Host Plants Association with Longhorn Beetles of Food Value: Traditional Knowledge of the Guaraní as Cultural Identity Keepers

The study of plant-insect interactions and how cultural groups perceive and manage them constitutes one of the interests of ethnoentomology. This work describes the association between host plants and longhorn beetles (Order: Coleoptera; Family: Cerambycidae), an important food among the Guaraní peoples of the province of Misiones, Argentina. Different management methods of host tree species are analyzed in order to promote the rearing of larvae for edible use. We also discuss a story about the mythical origin of cerambicids relayed by the Ava Chiripa Guaraní community. We reflect on the importance of the local worldview in the maintenance of ancestral practices, such as the cultural tasks involved in slash-and-burn agriculture and the intimate knowledge of biological relationships between the cerambycids and their woody host plants.

HrpL Regulon of Bacterial Pathogen of Woody Host Pseudomonas savastanoi pv. savastanoi NCPPB 3335

The Pseudomonas savastanoi species comprises a group of phytopathogenic bacteria that cause symptoms of disease in woody hosts. This is mediated by the rapid activation of a pool of virulence factors that suppress host defences and hijack the host’s metabolism to the pathogen’s benefit. The hrpL gene encodes an essential transcriptional regulator of virulence functions, including the type III secretion system (T3SS), in pathogenic bacteria. Here, we analyzed the contribution of HrpL to the virulence of four pathovars (pv.) of P. savastanoi isolated from different woody hosts (oleander, ash, broom, and dipladenia) and characterized the HrpL regulon of P. savastanoi pv. savastanoi NCPPB 3335 using two approaches: whole transcriptome sequencing (RNA-seq) and the bioinformatic prediction of candidate genes containing an hrp-box. Pathogenicity tests carried out for the P. savastanoi pvs. showed that HrpL was essential for symptom development in both non-host and host plants. The RNA-seq analysis of the HrpL regulon in P. savastanoi revealed a total of 53 deregulated genes, 49 of which were downregulated in the ΔhrpL mutant. Bioinformatic prediction resulted in the identification of 50 putative genes containing an hrp-box, 16 of which were shared with genes previously identified by RNA-seq. Although most of the genes regulated by HrpL belonged to the T3SS, we also identified some genes regulated by HrpL that could encode potential virulence factors in P. savastanoi.

Revision of the Hawaiian endemic leaf-mining moth genus Philodoria Walsingham (Lepidoptera: Gracillariidae): its conservation status, host plants and descriptions of thirteen new species

Philodoria Walsingham, 1907 is a threatened, Hawaiian endemic genus of leaf-mining gracillariid moths that feeds as larvae on many threatened and endangered Hawaiian endemic plants. These moths are poorly studied and species lack detailed descriptions of morphology, distribution data, and natural history information of adults and immatures. Based on extensive fieldwork from 2013 to 2016, and examination of museum specimens, we describe or redescribe 51 species, 13 which are new species and provide biological and distribution data for 41 species. The 13 new species and their host plants are: P. alakaiensis Kobayashi, Johns & Kawahara, sp. n. (Asteraceae: Dubautia sp.), P. funkae Kobayashi, Johns & Kawahara, sp. n. (Asteraceae: Wilkesia gymnoxiphium), P. haelaauensis Kobayashi, Johns & Kawahara, sp. n. (Urticaceae: Pipturus albidus, P. rockii, Pipturus sp.), P. hesperomanniella Kobayashi, Johns & Kawahara, sp. n. (Asteraceae: Hesperomannia arborescens and H. swezeyi), P. keaensis Kobayashi, Johns & Kawahara, sp. n. (host unknown), P. keahii Kobayashi, Johns & Kawahara, sp. n. (Asteraceae: Remya mauiensis), P. knudseniiella Kobayashi, Johns & Kawahara, sp. n. (Asteraceae: Dubautia knudsenii subsp. nagate and D. latifolia), P. lama Kobayashi, Johns & Kawahara, sp. n. (Ebanaceae: Diospyros sandwicensis and/or D. hillebrandii), P. limahuliensis Kobayashi, Johns & Kawahara, sp. n. (Malvaceae: Hibiscus waimeae subsp. hannerae), P. napaliensis Kobayashi, Johns & Kawahara, sp. n. (Ebanaceae: Diospyros sandwicensis and/or D. hillebrandii), P. obamaorum Kobayashi, Johns & Kawahara, sp. n. (Urticaceae: Pipturus albidus, Pipturus sp.), P. opuhe Kobayashi, Johns & Kawahara, sp. n. (Urticaceae: Urera kaalae and U. sandvicensis) and P. platyphylliella Kobayashi, Johns & Kawahara, sp. n. (Asteraceae: Dubautia platyphylla). Types of 30 species were examined, lectotypes of 16 species are designated, and a key to all Philodoria species and all Hawaiian leaf-mining moths are provided. We also present a new Hawaiian name for Philodoria, which we call Hunelele ʻelilau, meaning “tiny flier, leaf excavator”, referring to their life history and behavior. Philodoria feeds on five herbraceous and woody host plant families, and 41 species persist in localized populations in Hawaii as of 2016. Twelve species (P. alakaiensis, P. funkae, P. haelaauensis, P. hespermanniella, P. kauaulaensis, P. keaensis, P. keahii, P. knudsniiella, P. limahuliensis, P. platyphylliella, P. sciallactis, P. wilkesiella) appear to be severely threatened, as these species are rare or feed exclusively on plants that are endangered or rare. We were unable to document 10 species (P. costalis, P. lipochaetaella, P. micropetala, P. nigrella, P. nigrelloides, P. opuhe, P. pipturiana, P. pipturicola, P. pittosporella, P. spilota) after many efforts to sample in or near their historical habitats. We believe these species may be extinct. Given their restricted distribution and the fact that many species feed on rare and endangered plants, there is a risk that many more Philodoria species may go extinct unless immediate conservation measures are taken.

Assessment of Cytospora Isolates From Conifer Cankers in China, With the Descriptions of Four New Cytospora Species

Cytospora species are widely distributed and often occur as endophytes, saprobes or phytopathogens. They primarily cause canker and dieback diseases of woody host plants, leading to the growth weakness or death of host plants, thereby causing significant economic and ecological losses. In order to reveal the diversity of Cytospora species associated with canker and dieback diseases of coniferous trees in China, we assessed 11 Cytospora spp. represented by 28 fungal strains from symptomatic branches or twigs of coniferous trees, i.e., Juniperus procumbens, J. przewalskii, Picea crassifolia, Pinus armandii, P. bungeana, Platycladus orientalis in China. Through morphological observations and multilocus phylogeny of ITS, LSU, act, rpb2, tef1-α, and tub2 gene sequences, we focused on four novel Cytospora species (C. albodisca, C. discostoma, C. donglingensis, and C. verrucosa) associated with Platycladus orientalis. This study represented the first attempt to clarify the taxonomy of Cytospora species associated with canker and dieback symptoms of coniferous trees in China.

Cytospora (Diaporthales) in China

Members of the genus Cytospora are often reported as endophytes, saprobes or phytopathogens, primarily causing canker diseases of woody host plants. They occur on a wide range of hosts and have a worldwide distribution. Although several species have in the past been reported from China, the vast majority are not known from culture or DNA phylogeny. The primary aim of the present study was thus to clarify the taxonomy and phylogeny of a large collection of Cytospora species associated with diverse hosts in China. Cytospora spp. were collected in northeast, northwest, north and southwest China, indicating that the cold and dry environments favour these fungi. In this paper, we provide an assessment of 52 Cytospora spp. in China, focussing on 40 species represented by 88 isolates from 28 host genera. Based on a combination of morphology and a six-locus phylogeny (ITS, LSU, act1, rpb2, tef1-α and tub2), 13 new species and one new combination are introduced. The majority of the species investigated here appear to be host-specific, although further collections and pathogenicity studies will be required to confirm this conclusion.

Isolation, Characterization, and Pathogenicity of Two Pseudomonas syringae Pathovars from Populus trichocarpa Seeds

Pseudomonas syringae is a ubiquitous plant pathogen, infecting both woody and herbaceous plants and resulting in devastating agricultural crop losses. Characterized by a remarkable specificity for plant hosts, P. syringae pathovars utilize a number of virulence factors including the type III secretion system and effector proteins to elicit disease in a particular host species. Here, two Pseudomonas syringae strains were isolated from diseased Populustrichocarpa seeds. The pathovars were capable of inhibiting poplar seed germination and were selective for the Populus genus. Sequencing of the newly described organisms revealed similarity to phylogroup II pathogens and genomic regions associated with woody host-associated plant pathogens, as well as genes for specific virulence factors. The host response to infection, as revealed through metabolomics, is the induction of the stress response through the accumulation of higher-order salicylates. Combined with necrosis on leaf surfaces, the plant appears to quickly respond by isolating infected tissues and mounting an anti-inflammatory defense. This study improves our understanding of the initial host response to epiphytic pathogens in Populus and provides a new model system for studying the effects of a bacterial pathogen on a woody host plant in which both organisms are fully genetically sequenced.

Ectomycorrhizal Flora Formed by Main Forest Trees in the Irtysh River Region of Central and Northeastern Kazakhstan

In this study, the aim was to determine and identify symbiotically living ectomycorrhizas of the main tree species forming forests in central and northeastern Kazakhstan. Surveys were conducted on the right bank of the Irtysh River in a mixed forest of Pinus sylvestris, Picea obovata and Betula pendula trees. The collection was formed and the primary identification of voucher samples of fruiting bodies of macromycetes collected as ectomycorrhiza forming fungi was completed. In the collection and species identification of fruiting bodies, standard methods were used. A total of 30 ectomycorrhizas belonging to Agaricomycetes were identified. The distribution of 30 species into families is as follows: Suillaceae (8), Russulaceae (7), Cortinariaceae (4), Boletaceae (3), Tricholomataceae (2), Amanitaceae (1), Cantharellaceae (1), Gomphaceae (1), Gomphidiaceae (1), Paxillaceae (1), and Bankeraceae (1). The richest genus on account of the number of species was Suillus (8). Concerning the woody host species, 17 mycorrhizas were determined to build symbiosis with P. sylvestris, 8 mycorrhizas with B. pendula, 6 mycorrhizas with Populus tremula, 1 mycorrhiza with P. obovata, 1 mycorrhiza with Quercus robur, 1 mycorrhiza with Salix sp., and 1 mycorrhiza with Pinus densiflora Siebold and Zuccarini. Ectomycorrhizas should be used as a major performance-enhancing tool in afforestation and restoration studies in the Irtysh River basin under extreme ecological conditions and under climate change effects.

Diversity of woody-host infecting Phytophthora species in public parks and botanic gardens as revealed by metabarcoding, and opportunities for mitigation through best practice

The diversity of Phytophthora species in soils collected from 14 highly disturbed sites in northern Britain, including botanic gardens, arboreta, public parks and other amenity woodland sites, was analysed using a molecular technique known as DNA metabarcoding. This technique enables the identification of multiple species present in a single environmental sample based on a DNA ‘barcode’ unique to each species. The genus Phytophthora was targeted in this study due to its increasing impact on Britain’s forests and woodlands over thelast 20 years. The introduction and spread of new Phytophthora species into Britain has been strongly associated with the movement of traded containerised plants, with a number of Phytophthora outbreaks reported on host trees located in public gardens and parks that had recently undergone planting or landscape regeneration schemes. This study was undertaken to assess the extent to which these highly disturbed sites with extensive planting regimes act as harbours for woody-host infecting Phytophthora species. A total of 23 Phytophthora species, the majority of which are known to be pathogens of woody hosts, were detected across the 14 sites sampled. These included four quarantine-regulated pathogens and four species notpreviously recorded in Britain. Also detected were three as-yet undescribed Phytophthora species and nine oomycete sequences with no clear match to any known genus. There was no effect of geographical location, elevation, underlying soil type, host family or host health status on the Phytophthora assemblages at each site, suggesting that the Phytophthora communities detected are likely to comprise introduced species associated with planting programmes. P. austrocedri and P. pseudosyringae were two of the most abundant Phytophthoraspecies detected, both of which cause serious damage to trees and are regarded as fairly recent introductions to Britain. The practical implications of the findings in terms of mitigating Phytophthora introduction, spread and impact at botanic gardens, arboreta and urban parks are discussed.

Metabarcoding reveals a high diversity of woody host-associatedPhytophthoraspp. in soils at public gardens and amenity woodlands in Britain

Forests and woodlands worldwide are being severely impacted by invasivePhytophthoraspecies, with initial outbreaks in some cases occurring on host trees located in public parks and gardens. These highly disturbed sites with diverse planting practices may indeed act as harbours for invasivePhytophthorapathogens which are particularly well adapted to surviving in soil. High throughput Illumina sequencing was used to analysePhytophthoraspecies diversity in soil samples collected from 14 public garden/amenity woodland sites in northern Britain. Bioinformatic analyses revealed some limitations to using internal transcribed spacer as the barcode region; namely reporting of false positives and ambiguous species matches. Taking this into account, 35 distinct sequences were amplified across the sites, corresponding to 23 knownPhytophthoraspecies as well as twelve oomycete sequences with no match to any knownPhytophthoraspecies.Phytophthora pseudosyringaeandP. austrocedri, both of which cause serious damage to trees and are regarded as fairly recent introductions to Britain, were the two most abundantPhytophthoraspecies detected. There was no evidence that any of the detectedPhytophthoraspecies were more associated with any one type of host, healthy or otherwise. This study has demonstrated the ubiquity and diversity ofPhytophthoraspecies endemic in highly managed, extensively planted soil environments in Britain. Suggested improvements to the methodology and the practical implications of the findings in terms of mitigatingPhytophthoraspread and impact are discussed.

Trunk Disease Fungi Associated with Syzygium cumini in Iran

Syzygium cumini trees with dieback symptoms and cankers were observed in two provinces in Iran. Isolations were made from diseased branches and cankers and from asymptomatic S. cumini wood samples. Several trunk disease pathogens were identified based on morphological characteristics and by molecular methods, including Cadophora luteo-olivacea, Diplodia sapinea, D. seriata, Neoscytalidium hyalinum, Phaeoacremonium fraxinopennsylvanicum, P. krajdenii, P. parasiticum, P. viticola, and Pleurostoma richardsiae, which were isolated from S. cumini for the first time in the world. Pathogenicity tests conducted with all species confirmed their status as possible S. cumini pathogens. N. hyalinum was the most aggressive species and caused the longest lesions on inoculated shoots. The endophytic character of some fungal species isolated from asymptomatic wood of S. cumini is further discussed. Our results indicated that S. cumini is a new woody host to many known fungal trunk pathogens.