Resistance inducers and biochemical mechanisms in the control of anthracnose in cowpea

Authors

Jéssica Morais da Silva Rural Federal University of Pernambuco (Brasil)
Maria do Bom Conselho Lacerda Medeiros Rural Federal University of Pernambuco (Brasil)
João Tiago Correia Oliveira Rural Federal University of Pernambuco (Brasil)
Erika Valente de Medeiros Rural Federal University of Pernambuco (Brasil)
Cristina Maria de Souza-Motta Rural Federal University of Pernambuco (Brasil)
Keila Aparecida Moreira Rural Federal University of Pernambuco (Brasil)

Abiotic inducers, bean disease, biotic inducers, Vigna unguiculata (L.) Walp

Different responses are observed in

plants after infection by pathogens. The usage of systemic inducers, whether biotic or abiotic,

has the function to increase the enzymatic production of the plant defense system. In that sense,

our present research aims to evaluate the disease severity of anthracnose in the cowpea cultivar

“sempre-verde” infected with Colletotrichum lindemuthianum URM 5771 and subjected to

both biotic and abiotic resistance inducers, as well as evaluate the enzymatic activity of plant

defense. The experiment was performed in a greenhouse with a completely randomized splitplot

design with six treatments: four abiotic plant resistance inducers, acibenzolar-S-methyl,

β-aminobutyric acid, chitosan, and salicylic acid; one biotic inducer, the filamentous fungi

Trichoderma aureoviride URM 5158; and a control with only water. The plant leaves were

sampled at four time points, 4, 8, 12 and 20 days after inoculation with the plant pathogen, to

measure the enzymatic activity of β-1,3-glucanase, catalase, peroxidase, polyphenoloxidase,

and protease. The abiotic inducers acibenzolar-S-methyl, β-aminobutyric acid, and chitosan

and the biotic inducer presented the highest potential in reducing the anthracnose caused by C.

lindemuthianum URM 5771 in cowpea plants by showing the lowest values of injury severity

over time. The disease progression showed a proportionate shift in enzymatic activity in that the

inducers salicylic acid and T. aureoviride URM 5158 promoted the highest enzymatic activity

when compared to the other inducers. High correlations between the enzymatic activity of

peroxidase and polyphenoloxidase and anthracnose severity were observed in cowpea plants.

The use of abiotic and biotic resistance inducers presents high potential for anthracnose control

in cowpea plants; however, more studies should be carried out covering different environments,

plant cultivars and climatic conditions.