title: Histo-chemical and biochemical analysis reveals association of er1 mediated powdery mildew resistance and redox balance in pea.
abstract: Powdery mildew caused by Erysiphe pisi is one of the important diseases responsible for heavy yield losses in pea crop worldwide. The most effective method of controlling the disease is the use of resistant varieties. The resistance to powdery mildew in pea is recessive and governed by a single gene er1. The objective of present study is to investigate if er1 mediated powdery mildew resistance is associated with changes in the redox status of the pea plant. 16 pea genotypes were screened for powdery mildew resistance in field condition for two years and, also, analyzed for the presence/absence of er1 gene. Histochemical analysis with DAB and NBT staining indicates accumulation of reactive oxygen species (ROS) in surrounding area of powdery mildew infection which was higher in susceptible genotypes as compared to resistant genotypes. A biochemical study revealed that the activity of superoxide dismutase (SOD) and catalase, enzymes involved in scavenging ROS, was increased in, both, resistant and susceptible genotypes after powdery mildew infection. However, both enzymes level was always higher in resistant than susceptible genotypes throughout time course of infection. Moreover, irrespective of any treatment, the total phenol (TP) and malondialdehyde (MDA) content was significantly high and low in resistant genotypes, respectively. The powdery mildew infection elevated the MDA content but decreased the total phenol in pea genotypes. Statistical analysis showed a strong positive correlation between AUDPC and MDA; however, a negative correlation was observed between AUDPC and SOD, CAT and TP. Heritability of antioxidant was also high. The study identified few novel genotypes resistant to powdery mildew infection that carried the er1 gene and provided further clue that er1 mediated defense response utilizes antioxidant machinery to confer powdery mildew resistance in pea.
authors.affiliation: Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh 221007 India.
authors.forename: Chinmayee
authors.initials: C
authors.lastname: Mohapatra
authors.affiliation: Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh 221007 India. Electronic address: rc_vns@yahoo.co.in.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chand
authors.affiliation: Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh 221007 India.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Navathe
authors.affiliation: Marine Biotechnology and Ecology Division, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Sharma
mesh_terms: D000704:Analysis of Variance; D019540:Area Under Curve; D001203:Ascomycota / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D060467:Disease Resistance; D017343:Genes, Plant; D005838:Genotype; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D010084:Oxidation-Reduction; D018532:Pisum sativum / Q000166:cytology* / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D010636:Phenols / Q000378:metabolism; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D010636:Phenols; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase
keywords: Antioxidant enzymes; Pea; Powdery mildew; er1 gene