Biochemical, Histochemical and Enzymatic Studies in Relation to Sorghum Downy Mildew Infection of Resistant and Susceptible Genotypes of Maize

摘要

Biochemical, histochemical and enzymatic studies were conducted on indigenous susceptible, CM-500, NAI-127 and resistant, NAI-129, SKV-10 maize leaves infected with Peronosclerospora sorghi and sampling was done at 15, 30, 45, 60 and 75 days after infection with appropriate controls. Biochemical observations revealed high total sugars, starch and amino-acid content in resistant lines compared to susceptible in both inoculated and uninoculated leaves at all times whereas the total phenol and ortho dihydroxy phenols decreased during the first sampling, then later increased consistently in inoculated tissues at all the days. Further evidence, from leaf histochemical analysis draws the same trend as described in the above biochemical analysis. Upon pathogen attack, peroxidase (POX) and phenylalanine ammonia-lyase (PAL) activity increased drastically and high levels were maintained at all times. Higher levels of carbohydrates, amino-acids, different phenols and also elevated activity of POX and PAL in NAI-129, SKV-10 may play a role in inhibiting P. sorghi.