Elucidating the interactions between the rust Hemileia vastatrix and a Calonectria mycoparasite and the coffee plant

Sara Salcedo-Sarmiento; Carlos E Aucique-Pérez; Patrícia R Silveira; Adans A Colmán; André L Silva; Paloma S Corrêa Mansur; Fabrício Á Rodrigues; Harry C Evans; Robert W Barreto

doi:10.1016/j.isci.2021.102352

Elucidating the interactions between the rust Hemileia vastatrix and a Calonectria mycoparasite and the coffee plant

iScience. 2021 Mar 23;24(4):102352. doi: 10.1016/j.isci.2021.102352. eCollection 2021 Apr 23.

Authors

Sara Salcedo-Sarmiento¹, Carlos E Aucique-Pérez¹, Patrícia R Silveira¹, Adans A Colmán¹, André L Silva¹, Paloma S Corrêa Mansur¹, Fabrício Á Rodrigues¹, Harry C Evans^{1

2}, Robert W Barreto¹

Affiliations

¹ Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa-MG, Brazil.
² CAB International, UK Centre, Egham, Surrey, UK.

Abstract

Calonectria hemileiae, a fungus associated with pustules of the coffee leaf rust (CLR, Hemileia vastatrix) in Brazil, was tested in vitro and in planta to assess its biocontrol potential. The fungus inhibited the germination of rust spores by over 80%. CLR severity was reduced by 93% when Calonectria was applied to coffee leaf discs inoculated with H. vastatrix, whilst a reduction of 70-90% was obtained for in planta experiments. Mycoparasitism was demonstrated through the fulfillment of Koch's postulates. Elucidation of the biochemical interaction between Calonectria and Hemileia on coffee plants indicated that the mycoparasite was able to increase plant resistance to rust infection. Coffee plants sprayed with Calonectria alone showed greater levels of chitinase, β-1,3-glucanase, ascorbate peroxidase and peroxidase. Although effective in controlling the rust, fungicide applications damaged coffee photosynthesis, whereas no harm was caused by Calonectria. We conclude that C. hemileiae shows promise as a biocontrol agent of CLR.

Keywords: Biological Sciences; Plant Biology; Plant Pathology.