A three–decade survey of Brazilian Fusarium oxysporum f. sp. lycopersici races assessed by pathogenicity tests on differential tomato accessions and by molecular markers

Abstract

Aim: Physiological race determination of 143 Fusarium oxysporum f. sp. lycopersici (FOL) isolates collected along 30 years in major tomato-producing regions of Brazil. Materials and Results: Physiological races were determined via root-dipping inoculation of differential tomato accessions and by the PCR-based marker system of Hirano and Arie (2006). According to pathogenicity/virulence assays, five race 1, 23 race 2 and 115 race 3 isolates were identified. FOL race 1 and 2 isolates prevailed up to early 2000s. Afterwards, the large majority of the isolates was classified as the invasive race 3. Novel reports of race 3 were done in five states, thus expanding its geographical distribution. Using this PCRbased marker system, a precise discrimination was observed for all race 3 isolates. However, all race 1 and 2 isolates displayed only the cosmopolitan race 1-specific amplicon pattern. Conclusion:The development and/or validation of novel race-specific marker systems are necessary to allow a precise discrimination of the potentially endemic Brazilian FOL race 2. Significance and Impact of the Study: The present characterization of isolates indicates that distinct evolutionary mechanisms are acting to select new FOL races and/or genetic variants across agroecosystems around the globe. 1982). A repertoire of four dominant resistance factors (I, I-2, I-3 and I-7) has been characterized in distinct tomato accessions (Gonzalez-Cendales et al. 2016;Catanzariti et al. 2017). The I-2 gene from S. pimpinellifolium (located on chromosome 11) controls resistance to race 1 and race 2 isolates, displaying in its structure the nucleotide binding and leucine-rich repeat (LRR) motifs (Simons et al. 1998). The race 1-specific I gene was introgressed from S. pimpinellifolium (also located on chromosome 11) and it encodes an atypical membraneanchored, LRR receptor-like protein (Catanzariti et al. 2017). The FOL race 3 resistance gene I-3 from S. pennellii is located on chromosome 7. The I-3 gene encodes one S-receptor-like kinase and controls resistance to race

Fusarium species causing root rot and wilt in tomato in Brazil

“…It is important to note that Fusarium wilt in tomato plants, caused by the fungus F. oxysporum f. sp. lycopersici , has been a known problem in Brazil since 1938 and is currently widely distributed in various regions of the country, resulting in significant losses (Deslandes, 1940; Gonçalves et al., 2020; Oliveira et al., 2021).…”

“…Consensus sequences were assembled from bidirectional DNA sequences using SeqAssem v. 07/2008 (Hepperle, 2004). The sequences of reference isolates of species belonging to the Fusarium oxysporum species complex -FOSC (Lombardi et al, 2019;Maryani et al, 2019) and Fusarium solani species complex -FSSC (Geiser et al, 2020;Sandoval-Denis et al, 2019) that were available in the GenBank database were included in the analyses. Alignments were generated using CLUSTALW, as implemented in MEGAX software (Kumar et al, 2018).…”

Screening of tomato hybrids for resistance to Fusarium wilt

“…The female genitor was the commercial tomato cultivar Santa Clara ® , which is resistant to the main soil-borne pathogens in Brazil, including Verticillium dahliae and FOL races 1 and 2, and tolerant to root-knot nematodes (Meloidogyne spp.). The isolates FUS-027 (race 1), FUS-023 (race 2), and FUS-374 (race 3) from FOL were provided by Embrapa Hortaliças, Brasília, Brazil (Gonçalves et al 2021).…”

“…Globally, FOL races 1 and 2 can be managed by resistant cultivars carrying the resistance genes I-1 and I-2 (Ma et al 2013). In Brazil, few cultivars harboring the gene for resistance to race 3 are available for growers, and areas infested by the pathogen have already been observed in the main tomato-producing regions (Reis et al 2005, Barboza et al 2013, Gonçalves et al 2021.…”

Genetic Diversity and Population Structure of Fusarium oxysporum f. sp. conglutinans Race 1 in Northern China Samples

“…Thus far, most of the genetic diversity research in FO is to investigate the distribution of different physiological races. Physiological races also differentiate during the process of pathogen spread [ 21 ]. Knowledge about the genetic diversity and population structure of specific physiological races is still limited.…”