Defence responses of grapevine cultivars to powdery mildew: ontogenic resistance vs genetic resistance

2021 ◽  
Author(s):  
A Calonnec ◽  
J Jolivet ◽  
ML Ramaroson ◽  
M‐C Dufour ◽  
M‐F Corio‐Costet
2018 ◽  
Vol 10 (4) ◽  
pp. 279-284
Author(s):  
Zh. Ivanova ◽  
K. Vasileva ◽  
N. Velkov ◽  
S. Grozeva

Abstract. Powdery mildew, caused by Podosphaera xanthii and Golovinomyces cichoracearum, is an economically important disease in melon worldwide. Genetic resistance is one of the most suitable strategies to control powdery mildew. During the last few years several races of the pathogens have been reported. The need to develop resistant varieties is a challenge for each breeding program. Leaf disc assay was used in phytopathology and breeding programs as a rapid and reliable method for evaluation of disease resistance in a large number of plant materials. The purpose of this study was to establish species and races of powdery mildew in Plovdiv region, South Central Bulgaria; to develop a suitable system of pathogen isolation and cultivation; to determine the resistance levels in different melon genotypes available in Maritsa Vegetable Crops Research Institute (MVCRI) - Plovdiv collection by the leaf disc assay. Fifty-three melon genotypes, including lines, varieties, hybrids and ten differential lines were tested. The data showed that causal agent of powdery mildew was race 1 of P. xanthii in Plovdiv region. Our experimental results indicated that for the long-term storage of powdery mildew it is preferable to keep a whole plant under in vitro conditions. This allows the preservation of powdery mildew for two months before transferring on a new tissue. Thirty-four of the tested melon genotypes reacted as immune or resistant and nineteen as susceptible. Resistant melon genotypes are a suitable source in initiating a new breeding program aimed to increase resistance to powdery mildew.


Author(s):  
Reginah Pheirim ◽  
Noren Singh Konjengbam ◽  
Mayurakshee Mahanta

Powdery mildew is caused by an obligate parasite Erysiphe pisi and considered as one of the most important constraints causing yield reductions in pea. Development and utilization of genetic resistance is acknowledged as the most effective, economic and environmental friendly method of control. Therefore, development of cultivars with improved resistance to biotic stresses is a primary goal of plant breeding programs throughout the world. Three monogenic sources er1, er2 and Er3 have been described to govern the powdery mildew disease resistance. Several markers have been reported linked to resistant genes at varying distances in different mapping populations. Genetic markers linked to the disease resistance gene make the breeding process more efficient for the use of Marker Assisted Selection (MAS) strategy to aid in obtaining a complete powdery mildew resistance in pea.


2020 ◽  
Vol 21 (16) ◽  
pp. 5767
Author(s):  
Yuting Hu ◽  
Shengfu Zhong ◽  
Min Zhang ◽  
Yinping Liang ◽  
Guoshu Gong ◽  
...  

Photosynthesis is not only a primary generator of reactive oxygen species (ROS) but also a component of plant defence. To determine the relationships among photosynthesis, ROS, and defence responses to powdery mildew in wheat, we compared the responses of the Pm40-expressing wheat line L658 and its susceptible sister line L958 at 0, 6, 12, 24, 48, and 72 h post-inoculation (hpi) with powdery mildew via analyses of transcriptomes, cytology, antioxidant activities, photosynthesis, and chlorophyll fluorescence parameters. The results showed that H2O2 accumulation in L658 was significantly greater than that in L958 at 6 and 48 hpi, and the enzymes activity and transcripts expression of peroxidase and catalase were suppressed in L658 compared with L958. In addition, the inhibition of photosynthesis in L658 paralleled the global downregulation of photosynthesis-related genes. Furthermore, the expression of the salicylic acid-related genes non-expressor of pathogenesis related genes 1 (NPR1), pathogenesis-related 1 (PR1), and pathogenesis-related 5 (PR5) was upregulated, while the expression of jasmonic acid- and ethylene-related genes was inhibited in L658 compared with L958. In conclusion, the downregulation of photosynthesis-related genes likely led to a decline in photosynthesis, which may be combined with the inhibition of peroxidase (POD) and catalase (CAT) to generate two stages of H2O2 accumulation. The high level of H2O2, salicylic acid and PR1 and PR5 in L658 possible initiated the hypersensitive response.


Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 971 ◽  
Author(s):  
Antonín Dreiseitl

Powdery mildew caused by the airborne ascomycete fungus Blumeria graminis f. sp. hordei (Bgh) is one of most common diseases of barley (Hordeum vulgare). This, as with many other plant pathogens, can be efficiently controlled by inexpensive and environmentally-friendly genetic resistance. General requirements for resistance to the pathogens are effectiveness and durability. Resistance of barley to Bgh has been studied intensively, and this review describes recent research and summarizes the specific resistance genes found in barley varieties since the last conspectus. Bgh is extraordinarily adaptable, and some commonly recommended strategies for using genetic resistance, including pyramiding of specific genes, may not be effective because they can only contribute to a limited extent to obtain sufficient resistance durability of widely-grown cultivars. In spring barley, breeding the nonspecific mlo gene is a valuable source of durable resistance. Pyramiding of nonspecific quantitative resistance genes or using introgressions derived from bulbous barley (Hordeum bulbosum) are promising ways for breeding future winter barley cultivars. The utilization of a wide spectrum of nonhost resistances can also be adopted once practical methods have been developed.


Author(s):  
S. Priyanka ◽  
S. Rangaiah ◽  
R. Pavan

An effective and durable genetic resistance in black gram genotypes against powdery mildew provides a cost effective and reliable strategy to reduce the yield losses and save quality of the harvest. The identification of potential resistant source(s) is the most crucial step in disease resistance breeding. In the present study, out of 116 genotypes screened, genotype LBG-645 recorded lowest per cent disease severity of 0.77 and was found to be highly resistant to powdery mildew under green house condition. Under in vitro condition also, LBG-645 which was found to be highly resistant with 3.33×103 conidia colony, 0.94 per cent of leaf area covered by powdery mildew and 1.00 colony per leaflet was recorded. Hence, resistant genotype LBG-645 must be used in further breeding programme for the development of resistant varieties of black gram against powdery mildew.


2002 ◽  
Vol 92 (6) ◽  
pp. 671-675 ◽  
Author(s):  
Andrea Ficke ◽  
David M. Gadoury ◽  
Robert C. Seem

A fundamental principle of integrated pest management is that actions taken to manage disease should be commensurate with the risk of infection and loss. One of the less-studied factors that determines this risk is ontogenic, or age-related resistance of the host. Ontogenic resistance may operate at the whole plant level or in specific organs or tissues. Until recently, grape berries were thought to remain susceptible to powdery mildew (Uncinula necator) until late in their development. However, the development of ontogenic resistance is actually quite rapid in berries, and fruit become nearly immune to infection within 4 weeks after fruit set. Our objective was to determine how and at what stage the pathogen was halted in the infection process on ontogenically resistant berries. Adhesion of conidia, germination, and appressorium formation were not impeded on older berries. However, once berries were approximately 3 weeks old and older, few germlings were able to form secondary hyphae. Ontogenically resistant berries responded rapidly to infection by synthesis of a germin-like protein that had been previously shown to play a role in host defense against barley powdery mildew. On susceptible berries, cell discoloration around penetration sites indicated the oxidation of phenolic compounds; a process that was followed by localized cell death. However, the pathogen was still able to infect such cells prior to their death, continue secondary growth, and thereby colonize young berries. Formation of papillae was not involved in the differential resistance mechanism of older berries. In susceptible berries, papillae formed frequently at infection sites but did not always contain the pathogen, whereas in resistant berries, the pathogen was always halted prior to the formation of papillae. The host defense, which conditions ontogenic resistance, operates in the earliest stages of the infection process, in the absence of gross anatomical barriers, prior to the formation of a functional haustorium and prior to the development of a conspicuous penetration pore. We also found that diffuse powdery mildew colonies that were not visible in the field predisposed berries to bunch rot by Botrytis cinerea, increased the levels of infestation by spoilage microorganisms, and substantially degraded wine quality. Our improved understanding of the nature, causes, and stability of ontogenic resistance in the grapevine/ powdery mildew system has supported substantial changes in how fungicides are used to control the disease. Present applications are more focused on the period of maximum fruit susceptibility instead of following a calendar-based schedule. This has improved control, reduced losses, and in many cases reduced the number of fungicide applications required to suppress the disease. Particularly where fungicides are deployed in a programmatic fashion and ontogenic resistance is dynamic, there may be equivalent improvements to be made in other hostpathogen systems through studies of how host susceptibility changes through time.


2014 ◽  
Vol 104 (9) ◽  
pp. 954-963 ◽  
Author(s):  
Belachew Asalf ◽  
David M. Gadoury ◽  
Anne Marte Tronsmo ◽  
Robert C. Seem ◽  
Andrew Dobson ◽  
...  

Ontogenic or age-related resistance has been noted in many pathosystems but is less often quantified or expressed in a manner that allows the concept to be applied in disease management programs. Preliminary studies indicated that leaves and fruit of three strawberry cultivars rapidly acquired ontogenic resistance to the powdery mildew pathogen, Podosphaera aphanis. In the present study, we quantify the development of ontogenic resistance in controlled inoculations of 10 strawberry cultivars using diverse isolates of P. aphanis in New York and Florida, USA, and in Norway. We report the differential and organ-specific development of ontogenic resistance in the receptacle and externally borne strawberry achenes. We further report that rapid development of ontogenic resistance prior to unfolding of emergent leaves, rather than differential susceptibility of adaxial versus abaxial leaf surfaces, may explain the commonly observed predominance of powdery mildew on the lower leaf surfaces. Susceptibility of leaves and fruit declined exponentially with age. Receptacle tissue of berries inoculated at four phenological stages from bloom to ripe fruit became nearly immune to infection approximately 10 to 15 days after bloom, as fruit transitioned from the early green to the late green or early white stage of berry development, although the achenes remained susceptible for a longer period. Leaves also acquired ontogenic resistance early in their development, and they were highly resistant shortly after unfolding and before the upper surface was fully exposed. No significant difference was found in the susceptibility of the adaxial versus abaxial surfaces. The rapid acquisition of ontogenic resistance by leaves and fruit revealed a narrow window of susceptibility to which management programs might be advantageously adapted.


2021 ◽  
Vol 34 ◽  
pp. 02001
Author(s):  
Elena Ilnitskaya ◽  
Marina Makarkina ◽  
Valeriy Petrov

Downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necator) are the most common and economically significant fungal diseases in vineyards. The task of this work is to study the genotypes of new promising hybrid forms of table grapes for the presence of resistance genes to downy mildew (Rpv10 and Rpv3) and powdery mildew (Ren9) using DNA-markers. The study was carried out on table grape hybrids under the working names Agat dubovskiy, Akelo, Arabella, Artek, Dubovskiy rozovyi, Gamlet, Ispolin, Kishmish dubovskiy, Kurazh, Pestryi, Valensiya and registered variety Liviya. The studied genes were analyzed using markers UDV305 and UDV737 (Rpv3), GF09-46 (Rpv10), CenGen6 (Ren9). The following cultivars were used as reference genotypes: Saperavi severnyi (carries Rpv10 gene) and Regent (Rpv3 and Ren9). It was established that Rpv3 gene is carried by hybrids Kishmish dubovskiy, Agat dubovskiy, Kurazh, Valensiya, Akelo, Gamlet, Dubovskiy rozovyi, Pestryi. Ren9 gene was found in Artek, Agat dubovskiy, Kurazh, Ispolin, Valensiya, Arabella, Gamlet, Dubovskiy rozovyi, Pestryi. The Rpv10 gene was not detected in any of the analyzed grapevine samples. genotypes Agat dubovskiy, Kurazh, Gamlet, Dubovskiy rozovyi, Pestryi, Valensiya carry Rpv3 and Ren9 genes simultaneously. These grapevines have an elegant bunch and large berries that are attractive to consumers.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 888a-888 ◽  
Author(s):  
James D. McCreight ◽  
Michael D. Coffey ◽  
Thomas A. Turini ◽  
Michael E. Matheron

Races 1 and 2 of Podosphaera xanthii (syn. Sphaerotheca fuliginea) were defined in Imperial Valley, Calif. 1938 when P. xanthii overcame genetic resistance in `PMR 45'. Race 3 was first observed in the U.S. in 1976 in Texas; 15 additional races of P. xanthii have been reported in the literature since 1996. Races 1 and 2 have been common in Arizona and California based upon the effectiveness of the powdery mildew resistance genes in commercially available melon cultivars grown in these states. Field data from 11 commonly used melon P. xanthii race differentials in 2001 and 2002 indicated the presence of race 1 in the Imperial Valley and San Joaquin Valley of California, and Yuma, Arizona. In spring 2003, the powdery mildew race situation changed. The first evidence was the occurrence of a severe and widespread infection of powdery mildew in a commercial cantaloupe field. The 11 powdery mildew race differentials were susceptible to powdery mildew in a nearby replicated field test. PI 313970, a melon from India, was resistant to this apparent new race of powdery mildew.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 404A-404
Author(s):  
James W. Olmstead ◽  
Gregory A. Lang ◽  
Gary G. Grove

Most sweet cherry (Prunus avium L.) cultivars grown commercially in the Pacific Northwest U.S. are susceptible to powdery mildew caused by the fungus Podosphaera clandestina (Wall.:Fr.) Lev. The disease is prevalent in the irrigated arid region east of the Cascade Mountains in Washington State. Little is known about genetic resistance to powdery mildew in sweet cherry, although a selection (`PMR-1') was identified at the Washington State Unive. Irrigated Agriculture Research and Extension Center that exhibits apparent foliar immunity to the disease. The objective of this research was to characterize the inheritance of powdery mildew resistance from `PMR-1'. Reciprocal crosses between `PMR-1' and three high-quality, widely-grown susceptible cultivars (`Bing', `Rainier', and ëVaní) were made to generate segregating progenies for determining the mode of inheritance of `PMR-1' resistance. Progenies were screened for susceptibility to powdery mildew colonization using a laboratory leaf disk assay. Assay results were verified by natural spread of powdery mildew among the progeny seedlings in a greenhouse and later by placement among infected trees in a cherry orchard. Progenies from these crosses were not significantly different (P > 0.05) when tested for a 1:1 resistant to susceptible segregation ratio, indicating that `PMR-1' resistance is conferred by a single gene, which we propose to designate as PMR-1.


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