Urdbean Leaf Crinkle Virus Research Articles

Evaluation of antiviral principles for the induction of systemic resistance in blackgram (Vigna mungo) against Urdbean Leaf Crinkle Virus

Blackgram (Vigna mungo (L.) Hepper) is one of the important pulse crops grown all over the world. Among the virus diseases of blackgram, leaf crinkle caused by Urdbean Leaf Crinkle Virus (Ungrouped/ULCV) is an important disease which leads to considerable losses depending on the season and type of cultivar cultivated. Pre-inoculation spraying of blackgram plants with leaf extracts of Mirabilis jalapa or Bougainvillea spectabilis was found to reduce the leaf crinkle disease to about 90%. The suppression of the disease by the extract was not only due to direct inhibition of the virus. Pre-treatment of blackgram leaves with 10% leaf extracts of M. jalapa and B. spectabilis as foliar spray induced the accumulation of phenolics and enhanced the activities of peroxidase, phenylalanine ammonialyase and polyphenol oxidase. New isoforms of peroxidase and polyphenol oxidase were also induced by the treatments. The induced defense mechanism might have played a role in reducing the disease.

Pseudomonas fluorescens mediated systemic resistance against urdbean leaf crinkle virus in blackgram (Vigna mungo)

Studies were conducted to evaluate two specific strains of the novel plant growth promoting rhizobacterium (PGPR), Pseudomonas fluorescens for induced systemic resistance (ISR) against urdbean leaf crinkle virus (ULCV) in blackgram (Vigna mungo) under controlled conditions. Results of the studies revealed that the pre-inoculation application of blackgram plants with the strains of P. fluorescens viz., Pf1 and CHAO were found to reduce ULCV infection significantly. Soil and foliar application of P. fluorescens (Pf1) induced the accumulation of phenolics and enhanced the activities of peroxidase, phenylalanine ammonia lyase and polyphenol oxidase. New isoforms of peroxidase and polyphenol oxidase were also induced by the treatment. The induced defense mechanism might have played a role in reducing the disease.

Induction of systemic resistance in blackgram (Vigna mungo) against urdbean leaf crinkle virus by chemicals

The effect of chemicals on the induction of systemic resistance in blackgram (Vigna mungo) against urdbean leaf crinkle virus (ULCV) was studied. Pre-inoculation spraying of blackgram plants with resistance-inducing chemicals, namely salicylic acid and benzothiadiazole at 100 ppm concentration was found to be effective in reducing ULCV infection and increasing the incubation period of the virus under controlled conditions. The treatment of blackgram plants with salicylic acid and benzothiadiazole significantly increased the phenylalanine ammonialyase (PAL), peroxidase (PO) and polyphenol oxidase (PPO) activities. New isoforms of peroxidase and polyphenol oxidase were also induced by these treatments. A two-fold increase in accumulation of total phenol was observed in plants treated with salicylic acid and benzothiadiazole.

Studies on the Relationship of Urdbean Leaf Crinkle Virus and its Vectors, Aphis craccivora and Acyrthosiphon pisum

AbstractPre and Post‐virus‐acquisition starvation of Aphis craccivora Koch, and Acyrthosiphon pisum Harris resulted in appreciable increase in percentage of transmission of urdbean leaf crinkle virus. Highest transmission occured when aphids were starved for 90 min prior to virus‐acquisition. A. pisum and A. craccivora on 20 and 80 min of post‐acquisition starvation and 10 and 20 min of virus‐acquisition, respectively inoculated more number of plants. Both the aphids transmitted the virus in probes lasting for one min. However, beyond 5 min of successive transfer on test plants loss in transmissibility was apparent. Viruliferous aphid off the plant retained the virus for a much longer period than on maize plant. The virus appears to be non‐persistently borne in the aphids.