Characterization of New Small-Spored Alternaria Species Isolated from Solanaceae in Algeria

Abstract

Although large-spored Alternaria species of the section Porri are considered to be the major agents responsible for leaf spot and blight of Solanaceae, small-spored Alternaria species are also frequently isolated from symptomatic tissues. A survey of the north-western regions of Algeria during the 2017–2018 growing seasons revealed that amongst the 623 Alternaria isolates from tomato, potato, pepper, eggplant and black nightshade, 8% could not be morphologically assigned to either section Porri or section Alternaria. In order to more precisely determine the taxonomic position of these isolates, detailed morphological characterizations and multi-locus phylogenetic analyses were performed. Based on these analyses, the isolates were grouped into four main clades: section Ulocladioides, section Infectoriae, including two new species, section Embellisioides, and section Eureka, including one new species. These isolates were also characterized for their virulence under green-house conditions. They were able to produce leaf spot symptoms on tomato plants but with variable levels.

Pathogenicity and diversity of large‐spored Alternaria associated with three solanaceous vegetables (Solanum tuberosum, S. lycopersicum and S. melongena) in China

“…Disease incidence (DI) was recorded as the number of infected leaves/the number of inoculated leaves × 100. The disease severity index (DSI) was evaluated using a 1–4 rating scale slightly modified from Uwaremwe et al (2021) and Bessadat et al (2021). The scores were 1 = no symptoms (0 < d ≤ 10 mm), 2 = mild symptoms (10 < d ≤ 20 mm), 3 = obvious lesions (20 < d ≤ 30 mm) and 4 = severe lesions (30 mm < d ), where d is the diameter of lesions on the leaves.…”

“…This disease can lead to complete defoliation in severe cases, resulting in significant yield loss (Chaerani & Voorrips, 2006; Peralta et al, 2005). Brown spot initially exhibits on leaves as dark‐brown lesions that never develop the dark concentric rings (Bessadat et al, 2021). Many Alternaria species have been documented to cause foliar diseases on potato, tomato and eggplant.…”

Alternaria diseases on potato and tomato

“…When using molecular barcode markers, a combination of several loci is necessary. The most commonly used markers are ITS, GAPDH, RPB2, TEF1 and Alt a 1 (e.g., Kokaeva et al, 2022;Woudenberg et al, 2014), and most studies with a multilocus phylogeny employ these five or subset of them, with or without additional, less common loci like endoPG, histone H3, calmodulin and OPA 10-2 (e.g., Adhikari et al, 2020;Bessadat et al, 2021;Ding et al, 2019;Woudenberg et al, 2015). Recently, Dettman et al developed (Dettman & Eggertson, 2021, 2022 and tested (Dettman et al, 2023) new markers to achieve better identification of small-spored Alternaria.…”

Four New Species of Small-Spored Alternaria Isolated from Solanum tuberosum and S. lycopersicum in China

“…Porri comprising A. solani, A. blumeae, A. linariae, A. grandis and A. protenta infecting both potatoes and tomatoes [14,16]. Another type of Alternaria, small-spored Alternaria has been detected in a large number of the sampled leaves [17]. On potato, A. alternate (syn.…”