A first insight into the involvement of phytohormones pathways in coffee resistance and susceptibility to Colletotrichum kahawae

Abstract

Understanding the molecular mechanisms underlying coffee-pathogen interactions are of key importance to aid disease resistance breeding efforts. In this work the expression of genes involved in salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) pathways were studied in hypocotyls of two coffee varieties challenged with the hemibiotrophic fungus Colletotrichum kahawae, the causal agent of Coffee Berry Disease. Based on a cytological analysis, key time-points of the infection process were selected and qPCR was used to evaluate the expression of phytohormones biosynthesis, reception and responsive-related genes. The resistance to C. kahawae was characterized by restricted fungal growth associated with early accumulation of phenolic compounds in the cell walls and cytoplasmic contents, and deployment of hypersensitive reaction. Similar responses were detected in the susceptible variety, but in a significantly lower percentage of infection sites and with no apparent effect on disease development. Gene expression analysis suggests a more relevant involvement of JA and ET phytohormones than SA in this pathosystem. An earlier and stronger activation of the JA pathway observed in the resistant variety, when compared with the susceptible one, seems to be responsible for the successful activation of defense responses and inhibition of fungal growth. For the ET pathway, the down or non-regulation of ET receptors in the resistant variety, together with a moderate expression of the responsive-related gene ERF1, indicates that this phytohormone may be related with other functions besides the resistance response. However, in the susceptible variety, the stronger activation of ERF1 gene at the beginning of the necrotrophic phase, suggests the involvement of ET in tissue senescence. As far as we know, this is the first attempt to unveil the role of phytohormones in coffee-C. kahawae interactions, thus contributing to deepen our understanding on the complex mechanisms of plant signaling and defense.

The avocado genome informs deep angiosperm phylogeny, highlights introgressive hybridization, and reveals pathogen-influenced gene space adaptation

“…Another relevant enriched GO category among tandems is “ethylene-activated signaling pathway” ( P = 0.000463; Fisher’s exact test, Bonferroni-corrected), which annotates many different transcription factor duplicates. Ethylene signaling factors such as ERF1 (represented by 2 homologs) are heavily involved in pathogen-induced responses, including to infection by Colletotrichum and other necrotrophic fungi (58–61). Also identified are 3 homologs of EIN3, a transcription factor that initiates downstream ethylene responses, including fruit ripening (62).…”

Identification of Regulatory Networks of MicroRNAs and Their Targets in Response to Colletotrichum gloeosporioides in Tea Plant (Camellia sinensis L.)

“…Plant susceptibility to hemibiotrophs is a genetically complex process and comprises the coordinated action of a wide range of hormones, including ET, JA, SA, and abcisic acid (ABA) (Thomma et al, 1998; Berrocal-Lobo et al, 2002; Adie et al, 2007; García-Andrade et al, 2011). Study by Diniz et al (2017) has shown that there is a stronger activation of ERF1 gene at the beginning of the necrotrophic phase of hemibiotrophic fungi Colletotrichum kahawae in the susceptible variety of Coffea arabica , which suggests the involvement of ET in tissue senescence. ET pathway activation in the susceptible variety may be related with tissue damage promoted by the fungal necrotrophic phase.…”

Comparative Transcriptome Analysis to Identify Candidate Genes for FaRCg1 Conferring Resistance Against Colletotrichum gloeosporioides in Cultivated Strawberry (Fragaria × ananassa)

“…On the contrary, when JA level is augmented, the TIFY transcription factor could bind with LRR/F-box protein and cause degradation of TIFY repressors by 26S proteasome that ultimately leads to the downregulation of primary response genes ( Chung et al, 2008 ). A recent study showed that JA was found to be an important phytohormone in coffee plants against Colletotrichum kahawae ( Diniz et al, 2017 ). The von Willebrand factor A (VWA) is an extensively dispersed protein that comprises domain for interactions between proteins ( Whittaker and Hynes, 2002 ), and highly similar across diverse eukaryotes.…”