Penetration and biochemical changes induced by Pasteuria infected Heterodera cajani in cowpea roots

Studies were conducted to compare penetration and biochemical changes in cowpea cv. Pusa Komal infected with healthy Heterodera cajani J₂ and those parasitized with 20, 40 & 60 spores of Pasteuria penetrans. A significant decrease in per cent penetration of parasitized juveniles was recorded with an increase in spore encumbrance level, suggesting a negative correlation At 7 days after inoculation (DAI), 89% of healthy J₂ were able to penetrate the roots as against 73, 31.5 and 18% penetration at 20, 40 and 60 spores/J₂ levels a loss of 16.5, 57.5 and 71% penetration, respectively. Observations recorded on 5 metabolites at 1 h (HAI) 7, 14 & 21 DAI showed a decreasing trend in carbohydrates and an increasing trend in phenols, proteins, DNA, and RNA in all the inoculated plants as against uninoculated ones (control). Increase or decrease in respective metabolites was more apparent in plants inoculated with healthy J₂ than those parasitized with various levels of bacterial spores. These changes were apparent as early as 1 HAI and subsequently at 21 DAI.