Biology subjects

Aguilera-Galvez, C.

Publications and source records attributed to Aguilera-Galvez, C..

4 recordsLinked to original sources

bioRxiv2025

Transposon activity eliminates a crucial fungal secondary metabolite cluster while preserving pathogenicity

SummaryO_LITransposable elements can significantly influence the genome dynamics of clonal fungal plant pathogens. Tropical Race 4 (TR4) is a clonal lineage within the Fusarium oxysporum species complex that poses a substantial threat to global banana production. However, how transposable elements shape TR4s genome and adaptation remains underexplored. C_LIO_LIWe investigated the activity and impact of FoHeli1, a Helitron transposable element in the TR4 lineage, focusing on a Mozambican TR4 strain (M1) through a combination of genome analyses, metabolite profiling, and infection assays. C_LIO_LIFoHeli1 activity has been very recent within the TR4 lineage and is likely still ongoing. This has resulted in large structural variations in M1, including the loss of the conserved biosynthetic gene cluster required for the production of fusaric acid. We demonstrate that this deletion abolishes fusaric acid production and alters secondary metabolite profiles, but does not affect pathogenicity. C_LIO_LIOur results emphasize the significance of transposable elements, particularly FoHeli1, in reshaping the genetic and metabolic landscape of TR4 and challenge existing assumptions about the role of fusaric acid in pathogenicity. C_LI

microbiology↗

bioRxiv2024

Extensive intrachromosomal duplications in a virulence-associated fungal accessory chromosome

Filamentous fungi have evolved compartmentalized genomes consisting of conserved core regions and dynamic accessory regions, which aid the adaptation to changing environments including the interaction with host organisms. In the Fusarium oxysporum species complex, accessory regions play an important role during infection and it has been reported that these regions undergo extensive duplications, however, it is currently unknown how such duplications shape accessory regions. Moreover, the function of accessory regions apart from encoding virulence effectors is not completely understood. Here we determined the karyotype of F. oxysporum Tropical Race 4 (TR4), which causes the ongoing pandemic of Fusarium wilt of banana (FWB). We show that the single accessory chromosome of TR4 isolate II5 has undergone extensive intrachromosomal duplications, resulting in triplication of the chromosome size compared to other closely related TR4 strains. By obtaining mutant strains that have lost the accessory chromosome, we demonstrate that this chromosome is dispensable for vegetative growth but is required for full virulence on banana. Lastly, we found that the loss of chromosome 12 co-occurs with structural rearrangements of core chromosomes, which are generally co-linear between members of the F. oxysporum species complex. Together, our results provide new insights into the chromosome dynamics of the banana infecting TR4 lineage of the F. oxysporum species complex. SignificanceFusarium oxysporum is a major fungal plant pathogen that causes vascular wilt disease on a wide variety of agronomically important crops. A current epidemic of Fusarium wilt of banana (FWB), caused by tropical race 4 (TR4), poses a major threat to global banana production and threatens food security in tropical and subtropical regions where banana is an important staple crop. Controlling TR4 requires a better understanding of the molecular mechanisms underlying pathogenicity, including the evolution of pathogenicity-related accessory regions. Here we demonstrate that intrachromosomal duplications are a key mechanism of accessory chromosome evolution in the F. oxysporum species complex. We identified a single accessory chromosome and show that TR4 mutants that lost this accessory chromosome display significantly reduced virulence on banana plants. Our results provide insight into the evolution of accessory chromosomes in the F. oxysporum species complex, underscore their importance in pathogenicity, and provide new clues for the development of resistant banana plants.

microbiology↗

bioRxiv2023

Segmental Duplications Drive the Evolution of Accessory Regions in a Major Crop Pathogen

O_LIMany pathogens evolved compartmentalized genomes with conserved core and variable accessory regions which carry effector genes mediating virulence. The fungal plant pathogen Fusarium oxysporum has such accessory regions often spanning entire chromosomes. The presence of specific accessory regions influences the host range, and horizontal transfer of some accessory regions can modify the pathogenicity of the receiving strain. However, understanding how these accessory regions evolve in strains that infect the same host remains limited. C_LIO_LIHere, we define the pan-genome of 69 diverse Fusarium strains that cause Fusarium wilt of banana, a significant constraint to global banana production. In this diverse panel of Fusarium strains infecting banana, we analyzed the diversity and evolution of the accessory regions. C_LIO_LIAccessory regions in Fusarium strains infecting the same banana cultivar are highly diverse, and we could not identify any shared genomic regions and in planta induced effectors. We demonstrate that segmental duplications drive the evolution of accessory regions. Furthermore, we show that recent segmental duplications and aneuploidy occur specifically in accessory chromosomes and cause the expansion of accessory regions in F. oxysporum. C_LIO_LITaken together we conclude that extensive recent duplications drive the evolution of accessory regions in Fusarium, which contribute to the evolution of virulence. C_LI

genomics↗

bioRxiv2020

The Rpi-mcq1 resistance gene family recognizes Avr2 of Phytophthora infestans but is distinct from R2

Potato late blight, which is caused by the destructive oomycete pathogen Phytophthora infestans, is a major threat to global food security. Several nucleotide binding, leucine-rich repeat (NLR) Resistance to P. infestans (Rpi) genes have been introgressed into potato cultivars from wild Solanum species that are native to Mexico, but these were quickly defeated. Positional cloning in Solanum mochiquense, combined with allele mining in Solanum huancabambense, were used to identify a new family of Rpi genes from Peruvian Solanum species. Rpi-mcq1, Rpi-hcb1.1 and Rpi-hcb1.2 confer race-specific resistance to a panel of P. infestans isolates. Effector assays showed that the Rpi-mcq1 family mediates a hypersensitive response upon recognition of the RXLR effector AVR2, which had previously been found to be exclusively recognized by the family of R2 resistance proteins. The Rpi-mcq1 and R2 genes are distinct and reside on chromosome IX and IV, respectively. This is the first report of two unrelated R protein families that recognize the same AVR protein. We anticipate that this likely is a consequence of a geographically separated dynamic co-evolution of R gene families of Solanum with an important effector gene of P. infestans. Author summaryPotato is the largest non-grain staple crop and essential for food security world-wide. However, potato plants are continuously threatened by the notorious oomycete pathogen Phytophthora infestans that causes late blight. This devastating disease has led to the Irish famine more then 150 years ago, and is still a major threat for potato. Resistance against P. infestans can be found in wild relatives of potato, which carry resistance genes that belong to the nucleotide binding site-leucine-rich repeat (NLR) class. Known NLR proteins typically recognize a matching effector from Phytophthora, which leads to a hypersensitive resistance response (HR). For example, R2 from Mexican Solanum species recognizes AVR2 from P. infestans. So far, these R genes exclusively match to one Avr gene. Here, we identified a new class of NLR proteins that are different from R2, but also recognize the same effector AVR2. This new family of NLR occurs in South American Solanum species, and we anticipate that it is likely a product of a geographically separated co-evolution with AVR2. This is the first report of two unrelated R protein families that recognize the same AVR protein.

plant biology↗