Shaw is a major problem for the production of sorghum sorghum bicolor l. However, variability in the degree of resistance among maize genotypes to p. Comparison of host ranges of peronosclerospora philippinensis and p. A recent outbreak of sorghum downy mildew in texas has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, peronosclerospora sorghi.
Pdf peronosclerospora sorghi, o agente etiologico do. Grow resistant varieties like t 291, pj 7k, pj 23k, nandyal and bilichigan. Pdf simple sequence repeat markers useful for sorghum. In an initial study, electrophoresis was used to differentiate among three peronosclerospora species 4. Downy mildew dm is a major disease of maize that causes significant yield loss in subtropical and tropical regions around the world. Downy mildew disease, caused by peronosclerospora sorghi, is one of the most serious diseases of maize.
Methods for screening maize against downy mildew peronosclerospora sorghi methods for screening maize against downy mildew peronosclerospora sorghi cardwell, k. Morphological and molecular based identification of corn downy. Pdf on oct 29, 2015, jadhav kashmiri and others published molecular tagging of sorghum downy mildew peronosclerospora sorghi disease resistance loci in maize zea mays l. Several downy mildew resistant maize lines have been identified. To answer this hypothesis we collected sweet corn and field corn samples from three districts in east java province, indonesia. Control of sorghum downy mildew peronosclerospora sorghi.
In an area of nigeria where downy mildew of maize is present, histological assessment of maize seed revealed the presence of mycelium and oospores of peronosclerospora sorghi in the kernels. Downy mildew peronosclerospora maydis is considered one of the most destructive diseases for maize. Peronosclerospora sorghi an overview sciencedirect topics. The banding patterns of 12 enzymes were determined among six, two, and two isolates of p. Downy mildew was observed in the forest and guinea savanna ecologies, but no disease was detected in. Detection of seedborne infection of this pathogen is necessary to limit the spread of this pathogen. In the present study the molecular basis of resistance of maize to p. Metalaxyl apron 35sd, used as a seed treatment, was highly effective in controlling sorghum downy mildew of maize induced by peronosclerospora sorghi. Screening exotic sorghum germplasm, hybrids and elite. Peronosclerospora philippinensis pest rating proposals. Molecular comparison and dna fingerprinting of sporisorium reilianum and peronosclerospora sorghi relating to host specificity and host resistance. Tracing the signature of peronosclerospora maydis in maize. Biological control of downy mildew of maize caused by.
Analysis of defense genes expression in maize upon. Downy mildew of maize caused by peronosclerospora sorghi is one of the most destructive diseases of this crop world. Beside being dispersed by air, it is suspected that contaminated seeds also play a role in the dissemination of this disease. Brown stripe downy mildew sclerophthora rayssiae var. The map above is a summary of data from previous studies. Peronosclerospora sorghi infects susceptible plants though sexual oospores, which survive in the soil, and asexual sporangia which are disseminated by wind. The disease is caused by a soilborne fungus peronosclerospora sorghi but it is also airborne through conidia.
In cool, humid weather conidia are produced on the leaves of sytemically infected plants and on local lesions during the night, particularly on. A recombinant plasmid, pmly121, screened from a peronosclerospora sorghi library hybridizes only to dna of p. Peronosclerospora maydis may be confused with other peronosclerospora spp. Read peronosclerospora maydis found on maize, sweetcorn and plume sorghum in far north queensland, plant pathology on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Simple sequence repeat markers useful for sorghum downy mildew peronosclerospora sorghi and related species article pdf available in bmc genetics 91. Information about peronosclerospora sorghi diagnosis, including distribution and treatment advice. Pdf rapid and specific detection of peronosclerospora sorghi in.
Rapid and specific detection of peronosclerospora sorghi. The relative importance of the sexual cycle in each pathosystem can vary depending on factors that include climate, host, cropping practices, patterns of pathogen migration, and the inherent biology of each species. Factors affecting the production of conidia of peronosclerospora sorghi, causing sorghum downy mildew sdm, were investigated during1993and1994in zimbabwe. Peronosclerospora philippinensis purdue university. The disease is currently managed by seed treatment. Screening exotic sorghum germplasm, hybrids, and elite lines for resistance to a new virulent pathotype p6 of peronosclerospora sorghi causing downy mildew. Seed transmission of downy mildew of maize was demonstrated when grain purchased at local markets gave mean seedling infection rates of 123% untreated seeds and 100% in metalaxyl. Molecular comparison and dna fingerprinting of sporisorium.
Methods of inoculum delivery and timing of testrow planting were assessed for efficacy in promoting development of downy mildew peronosclerospora sorghi in susceptible maize, and for cost of. Cardwell international institute of tropical agriculture, pmb 5320, oyo rd, ibadan, nigeria in an area of nigeria where downy mildew of maize is present, histological assessment of maize seed revealed the presence of mycelium and oospores of peronosclerospora sorghi in the kernels. Commonly known as philippine downy mildew, this disease is caused by the species peronosclerospora philippinensis of the fungallike protist class oomycetes, which also has members such as water molds and phytophthora infestans, which caused the potato blight that led to the great irish famine its hosts are typically grasses, cultivated and wild sorghum, sugarcane, and maize found in most of. Brown stripe downy mildew is not a systemic disease, and the pathogen will only be present in infected leaves. Downy mildew, caused by peronosclerospora sorghi is one of the important diseases affecting maize zea mays l. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically point out the need for simply scored markers in order to differentiate among isolates and. Production of conidia by peronosclerospora sorghi on. Sorghum downy mildew peronosclerospora sorghi westan and uppal shaw occurs as either systemic or localized infection fig. Pdf o agente etiologico do mildio do sorgo, peronosclerospora sorghi, infecta as culturas do sorgo sorghum spp. General information about peronosclerospora sorghi prscso eppo global database. Quarantine restrictions probably maintained the usa free of sorghum downy mildew until the. The crop is hampered by several biotic stresses of which sorghum downy mildew disease is one of the most devastating diseases. Geographical distribution of peronosclerospora spp. Pdf biological control of downy mildew of maize caused by.
Maize in the us is susceptible to other downy mildew diseases, including sorghum downy mildew, caused by peronosclerospora sorghi, and crazy top, caused by sclerophthora macrospora. These infect both mono and dicotyledonous crops, ornamentals, and. Peronosclerospora philippinensis is commonly spread by wind and rain. Dew point temperature, and the effect of conidium age was characterized for an isolate of p. Get a printable copy pdf file of the complete article 1. Pdf sorghum sorghum bicolor ranks as the third most important staple cereal food crop in. This disease can be managed in the field by the use of pathogenfree seeds and. In this study, we analyzed the quantitative trait loci qtls involved in resistance to peronosclerospora sorghi sorghum dm, p. Rapid and specific detection of peronosclerospora sorghi in maize seeds by conventional and realtime pcr. Some dnabased approaches have been reported for other peronosclerospora spp. This chapter describes the biology of sexual reproduction in phytopathogenic oomycetes and its role in disease. Seed transmission of maize downy mildew peronosclerospora. On 73% of nights when conidia were detected rain had fallen within the.
Pdf rapid and specific detection of peronosclerospora. Detection of seedborne infection of this path peronosclerospora sorghi. Free and bound amino acids in healthy and diseased leaves of sorghum and maize infected by peronosclerospora sorghi. The primary source of inoculum is infected seeds and airborne spores play an important role in dispersal of the pathogen. Genes free fulltext identification and validation of. The effect of the environment on the germination, survival and infection of sorghum by conidia of peronosclerospora sorghi is unknown in africa. Plants grown from seeds treated with metalaxyl, or any mixture containing metalaxyl, remained free from the disease and had significantly higher grain yield than plants grown from seeds treated with thirambased fungicides or from untreated seeds. Identification of sources of resistance in sorghum to.
The systemic form is induced when the pathogen colonizes the meristematic foliar tissues. Shaw is the cause of sorghum downy mildew of both sorghum sorghum bicolor l and maize zea mays l. The pathogen is a fungallike protist in the oomycota, or water mold, class. Option 1 exdoc endorsement no 6122 1 larger grain borer prostephanus truncatus, khapra beetle trogoderma granarium, stewarts disease pantoea stewartii, maize downy mildew peronosclerospora maydis, sorghum downy mildew peronosclerospora sorghi, sugarcane downy mildew peronosclerospora sacchari and philippine downy mildew peronosclerospora philippinensis are.
Simple sequence repeat markers useful for sorghum downy. Effect of dew point temperature and conidium age on. Use of an atrich dna clone detection peronosclerospora. Incidence and geographical distribution of downy mildew on. Effects of dewperiod temperature on sporulation, germination of conidia, and systemic infection of maize by peronosclerospora sacchari. Sorghum sorghum bicolor ranks as the third most important staple cereal food crop in uganda after maize and millet. Incidence and geographical distribution of downy mildew peronosclerospora sorghi on maize zea mays were determined in a systematic survey of 181 maize fields in the major maize.
Information on the genetic diversity and population structure of p. Abstract the main objective of this work was to identify sources of resistance in sorghum sorghum bicolor to peronosclerospora sorghi, the causal agent of downy mildew, through the evaluation of 42 sorghum genotypes under natural infection in the field. Disease severity is highest in areas that receive 3978 inches of rain annually and in tropical climates. A variety of dm strains have been reported, and the resistance to them is polygenically controlled.