Powdery Mildew Resistant Varieties Research Articles

Genetic variability and association study of SSR markers for yield and powdery mildew disease in pea (Pisum sativum)

Makhyatmubi, one of the most popular local varieties of field pea (Pisum sativum L.) in Manipur has morpho- physiological bottlenecks such as tall nature and high susceptibility to fungus Erysiphe pisi causing powdery mildew disease. Therefore, an experiment was conducted during winter (rabi) seasons of 2018–19 and 2020–21 at College of Post-Graduate Studies in Agricultural Sciences (Central Agricultural University, Imphal, Manipur), Umiam, Meghalaya to generate genetic variability by hybridization of Makhyatmubi with Prakash variety which is a well-known powdery mildew resistant variety in India and possesses several contrasting characters. Fruitful heterosis was estimated with highest record in number of pods per plant (114.75%) and seed yield per plant (108.04%). These two characters also showed high PCV, GCV, heritability and GAM. Number of pods per plant (0.95) was found to have highest positive significant correlation with seed yield per plant. MP-5 and MP-119 recorded superior performance in several characters under study. For the association study of simple sequence repeats (SSR) markers, easily scorable polymorphic markers were selected for surveying association with the traits. Results revealed that SSR marker AA122 may be associated with seed yield and number of pods per plant while marker AA136 with number of seeds per pod. A5 marker was found to be associated with the powdery mildew disease. Hence, it can be employed for marker assisted selection (MAS) to identify and select pea genotypes exhibit resistance to powdery mildew disease.

Evaluation of Powdery Mildew Resistance and Agronomic Performance of Pyramided Mungbean Lines from Marker- Assisted Selection

Gene pyramiding is an effective strategy to provide a durable and high level of powdery mildew (PM) resistance in mungbean [Vigna radiata (L.) R. Wilczek]. The objectives of this study were to evaluate PM resistance levels of pyramided BC2F1 progenies derived from marker-assisted selection of KING (recurrent parent) × SUPER5 (donor parent) cross and measure their agronomic performance under fi eld condition. The results showed that the progenies with marker combinations linked to both PM resistance genes including I85420 + I42PL222, and I27R565 were more resistant to PM (average disease severity score of 3.80) than KING, check cv. CN72, and the progenies without any marker combinations (scores of 8, 8 and 6.75, respectively). While the progenies carrying only one resistance gene were identifi ed as containing either I85420 + I42PL222, or I27R565 which showed intermediate response score of 5.83. In addition, most of the pyramided lines produced higher yield per plant than KING because of their superior pods per plant, clusters per plant, and seeds per pod. In the future, these pyramided lines with two PM resistance genes can be further developed into new PM resistant varieties via marker-assisted backcross breeding or be used as potential PM resistant sources in mungbean breeding programs.

Brown rust (Puccinia triticina) and powdery mildew (Blumeria graminis) resistance of the winter durum wheat varieties at ARC “Donskoy”

In order to increase food grain production of winter durum wheat, which is of high quality for producing cereals and pasta, it is necessary to increase the sown areas, which require varieties that meet the requirements of modern production to develop highly productive varieties with specified grain quality parameters and resistance to diseases. Both for bread wheat and durum wheat the harmful diseases are leaf rust and powdery mildew. The generally accepted methods of fighting them is the development of pathogen resistant varieties. Breeding for the resistance of this crop has been carried out at the FSBSI Agricultural Research Center “Donskoy” since the middle of the last century, as a result of which there were developed the varieties with the constantly increasing level of resistance. Through different years, there were developed and sown the varieties ‘Novinka 5’, ‘Donchanka’, ‘Donskoy yantar’, ‘Terra’, ‘Agat Donskoy’, ‘Lazurit’ which were not infected by brown rust and powdery mildew. The purpose of the study was to identify new reliable sources of resistance to these diseases in order to use them in breeding programs for immunity. The study was carried out on infectious backgrounds in 2015–2021, using the North Caucasian populations of leaf rust and powdery mildew pathogens. In the trials there were identified 63 winter durum wheat varieties of different ecological and geographical origin from inter-station variety testing, 26 powdery mildew resistant varieties, 20 leaf rust resistant varieties and 17 varieties resistant to both pathogens. Among the identified varieties with group resistance there are both the Russian varieties ‘Krucha’, ‘Kermen’, ‘Krupinka’, ‘Dobryana’ and others, and foreign varieties ‘Akveduk’, ‘Andromeda’, ‘Kassiopeya’, ‘Afina’, Pributkova and others.

Genetic control of juvenile resistance to powdery mildew in spring bread wheat cultivars from the VIR collection

Background. Bread wheat (Triticum aestivum L.) is one of the major food crops of humankind. Powdery mildew, caused by Blumeria graminis f. sp. tritici, is the most destructive foliar disease capable of causing great yield losses in epidemic years. Breeding for resistance to powdery mildew is the most economical and effective way to control this disease. By now, 68 loci were identified to contain more than 90 alleles of resistance to powdery mildew in wheat. However, there is a permanent necessity in finding new sources of resistance.The objective of the present study was to characterize the seedling powdery mildew resistance in some spring bread wheat varieties from the VIR collection and determine the inheritance of powdery mildew resistance in these accessions.Materials and methods. The powdery mildew resistant varieties ‘SW Kungsjet’ (k-66036), ‘SW Kronjet’ (k-66097), ‘Boett’ (k-66353), ‘Batalj’ (k-67116), ‘Stilett’ (k-67119) ‘Pasteur’ (k-66093) were crossed with a resistant line ‘Wembley 14.31’ (k-62557) containing the Pm12 gene, and with ‘SW Milljet’ (k-64434); the variety ‘Sibirka Yartsevskaya’ (k-38587) was used as a susceptible parent and control. The hybrid populations F2 were inoculated with the fungus population from local field and evaluated. The powdery mildew population manifested virulence to Pm1a, Pm2, Pm3a-f, Pm4a-b, Pm5a, Pm6, Pm7, Pm8, Pm9, Pm10, Pm11, Pm16, Pm19, Pm28, and avirulence to Pm12. The degree of resistance was assessed on days 8 and 10 after the inoculation using the Mains and Dietz scale (Mains, Dietz, 1930). The castrated flowers in the spikes were pollinated using the twell-method (Merezhko et al., 1973). Chi-squared for goodness of fit test was used to determine deviation of the observed data from the theoretically expected segregation.Results. According phytopathological and genetic tests, juvenile resistance in the varieties ‘SW Kungsjet’, ‘SW Kronjet’, ‘Boett’, ‘Batalj’, ‘Stilett’ and ‘Pasteur’ is controlled by dominant genes, which differ from Pm1a, Pm2, Pm3a-f, Pm4a-b, Pm5a, Pm6, Pm7, Pm8, Pm9, Pm10, Pm11, Pm12, Pm16, Pm19, and Pm28. The varieties ‘SW Milljet’, ‘SW Kronjet’ and ‘Pasteur’ had identical resistance genes. Genetic control of juvenile resistance to powdery mildew in ‘Batalj’, ‘Boett’, ‘Stilett’, ‘SW Milljet’, ‘SW Kungsjet’, ‘Pasteur’ was governed by different genes.Conclusions. The varieties ‘SW Kungsjet’, ‘SW Kronjet’, ‘Boett’ have been maintaining adult and seedling resistance since 2005, and ‘Batalj’, ‘Stilett’ and ‘Pasteur’ since 2017. Seedling resistance of these varieties to local powdery mildew population is controlled by dominant genes. A high degree of resistance was displayed by ‘SW Kungsjet’ and ‘SW Kronjet’ in the Novosibirsk Province, while ‘SW Kungsjet’ was resistant to mildew populations of Tatarstan. The variety ‘Pasteur’ manifested seedling resistance to leaf rust, and ‘SW Kungsjet’ was resistant to loose smut. By summing all the results, it may be suggested that the varieties ‘SW Kungsjet’, ‘SW Kronjet’, ‘Boett’, ‘Batalj’, ‘Stilett’ and ‘Pasteur can serve as good donors of powdery mildew resistance in wheat breeding.

Comparative analysis of powdery mildew resistant and susceptible cultivated cucumber (Cucumis sativus L.) varieties to reveal the metabolic responses to Sphaerotheca fuliginea infection

BackgroundCucumber (Cucumis sativus L.) is a widely planted vegetable crop that suffers from various pathogen infections. Powdery mildew (PM) is typical disease caused by Sphaerotheca fuliginea infection and destroys the production of cucumber. However, the metabolic responses to S. fuliginea infection are largely unknown.ResultsIn our study, a PM resistant variety ‘BK2’ and a susceptible variety ‘H136’ were used to screen differentially accumulated metabolites (DAMs) and differentially expressed genes (DEGs) under S. fuliginea infection. Most of DEGs and DAMs were enriched in several primary and secondary metabolic pathways, including flavonoid, hormone, fatty acid and diterpenoid metabolisms. Our data showed that many flavonoid-related metabolites were significantly accumulated in BK2 rather than H136, suggesting an essential role of flavonoids in formation of resistant quality. Changes in expression of CYP73A, CYP81E1, CHS, F3H, HCT and F3’M genes provided a probable explanation for the differential accumulation of flavonoid-related metabolites. Interestingly, more hormone-related DEGs were detected in BK2 compared to H136, suggesting a violent response of hormone signaling pathways in the PM-resistant variety. The number of fatty acid metabolism-related DAMs in H136 was larger than that in BK2, indicating an active fatty acid metabolism in the PM-susceptible variety.ConclusionsMany differentially expressed transcription factor genes were identified under S. fuliginea infection, providing some potential regulators for the improvement of PM resistance. PM resistance of cucumber was controlled by a complex network consisting of various hormonal and metabolic pathways.

Research status and prospect of genes related with resistance to powdery mildew of wheat

Wheat (Triticum aestivum L.) is one of the major grain crops in the world. Wheat powdery mildew is a fungal disease caused by the infection of Blumeria graminis F. sp. tritici. It is one of the most severe wheat diseases globally, seriously affecting the yield and quality of wheat. At present, the main ways to control powdery mildew are the use of fungicides and the cultivation of disease-resistant varieties. The extensive spraying of fungicides causes pesticide residues and environmental pollution. At present, no matter wild type or artificially bred wheat powdery mildew resistant varieties are scarce, so it is urgent to cultivate resistant varieties quickly and efficiently. Traditional cross breeding has a long time and low efficiency. Still, it is a fast and effective way to get disease-resistant sorts by using modern molecular biological means to transfer disease-resistant genes into cultivated varieties. Although the cultivation of resistant varieties is the most economical and effective way to control powdery mildew in wheat, there are some limitations in the cultivation of resistant varieties by introducing resistance genes by conventional means in actual production. With the increase of disease each year, this situation will be more and more unable to meet the needs of wheat genetic improvement. It is urgent to explore a new way of breeding to improve the wheat to powdery mildew lasting broad-spectrum resistance. The disease-resistant breeding needs from cloning in plant and pathogen affinity interactions play a vital role in the study of disease genes and their mechanism of action. At present, in the wheat by manipulating disease genes make infected material gain lasting broad-spectrum resistance is less. In the case of disease genes and mutations after its disease-resistant mechanism are still not clear. So the breeding of resistant varieties need mining and utilization of resistance genes. The paper summarizes the harm and distribution of wheat powdery mildew, the genes resistance mechanism of wheat powdery mildew, and functional analysis, wheat powdery mildew resistance genes in the field of molecular biology research status, and VIGS, RNAi, such as for the prevention and control of wheat powdery mildew, explore new powdery mildew resistance genes and resistance regulation, breeding disease-resistant varieties of wheat provide the feasible scheme.

Genome wide characterization revealed MnMLO2 and MnMLO6A as candidate genes involved in powdery mildew susceptibility in mulberry.

Mulberry is a fast growing economically important tree for sericulture industry and contains compounds for preventing and treating several diseases and ailments. The quality and quantity of mulberry leaf available to produce silk fibre and for medicinal purpose is greatly affected by number of foliar diseases, out of which powdery mildew is the major one. Imparting genetic resistance becomes an important approach in disease management in mulberry as spraying of fungicides has harmful effects on silkworm growth and development. Deployment of non-functional susceptible genes such as Mildew resistance Locus O (MLO) against powdery mildew in few crops stimulated to identify and characterize MLO genes in mulberry. In this study, genome wide analysis identified 16 MLO genes in Morus notabilis. Phylogenetic analysis found that MnMLO2, MnMLO6A, MnMLO6B, MnMLO12A and MnMLO12B clustered with functionally characterized MLOs associated with powdery mildew susceptibility in dicot species. Gene expression analysis indicated increased transcript abundance of MnMLO2, MnMLO6A, and MnMLO12A in response to powdery mildew infection. Further, conserved motifs exclusive to functionally characterized MLOs were identified in MnMLO1C, MnMLO2 and MnMLO6A proteins. Combined analysis of the phylogenetic relationship, conserved motif analysis and gene expression in response to infection identified MnMLO2 and MnMLO6A as potential candidate genes involved in powdery mildew susceptibility in mulberry. Identification and deployment of natural and induced mutations in the candidate genes can be useful for mulberry breeding programs to develop powdery mildew resistant varieties.

Fungal endophytic communities of two wild Rosa varieties and the role of an endophytic Seimatosporium sp. in enhancing host plant powdery mildew resistance

The aim of the study was to evaluate the possible role of endophytic fungi (EF) on Rosa powdery mildew (PM) resistance. The endophytic fungal communities of two wild Rosa varieties with different PM susceptibilities were investigated through both culture-dependent and independent methods, and the antagonistic activities of endophytes against the PM pathogen were evaluated by pot experiments. There were more OTUs recovered from the PM resistant variety than from the PM susceptible variety. Similarly, the culturable EF from the PM resistant variety (1333 isolates) was more than that from the PM susceptible variety (670 isolates). Consistent with this, the colonization rate of culturable EF of the PM resistant variety was significantly higher than that of the PM susceptible variety at each PM stage (p < 0.05). In addition, it was found that the dominant EF of both varieties were different using culture-dependent and independent methods. The α-diversity of both culturable and un-culturable EF were similar except at the early stage of PM infection. Pot experiments showed that the strain M7SB 41 (Seimatosporium sp.) from PM resistant variety significantly enhanced host plant PM resistance. The results suggested that the endophytic fungal communities of two wild Rosa varieties with different PM susceptibilities were significantly different, and the PM resistant Rosa variety harbored more EF than susceptible Rosa variety, and some EF played an important role in host plant PM resistance.

Microsatellite genotyping and molecular screening of pea (Pisum sativum L.) germplasm with high-resolution melting analysis for resistance to powdery mildew

Pea (Pisum sativum, L.) is an important legume crops in the world especially for the cool-season, used both for human food and animal feed having high protein and vitamin content. As with many crops Gene Banks hold significant collections which in many cases have not been assessed through molecular genotyping. Yet, this pre-breeding step is highly important in order to design an efficient breeding strategy in order to develop varieties of high yield and quality being at the same time resistant to pathogenes. Microsatellite markers have been developed for most of the crops and when combined with High Resolution Melting analysis (HRM) they provide a fast, accurate and efficient method for the genotyping of plant species like Pisum sativum. We have used here seven microsatellite loci coupled with HRM analysis, which proved to be efficient in order to genotype, the thirty-five accessions of the Greek Gene Bank collection. Furthermore, we were able by using a specific functional marker to characterise and group these varieties and landraces for the presence of the powdery mildew resistance gene. This is a useful method in breeding for the fast and accurate tagging offspring for the presence of the resistant gene in a molecular assisted (MAS) breeding program for the development of powdery mildew resistant varieties.

TaEDS1 genes positively regulate resistance to powdery mildew in wheat.

Three EDS1 genes were cloned from common wheat and were demonstrated to positively regulate resistance to powdery mildew in wheat. The EDS1 proteins play important roles in plant basal resistance and TIR-NB-LRR protein-triggered resistance in dicots. Until now, there have been very few studies on EDS1 in monocots, and none in wheat. Here, we report on three common wheat orthologous genes of EDS1 family (TaEDS1-5A, 5B and 5D) and their function in powdery mildew resistance. Comparisons of these genes with their orthologs in diploid ancestors revealed that EDS1 is a conserved gene family in Triticeae. The cDNA sequence similarity among the three TaEDS1 genes was greater than 96.5%, and they shared sequence similarities of more than 99.6% with the respective orthologs from diploid ancestors. The phylogenetic analysis revealed that the EDS1 family originated prior to the differentiation of monocots and dicots, and EDS1 members have since undergone clear structural differentiation. The transcriptional levels of TaEDS1 genes in the leaves were obviously higher than those of the other organs, and they were induced by Blumeria graminis f. sp. tritici (Bgt) infection and salicylic acid (SA) treatment. The BSMV-VIGS experiments indicated that knock-down the transcriptional levels of the TaEDS1 genes in a powdery mildew-resistant variety of common wheat compromised resistance. Contrarily, transient overexpression of TaEDS1 genes in a susceptible common wheat variety significantly reduced the haustorium index and attenuated the growth of Bgt. Furthermore, the expression of TaEDS1 genes in the Arabidopsis mutant eds1-1 complemented its susceptible phenotype to powdery mildew. The above evidences strongly suggest that TaEDS1 acts as a positive regulator and confers resistance against powdery mildew in common wheat.

Loss-of-Function Mutations in CsMLO1 Confer Durable Powdery Mildew Resistance in Cucumber (Cucumis sativus L.).

Powdery mildew (PM) is a serious fungal disease of cucumber worldwide. The identification of resistance genes is very important for resistance breeding to ensure cucumber production. Here, natural loss-of-function mutations at an MLO homologous locus, CsMLO1, were found to confer durable PM resistance in cucumber. CsMLO1 encoded a cell membrane protein, was mainly expressed in leaves and cotyledons, and was up-regulated by PM at the early stage of host–pathogen interaction. Ectopic expression of CsMLO1 rescued the phenotype of the PM resistant Atmlo2 Atmlo12 double mutant to PM susceptible in Arabidopsis. Domesticated and wild resistant cucumbers originating from various geographical regions of the world were found to harbor three independent natural mutations that resulted in CsMLO1 loss of function. In addition, between the near-isogenic lines (NILs) of PM resistant and susceptible, S1003 and NIL(Pm5.1), quantitative RT-PCR revealed that there is no difference at expression levels of several genes in the pathways of ethylene, jasmonic acid or salicylic acid. Moreover, the two NILs were used for transcriptome profiling to explore the mechanism underlying the resistance. Several genes correlated with plant cell wall thickening are possibly involved in the PM resistance. This study revealed that loss of function of CsMLO1 conferred durable PM resistance, and that this loss of function is necessary but alone may not be sufficient for PM resistance in cucumber. These findings will facilitate the molecular breeding of PM resistant varieties to control this destructive disease in cucumber.

Screening Pea Germplasm Against Erysiphe polygoni for Disease Severity and Latent Period

Powdery mildew disease caused by Erysiphe polygoni DC significantly reduces yield quantity and quality of edible seed in pea (Pisum sativum L.). Development of powdery mildew–resistant varieties is an economical and environmentally friendly approach to managing the disease. One hundred forty-six pea accessions, collected from different countries, were screened against powdery mildew. It was determined that accessions 9057, 9370, 9375, 10609, 10612, 18293, 18412, 19598, 19611, 19616, 19727, 19750, 19782, 20126, 20152, 20171, It-96, No. 267, and No. 380 were resistant; accessions It-96 and No. 267 were highly resistant. The correlation between disease score and latent period was negative, suggesting that these parameters should be used simultaneously for more precise screening against powdery mildew. The resistant accessions selected might be used as powdery mildew–resistant parent(s) in breeding programs depending upon the nature and number of gene(s) controlling for resistance.

흰가루병 저항성 동양종 호박 품종 육성

To breed powdery mildew resistant varieties, 104 accessions of Cucurbita spp. germplasm were evaluated. Powdery mildew resistance and horticultural characteristics of the accessions were investigated in the field conditions. C. martinezii was selected for high resistance to powdery mildew in the field. The growth of powdery mildew pathogen and response of leaf surface tissue to the pathogen were observed after artificial inoculation to resistant C martinezii and susceptible C. moschata cv. `Wonye No.402`. Mycelium growth was very clearly different between resistant C. martinezii and susceptible C moschata cv. `Wonye No. 402` at 5 days after inoculation at the adult stage. Interspecific hybridization was attempted to transfer powdery mildew resistance gene(s) from C. martinezii to C. moschata. A single dominant gene action was postulated as deter mining powdery mildew resistance at the seedling stage. But for the effective selection of powdery mildew resistant individuals, it was established that adult plant resistance should be confirmed in the field conditions after the seedling test. Through the seedling and field tests, C. moschata lines resistant to powdery mildew and superior to horticultural characteristics, were selected after 2 backcrossing and 3 selfing generations. The fruit characteristics of newly developed lines were similar to those of the recurrent parent, `Jaechenjarae`.

Pricing Powdery-mildew-resistant Dogwoods: Simulated Impacts on the Nursery-industry Supply Chain

The University of Tennessee developed a flowering dogwood tree (Cornus florida) that is resistant to powdery mildew (Microspaera pulchra). A simulated cooperative game was created to estimate a university fee and predict the behavior of nursery growers and nursery product retailers. The simulation suggests a university fee of $3.51, leading to an average retail price premium for the resistant tree of $10.41. At this price level the simulation predicts that 62 percent of all retail dogwood trees sold would be powdery mildew resistant. Based on 1998 sales of 1.475 million dogwood trees nationwide, 914,500 were predicted to be the powdery mildew resistant varieties, resulting in $3.2 million in revenue for the university. Given this level of sales and markup pricing, the cost of the trees will rise in subsequent stages of the distribution channel, and revenues will increase as well. The simulation suggests nursery revenue will increase by nearly $4 million and costs by $3.2 million, resulting in a net nursery gain of $0.8 million. Similar computations for the retail level are $9.5 million in revenue and a net increase of $5.5 million.