Variety Of Host Plants Research Articles

Host Plant Variation and Lack of Genetic Differentiation in Populations of Dione (Agraulis) dodona Lamas & Farfán (Lepidoptera: Nymphalidae).

Simple SummaryIn this study, we analyzed the population genetics of Dione (A.) dodona Lamas and Farfán (Nymphalidae), a recently described butterfly from xerophytic environments of the western slopes of the Central Andes, associated with Malesherbia tenuifolia (Passifloraceae). Searches for additional host-plant species were carried out throughout its known distribution. In total, seven species of Malesherbia have been reported as host plants for D. (A.) dodona, extending its distribution as far north as 50 km. We obtained samples of the last larval instar in six localities on different host-plant species that have disjointed distributions. We inferred the genetic diversity and structure between populations by using microsatellites and mitochondrial COI markers. The results showed a weak genetic differentiation between the evaluated populations, suggesting a continuum of gene flow through high dispersal, along with the disjoint occurrence of the host plants.Dione (Agraulis) dodona (Nymphalidae: Heliconiinae) is a butterfly restricted to the western slopes of the Andes of Peru and Chile and is associated with Malesherbia tenuifolia in xerophytic environments. In this study, we found six additional species of host plants for D. (A.) dodona belonging to the genus Malesherbia (Passifloraceae). We used mitochondrial DNA sequences (COI) and microsatellites to screen genetic variation and investigate population structure in six geographic disjointed populations of D. (A.) dodona associated with distinct Malesherbia species. The PCoA analysis based on allele frequencies evidenced a lack of differentiation among populations and a low FST. The Bayesian cluster analyses revealed the existence of three genetically distinct groups, but almost all individuals present an admixture ancestry. An absence of isolation by distance pattern was observed. Possible scenarios are discussed: a bottleneck or recent colonization from interconnected populations from the south, and ongoing gene flow among local populations by high dispersal through a landscape formed of isolated populations of Malesherbia.

Back to the Wild: The Parasitoid Community of Lobesia botrana (Lepidoptera: Tortricidae) in a Grapevine-Free Natural Environment.

Simple SummaryIn a framework of sustainable agriculture, strategies aimed at preserving and enhancing pest natural enemies are crucial. However, knowledge about the parasitoid complex associated with a particular pest is often fragmentary. Herein, we investigated the parasitoids associated with the European grapevine moth, one of the main vine pests in the Mediterranean area, in a natural context, where the moth lives on Daphne gnidium, deemed as its original host plant. We observed a heterogeneous and complex community, consisting of a few predominant parasitoid species, followed by satellite species, and occasional parasitoids. Parasitic wasps, such as Campoplex capitator and Trichogramma spp., can be also found in the vineyards, thus understanding their dynamics in the wild could be useful to improve biological control strategies for managing EGVM populations.The European grapevine moth (EGVM), Lobesia botrana (Lepidoptera: Tortricidae), is one of the major concerns for vineyard managers in the Mediterranean area. It is a polyphagous moth, which develops on a wide variety of host plants, among which the spurge flax, Daphne gnidium (Thymelaeaceae), very likely represents its originary wild host plant. In this study, we investigated the parasitoid complex of L. botrana feeding on D. gnidium during a three-year sampling in a natural reserve in Tuscany, Italy, where this plant is extremely abundant while the grapevine is absent. A total of 24 species of parasitoids were obtained from eggs, larvae, and pupae of EGVM, belonging to 6 families of Hymenoptera and a family of Diptera. The ichneumonid wasp Campoplex capitator was the most abundant larval parasitoid. Four species of the genus Trichogramma were obtained from parasitized eggs during the first year of sampling, with a peak in the parasitisation during the EGVM 3rd generation. Some of the main EGVM parasitoids on spurge flax were also observed in vineyards, although a certain degree of redundancy was observed in the wild, due to several less frequent “satellite” species exploiting the same host. Overall, this research sheds light on the parasitoid community and dynamics of this important moth pest in a grapevine-free natural ecosystem, discussing the possible role of natural areas as ecological reservoirs of pest natural enemies.

Effects of Host Plants on Bacterial Community Structure in Larvae Midgut of Spodoptera frugiperda.

Simple SummaryThe gut microbiota plays an important role in insect physiology and behavior. The interaction among the different structures of gut bacterial community in the fall armyworm (FAW), Spodoptera frugiperda, and different host plants, and whether these different gut bacteria are responsible for the rapid spread of FAW to a variety of host plants after invasion are largely unexplored. In the present paper, we used a culture-independent approach targeting the bacterial 16S rRNA gene of gut bacteria of the 5th instar larvae of FAW fed on four different host plants. It aimed to analyze the effects of host plants on gut bacteria abundance, community structure and metabolic function. We found that host plants exerted considerable effects on the structure and composition of the gut bacteria in FAW and the differences among the four groups identified were significant. They were related to the detoxification and adaptation of FAW to toxic secondary metabolites of the host plant. These differences enabled the gut microbiome to perform different functions. This study lays a foundation for further studies on the function of intestinal bacteria in FAW and the adaptive mechanism to the host.The fall armyworm (FAW), Spodoptera frugiperda, is one of the most important invasive species and causes great damage to various host crops in China. In this study, the diversity and function of gut bacteria in the 5th instar larvae of FAW fed on maize, wheat, potato and tobacco leaves were analyzed through 16S rRNA sequencing. A total of 1324.25 ± 199.73, 1313.5 ± 74.87, 1873.00 ± 190.66 and 1435.25 ± 139.87 operational taxonomic units (OTUs) from the gut of FAW fed on these four different host plants were detected, respectively. Firmicutes, Proteobacteria and Bacteroidetes were the most abundant bacterial phyla. Beta diversity analysis showed that the gut bacterial community structure of larvae fed on different host plants was significantly differentiated. At the genus level, the abundance of Enterococcus in larvae fed on wheat was significantly lower than those fed on the other three host plants. Enterobacter and ZOR0006 were dominant in FAW fed on tobacco leaves, and in low abundance in larvae fed on wheat. Interestingly, when fed on Solanaceae (tobacco and potato) leaves which contained relative higher levels of toxic secondary metabolites than Gramineae (wheat and maize), the genera Enterococcus, Enterobacter and Acinetobacter were significantly enriched. The results indicated that gut bacteria were related to the detoxification and adaptation of toxic secondary metabolites of host plants in FAW. Further analysis showed that replication, repair and nucleotide metabolism functions were enriched in the gut bacteria of larvae fed on tobacco and potato. In conclusion, the gut bacterial diversity and community composition in FAW larvae fed on different host plants showed significant differences, and the insect is likely to regulate their gut bacteria for adaptation to different host plants.

A novel quorum quencher, Rhodococcus pyridinivorans XN-36, is a powerful agent for the biocontrol of soft rot disease in various host plants

Quorum sensing (QS) is a microbial cell–cell communication mechanism that regulates the virulence factor production in numerous pathogens, which plays a key role in microbial infections. QS-mediated microbial infections can be blocked via quorum quenching (QQ), which disrupts QS either by degradation of QS signals or interference of signal generation or perception. The pathogenicity of various diseases, including Pectobacterium carotovorum, is regulated by N-acyl homoserine lactone (AHL), a widely conserved QS signaling molecule. P. carotovorum can induce soft rot in a variety of crops and cause great economic losses to agricultural production. In this study, a newly isolated bacterium of Rhodococcus pyridinivorans XN-36 was identified as a novel QQ strain that can effectively degrade AHL and reduce the disease severity of P. carotovorum in host plants. Strain XN-36 was capable of rapidly degrading AHL without a lag phase, and over 85% of AHL (0.5 mmol·L−1) was degraded within 96 h. The metabolic intermediates of AHL biodegradation were detected and identified by gas chromatography-mass spectrometry (GC–MS) as lactamide and propenamide. Based on the chemical structure of AHL and intermediate metabolites, a novel metabolic pathway of AHL in strain XN-36 was proposed, which suggests that AHL could be degraded first by cleavage of its amide bond, followed by hydrolysis of the lactonic ring and subsequent metabolism. In addition, strain XN-36 participated in efficient degradation of a wide range of AHL signaling molecules including N-(3-oxohexanoyl)-L-homoserine lactone (OHHL), N-hexanoyl-L-homoserine lactone (C6HSL), N-(3-oxooctanoyl)-L-homoserine lactone (3OC8HSL), and N-(3-oxododecanoyl)-L-homoserine lactone (3OC12HSL). Furthermore, the application of strain XN-36 as a biocontrol agent could substantially alleviate the soft rot disease caused by P. carotovorum to suppress tissue maceration in a variety of host plants, including Chinese cabbage (Brassica pekinensis(Lour.) Rupr.), carrot (Daucus carota L.) and potato (Solanum tuberosum L.). Similarly, the application of crude enzymes of strain XN-36 significantly attenuated the disease incidence and severity in host plants. Enzyme activity test indicated that strain XN-36 has acylase activity. These findings expand the application of QQ strains as biocontrol agents, while opening up new prospects for the control of QS-mediated bacterial diseases.

Multiple knockout mutants reveal a high redundancy of phytotoxic compounds contributing to necrotrophic pathogenesis of Botrytis cinerea.

Botrytis cinerea is a major plant pathogen infecting more than 1400 plant species. During invasion, the fungus rapidly kills host cells, which is believed to be supported by induction of programmed plant cell death. To comprehensively evaluate the contributions of most of the currently known plant cell death inducing proteins (CDIPs) and metabolites for necrotrophic infection, an optimized CRISPR/Cas9 protocol was established which allowed to perform serial marker-free mutagenesis to generate multiple deletion mutants lacking up to 12 CDIPs. Whole genome sequencing of a 6x and 12x deletion mutant revealed a low number of off-target mutations which were unrelated to Cas9-mediated cleavage. Secretome analyses confirmed the loss of secreted proteins encoded by the deleted genes. Infection tests with the mutants revealed a successive decrease in virulence with increasing numbers of mutated genes, and varying effects of the knockouts on different host plants. Comparative analysis of mutants confirmed significant roles of two polygalacturonases (PG1, PG2) and the phytotoxic metabolites botrydial and botcinins for infection, but revealed no or only weak effects of deletion of the other CDIPs. Nicotiana benthamiana plants with mutated or silenced coreceptors of pattern recognition receptors, SOBIR1 and BAK1, showed similar susceptibility as control plants to infection by B. cinerea wild type and a 12x deletion mutant. These results raise doubts about a major role of manipulation of these plant defence regulators for B. cinerea infection. Despite the loss of most of the known phytotoxic compounds, the on planta secretomes of the multiple mutants retained substantial phytotoxic activity, proving that further, as yet unknown CDIPs contribute to necrosis and virulence. Our study has addressed for the first time systematically the functional redundancy of fungal virulence factors, and demonstrates that B. cinerea releases a highly redundant cocktail of proteins to achieve necrotrophic infection of a wide variety of host plants.

QTL Mapping of Resistance to Bacterial Wilt in Pepper Plants (Capsicum annuum) Using Genotyping-by-Sequencing (GBS)

Bacterial wilt (BW) disease, which is caused by Ralstonia solanacearum, is one globally prevalent plant disease leading to significant losses of crop production and yield with the involvement of a diverse variety of monocot and dicot host plants. In particular, the BW of the soil-borne disease seriously influences solanaceous crops, including peppers (sweet and chili peppers), paprika, tomatoes, potatoes, and eggplants. Recent studies have explored genetic regions that are associated with BW resistance for pepper crops. However, owing to the complexity of BW resistance, the identification of the genomic regions controlling BW resistance is poorly understood and still remains to be unraveled in the pepper cultivars. In this study, we performed the quantitative trait loci (QTL) analysis to identify genomic loci and alleles, which play a critical role in the resistance to BW in pepper plants. The disease symptoms and resistance levels for BW were assessed by inoculation with R. solanacearum. Genotyping-by-sequencing (GBS) was utilized in 94 F2 segregating populations originated from a cross between a resistant line, KC352, and a susceptible line, 14F6002-14. A total of 628,437 single-nucleotide polymorphism (SNP) was obtained, and a pepper genetic linkage map was constructed with putative 1550 SNP markers via the filtering criteria. The linkage map exhibited 16 linkage groups (LG) with a total linkage distance of 828.449 cM. Notably, QTL analysis with CIM (composite interval mapping) method uncovered pBWR-1 QTL underlying on chromosome 01 and explained 20.13 to 25.16% by R2 (proportion of explained phenotyphic variance by the QTL) values. These results will be valuable for developing SNP markers associated with BW-resistant QTLs as well as for developing elite BW-resistant cultivars in pepper breeding programs.

Molecular genotypic diversity of populations of brinjal shoot and fruit borer, Leucinodes orbonalis and development of SCAR marker for pesticide resistance.

The brinjal shoot and fruit borer, Leucinodes orbonalis is a destructive pest of Solanum melongena. The control of L. orbonalis with extensive application of synthetic chemical insecticides resulted in the development of resistance with known genetic heterogeneity among populations. Understanding the genetic diversity of their populations is important in developing strategies for their management. The present investigation was performed to characterize populations of L. orbonalis for their genetic diversity in the entire region of Tamil Nadu, South India using random amplified polymorphic DNA (RAPD) primers as a tool of the molecular marker. Among 60 random 10-mer primers, only ten primers generated reproducible and scorable banding profile. Among the ten different random primers, the primers namely OPG 7, OPG 8, OPS 2 and OPS 7 generated the highest genetic variation with over 80% genetic polymorphism. Phylogram analysis produced 18 clusters with eight major and ten minor clusters. Cluster analysis, statistical fitness, population structure and analysis of molecular variance confirmed the significant genetic variation among different populations. A trait specific marker obtained through RAPD was cloned, sequenced and used to develop a stable diagnostic SCAR marker for DNA fingerprinting to distinguish the populations. Amplification of this locus in the samples of 20 different populations indicated recognition of the trait for pesticide resistance in 12 populations. The results suggest that the biochemical nature of host plant varieties of this insect pest and variation in the application of different insecticides are essential contributing factors for the genotypic variations observed among populations of L. orbonalis.

A Review of the Scientific Literature on the Use of Reproductive Pheromones in the Management of Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is native to tropical and subtropical areas of the Americas but has recently invaded and established in several African and Asian countries, including India. It successfully oviposits and feeds on a variety of host plants, but its feeding damage to maize, Zea mays L., is of great concern in its native and expanded ranges. Conventional insecticides are the usual means of managing the pest, despite the adverse impacts of these chemistries on nontarget species, as well as human and environmental health. Botanicals, biological agents, cultural practices, host plant resistance, and genetically modified hosts also have been explored for management, as has the use of reproductive pheromones for management, monitoring, and decision making. We conducted a review of available scientific literature on the use of reproductive pheromones for monitoring, mass trapping, disrupting mating, and decision making in the management of S. frugiperda. Assembling this information in one location will facilitate additional research with pheromone-based management strategies and tactics, especially within expanded ranges of the pest.

Network mapping of root\u2013microbe interactions in Arabidopsis thaliana

Understanding how plants interact with their colonizing microbiota to determine plant phenotypes is a fundamental question in modern plant science. Existing approaches for genome-wide association studies (GWAS) are often focused on the association analysis between host genes and the abundance of individual microbes, failing to characterize the genetic bases of microbial interactions that are thought to be important for microbiota structure, organization, and function. Here, we implement a behavioral model to quantify various patterns of microbe-microbe interactions, i.e., mutualism, antagonism, aggression, and altruism, and map host genes that modulate microbial networks constituted by these interaction types. We reanalyze a root-microbiome data involving 179 accessions of Arabidopsis thaliana and find that the four networks differ structurally in the pattern of bacterial-fungal interactions and microbiome complexity. We identify several fungus and bacterial hubs that play a central role in mediating microbial community assembly surrounding A. thaliana root systems. We detect 1142 significant host genetic variants throughout the plant genome and then implement Bayesian networks (BN) to reconstruct epistatic networks involving all significant SNPs, of which 91 are identified as hub QTLs. Results from gene annotation analysis suggest that most of the hub QTLs detected are in proximity to candidate genes, executing a variety of biological functions in plant growth and development, resilience against pathogens, root development, and abiotic stress resistance. This study provides a new gateway to understand how genetic variation in host plants influences microbial communities and our results could help improve crops by harnessing soil microbes.

Phenology of greenhouse thrips (Heliothrips haemorrhoidalis) on kiwifruit vines, shelter trees and alternative host plants

The greenhouse thrips, Heliothrips haemorrhoidalis is a quarantine pest of kiwifruit. There is a need for reliable information on its phenology in kiwifruit orchards to inform the development of new management options. Numbers of larval, pupal and adult greenhouse thrips were counted on leaves of the two main kiwifruit cultivars Actinidia chinensis var. deliciosa (‘Hayward’) at two sites at different times and A. chinensis var. chinensis ‘Zesy002’ at one site. Greenhouse thrips were also counted on leaves of shelter tree species Cryptomeria japonica, and other plants present on kiwifruit orchards, blackberry (Rubus fruticosus s.l.), barberry (Berberis glaucocarpa), and wineberry (Aristotelia serrata) across a number of sites at different times. There was a strong seasonal pattern to the phenology of greenhouse thrips and it was relatively synchronous for all the host plants surveyed. In general, number of greenhouse thrips on foliage increased from January to peak in April or May before declining in late autumn or winter and remaining low until the following January or February. The phenology of greenhouse thrips followed the same seasonal pattern for a variety of host plants found on kiwifruit orchards at sites in the Bay of Plenty across two two-year time periods. Therefore, host species does not appear to be a factor affecting the phenology of thrips. Other, non-host factors such as microclimate may be important drivers of phenology but they require further study. The consistency of the seasonal pattern of relative abundance means that there is a well-defined window to target for thrips management.

Morphological evidence for paraphyly of Holopothrips Hood (Thysanoptera: Phlaeothripidae), a Neotropical genus of gall-inducing thrips

Abstract Holopothrips is a diverse group of thrips associated to galls in the Neotropics, with a variety of host plants and wide morphological diversity. Relationships to other Neotropical groups have been proposed, but are still untested, and the monophyly of the genus remains doubtful. Here, we perform a phylogenetic analysis of Holopothrips, based on morphological characters. A total of 87 species were included in the matrix and eight analyses were carried out, but all of them failed to recover Holopothrips as a monophyletic grouping. Bremer and Bootstrap support values were low, and the topologies varied among all analyses, with uncertain internal relations for the ingroup. These results indicate that the relationships for Holopothrips species, and the proposed related genera, are more complex than previously reported; and morphological characters may not be enough to recover the evolutionary story within this group. We also discuss the influences of different character coding, continuous characters and weighting schemes in our results.

Invasive grass negatively affects growth and survival of an imperiled butterfly

With only ~1% of native prairie remaining in North America, populations of many prairie-obligate species, including the imperiled Dakota skipper butterfly, have drastically declined in recent decades. Unfortunately, population recovery is impeded by an insufficient understanding of Dakota skipper biology. Because larvae have never been naturally observed in the wild, even basic life history elements including preferred host plant(s) are not well understood, and potential hosts have been inferred from grasses inhabiting remnant sites rather than direct observations. To improve our understanding of Dakota skipper biology and habitat needs and inform recovery efforts, we conducted a no-choice performance experiment offering larvae 1 of 5 commonly occurring native grasses and 2 pervasive invasive grass species found across their historic range. We monitored larvae during key life history intervals and evaluated host plant quality by measuring larval and pupal mass, time to pupation, and survivorship. Larvae fed on all offered host grasses, but mass, phenology, and survivorship varied among treatments. Larvae reared on prairie dropseed and porcupine grass had the highest survival, the shortest time to adulthood, and the greatest mass, whereas larvae provided smooth brome and Kentucky bluegrass fared poorly for all observed metrics. All other grasses offered during the study were deemed ‘medium’ quality. Our results suggest that although larvae can feed on a variety of potential host plants, these hosts vary in quality. Invasive grasses across prairies in North America may pose an ecological trap to the conservation of Dakota skipper and other prairie-obligate Lepidoptera.

Fall armyworm (Spodoptera frugiperda): A threat in crop production in Africa and Asia

Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), el gusano cogollero (FAW) es una plaga de cultivos con mas de 80 especies hospedadoras que causan graves danos a los cereales de maiz. El gusano cogollero, originario de la region tropical y subtropical de America, se ha extendido rapidamente por todo el mundo. Las larvas y los adultos del gusano cogollero danan las hojas jovenes, los verticilos de las hojas, las borlas o las mazorcas del maiz. Bajo una fuerte infestacion de gusano cogollero se produce una perdida de rendimiento del 50-80% en la cosecha de maiz. Esta plaga es capaz de reproducirse, migrar y alimentarse rapidamente de una gran variedad de plantas hospedantes, lo que dificulta su seguimiento. Sin embargo, hay varias medidas de control reportadas en varios paises. El manejo integrado de plagas (cultural, quimico y biologico) se usa ampliamente para controlar esta plaga. Debido a que la plaga se ha vuelto resistente a muchos insecticidas, no se recomienda su uso en las etapas iniciales de la infestacion. Pero, la ultima opcion para este manejo de plagas seriamente infestadas es el uso de pesticidas por debajo del umbral economico. Esta revision se centra en la distribucion de insectos, la biologia, el dano del maiz y las posibles estrategias para su manejo.

Interactions of Helicoverpa punctigera (Lepidoptera: Noctuidae) Larvae and Adults With Four Native Host Plants Relative to Field Use Patterns

Generalist insect herbivores may be recorded from a great variety of host plants. Under natural conditions, however, they are almost invariably associated with a few primary host species on which most of the juveniles develop. We experimentally investigated the interaction of the generalist moth Helicoverpa punctigera Wallengren (Lepidoptera: Noctuidae) with four of its native host plants, two designated primary hosts and two secondary hosts (based on field observations). We tested whether primary host plants support higher survival rates of larvae and whether they are more attractive to ovipositing moths and feeding larvae. We also evaluated whether relative attractiveness of host plants for oviposition matches larval survival rates on them-the preference-performance hypothesis. Moths laid significantly more eggs on two of the four host plant species, one of them a primary host, the other a secondary host. Larvae developed best when reared on the attractive secondary host, developed at intermediate levels on the two primary hosts, and performed worst on the less attractive secondary host. Relative attractiveness of the four host plants to caterpillars differed from that of the moths. Neither adult nor larval attraction to host plants fully supported the preference-performance hypothesis, but oviposition was better correlated with larval survival rates than was larval attraction. Our results suggest the relative frequency at which particular host species are used in the field may depend on factors not yet considered including the long-distance attractants used by moths and the relative distribution of host species.

White Peach Scale, Pseudaulacaspis pentagona (Targ.) (Hemiptera: Diaspididae), is affected by host plant variety in a blackcurrant orchard

The White Peach Scale (WPS), Pseudaulacaspis pentagona (Hemiptera: Diaspididae) is one of the most damaging armored scale insects as it is a pest of various crops, including ornamental plants and fruit trees. In France, P. pentagona has become one of the main threats towards blackcurrants ( Ribes nigrum L.), especially in Burgundy, the Loire Valley and the Rhone-Alpes where the cultivation of blackcurrants is not only an emblematic and cultural activity but also has economic importance. We determined the direct effect of blackcurrant varieties on the infestation rate, female body size, and parasitism rate of P. pentagona . Our study was conducted in a Burgundy (France) natural population of P. pentagona developing on two blackcurrant varieties ‘Noir de Bourgogne’ and ‘Royal de Naples’. This field study showed that WPS females feeding on ‘Noir de Bourgogne’ were more numerous, had a larger body, a larger shield, and were less parasitized compared to females feeding on ‘Royal de Naples’ at the same site. However, the high scale density and the low parasitism rate found overall on both varieties brings into question the benefits of a pest management strategy based on the change of the varieties used in blackcurrant orchards.

Multidimensional plasticity in the Glanville fritillary butterfly: larval performance is temperature, host and family specific.

Variation in environmental conditions during development can lead to changes in life-history traits with long-lasting effects. Here, we study how variation in temperature and host plant (i.e. the consequences of potential maternal oviposition choices) affects a suite of life-history traits in pre-diapause larvae of the Glanville fritillary butterfly. We focus on offspring survival, larval growth rates and relative fat reserves, and pay specific attention to intraspecific variation in the responses (G × E × E). Globally, thermal performance and survival curves varied between diets of two host plants, suggesting that host modifies the temperature impact, or vice versa. Additionally, we show that the relative fat content has a host-dependent, discontinuous response to developmental temperature. This implies that a potential switch in resource allocation, from more investment in growth at lower temperatures to storage at higher temperatures, is dependent on the larval diet. Interestingly, a large proportion of the variance in larval performance is explained by differences among families, or interactions with this variable. Finally, we demonstrate that these family-specific responses to the host plant remain largely consistent across thermal environments. Together, the results of our study underscore the importance of paying attention to intraspecific trait variation in the field of evolutionary ecology.

First Report of Colletotrichum siamense Causing Anthracnose of Monstera deliciosa in Zhanjiang, China.

Monstera deliciosa Liebm is an ornamental foliage plant (Zhen et al. 2020De Lojo and De Benedetto 2014). In July of 2019, anthracnose lesions were observed on leaves of M. deliciosa cv. Duokong with 20% disease incidence of 100 plants at Guangdong Ocean University campus (21.17N,110.18E), Guangdong Province, China. Initially affected leaves showed chlorotic spots, which coalesced into larger irregular or circular lesions. The centers of spots were gray with a brown border surrounded by a yellow halo (Supplementary figure 1). Twenty diseased leaves were collected for pathogen isolation. Margins of diseased tissue was cut into 2 × 2 mm pieces, surface-disinfected with 75% ethanol for 30 s and 2% sodium hypochlorite (NaOCl) for 60 s, rinsed three times with sterile water before isolation. Potato dextrose agar (PDA) was used to culture pathogens at 28℃ in dark. Successively, pure cultures were obtained by transferring hyphal tips to new PDA plates. Fourteen isolates were obtained from 20 leaves. Three single-spore isolates (PSC-1, PSC-2, and PSC-3) were obtained ,obtained, which were identical in morphology and molecular analysis (ITS). Therefore, the representative isolate PSC-1 was used for further study. The culture of isolate PSC-1 on PDA was initially white and later became cottony, light gray in 4 days, at 28 °C. Conidia were single celled, hyaline, cylindrical, clavate, and measured 13.2 to 18.3 µm × 3.3 to 6.5 µm (n = 30). Appressoria were elliptical or subglobose, dark brown, and ranged from 6.3 to 9.5 µm × 5.7 to 6.5 µm (n = 30). Morphological characteristics of isolate PSC-1 were consistent with the description of Colletotrichum siamense (Prihastuti et al. 2009; Sharma et al. 2013). DNA of the isolate PSC-1 was extracted for PCR sequencing using primers for the rDNA ITS (ITS1/ITS4), GAPDH (GDF1/GDR1), ACT (ACT-512F/ACT-783R), CAL (CL1C/CL2C), and TUB2 (βT2a/βT2b) (Weir et al. 2012). Analysis of the ITS (accession no. MN243535), GAPDH (MN243538), ACT (MN512640), CAL (MT163731), and TUB2 (MN512643) sequences revealed a 97-100% identity with the corresponding ITS (JX010161), GAPDH (JX010002), ACT (FJ907423), CAL (JX009714) and TUB2 (KP703502) sequences of C. siamense in GenBank. A phylogenetic tree was generated based on the concatenated sequences of ITS, GAPDH, ACT, CAL, and TUB2 which clustered the isolate PSC-1 with C. siamense the type strain ICMP 18578 (Supplementary figure 2). Based on morphological characteristics and phylogenetic analysis, the isolate PSC-1 associated with anthracnose of M. deliciosa was identified as C. siamense. Pathogenicity test was performed in a greenhouse at 24 to 30oC with 80% relative humidity. Ten healthy plants of cv. Duokong (3-month-old) were grown in pots with one plant in each pot. Five plants were inoculated by spraying a spore suspension (105 spores ml-1) of the isolate PSC-1 onto leaves until runoff, and five plants were sprayed with sterile water as controls. The test was conducted three times. Anthracnose lesions as earlier were observed on the leaves after two weeks, whereas control plants remained symptomless. The pathogen re-isolated from all inoculated leaves was identical to the isolate PSC-1 by morphology and ITS analysis, but not from control plants. C. gloeosporioides has been reported to cause anthracnose of M. deliciosa (Katakam, et al. 2017). To the best of our knowledge, this is the first report of C. siamense causing anthracnose on M. deliciosa in ChinaC. siamense causes anthracnose on a variety of plant hosts, but not including M. deliciosa (Yanan, et al. 2019). To the best of our knowledge, this is the first report of C. siamense causing anthracnose on M. deliciosa, which provides a basis for focusing on the management of the disease in future.

Survey of the citrus leprosis vector (Brevipalpus yothersi) and phytoseiids in spontaneous plants of an organic citrus orchard.

Citrus leprosis (CL) is one of the most important viral diseases in sweet orange orchards in Latin America. It is caused by members of at least five species of the so-called Brevipalpus-transmitted viruses (BTV), and the prevalent is Citrus leprosis virus C (CiLV-C). This virus has the broadest host range amongst all CL-associated viruses and is transmitted by Brevipalpus yothersi, a polyphagous mite that can colonize a large variety of host plants, including some spontaneous ground cover plants. But if, on one hand, spontaneous plants can host CL virus and vector, on the other hand, they can offer alternative food for predators, equally common in organic citrus orchards. Brevipalpus yothersi and predator mites were surveyed in 33 spontaneous plants of a Westin sweet orange orchard conducted under organic production system in Brazil, from June 2010 to April 2011. Predatory mites were identified as phytoseiids, and Iphiseiodes zuluagai was the prevalent species, representing 58% of all predators. Other phytoseiids were considered accidental species in the area. Ageratum conyzoides and Alternanthera tenella were the most represented plant host species to predators, comprising 28 and 10% of the total surveyed plants, respectively. Brevipalpus yothersi specimens were detected on various spontaneous species: A. conyzoides, A. tenella, Amaranthus deflexus, Bidens pilosa, Ipomoea quamoclit, I. cairica, Merremia cissoides, Solanum americanum, Panicum maximum, and, predominantly, Commelina benghalensis. The latter has been previously reported as host of CiLV-C as well and, therefore, it is recommended to eliminate this species from citrus orchards.

Intraspecific variation in host plant traits mediates taxonomic and functional composition of local insect herbivore communities

1. Host plant phenotypic traits affect the structure of the associated consumer community and mediate species interactions. Intraspecific variation in host traits is well documented, although a functional understanding of variable traits that drive herbivore community response is lacking. We address this gap by modelling the trait‐environment relationship using insect traits and host plant traits in a multilevel model.2. We compare herbivore assemblages from the canopy of the phenotypically variable tree Metrosideros polymorpha on Hawai‘i Island. Multiple distinct varieties of M. polymorpha frequently co‐occur, with variation in morphological traits. Using this system, we identify host and insect traits that underlie patterns of herbivore abundance and quantify the strength of host‐insect trait interactions.3. This work examines plant‐insect interactions at a community scale, across 36 herbivore species in three orders. We find that co‐occurring trees of varying phenotype support distinct communities. Leaf traits, including specific leaf area, trichome presence, and leaf nutrients, explain 46% of variation in insect communities. We find that feeding guild and nymphal life history are correlated with host plant traits, and we show that model predictions are improved by including the host and insect trait interaction.4. This study demonstrates how insect herbivores traits influence community response to morphologically variable hosts. Environmental heterogeneity indirectly affected herbivore community structure via intraspecific variation in host plants, providing an important source of variation for maintaining diversity in the broader community.

The genetic arms race between plant and Xanthomonas: lessons learned from TALE biology.

The pathogenic bacterial genus Xanthomonas infects a wide variety of host plants and causes devastating diseases in many crops. Transcription activator-like effectors (TALEs) are important virulence factors secreted by Xanthomonas with the ability to directly bind to the promoters of target genes in plant hosts and activate their expression, which often facilitates the proliferation of pathogens. Understanding how plants cope with TALEs will provide mechanistic insights into crop breeding for Xanthomonas defense. Over the past 30 years, numerous studies have revealed the modes of action of TALEs in plant cells and plant defense strategies to overcome TALE attack. Based on these findings, new technologies were adopted for disease management to optimize crop production. In this article, we will review the most recent advances in the evolutionary arms race between plant resistance and TALEs from Xanthomonas, with a specific focus on TALE applications in the development of novel breeding strategies for durable and broad-spectrum resistance.