Biology subjects

Cantu, D.

Publications and source records attributed to Cantu, D..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Genomic insights into the virulence repertoire and hemibiotrophic lifestyle of the grapevine black rot pathogen Phyllosticta ampelicida

Phyllosticta ampelicida, the causal agent of grapevine black rot, is a globally emerging pathogen that infects all grapevine green tissues, with young shoots and berries being particularly susceptible. Severe infections can result in total crop loss. To investigate its virulence repertoire, we generated a high-quality genome assembly of strain GW18.1 using long-read sequencing, resulting in 22 scaffolds, including four complete chromosomes and 12 chromosome arms, with a total genome size of 35.6 Mb and 10,289 predicted protein-coding genes. Two additional strains (TN2 and LB22.1) were sequenced with short reads to assess intraspecies diversity. Comparative genomics revealed a conserved virulence factor repertoire, including 314 carbohydrate-active enzymes (CAZymes), 17 cytochrome P450s, 35 peroxidases, and 20 secondary metabolite biosynthetic gene clusters (BGCs). Trophic lifestyle prediction based on gene content supports a biotrophic-like lifestyle consistent with hemibiotrophic pathogens. Broader comparisons with other Phyllosticta species and ten plant-pathogenic fungi pointed to species-specific features, while analysis of gene family evolution identified expansions and contractions in transporters and CAZymes. These genomic resources will support efforts to better understand and manage grapevine black rot.

genomics↗

bioRxiv2025

Leveraging foundation models to dissect the genetic basis of cluster compactness and yield in grapevine

Grape cluster compactness is a key trait that influence fruit quality, yield, and disease susceptibility. Understanding the genetic basis of this trait is essential for optimizing vineyard management and improving grapevine cultivars. In this study, we performed quantitative trait locus (QTL) mapping to identify genomic regions associated with cluster architecture and yield components in a bi-parental population derived from Vitis vinifera cv. Riesling x Cabernet Sauvignon. A total of 138 full-sibling progeny were evaluated over two growing seasons at Oakville, Napa Valley, California. Traditional yield-related traits were measured, including cluster number, total cluster weight, and average cluster weight. Additionally, an image-based phenotyping pipeline leveraging the foundation model Segment Anything Model (SAM) was employed to segment individual berries, measure their size and shape, and compute cluster compactness with minimal manual intervention. Trait correlations revealed that compact clusters tended to have a higher berry count but smaller berry size, highlighting the role of compactness in modulating cluster structure. Heritability estimates varied across traits, with berry dimensions and compactness displaying moderate to high heritability, indicating strong genetic control. Two parental linkage maps were constructed using a pseudo-test cross strategy. QTL mapping identified multiple loci associated with cluster architecture and yield components, with several stable QTLs detected across both years. Notably, a QTL for cluster compactness was found in both seasons on chromosome 1 in Cabernet Sauvignon. Other stable QTLs were associated with berry size (chromosomes 6 and 17) and berry count (chromosome 5 in Cabernet Sauvignon and chromosome 7 in Riesling). Additional QTLs were detected in a single year, reflecting the influence of environmental variation. Our findings provide valuable insights into the application of foundation models requiring no prior training and minimal intervention for high-quality segmentation and enhance our understanding of the genetic architecture of cluster compactness and yield traits. The genomic regions identified in this study offer promising targets for breeding programs aimed at improving grape quality and disease resistance.

genetics↗

bioRxiv2025

The Genetic Basis of Microbiome Recruitment in Grapevine and its Association with Fermentative and Pathogenic Taxa

O_LIWhile grapevine is an exceptional perennial model for studying host-microbiome interactions, the host genomes role in microbiome assembly is often masked by environmental factors. This research provides a first insight into the genetic mechanisms shaping berry-associated microbial communities. C_LIO_LIUsing QTL mapping in a newly established population of 140 F1-progeny grapevine genotypes in a complete random block design, we were able to control abiotic effects and investigate how the host genome influences grape berry-associated bacterial and fungal communities. C_LIO_LIWe identify significant associations between various microorganisms and the grape genome, including pathogenic fungi such as Botrytis spp. and fermentative yeasts such as Saccharomyces cerevisiae. Many of these taxa map to the same genetic loci associated with plant immune responses, suggesting that specific genetic loci broadly influence microbial community assembly in fruits. C_LIO_LIOur findings demonstrate that grapevine genetics significantly shape the microbiome, even under varying environmental conditions; moreover, that broad, rather than known symbiont-specific mechanisms control microbial colonization of fruit, revealing an emergent "domino" effect with implications for plant-fungal-bacterial interactions. We provide a framework for understanding genotype-microbiome interactions in perennial plants, enabling future targeted experiments to establish causal relationships in microbiome recruitment and offer a potential avenue for breeding programs advancing sustainable viticulture. C_LI

microbiology↗

bioRxiv2025

The Genetic Basis of Chloride Exclusion in Grapevines

Mediterranean regions are among the most important areas for global grape production, characterized by dry climates and frequent challenges associated with soil salinity. In these environments, chloride toxicity is a major factor limiting vine growth and fruit quality. Despite the critical role of chloride exclusion in salinity tolerance, the genetic mechanisms underlying this trait remain poorly understood. In this study, we leveraged one of the largest Vitis germplasm collections, comprising 335 accessions from 18 wild and cultivated Vitis species, to characterize natural variation in chloride exclusion. This diverse panel, which includes accessions from the southwestern United States and Mexico, captures a broad range of evolutionary adaptations to abiotic stress, providing an unprecedented opportunity to investigate the genetic basis of salinity tolerance. Using genome-wide association (GWA) and quantitative trait loci (QTL) mapping, we identified a major QTL on chromosome 8 containing candidate genes encoding cation/H exchangers (CHX), which are involved in ion transport and homeostasis. To validate these findings, we analyzed a mapping population derived from V. acerifolia longii 9018 and the commercial rootstock GRN3, confirming the chromosome 8 locus as a major determinant of chloride exclusion. Structural variant analysis revealed key non-synonymous substitutions within CHX genes, suggesting potential functional roles in salinity tolerance. Additionally, we discovered a novel QTL on chromosome 19 enriched with G-type lectin S-receptor-like serine/threonine-protein kinases, known regulators of stress signaling. By integrating extensive phenotypic and genomic data across a diverse Vitis collection, this study provides novel insights into the genetic architecture of chloride exclusion and identifies valuable candidate genes for breeding salt-tolerant rootstocks.

genetics↗

bioRxiv2025

Triterpenoid CDDO-EA Protects from Hyperglycemia, Hyperinsulinemia, and Obesity by Decreasing Energy Intake

Obesity is a significant factor in the development of type 2 diabetes (T2D). Treatment of obesity is pivotal in the prevention and management of T2D, and the development of new pharmacological therapies are studied for improving insulin resistance and glucose intolerance. Oleanolic acid derived triterpenoids, 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acids (CDDOs), are studied to elucidate the mechanisms by which they protect against obesity. However, there remain fundamental gaps in knowledge regarding the physiological and molecular mechanisms by which CDDOs protect against obesity. Our recently published studies showed that CDDO-ethyl amide (CDDO-EA) prevents skeletal muscle inflammation by inhibiting activation of nuclear factor kappa B (NF-{kappa}B) signaling. Moreover, CDDO-EA induced translocation of the glucose transporter, GLUT4, in skeletal muscle cells. We hypothesized that CDDO-EA protects from obesity-induced hyperglycemia in mice fed a high fat diet (HFD). Our results show that CDDO-EA protects from HFD-induced obesity but has no effect on body weight in mice fed a low-fat diet (LFD). Our data show that CDDO-EA inhibition of weight gain is associated with reduced caloric intake and glucose and insulin levels in mice fed a HFD. This highlights the potential of CDDO-EA as a therapeutic agent for obesity treatment and the protection against the development of T2D. IMPACT STATEMENTThe significance of our studies is that they define factors affected by CDDOs to maintain energy homeostasis and improve glucose metabolism to protect against obesity-induced insulin resistance. Our work examines metabolic factors affected by CDDO-EA by demonstrating that CDDO-EA protects from weight gain, glucose intolerance, and insulin resistance. Our research adds new knowledge on the anti-obesity and anti-diabetic properties of CDDO-EA by showing that incorporation of CDDO-EA in a high fat diet prevents obesity and an increase in glucose and insulin levels in an animal model of obesity and insulin resistance. Importantly, CDDO-EA incorporated in a low-fat diet does not affect body weight and caloric intake. Given that obesity is the major risk factor in the progression to T2D, our investigation on characterizing the metabolic effects of CDDO-EA on obesity advances and facilitates the use of CDDOs as candidates for the prevention and treatment of T2D.

molecular biology↗

bioRxiv2025

Smoke exposure triggers rapid transcriptional changes and reveals glycosyltransferases linked to smoke taint in ripening grape berries

With the increasing frequency of wildfires, vineyards are more often exposed to smoke, resulting in a higher risk of smoke taint in wine. This taint imparts undesirable "smoky" and "ashy" aromas and causes significant economic losses. Smoke-derived volatile phenols (VPs) in grape berries, metabolized into stable, non-volatile glycoconjugates via glycosyltransferases (GTs), underlie smoke taint formation. Here, we present the dwarf grapevine cultivar Pixie as a model system for smoke taint research. We generated a phased, telomere-to-telomere diploid genome using HiFi long-read sequencing, along with an expression atlas spanning 30 replicated samples across various tissues and developmental stages. We also constructed a second telomere-to-telomere assembly for Pinot Noir to assess GT expression during berry ripening in the field. Controlled smoke-exposure experiments profiled GT expression and enabled transcriptome-wide analyses at multiple time points. We measured VPs in both smoke-exposed and control samples, revealing 12 GT1 genes significantly upregulated by smoke, named Vitis vinifera smoke-inducible UGTs (VviSIUGTs). Their expression peaked one day post-exposure and declined by day three, mirroring glycoside accumulation dynamics. Gene co-expression network analyses highlighted stress-responsive modules enriched in these VviSIUGTs, while transcription factor binding site analyses pinpointed stress-related regulatory elements in their promoters. These findings provide new insights into the molecular basis of smoke taint and identify potential targets for breeding and biotechnological interventions aimed at developing grapevine cultivars with reduced susceptibility to smoke damage.

plant biology↗

bioRxiv2024

Evolutionary history of the grape sex-determining region in angiosperms and emergence of dioecy in Vitaceae

Dioecy, defined by the presence of either female or male flowers on separate individual plants, is rare in angiosperms. However, it has independently evolved multiple times from hermaphroditic ancestors. In Vitis spp., flower sex is determined by a [~]200-kbp region with five genes involved in flower development and sexual identity. This study traces the evolutionary history of the Vitis sex-determining region (SDR) to assess whether it evolved in a conserved flowering-related locus. We analyzed the conservation of the Vitis SDR across 42 plant genomes and found collinearity in all 39 angiosperms, but not in non-flowering plants. The number of collinear genes and their rank-normalized gene conservation score were higher in the Vitis SDR compared to the rest of the genome, indicating its importance for flowering. We further explored SDR conservation within the Vitaceae family by long-read sequencing and haplotype phasing of eight species, including the outgroup Leea coccinea. Similarly, the Vitis SDR was highly conserved across the Vitaceae genomes, although variations in region size, primarily attributed to differences in repetitive elements, were observed. Interestingly, no recombination suppression was found in the dioecious Tetrastigma, suggesting a different sex determination mechanism. In Muscadinia rotundifolia, linkage disequilibrium analysis, haplotype comparison, and gene expression profiling showed that muscadine grapes have similar SDR boundaries and candidate sex-determining genes as Vitis. These results suggest that dioecy emerged in a common ancestor of the two grape genera at a locus associated with flower morphology and fertility, highly conserved in flowering plants.

evolutionary biology↗

bioRxiv2024

De novo whole-genome assembly and annotation of a high-quality coffee variety from the primary origin of coffee, Coffea arabica var. Geisha

Geisha coffee is recognized for its unique aromas and flavors and accordingly, has achieved the highest prices in the specialty coffee markets. We report the development of a chromosome-level, well-annotated, genome assembly of Coffea arabica var. Geisha, considered an Ethiopian landrace thatrepresents germplasm from the Ethiopian center of origin of coffee. We used a hybrid de novo assembly approach combining two long-reads single molecule sequencing technologies, Oxford Nanopore and Pacific Biosciences, together with scaffolding with Hi-C libraries. The final assembly is 1.03GB in size with BUSCO assessment of the assembly completeness of 97.7% of single-copy orthologs clusters. RNAseq and IsoSeq data were used as transcriptional experimental evidence for annotation and gene prediction revealing the presence of 47,062 gene loci encompassing 53,273 protein-coding transcripts. Comparison of the assembly to the progenitor subgenomes, separated the set of chromosome sequences inherited from C. canephora from those of C. eugenioides., Corresponding orthologs between Geisha and Red Bourbon had a 99.67% median identity, higher than what we observe with the progenitor assemblies (median 97.28%). Both, Geisha and Red Bourbon contain an inversion on Chromosome 10 relative to the pseudomolecules of the genetic material inherited from the two progenitors that must have happened before the separation in the geographical migration of the two varieties. Lending support of a single allopolyploidization event that gave origin to C. arabica after the hybridization event with the two progenitor lines. Broadening the availability of high-quality genome assemblies of Coffea arabica varieties, paves the way for understanding the evolution and domestication of coffee, as well as the genetic basis and environmental interactions of why a variety like Geisha is capable of producing beans with such exceptional and unique high-quality.

genomics↗

bioRxiv2024

Genome analysis of the esca-associated Basidiomycetes Fomitiporia mediterranea, Fomitiporia polymorpha, Inonotus vitis, and Tropicoporus texanus reveals virulence factor repertoires characteristic of white-rot fungi

Some Basidiomycete fungi are important plant pathogens, and certain species have been associated with the grapevine trunk disease esca. We present the genomes of four species associated with esca: Fomitiporia mediterranea, Fomitiporia polymorpha, Tropicoporus texanus, and Inonotus vitis. We generated high-qualityphased genome assemblies using long-read sequencing. The genomic and functional comparisons identified potential virulence factors, suggesting their roles in disease development. Similar to other white-rot fungi known for their ability to degrade lignocellulosic substrates, these four genomes encoded a variety of lignin peroxidases and carbohydrate-active enzymes (CAZymes) such as CBM1, AA9, and AA2. The analysis of gene family expansion and contraction revealed dynamic evolutionary patterns, particularly in genes related to secondary metabolite production, plant cell wall decomposition, and xenobiotic degradation. The availability of these genomes will serve as a reference for further studies of diversity and evolution of virulence factors and their roles in esca symptoms and host resistance.

genomics↗

bioRxiv2023

Comparative pangenomic insights into the distinct evolution of virulence factors among grapevine trunk pathogens

The permanent organs of grapevines (V. vinifera L.), like other woody perennials, are colonized by various unrelated pathogenic ascomycete fungi secreting cell wall-degrading enzymes and phytotoxic secondary metabolites that contribute to host damage and disease symptoms. Trunk pathogens differ in the symptoms they induce and the extent and speed of damage. Isolates of the same species often display a wide virulence range, even within the same vineyard. This study focuses on Eutypa lata, Neofusicoccum parvum, and Phaeoacremonium minimum, causal agents of Eutypa dieback, Botryosphaeria dieback, and Esca, respectively. We sequenced fifty isolates from viticulture regions worldwide and built nucleotide-level, reference-free pangenomes for each species. Through examining genomic diversity and pangenome structure, we analyzed intraspecific conservation and variability of putative virulence factors, focusing on functions under positive selection, and recent gene-family dynamics of contraction and expansion. Our findings reveal contrasting distributions of putative virulence factors in the core, dispensable, and private genomes of each pangenome. For example, CAZymes were prevalent in the core genomes of each pangenome, whereas biosynthetic gene clusters were prevalent in the dispensable genomes of E. lata and P. minimum. The dispensable fractions were also enriched in Gypsy transposable elements and virulence factors under positive selection (polyketide synthases genes in E. lata and P. minimum glycosyltransferases in N. parvum). Our findings underscore the complexity of the genomic architecture in each species and provide insights into their adaptive strategies, enhancing our understanding of the underlying mechanisms of virulence.

genomics↗

bioRxiv2023

An effector deletion leads to the breakdown of partial grapevine resistance to downy mildew

Grapevine downy mildew, caused by the oomycete Plasmopara viticola, is a globally destructive disease that particularly affect the Eurasian wine grape V. vinifera. While genetically resistant varieties are becoming more accessible, populations of P. viticola are demonstrating rapid adaptability, successfully over-coming these resistances. Here we aimed to identify the avirulence genes involved in the interaction with the Rpv3.1-mediated resistance in grapevine. We sequenced the full genome of 136 P. viticola strains sampled in a natural population of Bordeaux (France) and characterized their development on both resistant and sensitive cultivars. The genome-wide association study allowed the identification of a genomic region associated with the breakdown of Rpv3.1 grapevine resistance (avrRpv3.1 locus). A diploid-aware reassembly of the P. viticola INRA-Pv221 genome allowed to detect structural variations in this locus, including a major 30 Kbp deletion. At the avrRpv3.1 locus, virulent P. viticola strains presented deletion on both haplotypes indicating that avirulence is recessive. The deletion involves two closely-related genes that encode proteins containing 800-900 amino acids with a signal peptide. The structure of the predicted proteins contains repeats of the LWY-fold structural modules, typical of oomycete effectors. Moreover, when these proteins were transiently expressed, they induced cell death in grapevines carrying Rpv3.1 resistance, confirming their avirulence nature. The first description of candidate effectors of P. viticola involved in the interaction with resistance gene provides valuable insights into the genetic mechanisms that enable P. viticola to adapt to grapevine resistance, laying a foundation for developing strategies to manage this damaging crop pathogen.

evolutionary biology↗

bioRxiv2023

A reference-unbiased super-pangenome of the North American wild grape species (Vitis spp.) reveals genus-wide association with adaptive traits

Capturing the genetic diversity of wild relatives is crucial for improving crops because wild species are valuable sources of agronomic traits that are essential to enhance the sustainability and adaptability of domesticated cultivars. Genetic diversity across a genus can be captured in super-pangenomes, which provide a framework for interpreting genomic variations. Here we report the sequencing, assembly, and annotation of nine wild North American grape genomes, which were phased and scaffolded at chromosome scale. We generate a reference-unbiased super-pangenome using pairwise whole-genome alignment methods, revealing the extent of the genomic diversity among wild grape species from sequence to gene level. The pangenome graph captures genomic variation between haplotypes within a species and across the different species, and it accurately assesses the similarity of hybrids to their parents. The species selected to build the pangenome are a great representation of the genus, as illustrated by capturing known allelic variants in the sex-determining region and for Pierces disease resistance loci. Using pangenome-wide association analysis, we demonstrate the utility of the super-pangenome by effectively mapping short-reads from genus-wide samples and identifying loci associated with salt tolerance in natural populations of grapes. This study highlights how a reference-unbiased super-pangenome can reveal the genetic basis of adaptive traits from wild relatives and accelerate crop breeding research.

genomics↗

bioRxiv2022

The grape powdery mildew resistance loci Ren2, Ren3, Ren4D, Ren4U, Run1, Run1.2b, Run2.1, and Run2.2 activate different transcriptional responses to Erysiphe necator

Multiple grape powdery mildew (PM) genetic resistance (R) loci have been found in wild grape species. Little is known about the defense responses associated with each R locus. In this study, we compare the defense mechanisms associated with PM resistance in interspecific crosses segregating for a single R locus from Muscadinia rotundifolia (Run1, Run1.2b, Run2.1, Run2.2), Vitis cinerea (Ren2), V. romanetii (Ren4D and Ren4U), and the interspecific hybrid Villard blanc (Ren3). By combining optical microscopy, visual scoring, and biomass estimation, we show that the eight R loci confer resistance by limiting infection at different stages. We assessed the defense mechanisms triggered in response to PM at 1 and 5 days post inoculation (dpi) via RNA sequencing. To account for the genetic differences between species, we developed for each accession a diploid synthetic reference transcriptome by incorporating into the PN40024 reference homozygous and heterozygous sequence variants and de novo assembled transcripts. Most of the R loci exhibited a higher number of differentially expressed genes (DEGs) associated with PM resistance at 1 dpi compared to 5 dpi, suggesting that PM resistance is mostly associated with an early transcriptional reprogramming. Comparison of the PM resistance-associated DEGs showed a limited overlap between pairs of R loci, and nearly half of the DEGs were specific to a single R locus. The largest overlap of PM resistance-associated DEGs was found between Ren3+, Ren4D+, and Ren4U+ genotypes at 1 dpi, and between Ren4U+ and Run1+ accessions at 5 dpi. The Ren3+, Ren4D+, and Ren4U+ were also found to have the highest number of R locus-specific DEGs in response to PM. Both shared and R locus-specific DEGs included genes from different defense-related categories, indicating that the presence of E. necator triggered distinct transcriptional responses in the eight R loci.

genetics↗

bioRxiv2022

Multigenic resistance to Xylella fastidiosa in wild grapes (Vitis sps.) and its implications within a changing climate

Xylella fastidiosa is a bacterium that infects crops like grapevines, coffee, almonds, citrus and olives, causing economically devastating damage. There is, however, little understanding of the genes that contribute to resistance, the genomic architecture of resistance, and the potential role of climate in shaping resistance, in part because major crops like grapevines (V. vinifera) are not resistant to the bacterium. Here we studied a wild grapevine species, Vitis arizonica, that segregates for resistance to X. fastidiosa. Using genome-wide association, we identified candidate genes that mediate the host response to X. fastidiosa infection. We uncovered evidence that resistance requires genes from multiple genomic regions, based on data from breeding populations and from additional Vitis species. We also inferred that resistance evolved more than once in the wild, suggesting that wild Vitis species may be a rich source for resistance alleles and mechanisms. Finally, resistance in V. arizonica was climate dependent, because individuals from low (< 10{degrees}C) temperature locations in the wettest quarter were typically susceptible to infection, likely reflecting a lack of pathogen pressure in these climates. Surprisingly, climate was nearly as effective a predictor of resistance phenotypes as some genetic markers. This work underscores that pathogen pressure is likely to increase with climate, but it also provides genetic insight and tools for breeding and transforming resistant crops.

genetics↗

bioRxiv2022

HiFi chromosome-scale diploid assemblies of the grape rootstocks 110R, Kober 5BB, and 101-14 Mgt

Cultivated grapevines are commonly grafted on closely related species to cope with specific biotic and abiotic stress conditions. The three North American Vitis species V. riparia, V. rupestris, and V. berlandieri, are the main species used for breeding grape rootstocks. Here, we report the diploid chromosome-scale assembly of three widely used rootstocks derived from these species: Richter 110 (110R), Kober 5BB, and 101-14 Millardet et de Grasset (Mgt). Draft genomes of the three hybrids were assembled using PacBio HiFi sequences at an average coverage of 53.1 X-fold. Using the tool suite HaploSync, we reconstructed the two sets of nineteen chromosome-scale pseudomolecules for each genome with an average haploid genome size of 494.5 Mbp. Residual haplotype switches were resolved using shared-haplotype information. These three reference genomes represent a valuable resource for studying the genetic basis of grape adaption to biotic and abiotic stresses, and designing trait-associated markers for rootstock breeding programs.

genomics↗

bioRxiv2022

Botrytis cinerea infection accelerates ripening and cell wall disassembly to promote disease in tomato fruit

Postharvest fungal pathogens benefit from the increased host susceptibility that occurs during fruit ripening. In unripe fruit, pathogens often remain quiescent and unable to cause disease until ripening begins, emerging at this point into destructive necrotrophic lifestyles that quickly result in fruit decay. Here, we demonstrate that one such pathogen, Botrytis cinerea, actively induces ripening processes to facilitate infections and promote disease. Assessments of ripening progression revealed that B. cinerea accelerated external coloration, ethylene production, and softening in unripe fruit, while mRNA sequencing of inoculated unripe fruit confirmed the corresponding upregulation of host genes involved in ripening processes, such as ethylene biosynthesis and cell wall degradation. Furthermore, an ELISA-based glycomics technique to assess fruit cell wall polysaccharides revealed remarkable similarities in the cell wall polysaccharide changes caused by both infections of unripe fruit and ripening of healthy fruit, particularly in the increased accessibility of pectic polysaccharides. Virulence and additional ripening assessment experiments with B. cinerea knockout mutants showed that induction of ripening is dependent on the ability to infect the host and break down pectin. The B. cinerea double knockout{Delta} bcpg1{Delta}bcpg2 lacking two critical pectin degrading enzymes was found to be incapable of emerging from quiescence even long after the fruit had ripened at its own pace, suggesting that the failure to accelerate ripening severely inhibits fungal survival on unripe fruit. These findings demonstrate that active induction of ripening in unripe tomato fruit is an important infection strategy for B. cinerea. One-Sentence SummaryPhysiological, transcriptional, and glycomic evidence indicates Botrytis cinerea hastens tomato fruit ripening to facilitate infection by a mechanism dependent on the fungal enzymes Bcpg1 and Bcpg2.

plant biology↗

bioRxiv2022

Insights into the domestication of avocado and potential genetic contributors to heterodichogamy

O_LIThe domestication history of avocado (Persea americana) remains unclear, in part due to a lack of suitable genomic tools. C_LIO_LIWe created a reference genome from the Gwen varietal, which is closely related to the economically dominant Hass varietal. We also compiled a database of 34 resequenced accessions that represented the three botanical races of P. americana. C_LIO_LIOur genome assembly had an N50 of 3.37 megabases, a BUSCO score of 91% and was scaffolded with a genetic map, producing 12 pseudo-chromosomes with 49,450 genes. We used the Gwen genome as a reference to investigate the population genomics of avocado. Our analyses were consistent with three separate domestication events; we estimated that the Mexican race diverged from the Lowland (formerly known as West Indian) and Guatemalan races >1 million years ago. We also identified putative targets of selective sweeps in domestication events; within the Guatemalan race, putative candidate genes were enriched for fruit development and ripening. We also investigated divergence between heterodichogamous flowering types. C_LIO_LIWith the help of a new reference genome, we inferred the domestication history of avocado and identified genes that may contribute to heterodichogamy, including genes with functions in pollination and floral development. C_LI

genomics↗

bioRxiv2021

The grape MYB24 mediates the coordination of light-induced terpene and flavonol accumulation in response to berry anthocyanin sunscreen depletion

The presence of naturally-occurring color mutants in plants has permitted the identification of many regulatory genes implicated in the synthesis of discrete metabolic compounds, mostly anthocyanins and carotenoids. Conversely, transcription factors that coordinate more than one specialized metabolic pathway seem challenging to screen from a forward genetics perspective. We explored the relationship between different branches of the phenylpropanoid and isoprenoid pathways while examining an infrequent berry skin color variegation in grapevine. Red and white berry skin sections were compared at the genetic, transcriptomic and metabolomic levels showing that, as in most cultivated white grape varieties, the uncolored skin section convened the non-functional alleles of the anthocyanin regulators MYBA1 and MYBA2, explaining the lack of pigments. In contrast, light-responsive flavonols and monoterpenes increased in anthocyanin-depleted areas. We disclosed an enrichment of the flavonol, terpene and carotenoid pathways among up-regulated genes from white-skin sections, accompanied by increased expressions of flavonol regulators and the still uncharacterized MYB24 gene. We used DAP-seq to examine the in vitro binding of affinity-purified MYB24 protein to genomic DNA and demonstrated its binding in the promoter regions of terpene (22) and carotenoid (6) genes, in addition to more than 30 photosynthesis and light-response genes, including the flavonol-regulator HY5 homologue (HYH). We confirmed the activation of TPS35 and HYH promoter:luciferase reporters in the presence of MYB24 and the grape bHLH MYC2, all of which correlate in their higher expression in white skin variegated sections. The integration of several datasets allowed to define a list of high confidence targets, suggesting MYB24 as a modulator of light responses including the synthesis of flavonoids (flavonols) and isoprenoids (terpenes, and putatively carotenoids). The correspondence between MYB24 and monoterpenes in all conditions surveyed implies that this regulatory network is broadly triggered towards berry ripening, and that the absence of anthocyanin sunscreens accelerates its activation most likely in a dose-dependent manner due to increased radiation exposure.

plant biology↗