Abstract
Coffea arabica L. is one of the most important cash crops worldwide; however, it is highly affected by coffee leaf rust caused by Hemileia vastatrix. A promising alternative to obtain resistance is the use of susceptibility genes of the host plant as targets for gene silencing or knockout. The present study aimed to identify proteins in C. arabica var. Catuaí Amarelo potentially involved in the susceptibility to H. vastatrix using a proteomic approach. Leaves from infected and non-infected (control) coffee plants were collected ten days after inoculation with H. vastatrix. Total proteins were extracted, and the peptides were evaluated by LC-MS/MS. Shotgun proteomics revealed 2.335 proteins, of which 288 were differentially accumulated when infected and non-infected coffee leaf samples were compared. Differential proteins were classified into biological processes associated to pathogen response such as defense, photosynthesis, response to fungus, response to stimuli, carbohydrate metabolism and stress response. To validate the expression of potential genes associated with susceptibility, naturally infected leaves under field conditions were collected. Total RNA was extracted from coffee leaves and submitted to RT-qPCR analysis. The results showed that 6 genes (GSTs, GPx, SOD, Bgluc, ALDOA, and 6GPHD) were upregulated in infected samples, showing a positive correlation with protein accumulation. Overall, this work contributes to a better understanding of the metabolic pathways that are affected during the C. arabica - H. vastatrix susceptible interaction. Furthermore, the knockout of the candidate genes by CRISPR technology can be performed to obtain coffee plants with improved resistance to H. vastatrix.