Native Host Plants Research Articles

Microbial Exudates as Biostimulants: Role in Plant Growth Promotion and Stress Mitigation.

Microbes hold immense potential, based on the fact that they are widely acknowledged for their role in mitigating the detrimental impacts of chemical fertilizers and pesticides, which were extensively employed during the Green Revolution era. The consequence of this extensive use has been the degradation of agricultural land, soil health and fertility deterioration, and a decline in crop quality. Despite the existence of environmentally friendly and sustainable alternatives, microbial bioinoculants encounter numerous challenges in real-world agricultural settings. These challenges include harsh environmental conditions like unfavorable soil pH, temperature extremes, and nutrient imbalances, as well as stiff competition with native microbial species and host plant specificity. Moreover, obstacles spanning from large-scale production to commercialization persist. Therefore, substantial efforts are underway to identify superior solutions that can foster a sustainable and eco-conscious agricultural system. In this context, attention has shifted towards the utilization of cell-free microbial exudates as opposed to traditional microbial inoculants. Microbial exudates refer to the diverse array of cellular metabolites secreted by microbial cells. These metabolites enclose a wide range of chemical compounds, including sugars, organic acids, amino acids, peptides, siderophores, volatiles, and more. The composition and function of these compounds in exudates can vary considerably, depending on the specific microbial strains and prevailing environmental conditions. Remarkably, they possess the capability to modulate and influence various plant physiological processes, thereby inducing tolerance to both biotic and abiotic stresses. Furthermore, these exudates facilitate plant growth and aid in the remediation of environmental pollutants such as chemicals and heavy metals in agroecosystems. Much like live microbes, when applied, these exudates actively participate in the phyllosphere and rhizosphere, engaging in continuous interactions with plants and plant-associated microbes. Consequently, they play a pivotal role in reshaping the microbiome. The biostimulant properties exhibited by these exudates position them as promising biological components for fostering cleaner and more sustainable agricultural systems.

First report of Corydalis speciosa Maxim. being a natural host plant for cucumber mosaic virus in Korea

First report of Corydalis speciosa Maxim. being a natural host plant for cucumber mosaic virus in Korea

Flowers of Impatiens glandulifera as hubs for both pollinators and pathogens

Flower infestation by pathogens may influence pollination effectiveness. At the same time, by sharing infested flowers, pollinators increase transmission of pathogens. In the presented study we identified fungi that colonised flowers of the invasive alien Himalayan balsam Impatiens glandulifera, one of the most nectar rewarding plants in Europe, as well as its pollinators. We determined factors (e.g., plant size, length of flower lower sepal and the width of its entry, air temperature and sun illuminance) that affect pathogen species presence and pollinators numbers. The study was conducted in three regions in Poland differing in time from the I. glandulifera invasion onset. It allowed embedding our results in the context of the evolution of increased competitive ability (EICA) hypothesis. With reference to this hypothesis we tested whether I. glandulifera from the two younger populations are more frequently pollinated than individuals from the old one, which may be a result of the higher infection prevalence in the flowers of individuals from the latter population. Harmful primary pathogens of I. glandulifera (e.g., Botrytis cinerea and Fusarium graminearum) were identified from its flowers. Although the knowledge of the impact of the recorded pathogen species on the pollinators that transmit them is still limited, these pathogens are known to cause devastating diseases of native plant species and to incur significant economic losses in crops. Therefore, the facilitation of their transmission by I. glandulifera in the invaded communities may pose a serious threat both to native biodiversity and nearby crop production. We did not find support for the EICA hypothesis that flower release from pathogens may increase the pollinator’s activity. Bombus hortorum was the most frequent visitor in the youngest surveyed population, while B. pascuorum was most frequent in the two others. So far the dominance of B. hortorum as a pollinator of I. glandulifera has not been recorded. A possible explanation is that flowers in the youngest population, with significantly wider entries than in the two older ones, were more accessible for this large bumblebee. We suggest that the shifts in flower dimensions may result from the evolutionary processes and/or phenotypic plasticity; however, this suggestion needs to be confirmed in further studies. At the same time, it can be expected that exceptionally frequent visits of B. hortorum in flowers of I. glandulifera in the youngest population may contribute to increasing transmission rate of pathogen species to the new native host plants that are particularly associated with this pollinator.

Host Specificity in Canopy Nesting Forms of Ochrogaster lunifer: The Larger Children Do Not Care

The 'mother knows best' hypothesis is tested in a species of processionary moth feeding on acacias and eucalypts in Australia. The processionary moth Ochrogaster lunifer (Lepidoptera: Notodontidae; Thaumetopoeinae) is a social caterpillar living in large colonies on a number of tree and shrub species. Five nesting types-canopy, trunk, tree-hugger, hanging, and ground-have been described, and this study deals with canopy nesters on various species of acacias (Acacia spp.) and eucalypts (Eucalyptus spp. and Corymbia spp.). Reciprocal transplant experiments conducted over three years confirm the 'mother knows best' hypothesis, as colonies performed better on the natal host plant than on the recipient ones. Young first instar larvae were less likely to establish on a non-natal host than the mature larvae, and all acacia-sourced canopy egg masses failed to establish on eucalypts. Large larvae were able to establish on transplant hosts. This suggests a strong preference-performance link at what is likely a species level, confirming preliminary results recently published on genetic divergence. Canopy nesting forms also have a lower realised fecundity than the ground nesting form on acacias from the same geographic area, but higher than another canopy nesting form from western Australia. Further observations on ecological and genetic traits are required to draw conclusions about the separation of lineages in the canopy nesting form of O. lunifer, by including populations from other parts of the range for both the herbivore and the host plants.

First Comprehensive Description of Salt Marsh Skipper (Panoquina panoquin) (Hesperiidae) Natural History: Confirmation of a Second Host Plant In Virginia Salt Marshes

In a rapidly changing world, a complete understanding of a butterfly species' natural history and information about each of the life stages from egg to adult is more important than ever. For many butterfly species, records on life history strategies and habitat requirements are often lacking, especially for immature stages. The salt marsh skipper (Panoquina panoquin) is one such example of an understudied species. As a specialist of salt marshes, studying these immature stages is important for understanding how this species interacts with and uses its habitat. The goal of this study was to fill in gaps in our knowledge of the natural history and habitat preferences of the salt marsh skipper. We conducted field surveys of ovipositing females in three Virginia coastal marshes (5 sites) between May and October 2021. In doing so, we characterized host plant use and oviposition microhabitat. We also tracked eggs and larvae to assess survival in relation to natal host plant. We observed the oviposition of 32 eggs, 15 of which were on Distichlis spicata and 17 on Spartina alterniflora. All life stages used S. alterniflora, including feeding by larvae, confirming this species as a novel host plant. S. alterniflora was the most abundant grass in egg plots and we found no difference between random and egg plot microhabitat. In the microhabitat analysis, we found that host plant use was largely associated with the more abundant of the two grasses in a plot. D. spicata, however, was preferred in cases of up to 26% more S. alterniflora cover relative to D. spicata. Lastly, we documented an overall successful hatching rate of 19% with equal risk of egg mortality on both host plants. While our results still indicate that the salt marsh skipper is a specialist, it has a broader range of habitat and might be able to cope with marsh decline better than previously thought.

Multiplex PCR for Discriminating Host Plant Associations of Hyalesthes obsoletus (Hemiptera: Cixiidae), a Key Vector and Driver of ‘Ca. Phytoplasma solani’ Epidemiology

Given the ecological and epidemiological specialization of Hyalesthes obsoletus, the principle vector of ‘Candidatus Phytoplasma solani’, the primary objective of this study was to develop molecular tools for discriminating three host plant associations of the vector populations: (i) Convolvulus arvensis–Urtica dioica (Ca–Ud), (ii) Vitex agnus-castus (Vac), and (iii) Crepis foetida (Cf). The genetic diversity of the nearly full-length mitochondrial COI gene (1467 bp) was analyzed and compared among previously reported and newly collected individuals of the three host plant associations on a wide geographic range. Multiplex PCR was designed and evaluated for discriminating H. obsoletus host plant associations based on the size of amplified fragments: 1084 bp for the Cf association, 645 bp for the Ca–Ud association, and 355 bp for the Vac association. Examples of the epidemiological value of combining data on the genetic characteristics of the vector and the pathogen are provided. The method is intended to facilitate an accurate identification of the vector’s phylogenetic lineage, natural host plant preference, and epidemiological transmission routes of ‘Ca. P. solani’. When applied to H. obsoletus specimens collected from cultivated plants within an agroecosystem and combined with ‘Ca. P. solani’ genotyping, the method should provide valuable information on disease epidemiology, source(s) of emergence, and transmission routes.

Feeding on an exotic host plant enhances plasma levels of phenoloxidase by modulating feeding efficiency in a specialist insect herbivore.

Background: Exotic plant species represent a novel resource for invertebrates and many herbivorous insects have incorporated exotic plants into their diet. Using a new host plant can have physiological repercussions for these herbivores that may be beneficial or detrimental. In this study, we compared how using an exotic versus native host plant affected the immune system response and feeding efficiency of a specialist lepidopteran, the common buckeye (Junonia coenia: Nymphalidae, Hübner 1822). Materials and Methods: In a lab experiment, larvae were reared on either the exotic host plant, Plantago lanceolata (Plantaginaceae), or the native host plant, Mimulus guttatus (Phrymaceae). Beginning at second instar feeding efficiency data were collected every 2days until fifth instar when immune assays were performed. Immune assays consisted of standing phenoloxidase activity, total phenoloxidase activity, and melanization. Results: Interestingly, we found that all three immune system parameters were higher on the exotic host plant compared to the native host plant. The exotic host plant also supported higher pupal weights, faster development time, greater consumption, and more efficient approximate digestibility. In contrast, the native host plant supported higher efficiency of conversion of ingested and digested food. The relationship between immunity and feeding efficiency was more complex but showed a large positive effect of greater host plant consumption on all immune parameters, particularly for the exotic host plant. While not as strong, the efficiency of conversion of digested food tended to show a negative effect on the three immune parameters. Conclusion: Overall, the exotic host plant proved to be beneficial for this specialist insect with regard to immunity and many of the feeding efficiency parameters and continued use of this host plant is predicted for populations already using it.

Effect of Fruit Volatiles from Native Host Plants on the Sexual Performance of Anastrepha fraterculus sp. 1 Males.

Anastrepha fraterculus sp.1 males are sexually stimulated by the aroma of fruit of its native host Psidium guajava (guava). Other hosts, which are exotic to A. fraterculus, do not enhance male sexual behavior. Here we evaluate the effects of fruit volatile exposure on male A. fraterculus sp. 1 sexual performance using other native hosts, under the hypothesis that male improvement derives from a common evolutionary history between A. fraterculus sp. 1 and its native hosts. Four species were evaluated: Eugenia myrcianthes, Juglans australis, Psidium cattleianum, and Acca sellowiana. Guava was used as a positive control. Males were exposed to fruit from 12:00 pm to 4:00 pm, from day 8 to day 11 post-emergence. On day 12, we evaluated their calling behavior and mating success. Both guava and P. cattleianum enhanced calling behavior. Mating success was enhanced only by guava and a trend was found for P. cattleianum. Interestingly, the two hosts belong to the Psidium genus. A volatile analysis is planned to identify the compounds responsible for this phenomenon. The other native fruits did not improve the sexual behavior of males. Implications of our findings in the management of A. fraterculus sp. 1 are discussed.

New records of false spider mites (Acari: Trombidiformes: Tenuipalpidae) in Greece

Two false spider mite species (Tetranychoidea: Tenuipalpidae) are reported in Greece. One new species, Aegyptobia insularis Stathakis and Vrettos sp. nov., collected from the Mediterranean shrub Phagnalon rupestre ssp. graecum (Asteraceae), is described. Dolichotetranychus summersi Pritchard and Baker is found on a new and probably natural host plant, the common couch grass Elymus repens (Poaceae); this is the first record of this mite in the Palearctic region. Females and deutonymphs of D. summersi are redescribed, based on the specimens from Greece.

STUDY OF PATHOGENICITY OF FIELD STRAINS OF XANTHOMONAS CAMPESTRIS BACTERIA

Gram-negative bacterium Xanthomonas campestris, which is the causative agent of bacterial diseases of many cultivated plants, annually leads to significant economic losses in many sarans of the world. The development of modern methods of combating this phytopathogen is an urgent task for agriculture. One of the promising methods is the use of bacteriophages, the selection of which requires working directly with bacteria that have pathogenic properties in relation to natural host plants. This paper presents the results of studying the pathogenicity of the existing collection of microorganisms in relation to various varieties of cabbage. 38 strains of Xanthomonas campestris bacteria were used as the object of the study. The pathogenicity of the selected crops was studied by methods of studying hypersensitivity on tobacco plants and by infiltration into natural host plants. Studies have shown that the bacteria had varying degrees of activity in relation to cabbage varieties F1, Agamer 611 and Siberian 60. At the same time, 21 of the 38 strains studied showed their pathogenic properties on plants of all three varieties. In most cases, characteristic V-shaped lesions were found on the leaves of plants, which eventually led to the withering of the entire leaf. In some cases, necrosis was observed at the sites of inoculation of the studied strain of bacteria. Analysis of the time of manifestation of symptoms of bacteriosis showed that strains previously isolated from affected plants visually showed their pathogenic properties 5-6 days earlier than strains isolated from seed material. The obtained results will be used in the future to select bacteriophages with the greatest spectrum of action against bacteria with pathogenic properties.

Oosporein Produced by Root Endophytic Chaetomium cupreum Promotes the Growth of Host Plant, Miscanthus sinensis, under Aluminum Stress at the Appropriate Concentration.

Chaetomium cupreum, a root endophyte in Miscanthus sinensis, enhances Al tolerance in M. sinensis by changing aluminum (Al) localization and the production of a siderophore, oosporein, which chelates Al for detoxification. Oosporein has various functions, including insecticidal activity, phytotoxicity, antifungal activity, and a siderophore. In our study, we focused on the detoxification effect of oosporein as a siderophore and on the growth of M. sinensis under Al exposure. In addition, the phytotoxicity of oosporein to M. sinensis was confirmed to compare with those in Lactuca sativa and Oryza sativa as control plants. Under Al stress, oosporein promoted plant growth in M. sinensis seedlings at 10 ppm, which was the same concentration as that detected in M. sinensis roots infected with C. cupreum in our previous study. Oosporein also showed low phytotoxicity to M. sinensis compared with L. sativa at even high concentrations of oosporein. These results suggest that the concentration of oosporein in M. sinensis roots would be maintained at the appropriate concentration to detoxify Al and would promote M. sinensis growth under Al stress, although oosporein would show low phytotoxicity to the natural host plant, M. sinensis, compared with the non-host plant, L. sativa.

Testing hypotheses of a coevolutionary key innovation reveals a complex suite of traits involved in defusing the mustard oil bomb

Coevolutionary interactions are responsible for much of the Earth's biodiversity, with key innovations driving speciation bursts on both sides of the interaction. One persistent question is whether macroevolutionary traits identified as key innovations accurately predict functional performance and selection dynamics within species, as this necessitates characterizing their function, investigating their fitness consequences, and exploring the selection dynamics acting upon them. Here, we used CRISPR-Cas9 mediating nonhomologous end joining (NHEJ) in the butterfly species Pieris brassicae to knock out and directly assess the function and fitness impacts of nitrile specifier protein (NSP) and major allergen (MA). These are two closely related genes that facilitate glucosinolate (GSL) detoxification capacity, which is a key innovation in mustard feeding Pierinae butterflies. We find NSP and MA are both required for survival on plants containing GSLs, with expression differences arising in response to variable GSL profiles, concordant with detoxification performance. Importantly, this concordance was only observed when using natural host plants, likely reflecting the complexity of how these enzymes interact with natural plant variation in GSLs and myrosinases. Finally, signatures of positive selection for NSP and MA were detected across Pieris species, consistent with these genes' importance in recent coevolutionary interactions. Thus, the war between these butterflies and their host plants involves more than the mere presence of chemical defenses and detoxification mechanisms, as their regulation and activation represent key components of complex interactions. We find that inclusion of these dynamics, in ecologically relevant assays, is necessary for coevolutionary insights in this system and likely others.

Immature Stages and New Host Plant Records for Three Species in the "Taygetis Clade" of Euptychiina in Southeastern Peru (Lepidoptera: Nymphalidae: Satyrinae).

We report here the immature stages and natural host plants for three species in the so-called "Taygetis clade" of the nymphalid butterfly subtribe Euptychiina, Taygetis echo (Cramer, 1775), Taygetis sosis Hopffer, 1874, and Pseudodebis valentina (Cramer, 1779). The study was carried out at Finca Las Piedras in Madre de Diosdepartment, Peru. Taygetis echo was observed utilizing a species of herbaceous bamboo, Olyra latifolia L. (Poaceae: Bambusoideae: Olyreae), T. sosis was found feeding on another species of herbaceous bamboo, Pariana lunata Nees (Poaceae: Bambusoideae: Olyreae), and P. valentina was found utilizing a species of woody bamboo, Guadua weberbaueri Pilg. (Poaceae: Bambusoideae: Bambuseae). We describe and provide photos of the immatures and host plants, as well as illustrations of the head capsules for each of these three species.

Immature stages, new host plant records and shelter structures of Troyus phyllides (Röber, 1925) and Thoon ponka Evans, 1955 in the Peruvian Amazon (Lepidoptera: Hesperiidae: Hesperiinae: Hesperiini)

We describe here for the first time the complete immature life cycles and shelter structures of two Neotropical skipper butterflies in the subtribe Moncina, Troyus phyllides (Röber, 1925) and Thoon ponka Evans 1955, along with new natural host plant records for these species at Finca Las Piedras, Madre de Dios, Peru. Four eggs and a preantepenultimate larva of T. phyllides, as well as three eggs of Thoon ponka were collected in nature and each passed through five larval instars to adulthood. Troyus phyllides fed on a herbaceous species, Lasiacis ligulata Hitchcock & Chase (Poaceae: Panicoideae: Paniceae), while T. ponka fed on two congeneric herbaceous bamboo species, Pariana lunata Nees and Pariana sp. (Poaceae: Bambusoideae: Olyreae). We present photos of all immature stages and host plants, as well as illustrations of the shelter structures and the head capsules for each of these two species.

Biological and Genetic Characterization of Physostegia Chlorotic Mottle Virus in Europe Based on Host Range, Location, and Time.

Application of high throughput sequencing (HTS) technologies enabled the first identification of Physostegia chlorotic mottle virus (PhCMoV) in 2018 in Austria. Subsequently, PhCMoV was detected in Germany and Serbia on tomatoes showing severe fruit mottling and ripening anomalies. We report here how prepublication data-sharing resulted in an international collaboration across eight laboratories in five countries, enabling an in-depth characterization of PhCMoV. The independent studies converged toward its recent identification in eight additional European countries and confirmed its presence in samples collected 20 years ago (2002). The natural plant host range was expanded from two to nine species across seven families, and we confirmed the association of PhCMoV presence with severe fruit symptoms on economically important crops such as tomato, eggplant, and cucumber. Mechanical inoculations of selected isolates in the greenhouse established the causality of the symptoms on a new indexing host range. In addition, phylogenetic analysis showed a low genomic variation across the 29 near-complete genome sequences available. Furthermore, a strong selection pressure within a specific ecosystem was suggested by nearly identical sequences recovered from different host plants through time. Overall, this study describes the European distribution of PhCMoV on multiple plant hosts, including economically important crops on which the virus can cause severe fruit symptoms. This work demonstrates how to efficiently improve knowledge on an emergent pathogen by sharing HTS data and provides a solid knowledge foundation for further studies on plant rhabdoviruses.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Heilipussquamosus (LeConte, 1824): clarification of the correct name for the "avocado tree girdler" with updates on its biology and distribution (Coleoptera, Curculionidae, Molytinae, Hylobiini).

A single species of the genus Heilipus Germar, 1824 is native to the south-eastern United States and was a pest of avocado in Florida in the mid-20th century. Two names-Heilipusapiatus (Olivier, 1807) and H.squamosus (LeConte, 1824)-have both recently been used as the valid name for this species, with H.apiatus also being recently used as the valid name for a species from French Guiana. Confusion surrounding the correct application of these names and the distribution of these species traces back to an erroneous distribution given in Olivier's 1807 description of H.apiatus and, although some authors clarified this previously, there continues to be confusion concerning the correct name. Outside of avocado-producing areas, this species was rarely collected and little was known about its biology. Recent observations on iNaturalist and BugGuide suggest the species is more widely distributed in the United States and less rare than it was previously thought to be. Heilipussquamosus (LeConte, 1824) is recognised as the valid name for the sole species of Heilipus occurring in the United States, while Heilipusapiatus (Olivier, 1807) is a very different species from French Guiana. Heilipussquamosus was previously recorded from eight States in the south-eastern United States and, after examining records from natural history collections, iNaturalist, BugGuide and literature sources, the species is newly recorded from an additional seven States: Arkansas, Kansas, Kentucky, Louisiana, Missouri, Oklahoma and Texas. Though native host plants have been unconfirmed by rearing records, the evidence indicating the possible host plants in the plant family Lauraceae is reviewed.

Experimental removal of extracellular egg‐associated microbes has long‐lasting effects for larval performance

Abstract Maternally transmitted microbes are ubiquitous. In insects, maternal microbes can play a role in mediating the insect immune response. Less is known about how ecological factors, such as resource use, interact with maternal microbes to affect immunity. In the context of a recent colonization of a novel host plant by the Melissa blue butterfly Lycaeides melissa, we investigated the interaction between host plant use and vertically transmitted, extracellular egg‐associated microbes in determining the strength of the insect immune response. We reared larvae on two different host plant species: a native host Astragalus canadensis and a novel host Medicago sativa. Egg‐associated microbes were removed through a series of antimicrobial egg washes prior to hatching. Immune response was measured through three assays: standing phenoloxidase (PO), total PO and melanization. We detected strong effects of microbial removal. Egg washing resulted in larvae with an increased immune response as measured by total PO—contrary to reports from other taxa. The effect of washing was especially strong for larvae consuming the native host plant. This result may explain why consumption of the egg casing is not a universal behaviour in insects, due to negative effects on larval immunity. Read the free Plain Language Summary for this article on the Journal blog.

Characterization of a rare habitat of Terfezia boudieri Chatin in the coastal dunes of northwestern Algeria

The study focuses on a species of desert truffle Terfezia boudieri Chatin, an edible hypogeous mushroom with food value and economic and ecological interest in Algeria. This fungal species commonly growing in arid and semi-arid regions of Algeria in association with Helianthemum spp. was collected for the first time in a rare natural habitat located on the coastal dunes of northwestern Algeria. Surveys carried out in the Dunes forest of Stidia made it possible to determine the pedoclimatic parameters and to identify the natural host plant essential for the development of T. boudieri ascomata and the accompanying plant species. The results revealed that this species of desert truffle grows in a semi-arid bioclimate with maritime influences, on sandy-loamy, alkaline and non-saline soil. The natural production of ascomata is irregular from year to year ; it is closely linked to a well-distributed rainfall from October to April with a maximum in December and an adequate temperature during the fungal growth season. Floristic surveys reveal the presence of a variable phytodiversity represented by 15 families including that of H. ledifolium (Cistaceae) ; the only natural host plant forming typical endomycorrhizae with T. boudieri. However, although T. boudieri is still harvested from the Dunes forest of Stidia, the protection and conservation of this forest remains a priority today due to the degradation not only of the rare natural habitat of T. boudieri and of its host plant but above all of the floristic procession often vulnerable to ecological hazards and anthropogenic constraints.

The Life History and Phylogeny of Samia watsoni (Saturniidae), A Relict Species Endemic to China

Samia watsoni was reared in Yunnan from eggs received from Zhejiang in 2021. A mature larva was found in the field on Pterostyrax corymbosus (Styracaceae) in 2020, so this tree was used as the hostplant in captivity. Larvae accepted other Styracaceae in captivity. There are probably other hostplants in nature, but captive larvae refused Ailanthus and Liquidambar. The mature larva is light bluish green, white dorsally, with red dorsal scoli and others blue. In captivity the cocoons were wrapped in a leaf attached to the hostplants, but half were spun at the bottom of the cage with weak peduncles, suggesting that some cocoons may occur on the ground in nature. Adults were observed to drink water along the edges of streams, and a functional proboscis is reported for other Attacini.

The tomato yellow leaf curl virus C4 protein alters the expression of plant developmental genes correlating to leaf upward cupping phenotype in tomato.

Tomato yellow leaf curl virus (TYLCV), a monopartite begomovirus in the family Geminiviridae, is efficiently transmitted by the whitefly, Bemisia tabaci, and causes serious economic losses to tomato crops around the world. TYLCV-infected tomato plants develop distinctive symptoms of yellowing and leaf upward cupping. In recent years, excellent progress has been made in the characterization of TYLCV C4 protein function as a pathogenicity determinant in experimental plants, including Nicotiana benthamiana and Arabidopsis thaliana. However, the molecular mechanism leading to disease symptom development in the natural host plant, tomato, has yet to be characterized. The aim of the current study was to generate transgenic tomato plants expressing the TYLCV C4 gene and evaluate differential gene expression through comparative transcriptome analysis between the transgenic C4 plants and the transgenic green fluorescent protein (Gfp) gene control plants. Transgenic tomato plants expressing TYLCV C4 developed phenotypes, including leaf upward cupping and yellowing, that are similar to the disease symptoms expressed on tomato plants infected with TYLCV. In a total of 241 differentially expressed genes identified in the transcriptome analysis, a series of plant development-related genes, including transcription factors, glutaredoxins, protein kinases, R-genes and microRNA target genes, were significantly altered. These results provide further evidence to support the important function of the C4 protein in begomovirus pathogenicity. These transgenic tomato plants could serve as basic genetic materials for further characterization of plant receptors that are interacting with the TYLCV C4.