Genetic diversity ofColletotrichum gloeosporioidesspecies complex associated withCitruswither‐tip of twigs in Tunisia using microsatellite markers

Abstract

Anthracnose Citrus disease has been associated with several symptoms worldwide and it is recently compromising Citrus production in the Mediterranean area. Four species complexes are mainly involved: Colletotrichum boninense, C. acutatum, C. gloeosporioides and C. truncatum. In this study, we investigated the genetic diversity of Colletotrichum spp. in Tunisia associated with wither‐tip of twigs on Citrus. Specific primers ITS4‐CgInt allowed the identification of C. gloeosporioides species complex in all the 54 isolates, sampled from three regions and four Citrus species. Overall, our genotypic analysis using 10 SSR markers showed a moderate diversity level in Tunisian C. gloeosporioides population and highlighted that C. gloeosporioides reproduce mainly clonally. In addition, heterothallic isolates were present in our population, suggesting that the pathogen population may undergo parasexual recombinations. The highest genetic diversity in C. gloeosporioides was recorded in Nabeul and on orange, which likely constitutes the area and the host of origin for the Citrus anthracnose disease in Tunisia. In addition, no population subdivision was detected at the geographic, host species or cultivars’ origin levels. However, our study identified two genetic subpopulations and indicated a rapid C. gloeosporioides population change at temporal scale that should be further examined over several consecutive growing seasons in order to understand its population dynamics.

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

“…Based on morphological characteristics and molecular techniques, 71 isolates (accounting for 83.5% of the total Colletotrichum isolates obtained in this study) were identified as C. siamense, confirming that C. siamense is the dominant species causing anthracnose of rubber tree, coffee, and areca palm in Hainan. The present results also suggest that genetic differentiation among C. siamense isolates from different hosts is small, consistent with the fact that C. gloeosporioides populations in Ethiopia (Moges et al, 2016) and Tunisia (Bahri et al, 2019) are characterized by low genetic differentiation. This may be explained by several factors.…”

“…siamense isolates from different hosts is small, consistent with the fact that C . gloeosporioides populations in Ethiopia (Moges et al, 2016) and Tunisia (Bahri et al, 2019) are characterized by low genetic differentiation. This may be explained by several factors.…”

“…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. However, C. siamense populations from different hosts in Hainan, China have not been studied for their genetic structure.…”

Genetic Evidence for Colletotrichum gloeosporioides Transmission Between the Invasive Plant Ageratina adenophora and Co-occurring Neighbor Plants

“…They can host among 470 different plants as a pathogen or an endophyte [49]. Most research of CGSC has focused on economic crops [50] or fruits [42]. In this study, we obtained 165 strains belonging to CGSC from three isolation sources (invasive plant A. adenophora healthy leaves and symptomatic leaves, and neighbor plants symptomatic leaves) in 11 geographic sites (belonging to four invasion ages of A. adenophora).…”

“…CGSC may be simpler to consider as a species complex rather than using intraspeci c designations for practical reasons [39,40]. Moreover, because genetic diversity in a species is generally limited, researches on population genetic diversity have been conducted on a species complex, such as CGSC [23,41,42]. In this study, therefore, all DNA sequences that were identi ed as the CGSC were included in subsequent genetic analyses.…”