Linkage mapping of candidate genes for induced resistance and growth promotion by trichoderma koningiopsis (th003) in tomato solanum lycopersicum

Induced systemic resistance (ISR) is a mechanism by which plants enhance defenses against any stress condition. ISR and growth promotion are enhanced when tomato (Solanum lycopersicum) is inoculated with several strains of Trichoderma ssp. This study aims to genetically map tomato candidate genes involved in ISR and growth promotion induced by the Colombian native isolate Trichoderma koningiopsis Th003. Forty-nine candidate genes previously identified on tomato plants treated with Th003 and T. hamatum T382 strains were evaluated for polymorphisms and 16 of them were integrated on the highly saturated genetic linkage map named “TOMATO EXPEN 2000”. The location of six unigenes was similar to the location of resistance gene analogs (RGAs), defense related ESTs and resistance QTLs previously reported, suggesting new possible candidates for these quantitative trait loci (QTL) regions. The candidate gene-markers may be used for future ISR or growth promotion assisted selection in tomato

Development and Characterization of Microsatellite Markers for the Cape Gooseberry Physalis peruviana

Physalis peruviana, commonly known as Cape gooseberry, is an Andean Solanaceae fruit with high nutritional value and interesting medicinal properties. In the present study we report the development and characterization of microsatellite loci from a P. peruviana commercial Colombian genotype. We identified 932 imperfect and 201 perfect Simple Sequence Repeats (SSR) loci in untranslated regions (UTRs) and 304 imperfect and 83 perfect SSR loci in coding regions from the assembled Physalis peruviana leaf transcriptome. The UTR SSR loci were used for the development of 162 primers for amplification. The efficiency of these primers was tested via PCR in a panel of seven P. peruviana accessions including Colombia, Kenya and Ecuador ecotypes and one closely related species Physalis floridana. We obtained an amplification rate of 83% and a polymorphic rate of 22%. Here we report the first P. peruviana specific microsatellite set, a valuable tool for a wide variety of applications, including functional diversity, conservation and improvement of the species

Fungal phytopathogens encode functional homologues of plant rapid alkalinisation factor (RALF) peptides

In this paper we describe the presence of genes encoding close homologues of an endogenous plant peptide, rapid alkalinisation factor (RALF), within the genomes of 26 species of phytopathogenic fungi. Members of the RALF family are key growth factors in plants, and the sequence of the RALF active region is well conserved between the plant and fungal proteins. RALF1-like sequences were observed in most cases; however, RALF27-like sequences were present in the Sphaerulina musiva and Septoria populicola genomes. These two species are pathogens of poplar and interestingly, the closest relative to their respective RALF genes is a poplar RALF27-like sequence. RALF peptides control cellular expansion during plant development, but were originally defined based on their ability to induce rapid alkalinisation in tobacco cell cultures. To test whether the fungal RALF peptides were biologically active in plants, we synthesized RALF peptides corresponding to those encoded by two sequenced genomes of the tomato pathogen Fusarium oxysporum f. sp. lycopersici. One of these peptides inhibited the growth of tomato seedlings and elicited responses in tomato and Nicotiana benthamiana typical of endogenous plant RALF peptides (ROS burst, induced alkalinisation and MAP kinas activation). Gene expression analysis confirmed that a RALF-encoding gene in Fusarium oxysporum f. sp. lycopersici was expressed during infection on tomato. However a subsequent reverse genetics approach revealed that the RALF peptide was not required by Fusarium oxysporum f. sp. lycopersici for infection on tomato roots. This study has demonstrated the presence of functionally active RALF peptides encoded within phytopathogens that harbour an as yet undetermined role in the plant-pathogen interactions. This article is protected by copyright. All rights reserved.The authors would like to thank Dr Markus Albert for technical advice on the alkalinization assay. PSS is an Australian Research Council Future Fellow (FT110100698). BS is supported by an Australian Research Council Discovery Early Career Award (DE150101897). ET is supported by an Australian Postgraduate Award and a Grains Research and Development Corporation Scholarship

Analysis of Fusarium oxysporum effectors shared between strains that infect cape gooseberry and tomato

Physalis peruviana, known as cape gooseberry, is a solanaceous plant native to tropical South America, typically growing in the Andes at 2000 m. Its economic value has grown due to its nutritional and medicinal properties. However, a vascular wilt disease caused by a newly discovered forma specialis of Fusarium oxysporum, (here designated f. sp. physali [Foph]), has become one of the limiting factors in cape gooseberry production, with losses up to 90%. The F. oxysporum species complex incudes numerous formae speciales (special forms), which are the causal agents of vascular wilt disease in a broad range of plants, including economically important crops such as banana, cotton, melon, tomato and recently, cape gooseberry. F. oxysporum f. sp. lycopersici (Fol) causes wilt disease on tomato. At least fourteen small secreted in xylem (SIX) proteins have been identified from the xylem sap of Fol-infected tomato plants. Five are associated with virulence and three are recognised by resistance proteins in the host. However, the function of most of these SIX proteins remains unclear. In this project, six homologues of Fol SIX genes (SIX1a, SIX1b, SIX7, SIX10, SIX12 and SIX15) and a homologue of Ave1 (an avirulence gene present in the broad-host-range wilt-pathogen Verticillium dahliae, with homologues in many other phytopathogens including Fol), were identified in Foph. These and other candidate effector genes were identified by mapping Foph RNAseq data against the Fol lineage-specific transcriptome and candidate F. oxysporum effector genes identified in other formae speciales in other studies. The Foph SIX gene and Ave1 homologues were found to encode proteins with 70 to 100% identity to their Fol counterparts, with the latter suggesting recent horizontal transfer of a cluster of SIX genes comprising SIX7, SIX10, SIX12 and SIX15. The Foph SIX1a and SIX1b proteins are 74% and 80% identical, respectively, to their Fol counterpart. Both homologues were tested in a ΔSIX1 strain of Fol to see if they could complement the virulence function of Fol SIX1 in tomato. The results showed no restoration of virulence for ten SIX1a and six SIX1b transformants tested, suggesting that their function might be restricted to cape gooseberry pathogenicity. Foph SIX1a and SIX1b transformants were also tested to see if they might be recognised by tomato plants carrying the I-3 resistance gene, which enables recognition of Fol SIX1 (i.e. Avr3). The results indicated that SIX1a was not recognised while SIX1b was recognised, suggesting that Foph-SIX1b may be recognised by I-3 as an avirulence factor and that the I-3 resistance gene could potentially be used in cape gooseberry plants to mediate Foph resistance. VI To investigate the function of SIX7, SIX10 and SIX12, a triple gene knockout strategy was initiated to assess their role in Fol virulence. This strategy included the use of the HSVtk (Herpes Simplex Virus thymidine kinase) gene as a counter selection marker against the ectopic insertion of transfer DNA (T-DNA) during fungal transformation by Agrobacterium tumefaciens. However, after several transformation attempts no gene knockouts were obtained. Attempts to produce single (SIX10) and double (SIX7 and SIX12) knockouts also failed. The Fol Rapid Alkalinisation Factor (RALF) gene was also subjected to gene disruption using this approach. Four RALF knockouts were obtained out of 44 transformants thereby validating the gene deletion strategy described above. Pathogenicity tests in tomato showed that these four mutants all developed disease symptoms that were not significantly different from those of wild type Fol under the assay conditions used

Evidence for horizontal gene transfer and separation of effector recognition from effector function revealed by analysis of effector genes shared between cape gooseberry- and tomato-infecting formae speciales of Fusarium oxysporum

RNA sequencing (RNAseq) reads from cape gooseberry plants (Physalis peruviana) infected with Fusarium oxysporumf. sp. physali (Foph) were mapped against the lineage‐specific transcriptome of Fusarium oxysporumf. sp. lycopersici (Fol) to look for putative effector genes. Homologues of Fol SIX1(designated SIX1a and SIX1b), SIX7, SIX10, SIX12, SIX15 and Ave1were identified. The near identity of the Foph and Fol SIX7, SIX10 and SIX12genes and their intergenic regions suggest that this gene cluster may have undergone recent lateral transfer. Foph SIX1a and SIX1bwere tested for their ability to complement a SIX1 knockout mutant of Fol. This mutant shows reduced pathogenicity on susceptible tomato plants, but is able to infect otherwise resistant tomato plants carrying the I‐3 gene for Fusarium wilt resistance (SIX1 corresponds to Avr3). Neither SIX1a nor SIX1b could restore full pathogenicity on susceptible tomato plants, suggesting that any role they may play in pathogenicity is likely to be specific to cape gooseberry. SIX1b, but not SIX1a, was able to restore avirulence on tomato plants carrying I‐3.These findings separate the recognition of SIX1 from its role as an effector and suggest direct recognition by I‐3. A hypervariable region of SIX1undergoing diversifying selection within the F. oxysporum species complex is likely to play an important role in SIX1 recognition. These findings also indicate that I‐3could potentially be deployed as a transgene in cape gooseberry to protect this emerging crop from Foph.Alternatively, cape gooseberry germplasm could be explored for I‐3homologues capable of providing resistance to Foph.J.S. was supported by a scholarship from the Administrative Department of Science, Technology and Innovation (COLCIENCIAS), Colombia. We are grateful to ANU Plant Culture staff for their assistanc

LINKAGE MAPPING OF CANDIDATE GENES FOR INDUCED RESISTANCE AND GROWTH PROMOTION BY Trichoderma koningiopsis (Th003) IN TOMATO Solanum lycopersicum

Induced systemic resistance (ISR) is a mechanism by which plants enhance defenses against any stress condition. ISR and growth promotion are enhanced when tomato (Solanum lycopersicum) is inoculated with several strains of Trichoderma ssp. This study aims to genetically map tomato candidate genes involved in ISR and growth promotion induced by the Colombian native isolate Trichoderma koningiopsis Th003. Forty-nine candidate genes previously identified on tomato plants treated with Th003 and T. hamatum T382 strains were evaluated for polymorphisms and 16 of them were integrated on the highly saturated genetic linkage map named “TOMATO EXPEN 2000”. The location of six unigenes was similar to the location of resistance gene analogs (RGAs), defense related ESTs and resistance QTLs previously reported, suggesting new possible candidates for these quantitative trait loci (QTL) regions. The candidate gene-markers may be used for future ISR or growth promotion assisted selection in tomato

Processes of communication and dissemination of science: the challenges of science policy guidelines in Colombia

IntroductionThe present study aims to identify the characteristics of public policy relating to the Social Appropriation of Knowledge (SAK) in Colombia, generated between 2020 and 2021, on the communication and dissemination of science. Furthermore, the study aims to determine what incentives are offered by these policies to promote the communication and dissemination of science, and what importance is given to the use of digital scenarios.MethodThis is done through a comparative analysis of Colombia’s guidelines of public science policies using a bibliographical review.Results and discussionWith this analysis, it is concluded that the policies resulting from 22 years of reflection in Colombia aim to strengthen the SAK in the communication of science, understood in specific relation to dissemination, which is understood as activities that make scientific knowledge accessible to a much wider audience.ConclusionThe digital scenarios are proposed as communicative spaces to spread knowledge to communities and strengthen the science-society relationship

Characterization of Pathogenic and Nonpathogenic Fusarium oxysporum Isolates Associated with Commercial Tomato Crops in the Andean Region of Colombia

In Colombia, tomato production under protected conditions represents an important economic contribution to the agricultural sector. Fusarium wilt diseases, caused by pathogenic formae speciales of the soil-borne fungus Fusarium oxysporum Schltdl., cause significant yield losses in tomatoes throughout the world. Investigation of the F. oxysporum–tomato pathosystem in Colombia is required to develop appropriate alternative disease management. In this study, 120 fungal isolates were obtained from four different departments in the Central Andean Region in Colombia from tomato crops with symptoms of wilt disease. A molecular characterization of the fungal isolates was performed using the SIX1, SIX3, and SIX4 effector genes of Fusarium oxysporum f. sp. lycopersici W.C. Snyder & H.N. Hansen (Fol). Additionally, we developed a new specific marker to distinguish between Fusarium oxysporum f. sp. radicis-lycopersici Jarvis & Shoemaker (Forl) and Fol isolates. Furthermore, a phylogenetic analysis using the Translation Elongation Factor 1-alpha (EF1a) gene was performed with the collected isolates. Two isolates (named Fol59 and Fol-UDC10) were identified as Fol race 2, four isolates were identified as Forl, six isolates were identified as F. solani, and most of the isolates were grouped within the F. oxysporum species complex. The phylogenetic tree of EF1a showed that most of the isolates could potentially correspond to nonpathogenic strains of F. oxysporum. Additional pathogenicity assays carried out with Fol59 and Fol-UDC10 confirmed that both isolates were highly virulent strains. This study represents a contribution to the understanding of the local interaction between tomatoes and F. oxysporum in Colombia

Plant material used for SSR development and characterization.

<p>ILS* = Introduction maintained at La Selva Research Center, CORPOICA; NA = Not available; ⁺NA = Not available (<i>in vitro</i> propagated material).</p

Polymorphisms in <i>Physalis peruviana</i> SSR loci.

<p>Polymorphisms in <i>Physalis peruviana</i> SSR loci.</p