scholarly journals AGENT OF BARLEY LEAVES NET BLOTCH: BIOLOGY, ETIOLOGY, VIRULENCE, RESISTANCE OF THE HOST-PLANTS (OVERVIEW)

Author(s):  
I. L. Astapchuk
Keyword(s):  
2017 ◽  
Vol 107 (7) ◽  
pp. 878-884 ◽  
Author(s):  
Barsha Poudel ◽  
Simon R. Ellwood ◽  
Alison C. Testa ◽  
Mark McLean ◽  
Mark W. Sutherland ◽  
...  

Pyrenophora teres f. teres and P. teres f. maculata cause net form and spot form, respectively, of net blotch on barley (Hordeum vulgare). The two forms reproduce sexually, producing hybrids with genetic and pathogenic variability. Phenotypic identification of hybrids is challenging because lesions induced by hybrids on host plants resemble lesions induced by either P. teres f. teres or P. teres f. maculata. In this study, 12 sequence-specific polymerase chain reaction markers were developed based on expressed regions spread across the genome. The primers were validated using 210 P. teres isolates, 2 putative field hybrids (WAC10721 and SNB172), 50 laboratory-produced hybrids, and 7 isolates collected from barley grass (H. leporinum). The sequence-specific markers confirmed isolate WAC10721 as a hybrid. Only four P. teres f. teres markers amplified on DNA of barley grass isolates. Amplified fragment length polymorphism markers suggested that P. teres barley grass isolates are genetically different from P. teres barley isolates and that the second putative hybrid (SNB172) is a barley grass isolate. We developed a suite of markers which clearly distinguish the two forms of P. teres and enable unambiguous identification of hybrids.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aurélie Backes ◽  
Nathalie Vaillant-Gaveau ◽  
Qassim Esmaeel ◽  
Essaid Ait Barka ◽  
Cédric Jacquard

AbstractRecognized as the causal agent of net blotch, Drechslera teres is responsible for major losses of barley crop yield. The consequences of this leaf disease are due to the impact of the infection on the photosynthetic performance of barley leaves. To limit the symptoms of this ascomycete, the use of beneficial bacteria known as “Plant Growth Promoting Rhizobacteria” constitutes an innovative and environmentally friendly strategy. A bacterium named as strain B25 belonging to the genus Burkholderia showed a strong antifungal activity against D. teres. The bacterium was able to limit the development of the fungus by 95% in detached leaves of bacterized plants compared to the non-bacterized control. In this study, in-depth analyses of the photosynthetic performance of young barley leaves infected with D. teres and/or in the presence of the strain B25 were carried out both in and close to the necrotic area. In addition, gas exchange measurements were performed only near the necrotic area. Our results showed that the presence of the beneficial bacterium reduced the negative impact of the fungus on the photosynthetic performance and modified only the net carbon assimilation rate close to the necrotic area. Indeed, the presence of the strain B25 decreased the quantum yield of regulated non-photochemical energy loss in PSII noted as Y(NPQ) and allowed to maintain the values stable of maximum quantum yield of PSII photochemistry known as Fv/Fm and close to those of the control in the presence of D. teres. To the best of our knowledge, these data constitute the first study focusing on the impact of net blotch fungus and a beneficial bacterium on photosynthesis and respiratory parameters in barley leaves.


2021 ◽  
Vol 12 ◽  
Author(s):  
Aurélie Backes ◽  
Gea Guerriero ◽  
Essaid Ait Barka ◽  
Cédric Jacquard

Net blotch, induced by the ascomycete Pyrenophora teres, has become among the most important disease of barley (Hordeum vulgare L.). Easily recognizable by brown reticulated stripes on the sensitive barley leaves, net blotch reduces the yield by up to 40% and decreases seed quality. The life cycle, the mode of dispersion and the development of the pathogen, allow a quick contamination of the host. Crop residues, seeds, and wild grass species are the inoculum sources to spread the disease. The interaction between the barley plant and the fungus is complex and involves physiological changes with the emergence of symptoms on barley and genetic changes including the modulation of different genes involved in the defense pathways. The genes of net blotch resistance have been identified and their localizations are distributed on seven barley chromosomes. Considering the importance of this disease, several management approaches have been performed to control net blotch. One of them is the use of beneficial bacteria colonizing the rhizosphere, collectively referred to as Plant Growth Promoting Rhizobacteria. Several studies have reported the protective role of these bacteria and their metabolites against potential pathogens. Based on the available data, we expose a comprehensive review of Pyrenophora teres including its morphology, interaction with the host plant and means of control.


EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
James P. Cuda ◽  
Patricia Prade ◽  
Carey R. Minteer-Killian

In the late 1970s, Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae), was targeted for classical biological control in Florida because its invasive properties (see Host Plants) are consistent with escape from natural enemies (Williams 1954), and there are no native Schinus spp. in North America. The lack of native close relatives should minimize the risk of damage to non-target plants from introduced biological control agents (Pemberton 2000). [...]


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