scholarly journals Transgenic Expression of the Functional Fragment Hpa110-42 of the Harpin Protein Hpa1 Imparts Enhanced Resistance to Powdery Mildew in Wheat

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 448-455 ◽  
Author(s):  
Defu Wang ◽  
Yajun Wang ◽  
Maoqiang Fu ◽  
Shuyuan Mu ◽  
Bing Han ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Bacterial Blight ◽  
Fungal Species ◽  
Effective Control ◽  
Transgenic Expression ◽  
Rice Bacterial Blight ◽  
Harpin Protein ◽  
Transgenic Lines ◽  
Bacterial Blight Pathogen ◽  
Pathogen Populations

Powdery mildew, one of devastating diseases of wheat worldwide, is caused by Erysiphe graminis f. sp. tritici, a fungal species with constant population changes, which often poses challenges in disease management with host resistance. Transgenic approaches that utilize broad-spectrum resistance may limit changes of pathogen populations and contribute to effective control of the disease. The harpin protein Hpa1, produced by the rice bacterial blight pathogen, can induce resistance to bacterial blight and blast in rice. The fragment comprising residues 10 through 42 of Hpa1, Hpa110-42, is reportedly three- to eightfold more effective than the full-length protein. This study evaluated the transgenic expression of the Hpa110-42 gene for resistance to powdery mildew in wheat caused by E. graminis f. sp. tritici. Nine Hpa110-42 transgenic wheat lines were generated. The genomic integration of Hpa110-42 was confirmed, and expression of the transgene was detected at different levels in the individual transgenic lines. Following inoculation with the E. graminis f. sp. tritici isolate Egt15 in the greenhouse, five transgenic lines had significantly higher levels of resistance to powdery mildew compared with nontransformed plants. Thus, transgenic expression of Hpa110-42 conferred resistance to one isolate of E. graminis f. sp. tritici in wheat in the greenhouse.

scholarly journals Identification of Resistance Genes Effective Against Rice Bacterial Blight Pathogen in Eastern India

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 506-512 ◽  
Author(s):  
Marella Lalitha Shanti ◽  
M. L. C. George ◽  
C. M. Vera Cruz ◽  
M. A. Bernardo ◽  
R. J. Nelson ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Bacterial Blight ◽  
Blight Resistance ◽  
Bacterial Blight Resistance ◽  
Single Strain ◽  
Rice Bacterial Blight ◽  
Virulence Analysis ◽  
Bacterial Blight Pathogen ◽  
Polymerase Chain ◽  
Pathogen Populations

Breeding for bacterial blight resistance in rice requires an understanding of the contemporary pathogen populations in the locations where resistance genes are to be deployed. We characterized 450 strains of Xanthomonas oryzae pv. oryzae collected from three states of India using polymerase chain reaction fingerprinting and virulence analysis. This pathogen collection was differentiated into 17 haplotypes (12 lineages at 80% similarity level). Significant differences in the distribution of haplotypes were observed among regions. Virulence analysis of the pathogen collection revealed nine pathotypes. Among the populations from three regions, the Orissa population was the most diverse, consisting of 11 out of 17 haplotypes and five out of nine pathotypes detected in the total collection. Representative pathotypes were used to evaluate seven near-isogenic lines carrying individual bacterial blight resistance genes (Xa3, Xa4, xa5, Xa7, Xa10, xa13, and Xa21) and gene pyramids. Pathogen strains compatible to individual genes were present in detectable frequencies, although no single strain could overcome all resistance genes. Gene combinations Xa4 + xa5, xa5 + Xa21, and Xa4 + xa5 + Xa21 conferred a broad spectrum of resistance to all the strains evaluated, supporting the strategy of pyramiding appropriate resistance genes.

scholarly journals Two virulent sRNAs identified by genomic sequencing target the type III secretion system in rice bacterial blight pathogen

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Yiqun Hu ◽  
Liyuan Zhang ◽  
Xuan Wang ◽  
Fengli Sun ◽  
Xiangxin Kong ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Bacterial Blight ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Genomic Sequencing ◽  
Type Iii ◽  
Rice Bacterial Blight ◽  
Bacterial Blight Pathogen

scholarly journals An xa5 Resistance Gene-Breaking Indian Strain of the Rice Bacterial Blight Pathogen Xanthomonas oryzae pv. oryzae Is Nearly Identical to a Thai Strain

2020 ◽  
Vol 11 ◽  
Author(s):  
Sara C. D. Carpenter ◽  
Prashant Mishra ◽  
Chandrika Ghoshal ◽  
Prasanta K. Dash ◽  
Li Wang ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Bacterial Blight ◽  
Xanthomonas Oryzae ◽  
Rice Bacterial Blight ◽  
Indian Strain ◽  
Bacterial Blight Pathogen

Biological control of rice bacterial blight by plant-associated bacteria producing 2,4-diacetylphloroglucinol

2006 ◽  
Vol 52 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Palaniyandi Velusamy ◽  
J Ebenezar Immanuel ◽  
Samuel S Gnanamanickam ◽  
Linda Thomashow
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Bacterial Blight ◽  
Field Experiments ◽  
Screening Method ◽  
Xanthomonas Oryzae ◽  
Rice Bacterial Blight ◽  
Fluorescent Pseudomonas ◽  
Tn5 Mutants ◽  
Bacterial Blight Pathogen

Certain plant-associated strains of fluorescent Pseudomonas spp. are known to produce the antimicrobial antibiotic 2,4-diacetylphloroglucinol (DAPG). It has antibacterial, antifungal, antiviral, and antihelminthic properties and has played a significant role in the biological control of tobacco, wheat, and sugar beet diseases. It has never been reported from India and has not been implicated in the biological suppression of a major disease of the rice crop. Here, we report that a subpopulation of 27 strains of plant-associated Pseudomonas fluorescens screened in a batch of 278 strains of fluorescent pseudomonads produced DAPG. The DAPG production was detected by a PCR-based screening method that used primers Phl2a and Phl2b and amplified a 745-bp fragment characteristic of DAPG. HPLC,1H NMR, and IR analyses provided further evidence for its production. We report also that this compound inhibited the growth of the devastating rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae in laboratory assays and suppressed rice bacterial blight up to 59%–64% in net-house and field experiments. Tn5 mutants defective in DAPG production (Phl–) of P. fluorescens PTB 9 were much less effective in their suppression of rice bacterial blight.Key words: biocontrol, 2,4-diacetylphloroglucinol, Pseudomonas fluorescens, rice, Xanthomonas oryzae pv. oryzae.

scholarly journals Timing of triazole-based spray schedules for controlling mungbean powdery mildew in Australia: a meta-analysis.

2021 ◽  
Author(s):  
Paul Melloy ◽  
Emerson Medeiros del Ponte ◽  
Adam H. Sparks
Keyword(s):  
Powdery Mildew ◽  
Fungicide Resistance ◽  
Meta Analysis ◽  
Indirect Costs ◽  
Fungal Species ◽  
Effective Control ◽  
Eastern Region ◽  
Podosphaera Xanthii ◽  
Yield Data

Abstract Powdery mildew (PM), caused by two fungal species, Podosphaera xanthii and Erysiphe vignae, is a yield limiting foliar disease commonly found in mungbean (Vigna radiata) cropping areas of eastern region of Australia. Effective control of PM afflicting mungbeans relies largely on fungicide applications, mainly of the triazole group. Uncertainty in the current fungicide spray schedule recommendations, which advise commencing with a spray at the first sign of PM, prompted this study to evaluate PM severity and crop yield data obtained from fungicide trials which tested spray schedules starting before (Early) or after (Late) first signs, applied singly or combined with a follow-up spray. A meta-analytic approach was employed to obtain estimates of the yield and PM severity difference between plots sprayed with specific triazole-based sprays schedules and untreated plots. From 26 trials, 15 and 14 met the criteria for inclusion in the yield and PM severity analysis respectively. The schedule with the first spray starting at first sign with a follow-up spray 14 days later, resulted in significantly lower disease severity compared to all other schedules, however, the yield protected was only numerically higher and not statistically different compared to: single-spray at first sign, single-spray Late or two-spray starting Late. While PM severity was lower in the Early sprayed plots compared to untreated plots, yield did not differ. These findings support the current recommendations and provide evidence that the first spray could be delayed up to a week and save an additional spray that may be unnecessary, thus reducing direct fungicide costs as well as indirect costs due to fungicide resistance.

PCR-mediated identification and characterization of rice bacterial blight pathogen (Xanthomonas oryzae pv. Oryzae) isolates collected from Sindh province of Pakistan

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Muhammad Tahir Khan ◽  
Javed Asghar Tariq ◽  
Muhammad Arif ◽  
Shafquat Yasmeen ◽  
Imtiaz Ahmed Khan
Keyword(s):  
Bacterial Blight ◽  
Xanthomonas Oryzae ◽  
Rice Bacterial Blight ◽  
Sindh Province ◽  
Bacterial Blight Pathogen ◽  
Identification And Characterization

scholarly journals A strain of an emerging Indian pathotype of Xanthomonas oryzae pv. oryzae defeats the rice bacterial blight resistance gene xa13 without inducing a clade III SWEET gene and is nearly identical to a recent Thai isolate

2018 ◽  
Author(s):  
Sara C. D. Carpenter ◽  
Prashant Mishra ◽  
Chandrika Ghoshal ◽  
Prasanta Dash ◽  
Li Wang ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Bacterial Blight ◽  
Xanthomonas Oryzae ◽  
Host Susceptibility ◽  
Transcription Activator ◽  
Rice Bacterial Blight ◽  
Indian Strain ◽  
Bacterial Blight Pathogen ◽  
Insight Into ◽  
S Genes

AbstractThe rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) injects transcription activator-like effectors (TALEs) that bind and activate host ‘susceptibility’ (S) genes important for disease. Clade III SWEET genes are major S genes for bacterial blight. The resistance genes xa5, which reduces TALE activity generally, and xa13, a SWEET11 allele not recognized by the cognate TALE, have been effectively deployed. However, strains that defeat both resistance genes individually were recently reported in India and Thailand. To gain insight into the mechanism(s), we completely sequenced the genome of one such strain from each country and examined the encoded TALEs. Strikingly, the two strains are clones, sharing nearly identical TALE repertoires, including a TALE known to activate SWEET11 strongly enough to be effective even when diminished by xa5. We next investigated SWEET gene induction by the Indian strain. The Indian strain induced no clade III SWEET in plants harbouring xa13, indicating a pathogen adaptation that relieves dependence on these genes for susceptibility. The findings open a door to mechanistic understanding of the role SWEET genes play in susceptibility and illustrate the importance of complete genome sequence-based monitoring of Xoo populations in developing varieties with effective disease resistance.

Timing of Triazole-Based Spray Schedules for Managing Mungbean Powdery Mildew in Australia: a Meta-Analysis

Plant Disease ◽  
2021 ◽  
Author(s):  
Paul Melloy ◽  
Emerson Medeiros Del Ponte ◽  
Adam H. Henry Sparks
Keyword(s):  
Powdery Mildew ◽  
Crop Yield ◽  
Meta Analysis ◽  
Disease Onset ◽  
Indirect Costs ◽  
Fungal Species ◽  
Effective Control ◽  
Eastern Region ◽  
Yield Data

Powdery mildew (PM), caused by two fungal species, Podosphaera xanthii and Erysiphe vignae, is a yield limiting foliar disease commonly found in mungbean (Vigna radiata) cropping areas of eastern region of Australia. Effective control of the disease relies largely on fungicide applications, mainly of the triazole group. Uncertainty in the current fungicide spray schedule recommendations, which advise commencing with a spray at the first signs of PM, prompted this study to evaluate PM severity and crop yield data obtained from fungicide trials which also tested spray schedules starting before (early) or after (late) first signs, applied singly or combined with a follow-up spray. A meta-analytic approach was employed to obtain mean differences of the PM severity and crop yield between plots sprayed with specific triazole-based spray schedules and nontreated plots. From 26 trials, 14 and 15 met the criteria for inclusion in the respective PM severity and yield analyses. The schedule with the first spray starting at first sign, with a follow-up spray 14 days later, resulted in significantly lower disease severity compared to all other schedules. However, the yield protected was only numerically higher and not statistically different compared to: single-spray at first sign, single-spray late or two-spray starting late. PM severity and yield in the early sprayed plots did not differ from the nontreated plots. These findings support the current recommendations and provide additional evidence that yields are still protected when delaying the first spray up to a week after disease onset. They also suggest that additional sprays may not always be necessary, thus reducing direct fungicide costs, indirect costs due to fungicide insensitivity and potential adverse effects to the environment.

scholarly journals Movement of Xanthomonas oryzae pv. oryzae in Southeast Asia Detected Using PCR-Based DNA Fingerprinting

1997 ◽  
Vol 87 (3) ◽  
pp. 302-309 ◽  
Author(s):  
M. L. C. George ◽  
M. Bustamam ◽  
W. T. Cruz ◽  
J. E. Leach ◽  
R. J. Nelson
Keyword(s):  
Bacterial Blight ◽  
Restriction Analysis ◽  
Genetic Relationships ◽  
The Philippines ◽  
Xanthomonas Oryzae ◽  
Regional Differentiation ◽  
Bacterial Blight Pathogen ◽  
Pcr Method ◽  
Polymerase Chain ◽  
Pathogen Populations

Two outwardly directed primers complementary to sequences in IS1112, a repetitive element isolated from Xanthomonas oryzae pv. oryzae, were used to fingerprint DNA from a set of 71 bacterial blight pathogen strains using polymerase chain reaction (PCR), PCR-based restriction analysis, and ligation-mediated PCR. To allow amplification of long DNA fragments, standard amplification conditions were altered to increase the pH, add dimethylsulfoxide, decrease denaturation time, and increase extension time. Bands ranging in size from 100 bp to 7 kb and in number from 13 to 48 bands per strain were amplified. The three methods revealed useful polymorphisms among individual strains and allowed their genetic relationships to be efficiently deduced. Good correlation was found between the major clusters obtained by the three methods. The PCR method gave the most robust clusters and was most efficient in terms of speed, simplicity, and economy. Using PCR and restriction fragment length polymorphism to compare strains of the bacterial blight pathogen from Indonesia and the Philippines, we found that, whereas there is regional differentiation of the pathogen populations, the predominant strains in the pathogen collections from both countries are closely related. This indicates the occurrence of regional movement, perhaps as a consequence of germ plasm exchange.

Sign in / Sign up

Export Citation Format

Share Document