Geminiviridae and Alphasatellitidae Diversity Revealed by Metagenomic Analysis of Susceptible and Tolerant Tomato Cultivars across Distinct Brazilian Biomes.

The diversity of Geminiviridae and Alphasatellitidae species in tomatoes was assessed via high-throughput sequencing of 154 symptomatic foliar samples collected from 2002 to 2017 across seven Brazilian biomes. The first pool (BP1) comprised 73 samples from the North (13), Northeast (36), and South (24) regions. Sixteen begomoviruses and one Topilevirus were detected in BP1. Four begomovirus-like contigs were identified as putative novel species (NS). NS#1 was reported in the semi-arid (Northeast) region and NS#2 and NS#4 in mild subtropical climates (South region), whereas NS#3 was detected in the warm and humid (North) region. The second pool (BP2) comprised 81 samples from Southeast (39) and Central-West (42) regions. Fourteen viruses and subviral agents were detected in BP2, including two topileviruses, a putative novel begomovirus (NS#5), and two alphasatellites occurring in continental highland areas. The five putative novel begomoviruses displayed strict endemic distributions. Conversely, tomato mottle leaf curl virus (a monopartite species) displayed the most widespread distribution occurring across the seven sampled biomes. The overall diversity and frequency of mixed infections were higher in susceptible (16 viruses + alphasatellites) in comparison to tolerant (carrying the Ty-1 or Ty-3 introgressions) samples, which displayed 9 viruses. This complex panorama reinforces the notion that the tomato-associated Geminiviridae diversity is yet underestimated in Neotropical regions.

Novel plant-associated genomoviruses from the Brazilian Cerrado biome.

The discovery rate of new plant viruses has increased due to studies involving high-throughput sequencing (HTS), particularly for single-stranded DNA viruses of the family Genomoviridae. We carried out an HTS-based survey of genomoviruses in a wide range of native and exotic trees grown in the Brazilian Cerrado biome, and the complete genome sequences of two novel members of the family Genomoviridae from two distinct genera were determined. Specific primers were designed to detect these genomoviruses in individual samples. A new gemykolovirus (Tecoma stans associated gemykolovirus) was detected in Tecoma stans, and a new gemykibivirus (Ouratea duparquetiana associated gemykibivirus) was detected in Ouratea duparquetiana. A gemykrogvirus related to Gila monster associated gemykrogvirus (80% pairwise identity) was also detected in foliar samples of Trembleya parviflora. Our pilot study paves the way for a better characterization of this diverse collection of genomoviruses as well as their interactions with the associated tree species.

Tomato golden net virus and tomato yellow net virus: two novel New World begomoviruses with monopartite genomes.

Two novel tomato-infecting begomoviruses were discovered via high-throughput sequencing in Brazil. Both viruses were also Sanger-sequenced and displayed DNA-A components phylogenetically related to New World bipartite begomoviruses. The names tomato golden net virus (ToGNV) and tomato yellow net virus (ToYNV) were proposed. The majority of the New World begomoviruses has bipartite genomes. However, extensive analyses revealed that ToGNV and ToYNV have monopartite genomes, because no cognate DNA-B components were detected. Hence, they may comprise a unique group of monopartite New World begomoviruses, which have enormous biological, molecular, and plant breeding interest.

Confirmation of Groundnut ringspot orthotospovirus (GRSV) Infection in Eggplant Cultivars in Brazil.

Eggplant (Solanum melongena L.) is an economically important vegetable crop in Brazil, especially in family-based farming. Eggplant hybrids 'Ciça' and 'Napoli' (≈ 400 plants) were detected exhibiting virus-like symptoms (5-20% incidence) in field surveys (2015-2018) in Brasília-DF (Figure 1). Symptoms included chlorosis, mosaic and apical leaf deformation. Six symptomatic leaf samples were collected from fruit-bearing plants (around 100 days after planting) aiming at verifying the potential orthotospovirus infection. Double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was carried out with polyclonal antibodies (produced at Centro Nacional de Pesquisa de Hortaliças - CNPH) against the N gene coat protein of the three major orthotospoviruses: tomato spotted wilt orthotospovirus (TSWV), groundnut ringspot orthotospovirus (GRSV) and, tomato chlorotic spot orthotospovirus (TCSV). Strong serological reactions were observed only against GRSV antibodies in the extracts from symptomatic samples, but not in the controls. To confirm the causal agent of those symptoms, total RNA was extracted from infected leaf samples via the standard Trizol® (Sigma) protocol and subsequently used in a two-step reverse transcriptase polymerase chain reaction (RT-PCR) approach. Synthesis of the cDNA was carried out with the J13 primer (5'-CCC GGA TCC AGA GCA AT-3') (Cortez et al., 2001) followed by PCR assays with the primer pair BR60 (5'-AGA GCA ATC GTG TCA-3`) and BR65 (5`-ATC AAG CCT TCT GAA AGT CAT-3') (Eiras et al., 2002). This primer set amplifies a fragment of 453 bp including the 3' untranslated region at the 3' terminus of the S RNA and the protein N-coding gene of at least five species: TSWV, GRSV, TCSV, chrysanthemum stem necrosis orthotospovirus (CSNV) and zucchini lethal chlorosis orthotospovirus (ZLCV). In addition, GRSV-specific primers (LNA Reis, unpublished) were used for amplification of all three segments: L segment: LF/LR (5'-AAC AGG ATT CAG CAA TAT GG-3'/ 5'-AAT TCC TTG AAG ACA ATT GTG T -3'); M segment: MF/MR (5'-TTT GTC CAA CCA TAC CAG ACC C- 3' / 5'-GGC TTC AAT AAA GGC TTG GG-3') and, S segment: SF/SR (5'-TTC AAA CTC AGT TGT ACT CTG A-3'/5'-TTA CTT TCG ATC TGG TTG AA- 3'). Amplicons with 509 bp (MT043204), 289 bp (MT043205), and 901 bp (MT043203) were obtained for L, M and S segments of the eggplant isolate DF-687. PCR amplicons corresponding to a segment of the N-coding gene (396 bp) of a second eggplant isolate (BJL02; MK176337) were obtained with the primer pair BR60/BR65 and subjected to Sanger dideoxy sequencing at CNPH. Alignments of nucleotide sequences of both isolates revealed identity levels varying around 99% to the corresponding genomic regions of a large set of GRSV isolates from GenBank database. PCR assays using total RNA as template yielded 494 bp amplicons solely with GRSV-specific primers (Webster et al., 2011), but no products were obtained with TSWV-specific primers (Adkins and Rosskopf, 2002), confirming the former as the sole causal agent of the field symptoms. Leaves of eggplant cv. 'Ciça' and indicator hosts, including Nicotiana rustica, Capsicum chinense 'PI 159236' (with the Tsw gene), and S. lycopersicum cv. Santa Clara were rub inoculated with extracts prepared from eggplant samples naturally infected with GRSV. Mosaic, necrotic ringspots and systemic leaf deformation symptoms were observed around ten days after inoculation on newly emerged leaves of all inoculated plants. GRSV infection was confirmed by DAS-ELISA and RT-PCR ten days after inoculation. Eggplant was erroneously listed as a host of GRSV in Brazil (Kitajima, 2020). Hence, this is the first report of eggplant infection by this virus in South America. No significant yield losses have been observed in eggplant due to GRSV infection since the overall symptoms are often mild. However, this natural host of GRSV might impact disease management strategies since eggplant is quite often cultivated under family-based farming conditions as a companion crop of highly susceptible tomato, sweet-pepper, and lettuce cultivars. References: Adkins, S., and Rosskopf, E. N. 2002. Plant Dis. 86: 1310. Cortez, I., et al. 2001. Arch. Virol. 146:265. Eiras, M. et al., 2002. Fitopatol. Bras. 27:285. Kitajima, E.W. 2020. Biota Neotrop. 20: e2019932. Webster, C. G., et al. 2011. Virology 413: 216.

Complete genome sequence of a novel bipartite begomovirus infecting the legume weed Macroptilium erythroloma.

The natural occurrence of mixed infections and large populations of the polyphagous vector (Bemisia tabaci) are the main factors associated with the intensification of the genetic flow among begomoviruses in Neotropical areas, contributing to the emergence of novel recombinants. Here, high-throughput sequencing and metagenomic analyses were employed to discover and characterize a novel recombinant bipartite begomovirus, tentatively named "macroptilium bright yellow interveinal virus" (MaBYIV) in the weed Macroptilium erythroloma (Fabaceae). Recombination signals were detected in MaBYIV, involving bean golden mosaic virus (BGMV) and tomato mottle leaf curl virus (ToMoLCV) genome components. All of the original MaBYIV-infected M. erythroloma plants were found to have mixed infections with BGMV. MaBYIV was transmitted to bean and soybean cultivars via B. tabaci MEAM 1, indicating that M. erythroloma may play a role as a year-round reservoir of a potential new viral pathogen of economically important legume crops.

New genus of trichomatous coelomycete on Myrcia fenzliana from the Brazilian Cerrado.

Megacoelomyces (type species: Megacoelomyces sanchezii), an ascomycete asexual morph infecting Myrcia fenzliana (Myrtaceae) from the Brazilian Cerrado, is described as a new genus in the Phaeosphaeriaceae (Pleosporales, Dothideomycetes, Ascomycota), based on multilocus phylogeny (three nuclear ribosomal DNA and two protein-coding genes) in addition to morphological (light and scanning electron microscopy) and ecological data.

Tomato yellow vein streak virus and Tomato golden vein virus: a reappraisal of the classification status of two South American Begomovirus species based upon genome-wide pairwise identity of multiple isolates.

Tomato yellow vein streak virus (ToYVSV) and tomato golden vein virus (TGVV) are begomoviruses reported infecting tomatoes and other hosts across South America. However, their close phylogenetic relationship has generated uncertainties about their taxonomic status and nomenclature. In fact, genomic DNA-A identity levels of isolates reported with an identical virus name may range from 89-100%. In view of the potential inaccuracy regarding the classification status of these viruses (strains vs. distinct species), we carried out a comprehensive set of analyses employing all 45 available isolates with complete DNA-A sequences with either ToYVSV or TGVV designation. Two clear-cut clusters were identified and they were consistent with the current criteria for Begomovirus species demarcation. Moreover, our reappraisal confirmed a large array of misnamed isolates and recognized a distinctive set of virus species-specific genomic, biological, and ecological features. Hence, the present work gives support to the notion that these viruses are closely-related, but they are distinct and valid Begomovirus species. From the breeding standpoint, this information will be useful in guiding germplasm screening strategies searching for sources of large-spectrum resistance to isolates of both viruses.

Diversity of tomato-infecting begomoviruses and spatiotemporal dynamics of an endemic viral species of the Brazilian Atlantic rain forest biome.

Yield losses induced by a complex of begomoviruses are observed across all major tomato-producing areas in Brazil. Tomato severe rugose virus (ToSRV) is the most widespread begomovirus in the country. Conversely, tomato common mosaic virus (ToCmMV) displays a more restricted geographical distribution to areas associated with the Atlantic Rain Forest (ARF) biome, encompassing the States of Espírito Santo-ES, Minas Gerais-MG, and Rio de Janeiro-RJ. Here, we characterized 277 tomato-infecting isolates collected in fields located within the ARF biome from 2006 to 2018. ToSRV displayed the highest prevalence (n = 157), followed by ToCmMV (n = 95) and tomato interveinal chlorosis virus (n = 14). Four other begomoviruses were also detected, but with very low incidences. ToCmMV was the predominant begomovirus in the ARF biome up to 2014-2015 with very low ToSRV incidence. Subsequently, ToSRV became the most prevalent species in ES and RJ, but ToCmMV was still predominating in the "Zona da Mata" meso-region in MG. Due to the remarkable endemic distribution of ToCmMV, we carried out phylogeographical studies of this virus using information from all 28 available isolates with complete DNA-A sequences. The closest common ancestor of ToCmMV was more likely originated around Coimbra-MG area ≈ 25 years before the formal report of this viral species. So far, all surveys indicated tomatoes as the only natural hosts of ToCmMV with outbreaks occurring mainly (but not exclusively) in highland areas. ToSRV shows a more widespread incidence across both highland and lowland areas of the ARF biome.

Molecular Characterization of Hovenia Dulcis-Associated Virus 1 (HDaV1) and 2 (HDaV2): New Tentative Species within the Order Picornavirales.

In a systematic field survey for plant-infecting viruses, leaf tissues were collected from trees showing virus-like symptoms in Brazil. After viral enrichment, total RNA was extracted and sequenced using the MiSeq platform (Illumina). Two nearly full-length picorna-like genomes of 9534 and 8158 nucleotides were found associated with Hovenia dulcis (Rhamnaceae family). Based upon their genomic information, specific primers were synthetized and used in RT-PCR assays to identify plants hosting the viral sequences. The larger contig was tentatively named as Hovenia dulcis-associated virus 1 (HDaV1), and it exhibited low nucleotide and amino acid identities with Picornavirales species. The smaller contig was related to insect-associated members of the Dicistroviridae family but exhibited a distinct genome organization with three non-overlapping open reading frames (ORFs), and it was tentatively named as Hovenia dulcis-associated virus 2 (HDaV2). Phylogenetic analysis using the amino acid sequence of RNA-dependent RNA polymerase (RdRp) revealed that HDaV1 and HDaV2 clustered in distinct groups, and both viruses were tentatively assigned as new members of the order Picornavirales. HDaV2 was assigned as a novel species in the Dicistroviridae family. The 5' ends of both viruses are incomplete. In addition, a nucleotide composition analysis (NCA) revealed that HDaV1 and HDaV2 have similarities with invertebrate-infecting viruses, suggesting that the primary host(s) of these novel virus species remains to be discovered.

Transmission of the Bean-Associated Cytorhabdovirus by the Whitefly Bemisia tabaci MEAM1.

The knowledge of genomic data of new plant viruses is increasing exponentially; however, some aspects of their biology, such as vectors and host range, remain mostly unknown. This information is crucial for the understanding of virus-plant interactions, control strategies, and mechanisms to prevent outbreaks. Typically, rhabdoviruses infect monocot and dicot plants and are vectored in nature by hemipteran sap-sucking insects, including aphids, leafhoppers, and planthoppers. However, several strains of a potentially whitefly-transmitted virus, papaya cytorhabdovirus, were recently described: (i) bean-associated cytorhabdovirus (BaCV) in Brazil, (ii) papaya virus E (PpVE) in Ecuador, and (iii) citrus-associated rhabdovirus (CiaRV) in China. Here, we examine the potential of the Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) to transmit BaCV, its morphological and cytopathological characteristics, and assess the incidence of BaCV across bean producing areas in Brazil. Our results show that BaCV is efficiently transmitted, in experimental conditions, by B. tabaci MEAM1 to bean cultivars, and with lower efficiency to cowpea and soybean. Moreover, we detected BaCV RNA in viruliferous whiteflies but we were unable to visualize viral particles or viroplasm in the whitefly tissues. BaCV could not be singly isolated for pathogenicity tests, identification of the induced symptoms, and the transmission assay. BaCV was detected in five out of the seven states in Brazil included in our study, suggesting that it is widely distributed throughout bean producing areas in the country. This is the first report of a whitefly-transmitted rhabdovirus.

Natural Infection of Tomatoes (Solanum lycopersicum) by Euphorbia yellow mosaic virus Isolates across Four Brazilian States.

Severe yield losses induced by a complex of whitefly-transmitted Begomovirus species (family Geminiviridae) have been reported in tomatoes in Brazil (Reis et al. 2020). Nine isolates were obtained from tomato plants exhibiting begomovirus-like symptoms (viz. apical and interveinal chlorosis, yellow spots, and stunting) during independent field surveys: one isolate in Sumaré, São Paulo-SP State (isolate SP-066) in 2001, two in Serra Negra, Minas Gerais-MG (MG-012 and MG-016) in 2002, five in Caxias do Sul, Rio Grande do Sul-RS (RS-039, RS-045, RS-046, RS-047 and RS-058) in 2011 and one in Domingos Martins, Espírito Santo-ES (ES-148) in 2016. Disease incidence across all sampled fields ranged from 30% (in Domingos Martins-ES) to 90% in Sumaré-SP. Total DNA extraction was done by a modified CTAB method (Boiteux et al., 1999). Begomovirus infection was confirmed in all isolates by selective amplification of viral DNA-A segments using the primer pairs 'PAL1v1978 / PAR1c496' (Rojas et al., 1993) and 'BegomoAFor1' / 'BegomoARev1' (Ha et al., 2006), which produce two large and non-overlapping segments (≈1120 bp and ≈1205 bp, respectively). These PCR amplicons were initially characterized via direct Sanger dideoxy sequencing at CNPH. BLASTn analysis of the partial DNA-A genomes of these nine isolates indicated identity levels of 95-97% to three euphorbia yellow mosaic virus (EuYMV) reference isolates (= KY559532, JF756674, and KY559583) found infecting the weed Euphorbia heterophylla L. The entire DNA-A (2,609 nts = MN746971) and DNA-B (2,579 nts = MN746970) components of the MG-016 isolate were obtained via high-performance sequencing using Illumina HiSeq 2500 system (Macrogen Inc., South Korea). Sequences were assembled with the CLC Genomics Workbench program 10. Contigs were validated by BLASTx and BLASTn and compared to the ssDNA virus database at NCBI (www.ncbi.nlm.nih.gov). The fully-characterized MG-016 isolate displayed identity levels ranging from 97 to 99% to the EuYMV reference isolates as well as similar genomic features such as the conserved TATA box, nonanucleotide, and iterons (that were in agreement with a cognate nature of the DNA-A and DNA-B components). A partial sequence of the DNA-B genome was also obtained for the MG-012 isolate (MT7831942). The isolates MG-012 and MG-016 were found in mixed infections with tomato severe rugose virus (ToSRV) and tomato golden vein virus (TGVV), respectively. In addition, the complete DNA-A genomes of ES-148 (MN746972) and SP-066 (MN782438) were also obtained via a combination of primer walking and Sanger dideoxy sequencing, displaying 96-98% identity to EuYMV isolates. To our knowledge, this is the first report of multiple and independent events of natural infection of tomatoes by EuYMV isolates. Our results confirm the natural host status of tomatoes to EuYMV isolates as indicated in previous infectivity assays using biolistic inoculation (Barreto et al., 2013). The weed E. heterophylla is widely disseminated and very often present within tomato fields due to its higher levels of tolerance to the major herbicide (metribuzin) employed in this crop. Therefore, this weed may act as a persistent reservoir of tomato-infecting EuYMV isolates, which may allow the selection of viral populations potentially more adapted to this vegetable crop.

Metagenomics of Neotropical Single-Stranded DNA Viruses in Tomato Cultivars with and without the Ty-1 Gene.

A complex of begomoviruses (Geminiviridae) can cause severe tomato yield losses in the neotropics. Here, next-generation sequencing was employed for large-scale assessment of single-stranded (ss)DNA virus diversity in tomatoes either harboring or lacking the large-spectrum begomovirus tolerance Ty-1 gene. Individual leaf samples exhibiting begomovirus-like symptoms (n = 107) were field-collected, circular DNA-enriched, subdivided into pools (with and without Ty-1), and Illumina-sequenced. Virus-specific PCR and Sanger dideoxy sequencing validations confirmed 15 distinct ssDNA virus/subviral agents (occurring mainly in mixed infections), which highlight the potential drawbacks of employing virus-specific resistance in tomato breeding. More viruses (14 versus 6 species) were observed in tomatoes without the Ty-1 gene. A gemycircularvirus (Genomoviridae), a new alpha-satellite, and two novel Begomovirus species were identified exclusively in samples without the Ty-1 gene. A novel begomovirus was found only in the Ty-1 pool, being the only species associated with severe symptoms in Ty-1 plants in our survey. Our work is the first step towards the elucidation of the potential begomovirus adaptation to Ty-1 and its specific filtering effects on a subset of ssDNA viral/subviral agents.

An isolate of sweet potato chlorotic stunt virus from Brazil with a distinct genome organization.

Sweet potato chlorotic stunt virus (SPCSV; genus Crinivirus, family Closteroviridae), is an economically important pathogen of sweet potato. In the present work, the nucleotide sequences of two RNA segments of SPCSV (isolate SPCSV-UNB-01) were determined by MiSeq Illumina sequencing of samples of sweet potato plants grafted onto Ipomoea setosa. A comparative analysis of the genome organization of SPCSV-UNB-01 and other SPCSV sequences showed that RNA1 was lacking p22, and p5.1 and that p5.2. was absent in RNA2, indicating a unique genomic pattern. SPCSV-UNB-01 contained longer p6 and p5 regions, with little similarity to orthologous sequences. Sequence comparison did not reveal any previously identified functional domains within these open reading frames (ORFs). No recombination or rearrangement events were detected. Phylogenetic analysis suggested the possibility of separate entries of SPCSV into South America based on the genetic distance between SPCSV-UNB-01 and the Peruvian isolate m2-47. Samples from northeastern Brazil (State of Pernambuco) were positive for SPCSV when tested using specific primers for the major coat protein (CP) gene. This is the first full-length genome sequence of SPCSV-UNB-01 from Brazil.

Nanopore sequencing of a novel bipartite New World begomovirus infecting cowpea.

A new bipartite begomovirus (family Geminiviridae) was detected on cowpea (Vigna unguiculata) plants exhibiting bright golden mosaic symptoms on leaves under field conditions in Brazil. Complete consensus sequences of DNA-A and DNA-B components of an isolate of the virus (PE-088) were obtained by nanopore sequencing and confirmed by Sanger sequencing. The genome components presented the typical genomic organization of New World (NW) begomoviruses. Pairwise sequence comparisons revealed low levels of identity with other begomovirus species previously reported infecting cowpea around the world. Phylogenetic analysis using complete sequences of DNA-A components revealed that the closest relatives of PE-088 (85-87% nucleotide sequence identities) were three legume-infecting begomoviruses from Brazil: bean golden mosaic virus, macroptilium common mosaic virus and macroptilium yellow vein virus. According to the current classification criteria, PE-088 represents a new species in the genus Begomovirus, tentatively named as cowpea bright yellow mosaic virus (CoBYMV).

Complete Genome Sequences of Sweet potato feathery mottle virus and Sweet potato virus G from Brazil.

In Brazil, Potyvirus species in sweet potatoes have been detected mostly by serology. Here, we report the complete genome sequences of two Potyvirus species, Sweet potato feathery mottle virus strain (SPFMV-UNB-01) and Sweet potato virus G strain (SPVG-UNB-01).

Exosomes secreted by cardiomyocytes subjected to ischaemia promote cardiac angiogenesis.

AIMS: Myocardial infarction (MI) is the leading cause of morbidity and mortality worldwide and results from an obstruction in the blood supply to a region of the heart. In an attempt to replenish oxygen and nutrients to the deprived area, affected cells release signals to promote the development of new vessels and confer protection against MI. However, the mechanisms underlying the growth of new vessels in an ischaemic scenario remain poorly understood. Here, we show that cardiomyocytes subjected to ischaemia release exosomes that elicit an angiogenic response of endothelial cells (ECs). METHODS AND RESULTS: Exosomes secreted by H9c2 myocardial cells and primary cardiomyocytes, cultured either in control or ischaemic conditions were isolated and added to ECs. We show that ischaemic exosomes, in comparison with control exosomes, confer protection against oxidative-induced lesion, promote proliferation, and sprouting of ECs, stimulate the formation of capillary-like structures and strengthen adhesion complexes and barrier properties. Moreover, ischaemic exosomes display higher levels of metalloproteases (MMP) and promote the secretion of MMP by ECs. We demonstrate that miR-222 and miR-143, the relatively most abundant miRs in ischaemic exosomes, partially recapitulate the angiogenic effect of exosomes. Additionally, we show that ischaemic exosomes stimulate the formation of new functional vessels in vivo using in ovo and Matrigel plug assays. Finally, we demonstrate that intramyocardial delivery of ischaemic exosomes improves neovascularization following MI. CONCLUSIONS: This study establishes that exosomes secreted by cardiomyocytes under ischaemic conditions promote heart angiogenesis, which may pave the way towards the development of add-on therapies to enhance myocardial blood supply.

Recessive Resistance Derived from Tomato cv. Tyking-Limits Drastically the Spread of Tomato Yellow Leaf Curl Virus.

The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread.

An overlooked source of fungal diversity: novel hyphomycete genera on trichomes of cerrado plants.

Eight monotypic hyphomycete genera new to science are described from the trichomes of native plants growing in the cerrado of Brazil: Trichomatoclava cerradensis, Echinoconidiophorum cerradense, Globoconidiopsis cerradensis, Globoconidium cerradense, Helminthosporiomyces cerradensis, Trichomatosphaera [corrected] cerradensis , Phragmoconidium cerradense, and Vesiculohyphomyces cerradensis gens. spp. nov. Two of the new genera were found on hosts belonging in Myrtaceae, and one of each of the following families: Icacinaceae, Malphigiaceae, Fabaceae, Dilleniaceae, Chrysobalanaceae, and Caryocaraceae. These discoveries suggest that the trichomes of neotropical plants are an unexplored source of novel fungal diversity, and merit more attention in biodiversity surveys.

New Stenella and Parastenella species from the Brazilian cerrado.

Five new Stenella species were found on native cerrado plants. Stenella erythroxyli-campestris, S. erythroxyli-suberosi and S. erythroxylicola were associated with plant species belonging in the family Erythroxylaceae; S. cyrtopodii was found infecting the rare Cyrtopodium eugenii (Orchidaceae), and S. ocoteae occurred on Ocotea sp. (Lauraceae). Finally Parastenella callisthenis-fasciculatae was collected on a Vochysiaceae (viz. Callisthene fasciculate) endemic to the cerrado.