Fusarium oxysporum f. sp. mori, a New Forma Specialis Causing Fusarium Wilt of Blackberry

Abstract

Fusarium oxysporum has recently been identified as the cause of a wilt disease affecting blackberry in California and Mexico. Thirty-six isolates of F. oxysporum obtained from symptomatic blackberry plants in California and Mexico were comprised of nine distinct somatic compatibility groups (SCGs). Phylogenetic analysis of a concatenated data set, consisting of sequences of the translation elongation factor 1-α and β-tubulin genes and the intergenic spacer of the ribosomal DNA, identified nine three-locus sequence types, each of which corresponded to an SCG. Six SCGs were present only in California, two only in Mexico, and one in both California and Mexico. An isolate associated with the most common SCG in California was tested for pathogenicity on blueberry, raspberry, strawberry, and lettuce. All blueberry, raspberry, and lettuce plants that were inoculated remained healthy, but two of the five strawberry cultivars tested developed symptoms. The three strawberry cultivars that were resistant to the blackberry pathogen were also resistant to F. oxysporum f. sp. fragariae, the cause of Fusarium wilt of strawberry. We propose to designate strains of F. oxysporum that are pathogenic to blackberry as Fusarium oxysporum f. sp. mori forma specialis nov.

Host range studies of Fusarium oxysporum, causal agent of seedling wilt disease of Acacia mangium

“…Moreover, when a plant is grown in contaminated soil, there is a high risk of damage to crops. A similar incident was reported by Pastrana et al (2017) in which F. oxysporum from blackberry also caused sudden death in strawberries. Another study also revealed that F. oxysporum from cactus causes root and stem rot diseases in Euphorbia (Bertetti et al 2017).…”

Pathogenic Microorganisms Infecting Berries in Mexico

“…However, in the cases of Colletotrichum and Fusarium, the presence of species complexes makes difficult to establish the correct identification of the involved species due to the probable presence of cryptic species. To identify species in these species complexes is necessary to use several molecular markers (Pastrana et al 2017;Hernández-Cruz et al. 2020).…”

“…These microorganisms induce diseases in most of the plant organs such as leaves, stems, inflorescences, fruits, and roots, reducing crop yields during pre-and postharvest. Several species are becoming a problem in berries worldwide, some as the bacteria Xanthomonas fragariae in strawberry (Kastelein et al 2014;Kamangar et al 2017;Wang et al 2017), the oomycete Phytophthora cinnamomi inducing crown and root rot in V. corymbosum (Tamietti 2003;Larach et al 2009;Huarhua et al 2018), the fungi Fusarium oxysporum causing wilt disease in blackberry (Gordon et al 2016;Pastrana et al 2017) and blueberries (Liu et al 2014;Moya-Elizondo et al 2019), or several species of Lasiodiplodia in different berries, as Lasiodiplodia theobromae causing dieback in strawberry (Nam et al 2016) or inducing stem blight and dieback of blueberry plants (Wright and Harmon 2009;Scarlett et al 2019;Rodríguez-Gálvez et al 2020).…”

Pathotypes of Fusarium oxysporum f. sp. fragariae express discrete repertoires of accessory genes and induce distinct host transcriptional responses during root infection

“…Lastly, we included an isolate of F. oxysporum f. sp. mori, GL1804, which causes Fusarium wilt of blackberry and can asymptomatically colonize strawberry (unpublished data) (Pastrana et al, 2017).…”