Witches’ broom resistant genotype CCN51 shows greater diversity of symbiont bacteria in its phylloplane than susceptible genotype catongo

Abstract

BackgroundTheobroma cacao L. (cacao) is a perennial tropical tree, endemic to rainforests of the Amazon Basin. Large populations of bacteria live on leaf surfaces and these phylloplane microorganisms can have important effects on plant health. In recent years, the advent of high-throughput sequencing techniques has greatly facilitated studies of the phylloplane microbiome. In this study, we characterized the bacterial microbiome of the phylloplane of the catongo genotype (susceptible to witch’s broom) and CCN51 (resistant). Bacterial microbiome was determined by sequencing the V3-V4 region of the bacterial 16S rRNA gene.ResultsAfter the pre-processing, a total of 1.7 million reads were considered. In total, 106 genera of bacteria were characterized. Proteobacteria was the predominant phylum in both genotypes. The exclusive genera of Catongo showed activity in the protection against UV radiation and in the transport of substrates. CCN51 presented genus that act in the biological control and inhibition in several taxonomic groups. Genotype CCN51 presented greater diversity of microorganisms in comparison to the Catongo genotype and the total community was different between both. Scanning electron microscopy analysis of leaves revealed that on the phylloplane, many bacterial occur in large aggregates in several regions of the surface and isolated nearby to the stomata.ConclusionsWe describe for the first time the phylloplane bacterial communities of T. cacao. The Genotype CCN51, resistant to the witch’s broom, has a greater diversity of bacterial microbioma in comparison to Catongo and a greater amount of exclusive microorganisms in the phylloplane with antagonistic action against phytopathogens.Electronic supplementary materialThe online version of this article (10.1186/s12866-018-1339-9) contains supplementary material, which is available to authorized users.

Phyllosphere microbial diversity and specific taxa mediate within-cultivar resistance to Phytophthora palmivora in cacao

“…Higher prokaryotic diversity was observed in the more resistant field accession MITC-331, a result that is consistent with a comparison of two cacao cultivars contrasting in resistance to the cacao pathogen Moniliophthora perniciosa . In that greenhouse study, the resistant cultivar CCN-51 had higher phylloplane bacterial diversity than the more susceptible cultivar Catongo ( 58 ). A diverse prokaryotic phylloplane community may be protective against pathogens independent of host genotype, perhaps by niche exclusion or the greater likelihood that a diverse community contains taxa capable of inhibiting pathogens.…”

Salicylic Acid-Mediated Disturbance Increases Bacterial Diversity in the Phyllosphere but Is Overcome by a Dominant Core Community

“…Culture-dependent studies carried out on the phyllosphere have shown that SA signaling modulates leaf endophytic communities ( Kniskern et al, 2007 ). Historically, culture-independent studies of the impact of SA have been largely limited to the rhizosphere or root endosphere, despite the status of SA as a foliar phytohormone ( Lebeis et al, 2015 ) and the emerging understanding of the importance of the phyllosphere as an antagonist for pathogens and its potential for dysbiosis ( Vorholt, 2012 ; Carvalho and Castillo, 2018 ; Santana et al, 2018 ; Stone et al, 2018 ; Chen T. et al, 2020 ). The potential for phytohormone signaling and plant immunity to coordinate homeostasis and dysbiosis in the plant phyllosphere has also been an area of considerable interest ( Chen T. et al, 2020 ; Gupta et al, 2021 ; Pfeilmeier et al, 2021 ).…”

“…Plant phyllospheres are colonized by diverse microbial taxa, including nematodes, archaea, algae and protists; however, the most prevalent microorganisms, both with respect to abundance and current scientific understanding, are fungi and, particularly, bacteria ( Vorholt, 2012 ; Trivedi et al, 2020 ). The stable phyllosphere confers fitness benefits to its host plant, including the acquisition and biological availability of essential elements; UV and drought tolerance; growth promotion; and the competitive exclusion of plant pathogens ( Vorholt, 2012 ; Carvalho and Castillo, 2018 ; Santana et al, 2018 ; Stone et al, 2018 ). Interactions between the host plant and the phyllosphere microbiome maintain a homeostatic state within the microbial community and, as in many ecological communities, in the homeostatic phyllosphere there is often a prevalence of few, dominant microbial taxa ( Vorholt, 2012 ; Kembel et al, 2014 ; Ottesen et al, 2016 ).…”

Effects of synthetic and environmentally friendly fungicides on powdery mildew management and the phyllosphere microbiome of cucumber

“…For example, endophytic bacteria (not in total leaves) were less diverse in the Arabidopsis leaves of susceptible genotypes [55]. The cocoa genotype that resisted witches' broom showed a greater diversity of symbiont bacteria in its phylloplane than a susceptible genotype [56]. On pumpkin, the richness and diversity of the fungal community on powdery mildew-infected leaves were significantly lower on severely infected leaves than on lightly infected leaves [29].…”