Coffee bacterial diseases: a plethora of scientific opportunities

Abstract

Coffee is a very important crop for several tropical countries across different continents. The diseases bacterial halo blight (BHB), bacterial leaf spot (BLS), bacterial leaf blight (BLB) and coffee leaf scorch (CLS), caused by the bacterial pathogens Pseudomonas syringae pv. garcae (Psgc), P. syringae pv. tabaci (Psta), Pseudomonas cichorii (Pch) and Xylella fastidiosa subsp. pauca (Xfp), respectively, cause significant reductions in coffee production, although other minor bacterial diseases have also been reported in some countries. Little research progress has been made on aspects that are relevant for control and management of these diseases. In all cases, there is an urgent need to develop rapid and more reliable methods for early detection of the pathogens in order to minimize their negative impact on coffee production. Because of the high rate of intra‐ and intersubspecific recombination occurring in X. fastidiosa, a permanent revision of the detection methods is necessary. Greater efforts should be made to understand the genetic and virulence diversity of Psgc, Psta and Pch populations. Early studies reported the identification of potential sources of resistance against Psgc and Psta, but, to date, no resistance gene has been isolated. Little effort has been made to understand the biology and molecular mechanisms underlying the interaction between Coffea spp. and these pathogenic bacteria. This review discusses the recent progress on the molecular mechanisms used by these bacteria to cause diseases on other plant species, in order to provide a guideline for the establishment of future research programmes.

Genomic variability and plasticity of Pseudomonas causing coffee leaf spots in Minas Gerais state, Brazil

“…Although Pcg and Pat are part of the P. syringae species complex (Dillon, Thakur, et al, 2019), they belong to different phylogroups, namely phylogroups 3 and 4, respectively, indicating sufficient genomic divergence for species separation (Gomila et al, 2015;Raimundi, 2017). It is estimated that these three pathogens together cause about 70% production losses under nursery and field conditions, mainly in the Brazilian states of Paraná, São Paulo and Minas Gerais (Badel & Zambolim, 2019). Pcg, Pat and Pch cause symptoms on coffee plants often phenotypically indistinguishable and have been shown to be sympatric and to occur in mixed infections (Raimundi, 2013).…”

“…Even though leaf spot symptoms caused by these three bacterial pathogens cause a great negative impact on coffee production, their genetic and pathogenic variability have not been sufficiently investigated (Badel & Zambolim, 2019). A recent study conducted with strains from Minas Gerais state showed that of the three molecular markers commonly used in repetitive element palindromic PCR (rep-PCR), REP detected genetic variation in Pcg and Pch, ERIC only in Pat and BOX only in Pch (Raimundi, 2017).…”

A Review of Potential Impacts of Climate Change on Coffee Cultivation and Mycotoxigenic Fungi

“…The insect damage is known to cause an increase in fungal infection [ 8 ]. Bacterial diseases include halo blight, leaf spot, and coffee leaf scorch and are responsible for significant reductions in coffee yields [ 18 ]. Fungal diseases include coffee berry disease, coffee wilt disease, and coffee leaf rust.…”

Chemical Composition, Production of Secondary Metabolites and Antioxidant Activity in Coffee Cultivars Susceptible and Partially Resistant to Bacterial Halo Blight

“…Coffee is a crop of significant economic importance in many countries including Brazil, and several factors limit coffee production, including fungal and bacterial diseases [ 17 ]. The bacterial halo blight of coffee (BHB) caused by Pseudomonas syringae pv .…”

“…The bacterial halo blight of coffee (BHB) caused by Pseudomonas syringae pv . garcae [ 18 , 19 ], is a disease that has caused losses in nurseries and fields established in regions subjected to strong winds, mild temperatures, and frequent and well-distributed rains [ 17 , 20 ]. Among the coffee ( Coffea arabica L.) cultivars planted in Brazil, the Mundo Novo 376/4 cultivar corresponds to almost half of the planted area.…”