in barley via yet unknown mechanisms. Most of the chemicals identified to be effective in partially relieving mlo resistance in barley also to some extent compromised powdery mildew resistance in an Arabidopsis mlo2 mlo6 double mutant. In summary, our study identified novel suppressors of mlo resistance that may serve as valuable probes to unravel further the molecular processes underlying this unusual type of disease resistance.

scholarly journals Naturally Occurring Broad-Spectrum Powdery Mildew Resistance in a Central American Tomato Accession Is Caused by Loss of Mlo Function

2008 ◽  
Vol 21 (1) ◽  
pp. 30-39 ◽  
Author(s):  
Yuling Bai ◽  
Stefano Pavan ◽  
Zheng Zheng ◽  
Nana F. Zappel ◽  
Anja Reinstädler ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Broad Spectrum ◽  
Powdery Mildew Resistance ◽  
Candidate Gene Approach ◽  
Loss Of Function ◽  
Virus Induced Gene Silencing ◽  
Coding Region ◽  
Oidium Neolycopersici ◽  
Tomato Cultivar ◽  
Mildew Resistance

The resistant cherry tomato (Solanum lycopersicum var. cerasiforme) line LC-95, derived from an accession collected in Ecuador, harbors a natural allele (ol-2) that confers broad-spectrum and recessively inherited resistance to powdery mildew (Oidium neolycopersici). As both the genetic and phytopathological characteristics of ol-2–mediated resistance are reminiscent of powdery mildew immunity conferred by loss-of-function mlo alleles in barley and Arabidopsis, we initiated a candidate-gene approach to clone Ol-2. A tomato Mlo gene (SlMlo1) with high sequence-relatedness to barley Mlo and Arabidopsis AtMLO2 mapped to the chromosomal region harboring the Ol-2 locus. Complementation experiments using transgenic tomato lines as well as virus-induced gene silencing assays suggested that loss of SlMlo1 function is responsible for powdery mildew resistance conferred by ol-2. In progeny of a cross between a resistant line bearing ol-2 and the susceptible tomato cultivar Moneymaker, a 19-bp deletion disrupting the SlMlo1 coding region cosegregated with resistance. This polymorphism results in a frameshift and, thus, a truncated nonfunctional SlMlo1 protein. Our findings reveal the second example of a natural mlo mutant that possibly arose post-domestication, suggesting that natural mlo alleles might be evolutionarily short-lived due to fitness costs related to loss of mlo function.

scholarly journals Accumulation of a Protein Associated with Plant Defense in Powdery Mildew Resistant Dogwood (Cornus florida)

2006 ◽  
Vol 24 (2) ◽  
pp. 115-118
Author(s):  
M.T. Mmbaga ◽  
F.J. Avila ◽  
E.F. Howard ◽  
E.L. Myles
Keyword(s):  
Powdery Mildew ◽  
Plant Defense ◽  
Powdery Mildew Resistance ◽  
Cornus Florida ◽  
Defense Proteins ◽  
Mildew Resistance ◽  
Flowering Dogwood ◽  
Plant Defense Proteins ◽  
Powdery Mildew Pathogen ◽  
High Level

Abstract This study was conducted to better understand the nature of powdery mildew resistance in flowering dogwood (Cornus florida L.) and in particular to determine if inducible plant defense proteins are associated with powdery mildew resistance. Results from this study showed an accumulation of a new protein in resistant plants, but not in susceptible plants that were challenged with powdery mildew pathogen (Erysiphe (Sect. Microsphaera) pulchra). The protein accumulated in a high level in the resistant selections at 48 hr after inoculation with the pathogen and that was consistent with the production of pathogenesis related (PR) proteins. The protein was characterized as having an isoelectric point of 7.5 ± 0.5 and molecular weight of 18 ± 2 KD. Partial sequence analysis of this protein revealed homology with PR-10 protein associated with drought resistance in potato and was analogous to other proteins related to resistance in other crops. Repeated analysis showed similar results and suggested that a biochemical mode of resistance involving plant defense proteins may be associated with powdery mildew resistance in flowering dogwood.

scholarly journals Expression Pattern Analysis of Four Mlo Genes from Rose

2015 ◽  
Vol 140 (4) ◽  
pp. 333-338 ◽  
Author(s):  
Xianqin Qiu ◽  
Hongying Jian ◽  
Qigang Wang ◽  
Kaixue Tang ◽  
Manzhu Bao
Keyword(s):  
Powdery Mildew ◽  
Quantitative Polymerase Chain Reaction ◽  
Expression Patterns ◽  
Early Time ◽  
Resistance Locus ◽  
Loss Of Function ◽  
Powdery Mildew Fungus ◽  
Mildew Resistance ◽  
Powdery Mildew Pathogen ◽  
External Stimuli

Rose (Rosa hybrida) is one of the most economically important ornamentals worldwide. Powdery mildew (Podosphaera pannosa) is a major disease in cut and potted roses. In dicots such as arabidopsis (Arabidopsis thaliana), pea (Pisum sativum), and tomato (Solanum lycopersicum), loss-of-function mutations in mildew resistance locus o (Mlo) genes confer high levels of broad-spectrum resistance to powdery mildew. Here, we present spatiotemporal expression patterns of four Mlo genes from R. hybrida based on real-time fluorescence quantitative polymerase chain reaction (qPCR). Phylogenetically closely related R. hybrida mildew resistance locus o (RhMLO) genes showed similar or overlapping tissue specificity and analogous responsiveness to external stimuli. RhMLO1 and RhMLO2 transcriptional levels were upregulated more than 2-fold by external stimuli, especially by inoculation with powdery mildew fungus P. pannosa at early time points. This phenomenon was not found for RhMLO3 or RhMLO4. The results indicated that RhMLO1 and RhMLO2 might play important roles in rose–powdery mildew pathogen interactions. Our findings may provide useful information for the study of mechanisms of powdery mildew susceptibility in rose.

scholarly journals Durable broad-spectrum powdery mildew resistance in pea er1 plants is conferred by natural loss-of-function mutations in PsMLO1

2011 ◽  
Vol 12 (9) ◽  
pp. 866-878 ◽  
Author(s):  
MATT HUMPHRY ◽  
ANJA REINSTÄDLER ◽  
SERGEY IVANOV ◽  
TON BISSELING ◽  
RALPH PANSTRUGA
Keyword(s):  
Powdery Mildew ◽  
Broad Spectrum ◽  
Powdery Mildew Resistance ◽  
Loss Of Function ◽  
Mildew Resistance

Identification and SSR Mapping of Two Powdery Mildew Resistance Genes in Wild Emmer (Triticum dicoccoides) Accessions IW3 and IW10

2009 ◽  
Vol 35 (5) ◽  
pp. 761-767 ◽  
Author(s):  
Gen-Qiao LI ◽  
Ti-Lin FANG ◽  
Hong-Tao ZHANG ◽  
Chao-Jie XIE ◽  
Zuo-Min YANG ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Triticum Dicoccoides ◽  
Wild Emmer ◽  
Mildew Resistance

Identification of Powdery Mildew Resistance Gene in Pea Line X9002

2015 ◽  
Vol 41 (4) ◽  
pp. 515 ◽  
Author(s):  
Zhong-Yi WANG ◽  
Hai-Ning FU ◽  
Su-Li SUN ◽  
Can-Xin DUAN ◽  
Xiao-Fei WU ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Gene ◽  
Powdery Mildew Resistance ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance
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