Endophytic bacterial diversity in the phyllosphere of Amazon Paullinia cupana associated with asymptomatic and symptomatic anthracnose

Abstract

Endophytes colonize an ecological niche similar to that of phytopathogens, which make them candidate for disease suppression. Anthracnose is a disease caused by Colletotrichum spp., a phytopathogen that can infect guarana (Paullinia cupana), an important commercial crop in the Brazilian Amazon. We investigated the diversity of endophytic bacteria inhabiting the phyllosphere of asymptomatic and symptomatic anthracnose guarana plants. The PCR-denaturation gradient gel electrophoresis (PCR-DGGE) fingerprints revealed differences in the structure of the evaluated communities. Detailed analysis of endophytic bacteria composition using culture-dependent and 16S rRNA clone libraries revealed the presence of Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes, and Acidobacteria phyla. Firmicutes comprised the majority of isolates in asymptomatic plants (2.40E−4). However, cloning and sequencing of 16S rRNA revealed differences at the genus level for Neisseria (1.4E−4), Haemophilus (2.1E−3) and Arsenophonus (3.6E−5) in asymptomatic plants, Aquicella (3.5E−3) in symptomatic anthracnose plants, and Pseudomonas (1.1E−3), which was mainly identified in asymptomatic plants. In cross-comparisons of the endophytic bacterial communities as a whole, symptomatic anthracnose plants contained higher diversity, as reflected in the Shannon–Weaver and Simpson indices estimation (P < 0.05). Similarly, comparisons using LIBSHUFF and heatmap analysis for the relative abundance of operational taxonomic units (OTUs) showed differences between endophytic bacterial communities. These data are in agreement with the NMSD and ANOSIM analysis of DGGE profiles. Our results suggest that anthracnose can restructure endophytic bacterial communities by selecting certain strains in the phyllosphere of P. cupana. The understanding of these interactions is important for the development of strategies of biocontrol for Colletotrichum.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-015-1037-0) contains supplementary material, which is available to authorized users.

Fusarium Head Blight Modifies Fungal Endophytic Communities During Infection of Wheat Spikes

“…Similarly, bacterial diversity increased in Paullinia cupana leaves affected by anthracnose symptoms (Colletotrichum spp.) compared to leaves with no symptoms [44]. A similar tendency was detected, although not statistically significant, for bacterial communities in tomato roots attacked by the nematode Meloidogyne incognita when compared to non-infected roots [45].…”

Diversity of cultivable fungal endophytes in Paullinia cupana (Mart.) Ducke and bioactivity of their secondary metabolites

“…However, plant diseases like anthracnose and oversprouting, caused by Colletotrichum guaranicola F. C. Albuq and Fusarium decemcellulare Brick, respectively, have seriously damaged P . cupana crops and limited their expansion and productivity [ 15 – 18 ]. There are promising alternatives for disease control–such as cultivation of resistant P .…”

“…Some studies have reported the endophytic fungal diversity of P . cupana leaves [ 18 , 29 , 30 ] and endophytic bacterial diversity of P . cupana leaves, seeds and roots [ 31 , 32 ].…”

Endophytic cultivable bacterial community obtained from the Paullinia cupana seed in Amazonas and Bahia regions and its antagonistic effects against Colletotrichum gloeosporioides

“…In the AM, the disease incidence is higher than in BA, suggesting that some types of selection might be responsible for selection against Colletotrichum in AM, maintaining more antagonistic bacterial isolates in seeds. In bacterial isolated from leaves of asymptomatic and symptomatic guarana plants, was observed that symptomatic plants (with anthracnose) contained higher numbers of bacteria and increased genera diversity compared with asymptomatic plants [25]. These results suggested that anthracnose restructure endophytic bacterial communities through the selection of certain isolates in the phyloplane of P. cupana.…”

“…However, in general, the number and species variation is higher in other plant organs and tissues compared with seeds. In the leaves of guarana obtained from the Amazonas, the numbers varying from 10 4 to 10 5 CFU/g [25]. The isolation of endophytes in seeds is used to examine beneficial microorganisms that might be transferred early to seedlings contributing to promote plant growth, the biological control of pests and other advantages.…”