Phylogeny, morphology and pathogenicity of Elsinoë ampelina, the causal agent of grapevine anthracnose in Brazil and Australia

Abstract

Anthracnose caused by Elsinoë ampelina is one of the most important table grape diseases in humid regions in Brazil and Australia. The objective of this study was to characterize E. ampelina isolates from Brazil and Australia by means of phylogenetic analyses, morphological features and pathogenicity tests. Phylogenetic relationships among 35 isolates were determined based on a data set of internal transcribed spacer (ITS), histone H3 (HIS3) and elongation factor 1‐α (TEF) sequences. In phylogenetic tree analyses, using a combined ITS and TEF sequence alignment, all E. ampelina isolates were clustered together in a single well‐supported clade. In contrast to the absence of genetic variability within ITS and TEF sequences, HIS3 sequences showed 54 polymorphic sites. The haplotype network generated from HIS3 data set showed four distinct haplotypes. EA1 was the predominant haplotype including 29 isolates from both countries. High genetic variability was observed in two Brazilian isolates, haplotype EA4, which may have lost the intron region during species evolution. Colony colours differed between Brazilian and Australian isolates, but showed similar wrinkled colony texture, absence of spores, sparse‐to‐absent white aerial mycelium and slow growth (0.049–0.060 mm/day). Brazilian isolates produced conidia of 5.65 × 2.65 μm, larger than conidia from Australian isolates, which measured 5.14 × 2.30 μm. In pathogenicity tests, all nine Australian isolates inoculated were pathogenic on detached canes and potted vines of table grape.

Emergent Ascomycetes in Viticulture: An Interdisciplinary Overview

“…The symptoms were assessed in variable times of incubation. The results obtained by these assays were consistent and were applied for pathogenicity analysis (Tharapreuksapong et al, 2009; Santos et al, 2018a), germplasm characterization (Kono et al, 2012) and genetic analysis (Tantasawat et al, 2012; Poolsawat et al, 2013).…”

“…For these purposes, in vitro production of conidia of E. ampelina proved to be a major challenge, due to its poor and unstable sporulation in culture. Even though Hopkins and Harris (2000) produced conidia from 3 to 4 week old cultures of E. ampelina maintained on potato dextrose agar (PDA), other researchers were unable to reproduce these results (Santos et al, 2018a; Santos et al, 2018b). In order to improve the yield of conidia, Yun et al (2006) transferred the pathogen in Fries liquid medium and incubated it in a shaking incubator (140 rpm) at 28°C for 10 days.…”

“…The study revealed the following three indispensable conditions for conidial production: (i) the density of colonies in pre-culture should be lesser than 2.5 colonies per cm 2 ; (ii) depending on colony density, colonies should grow for 4 to 9 days on PDA; and (iii) grown colonies should be cultured in water with shaking (150 rpm) for 8 to 10 h in the dark at 24°C. Santos et al (2018a) used a similar protocol. Conidial suspensions were obtained by placing E. ampelina cultures in rainwater and shaking at 200 rpm in darkness for 7 days to induce sporulation.…”

“…However, consistent results were obtained at temperatures ranging from 20 to 28°C. Inoculations using conidia suspension were also performed on detached canes (Santos et al, 2018a), on detached leaves (Tharapreuksapong et al, 2009; Kono et al, 2012) and on leaf pieces (Poolsawat et al, 2012). After the inoculation, the tissues were maintained under high humidity at 25-27°C.…”

Cycle, physicochemical characterization and climatic adaptation of a white hybrid grape on different rootstocks

“…Brazil, however, has great potential for wine production, because new markets for white and sparkling wines are promising (OIV 2016). The grape cycle, though, is problematic in some wine regions due to high rainfall and the development of diseases such as powdery mildew, downy mildew and anthracnose, which reduce fruit quality and cause up to 100% crop loss (Amorim et al 2016;Santos et al 2018b). Some grape-breeding programs in Brazil have also developed new cultivars with good climatic adaptation and characteristics for making wine.…”