Multiple resistance to bacterial halo blight and bacterial leaf spot in Coffea spp.*

Abstract

Breeding for genetic resistance is an important method of crop disease management, due to the numerous benefits and low cost of establishment. In this study, progenies of 11 Coffea species and 16 wild C. arabica accessions were tested for their response to Pseudomonas syringae pv. garcae, the causal agent of bacterial halo blight, a widespread disease in the main coffee-producing regions of Brazil and considered a limiting factor for cultivation in pathogen-favorable areas; and also to P. syringae pv. tabaci, causal agent of bacterial leaf spot, a highly aggressive disease recently detected in Brazil. Separate experiments for each disease were carried out in a greenhouse, with artificial pathogen inoculations and ideal moisture conditions for disease development. The results showed that C. canephora, C. congensis, C. eugenioides, C. stenophylla, and C. salvatrix progenies, the wild C. arabica accessions Dilla & Alghe and Palido Viridis, and cultivar IPR 102 contain satisfactory levels of simultaneous resistance against bacterial halo blight and bacterial leaf spot. These results are useful in breeding programs for durable resistance to multiple biotic agents, providing new combinations of resistance alleles by hybridization, as well as for phytopathological studies, to identify infraspecific variability of the pathogens.

Resistance of genotypes and defence compounds against bacterial halo blight of coffee

“…The results of severity of cultivars IPR 102 and Mundo Novo 376/4, considered resistant and susceptible to BHB, respectively, in this study, confirmed this classification of resistance to BHB, as verified in other studies (Ito et al., 2008; Sera et al., 2017; Rodrigues et al., 2019; Fernandes et al., 2020). Among the evaluated genotypes from the germplasm bank to BHB resistance, eight genotypes showed disease severity similar to cultivar IPR 102, for example, UFV 7158 genotype and Catiguá MG2 cultivar.…”

Ethiopian coffee germplasm is a valuable resistance gene pool to brazilian Pseudomonas syringae PVS garcae and tabaci

“…tabaci (Fernandes et al, 2020), however in the latter case, it had not been confirmed, as it was a field study, without controlled inoculation. Rodrigues et al (2019) also identified high resistance in the cultivar IPR 102 for both P. syringae pathovars, however for the latter, susceptible segregating plants were found, indicating that it is necessary to make selections within that cultivar to identify individual plants with homozygous resistance.…”

Differences between the Leaf Mycobiome of Coffea arabica and Wild Coffee Species and Their Modulation by Caffeine/Chlorogenic Acid Content

“…The absence of most fungi in C. arabica (including Phoma antagonists) indicates that the complex interaction network of the various C. racemosa/C. stenophylla fungi may protect them from pathogens, which is seen in practice, because non-domesticated coffee plants are more resistant to diseases [35]. In fact, higher microbiome diversity is known to provide several benefits to the host [36].…”