Can the leaf age influence the susceptibility to bacterial-leaf-spot and bacterial-halo-blight on coffee seedlings?

Abstract

Pseudomonas syringae van Hall, 1902, causes yield losses in innumerous economic important crops. On coffee trees, P. syringae pv. garcae causes the bacterial-halo-blight (BHB) and P. syringae pv. tabaci the bacterial-leaf-spot (BLS). Recently, these diseases incidence has increase in occurrence areas and aggressiveness in Brazil. Although leaf age plays a role in the severity response of BHB, it is not known yet if this phenomenon also occurs in coffee-BLS interaction, and with highly virulent strains. So, we examined differences in the diseases severity by inoculation of P. syringae pv. garcae and P. syringae pv. tabaci strains on coffee leaves with different ages, to compare this aspect with coffee-BLS interaction. Our results showed that, for both pathovars, the severity was greater at the first internodes leaves, although for the most aggressive strains it was quite similar on any leaf age.

Pseudomonas syringae coffee blight is associated with the horizontal transfer of plasmid‐encoded type III effectors

“…Phylogenetic relationships inferred from the concatenated core genome identify six coffee isolates from primary phylogroup 3 (PG3), 42 coffee isolates from primary phylogroup 4 (PG4), and five coffee isolates from secondary phylogroup 11 (PG11; Figs 1, S3), which we designated coffee blight PG3 (CB.PG3), CB.PG4, and CB.PG11. Coffee isolates in our collection that were previously collected by other groups are also found in PG4, including the pathotype strain P. syringae pv garcae ICMP4323 (also known as ATCC19864; Amaral et al ., 1956; Young et al ., 1978).…”

“…Coffee blight is the most prominent bacterial disease of coffee and an important emerging threat that can result in dramatic losses (Nair, 2010). The disease was first described in Garça, São Paulo, Brazil, in 1955 and attributed to Psg (Amaral et al ., 1956; Maciel et al ., 2018). Coffee blight pathogens can exist as epiphytes on healthy plants during cool and wet seasons and enter the plant tissue through wounds or natural openings (Badel & Zambolim, 2019).…”

Efficiency of inoculation methods for the assessment of bacterial halo blight in coffee seedlings

“…Despite wounding methods have been demonstrated to have more severe symptoms for inoculating Pcg, the inoculation by spraying phytopathogenic bacterial solutions is often utilized in scientific research (Amaral et al., 1956; Araújo et al., 2005; Belan et al., 2013; Botrel, 2013; Halfeld‐Vieira & Nechet, 2006; Malavolta Júnior et al., 2002; Rodrigues et al., 2017; TAF, 2007; Yamada, 2014). The similarity of atomization or spraying with nonmechanized field conditions is one of the reasons for this being a frequently used method; furthermore, it does not cause injury to the foliar tissue, so it does not break the natural defence barriers of plants.…”

“…garcae) (Barta & Willis, 2005), has become a significant challenge for Brazilian coffee (Coffea arabica L.) production in the past decade. This disease was first reported in 1955 in the city of Garça, São Paulo, as a natural occurrence in coffee trees (Amaral et al, 1956). Initially, it was not considered a significant economic threat for several years.…”