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Arachidonic acid‐induced hypersensitive cell death as an assay of downy mildew resistance in pearl millet
Author(s) -
GEETHA S.,
SHETTY SUDHEER A,
SHETTY H SHEKAR,
PRAKASH H S
Publication year - 1996
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1996.tb05734.x
Subject(s) - downy mildew , biology , pennisetum , genotype , pathogen , virulence , plant disease resistance , hypersensitive response , cultivar , graminicola , agronomy , horticulture , microbiology and biotechnology , gene , genetics
Summary. Arachidonic acid (AA) induces hypersensitive response (HR) on coleoptile/root regions of two‐day‐old pearl millet seedlings. The response is comparable to the HR induced by the downy mildew pathogen, Sclerospora graminicola. A time gap in the appearance of cell necrosis among genotypes of pearl millet was related to the degree of resistance to downy mildew. Based on the time required for the development of necrotic spots induced by AA, the pearl millet genotypes were categorised as highly resistant/resistant (HR in 3–6 h), susceptible (HR in 7–12 h) and highly susceptible (HR in 13 h and above). The percentage disease incidence in each genotype was compared with the time required for the development of AA‐induced HR. The appearance of hypersensitive cell necrosis was rapid in genotypes having high resistance to downy mildew and was slow in genotypes with high susceptibility. This simple method of screening various pearl millet genotypes in the absence of the pathogen aids in identifying the downy mildew resistant/susceptible host cultivars without the risk of introducing the virulent race of the pathogen.