Effect of pre- and post-inoculation application of amino acids on induction of resistance, peroxidase activity against Albugo candida (Pers) Kuntze in Indian mustard [Brassica juncea (L.) Czern & Coss.]

Abstract

In the present investigation, the mustard genotype EC-399301 (RESJ-177) (white rust- susceptible at
cotyledonary leaf stage but resistant at the true leaf stage), when treated with the amino acids at the
cotyledonary leaf stage following inoculation application ofA. candida showed no development symptoms in
contrast to profuse development of white rust (WR) pustules on cotyledons of similarly inoculated check
plant of the same genotype. Thus, revealed induction of host resistance of otherwise susceptible
cotyledonary stage of EC-399301. No development of symptom due to the amino acids was characterized by
expression of hypersensitive-like necrotic lesions on the cotyledons in L-proline (@1000 ppm), L-Glutamic
acid (@1000 ppm), L-Cystine Hydrochocnloride (@1500 ppm) treatments. The significant high peroxidase
activity was recorded in treatment L-Cystine at 2000 ppm (0.073 unit/mg) in comparison to check (0.04 unit/
mg). Subsequent post inoculation application of A. candida, no symptom development due to the amino acids
was characterized by expression of hypersensitive-like necrotic regions on the cotyledons in all treatments of
amino acids @ 2000 ppm except L-Tyrosine. The peroxidase activity was recorded in the range of 0.013-
0.367 unit/mg in comparison to check (0.049 unit/mg). In both the cases of inoculation
application of the above amino acids, hypersensitive response of the treated cotyledons was associated with
concomitant increase in the peroxidase activity. The results, thus, revealed induction of host resistance of
otherwise susceptible cotyledonary stage of EC-399301.