Utility of internally transcribed spacer region ofrDNA(ITS) andβ‐tubulin gene sequences to infer genetic diversity and migration patterns ofColletotrichum truncatuminfectingCapsicumspp.

Abstract

Anthracnose is among the most economically important diseases affecting pepper (Capsicum spp.) production in the tropics and subtropics. Of the three species of Colletotrichum implicated as causal agents of pepper anthracnose, C. truncatum is considered to be the most destructive in agro‐ecosystems worldwide. However, the genetic variation and the migration potential of C. truncatum infecting pepper are not known. Five populations were selected for study and a two‐locus (internally transcribed spacer region, ITS1‐5.8S‐ITS2, and β‐tubulin, β‐TUB) sequence data set was generated and used in the analyses. Sequences of the ITS region were less informative than β ‐tubulin gene sequences based on comparisons of DNA polymorphism indices. Trinidad had the highest genetic diversity and also had the largest effective population size in pairwise comparisons with the other populations. The Trinidad population also demonstrated significant genetic differentiation from the other populations. AMOVA and STRUCTURE analyses both suggested significant genetic variation within populations more so than among populations. A consensus Maximum Likelihood tree based on β‐TUB gene sequences revealed very little intraspecific diversity for all isolates except for Trinidad. Two clades consisting solely of Trinidad isolates may have diverged earlier than the other isolates. There was also evidence of directional migration among the five populations. These findings may have a direct impact on the development of integrated disease management strategies to control C. truncatum infection in pepper.

Population structure, pathogenicity, and fungicide sensitivity of Colletotrichum siamense from different hosts in Hainan, China

“…Understanding the past and recent migration routes of a pathogen is crucial to understand current epidemics, develop risk‐assessment models, and apply management measures effectively. Some previous studies have investigated the genetic structure of Colletotrichum species by using random amplified polymorphic DNA (Xiao et al, 2004), inter‐simple sequence repeat markers (Rockenbach et al, 2016), simple sequence repeat markers (Bahri et al, 2019; Moges et al, 2016), and single nucleotide polymorphisms (SNPs; Li et al, 2016; Rampersad et al, 2013, 2016). However, C .…”

Phylogenetic analysis shows that New Zealand isolates of Neonectria ditissima are similar to European isolates

“…Another possibility is that insufficient time has elapsed since the geographic dispersal of apple germplasm from Europe to New Zealand for genetic drift to occur. Although sequencing the β-tubulin and ITS gene regions was able to show several clades for Colletotrichum truncatum infecting Capsicum (Rampersad et al 2016), these may be related to Trinidad being the origin, and showing greater genetic diversity than the sub-populations exported with Capsicum over the past 189-500 years. Other studies showing separate clades by sequencing these gene regions considered separation events of thousands of years (Banke et al 2004;Aggarwal et al 2018;Maya et al 2020;Andrew et al 2021).…”

The state-of-the-art in the genetics of resistance to the colletotrichum species complex in Capsicum

“…Anthracnose is a disease that occurs worldwide, caused by various fungal species of the genus Colletotrichum, and has been described as an obstacle to produce sweet and chili peppers in various countries. As the disease onset and development are favored by high temperatures and humidity (RAHMIYAH et al 2018), anthracnose epidemics are problematic in tropical and subtropical regions (RAMPERSAD et al 2016;SAXENA et al 2016). The disease can occur in pre and postharvest (REIS et al 2009;SILVA et al 2019;PEDROSO et al 2020).…”