Ornamental Trees Research Articles

A report on positive phototaxis exhibited by newly emerged bagworm caterpillars (Lepidoptera: Psychidae)

The bagworm, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae) is a polyphagous moth that defoliates ornamental shrubs and trees. It has been reported as an emerging pest in the coastal agroecosystem of Odisha, India. A small experiment demonstrated that bagworm's newly emerged larva (NEL) was positively phototactic under white and UV light. After emerging in the rearing box, the larva was exposed to 3 volts of LED white and UV lights. After which, its phototactic behaviour was observed. Considering this report, light traps can be used to catch this nuisance species, which may now be more manageable. Hanging light sources on infested plant branches may be one technique, and when larvae congregate on that area of the branch, it may be easy to remove and kill them.

Citrus Fruit Movement Assessment Related to Fruit Damage during Harvesting with an Experimental Low-Frequency–High-Amplitude Device

The profitability of fresh citrus crops outlines the possibility of using mechanical systems to reduce the high cost of the manual harvesting operation. In this line, an experimental light shaker with low frequency and high amplitude and a hydraulic arm was developed. This device had been successfully used for harvesting ornamental citrus trees. In previous studies, it was proven that the removal percentage was adequate, but the percentage of slightly damaged fruit increased compared to a traditional fruit trunk shaker. Visualizing the fruit movements in high-speed video recording images during harvesting, a higher impact level was observed due to the higher amplitude. The aim of this study was to analyze the fruit movement during the vibration with the experimental shaker compared to the movement when vibrating with an orchard tractor mounted trunk shaker related to the increase of slightly damaged fruit when using the experimental shaker. Fruit movement parameters (fruit distance, fruit displacement, speed and acceleration) when using the two harvesting systems (experimental shaker and trunk shaker) were compared analyzing the high-speed video recordings. Results showed that the higher vibration amplitude produced a maximum distance experienced by the fruits (maximum displacement of 0.135 m with the experimental shaker compared to 0.078 m with the trunk shaker) that could cause a higher damage level (74% of slightly damaged fruits using the experiemntal shaker compared to 14% using the trunk shaker).

Pesticide Injection and Drenching

Drenching and injection are two pesticide application methods that are particularly effective in controlling some of the most troublesome insect pests of ornamental landscape trees. This 4-page document describes the equipment and procedures you will need to carry out either of these methods. Written by Frederick M. Fishel and published by the UF/IFAS Agronomy Department, January 2018.http://edis.ifas.ufl.edu/pi274 This new revision by Ryan Klein and Adam Dale expands and updates the original 2018 version by Fred Fishel. Original version: Fishel, Frederick M. 2018. “Pesticide Injection and Drenching: PI274, 1/2018”. EDIS 2018 (1).

Cytospora friesii and Sydowia polyspora are associated with the sudden dieback of Abies concolor in Southern Europe

Abies concolor was introduced to Europe in the 19<sup>th</sup> century and commonly planted as an ornamental tree. In 2018, after several very warm and dry vegetation seasons, which has likely caused abiotic stress in the trees, a sudden dieback of A. concolor was observed in the city of Aranđelovac in Serbia. The external symptoms were the rapid discoloration of needles in a larger part of the crown and eventually the dieback of the trees. The aim of this study was to identify the possible agents of damage by analysing the fungal communities associated with symptomatic needles using high-throughput sequencing as no symptoms of damage were seen on the branches or stems. Symptomatic needles were collected from the lower branches of five standing trees. Half of the needles were surface sterilised and the remaining were left unsterilised. DNA was extracted, amplified using ITS2 rDNA as a marker and sequenced. Quality filtering showed the presence of 6 191 high quality reads, which, following a clustering analysis, was found to represent 79 non-singletons fungal taxa. The most common fungi in both surface sterilised and unsterilised needles were the pathogens Cytospora friesii (59.7%) and Sydowia polyspora (20.6%). The results demonstrated that C. friesii and S. polyspora can cause a rapid decline of A. concolor trees subjected to abiotic stress.

High-Density Linkage Mapping and Identification of Quantitative Trait Loci Associated with Powdery Mildew Resistance in Flowering Dogwood (Cornus florida)

Flowering dogwood (Cornus florida L.) is a popular, spring-blooming ornamental tree native to the eastern United States. The species is in general very susceptible to powdery mildew caused by Erysiphe pulchra, which disfigures leaves, decreases growth, and negatively affects flowering. Breeding for resistance has been recognized as an ideal strategy for controlling the disease in C. florida, but efforts have been hindered by the rarity of PM resistance in available germplasm and knowledge of its genetic control. In this study, we mapped quantitative trait loci (QTL) associated with PM resistance/tolerance in two full sibling populations segregating for PM response: Rutgers H4AR15P25 (P25) × Rutgers H4AR15R28 (P28) (n = 195) and Rutgers H4AR15R25 × Rutgers H4AR15P35 (P35) (n = 83). High-density genetic linkage maps were constructed for the mapping populations using double digest restriction-site associated DNA sequencing-derived single nucleotide polymorphisms (SNPs) and simple sequence repeats (SSRs). The P25 × P28 map consisted of 2265 markers, spanning 1520 cM and 11 linkage groups (LGs) with an average marker spacing of 0.69 cM. The P25 × P35 map was constructed with 1788 markers, spanning 1256 cM and 11 LGs, with an average marker spacing of 0.72 cM. The maps had 604 markers in common and exhibited excellent collinearity. Through multiple QTL model mapping, one major QTL (LOD = 11.36 and R2 = 58.9%) was identified in P25 × P35. Furthermore, a minor QTL (LOD = 3.30 and R2 = 7.8%) was detected in P25 × P28. Due to their proximity onLG3, these QTL may be designating the same locus or tightly linked loci. The negative additive effects of both QTL signify that the PM susceptible male parents were contributing susceptibility alleles to the progeny. This is the first report of QTL associated with PM response on LG3 in C. florida and lays the groundwork for the development of marker-assisted selection for PM resistance in C. florida breeding programs.

The complete chloroplast genome sequence of Sloanea leptocarpa (Elaeocarpaceae) from China

Sloanea leptocarpa Diels, 1931 of the Elaeocarpaceae is an endemic plant from China distributed in subtropical evergreen broad-leaved forests and an excellent ornamental tree. The only available chloroplast genomic resource of the genus at present is that of S. sinensis (Hance) Hemsl., 1900 from eastern China. Here, we report the complete chloroplast genome sequence of S. leptocarpa which is less common than S. sinensis. The complete chloroplast genome of S. leptocarpa is 158,077 bp in length, and shows quadripartite organization including a pair of inverted repeat regions (IRs) (24,963 bp) that is divided by a large single-copy (LSC) region (88,519 bp) and a small single-copy (SSC) region (19,632 bp). The circular chloroplast genome of S. leptocarpa contains 119 unique genes, composed of 74 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis involving 52 species with complete chloroplast genomes supported that S. leptocarpa is closely related to S. sinensis. This finding is in agreement with previous studies in which Elaeocarpaceae belongs to Oxalidales instead of Malvales and provides additional evidence for the monophyly of the Sloanea, a sister clade of the Elaeocarpus.

Enantia chlorantha: A review

Enantia chlorantha (Dokita Igbo, Awogba, Awopa), depending on the dialect of the Yoruba speaking people of the South west and (Erumeru), South Eastern Nigeria. It is widely distributed along the coasts of West and Central Africa and common in the forest regions of Nigeria. It belongs to the family Annonaceae and the trade name is Africa yellow wood. It is an ornamental tree which may grow up to 30 m high, with dense foliage and spreading crown. The plant extracts have been widely used in folk medicine for the treatment of a large number of human ailments especially in rural communities in Nigeria. The stem bark is mostly preferred (even though the roots and the leaves may also be used), and decoctions, tinctures or infusions may be prepared. In Nigeria, E. chlorantha preparations can be made in the form of a drink, called ‘agbo’, or in the form of a powder, referred to as ‘agunmu’. Generally, in different places and cultures, it has found wide applications in folk medicine as a therapeutic agent for treating myriad of sickness and disease conditions such as malaria, aches, wounds, boils, vomiting, yellow fever, chills, sore, hepatitis, worms, intestinal spasms, sexual asthenia, jaundice, urinary tract infections, typhoid fever, leprosy spots, tuberculosis, gastric and duodenal ulcers. It also serves as a haemostatic agent, and as a uterine stimulant. Its medicinal properties range from preventing to curative while the pharmacological activities include antimalarial, antimicrobial and antibacterial, antioxidant, anti-Helicobacter pylori, anticonvusant, anti-inflammatory, analgesic and antipyretic, antiviral, gastro protective and enhancing male fertility. Saponins, flavonoids, alkaloids, phenols, reducing sugar and cardiac glycosides are some of the bioactive constituents present in the plant extracts which support its multiple properties and uses in traditional medicine. Palmatine, coloumbamine and jatrorrhizine are specific active principles isolated from the stem bark of Enantia chlorantha alkaloids. The aqueous extract of Enantia chlorantha is not toxic in acute intake up to 500 mg/kg body weight, but doses greater than 500mg/kg body weight can cause lungs, hepatic and kidney disorders following medium to long-term use. This review attempts to highlight the novelty of Enantia chlorantha: evaluating the traditional uses, nutritional, phytochemistry, biochemistry, pharmacology and medicinal potentials of this plant.

FEATURES OF REPRODUCTION AND PROSPECTS FOR THE USE OF INTRODUCED PLANTS OF THE GENUS ACTINIDIA LINDL. IN THE LANDSCAPE GARDENING OF THE RIGHT-BANK FOREST-STEPPE ZONE OF UKRAINE

The state of plantings of species and varieties of actinidia (Actinidia Lindl.) growing on the territory of the Uman National Horticultural University and their suitability for vertical gardening have been investigated and analyzed. It was found that in the green spaces of the university, a significant part was occupied by ornamental trees and shrubs, and plants of promising introduced species and varieties of the genus Actinidia Lindl. were used in landscaping much less common. It has been found out that it is possible to carry out landscaping of the walls of buildings in a short time in a lesser area, as well as isolate individual sections with hedges with the design of landscape gardening structures with the use of plants of new and promising introduced varieties of actinidia and landscape design instruments. The influence of the actinidia plants used in terms of varietal composition on the microclimate of the territory of the Uman NUS was assessed and recommendations were made on the working-out of theoretical proposals for landscaping and agrotechnological methods of growing maternal plants for interior in landscape gardening. It was cleared that the introduced species and varieties of the genus Actinidia Lindl. still remain rare in landscape architecture and forestry due to insufficient knowledge of the biological characteristics of plant growth and development in new cultivation conditions, agrotechnological measures for their own root propagation and cultivation of planting material. It is found that one of the effective methods of propagation of the studied varieties of actinidia in the conditions of the Right-Bank Forest-Steppe Zone of Ukraine is green stem cuttings — by semi-lignified cuttings with leaves. Green stem cuttings of the studied actinidia varieties have a low regenerative ability and are classified as medium-rooted. It has been established that the most important factors inducing the regenerative ability of cuttings and the quality of planting material are the dates of cuttings, the type of cutting and its metamerism, the agrotechnological conditions of rooting, as well as the preparation of cuttings for rooting and methods of treatment with biologically active substances of auxin nature. It has been find out that not all the varieties of actinidia are characterized by high regenerative capacity when rooted by stem cuttings under conditions of finely dispersed moisturizing.

Effects of biochar as a peat-based substrate component on morphological, photosynthetic and biochemical characteristics of Rhododendron delavayi Franch.

Biochar could be a promising peat substitute for horticultural plant production. We evaluated the feasibility of rice husk biochar (RHB) and wood chip biochar (WCB) as a peat-based substrate component for the cultivation of Rhododendron delavayi Franch., that is an ornamental dwarf tree species. A pot experiment was conducted to test the effects of RHB and WCB treatments at five application rates ( 0, 10, 20, 30, and 40% by volume) on morphological, photosynthetic and biochemical characteristics of R. delavayi. The substrate properties, plant growth, root traits, photosynthetic and biochemical parameters were analyzed. The addition of 20% WCB or 30-40% RHB enhanced the growth and photosynthetic activity of R. delavayi seedling, including increased plant height, numbers of leaves, leaf area, root surface area and root tip numbers, as well as improved total chlorophylls content and net photosynthetic rate. The addition of 40% RHB significantly increased the contents of carotenoids, polyphenols and anthocyans, indicating an enhanced antioxidant activity of R. delavayi seedlings. The mixed substrates (20% WCB, 30% RHB and 40% RHB) all have balanced aeration porosity and water holding porosity, suitable pH and electrical conductivity, and increased plant nutrient supply (especially K, Fe and Mn). However, the 40% WCB substrate depressed seedlings growth and reduced total chlorophylls content and net photosynthetic rate. The negative effects were linked to its low water holding porosity, high alkalinity and salinity, as well as high content of phytotoxic compounds, such as polycyclic aromatic hydrocarbons and volatile matter. In conclusion, a peat-based substrate containing 20% WCB or 30–40% RHB is a more favorable growth media for obtaining high-quality R. delavayi seedlings, while achieving sustainable horticulture production.

3D environmental urban BIM using LiDAR data for visualisation on Google Earth

Digitisation and building information modelling (BIM) technology are being adopted in the construction industry, but their application in the sustainable development of urban planning and civil engineering has been limited. A methodology was developed to generate 3D urban maps, which represent a potential environmental exposure related to urban green infrastructure. The methodology incorporated 3D geometric data obtained by Laser Imaging Detection and Ranging (LiDAR), location and information of green infrastructure, and meteorological data (direction and velocity of wind) into a single 3D BIM model to estimate the potential levels of exposure to urban green infrastructure by applying a modified aerobiological index to create risk maps for ornamental trees (AIROT). The BIM model facilitated a 3D visualisation of the exposure in urban environments by exporting information to GIS software, which could then be visualised on Google Earth. The main advance of the developed methodology is its applicability to any urban environment for determining and reducing aerobiological health risks in civil engineering.

A Review on Phytochemical Pharmacological and Biological Activities of Thuja Occidentalis

Thuja occidentalis plant of Cupressaceae family originated in Eastern North America and is now planted as an ornamental tree in Europe and Brazil, where it is known as the "tree of life" or "white cedar." It's often used to treat liver problems, enuresis, amenorrhea, bullous bronchitis, psoriasis, cystitis, uterine carcinomas, diarrhoea, and rheumatism in traditional medicine. Due to the presence of essential oil, coumarins, flavonoids, tannins, and proanthocyanins, the chemical ingredients of T. occidentalis have piqued researchers' curiosity for decades. Antioxidant, anti-inflammatory, antibacterial, antifungal, anticancer, antiviral, gastrointestinal tract protective action, radioprotection, antipyretic, and lipid metabolism regulating activity are all examples of pharmacology. As a result, the current study is a compilation of all essential material for T. occidentalis, including phytochemical, biological and a detailed examination of their pharmacological properties.The current review represents a synthesis of all relevant information for Thuja occidentalis, including phytochemical, biologicaland a thorough analysis of their pharmacological activities, in order to promote all of the biological activities demonstrated thus far, rather than focusing on a single biological activity.

Sooty canker, a destructive disease of banyan (Ficus benghalensis L.) trees in landscapes of Kish Island (Iran)

Ficus benghalensis L (banyan tree) has been planted as ornamental tree in parks, landscapes as well as along roads and streets in many southern cities of Iran. During field surveys conducted in Kish Island (Hormozgān province) an unusual decline was noticed on F. benghalensis. Affected trees exhibited bark necrosis, peeled off bark and cankers on branches and aerial roots, yellowing and defoliation, branch dieback and eventually death. A black sooty mass of fungal spores under the bark as well as wood discoloration in cross sections were also observed on infected parts of trees and pruning wood debris. Samples were collected from all affected parts of trees showing disease symptoms, pruning wood debris as well as rove arthropods in close proximity to the trees for the presence of fungal inoculum. In this study 239 Botryosphaeriaceae-like isolates were obtained from discoloured wood tissues, pruning wood debris and from the bodies of collected arthropods. Based on morphological characteristics and DNA sequence data of ITS and tef-1α gene regions, isolates were identified as Lasiodiplodia theobromae and Neoscytalidium dimidiatum. Pathogenicity of both species was performed on the branches of banyan trees and L. theobromae was more virulent, based on the length of necrotic lesions in the wood, than those of N. dimidiatum. This study is the first report of N. dimidiatum associated with sooty canker and dieback of F. benghalensis worldwide. Our study showed for the first time that L. theobromae and N. dimidiatum can also be associated with some arthropods. Our outcomes can improve the management strategies of trunk diseases caused by Botryosphaeriaceae species on ornamental trees in landscapes.

Microsatellite Loci Reveal High Genetic Diversity, Mutation, and Migration Rates as Invasion Drivers of Callery Pear (Pyrus calleryana) in the Southeastern United States.

Pyrus calleryana Decne. (Callery pear) is a deciduous tree native to China, Japan, Korea, and Taiwan. It is a popular ornamental tree in the United States (US) with early spring blooms and vibrant fall color. There are at least 26 cultivars of P. calleryana available in the US of which “Bradford” is the most well-known. Open-pollinated P. calleryana escapees are becoming one of the most common invasive tree species in the eastern United States. Developing better management practices for invasive P. calleryana requires detailed knowledge about reproductive biology and genetic diversity of the species, however, little is currently known about genetic variability within those open-pollinated populations. We investigated genetic diversity and population structure of non-cultivated, escaped P. calleryana populations within a ∼177 km radius in the southeastern United States. Because P. calleryana exhibits a range of morphological variation with great evolutionary potential, we hypothesized that a high genetic diversity would be manifested among escaped P. calleryana. Using 15 previously developed microsatellite loci, we genotyped 180 open-pollinated P. calleryana individuals that were collected across six naturally occurring sites in Tennessee, Georgia, and South Carolina, United States. Our results demonstrated the presence of a population structure with high genetic diversity, high gene flow, and high genetic differentiation between individuals across collection sites. Our results revealed that P. calleryana populations had differentiated shortly after the introduction to the US, most likely from specimens imported from Asia, consistent with historical records and our prior findings. The high invasive potential of the species is perhaps best underscored by transformation of P. calleryana specimens introduced from Asia into escape populations at continental scale across the United States. Our data also provided novel insight into potential issues that could be problematic for the future as P. calleryana may pose a potential threat to the economy, ecology, and native biodiversity in invaded areas.

Plastid genomes reveal evolutionary shifts in elevational range and flowering time of Osmanthus (Oleaceae).

Species of Osmanthus are economically important ornamental trees, yet information regarding their plastid genomes (plastomes) have rarely been reported, thus hindering taxonomic and evolutionary studies of this small but enigmatic genus. Here, we performed comparative genomics and evolutionary analyses on plastomes of 16 of the 28 currently accepted species, with 11 plastomes newly sequenced. Phylogenetic studies identified four main lineages within the genus that are here designated the: “Caucasian Osmanthus” (corresponding to O. decorus), “Siphosmanthus” (corresponding to O. sect. Siphosmanthus), “O. serrulatus + O. yunnanensis,” and “Core Osmanthus: (corresponding to O. sect. Osmanthus + O. sect. Linocieroides). Molecular clock analysis suggested that Osmanthus split from its sister clade c. 15.83 Ma. The estimated crown ages of the lineages were the following: genus Osmanthus at 12.66 Ma; “Siphosmanthus” clade at 5.85 Ma; “O. serrulatus + O. yunnanensis” at 4.89 Ma; and “Core Osmanthus: clade at 6.2 Ma. Ancestral state reconstructions and trait mapping showed that ancestors of Osmanthus were spring flowering and originated at lower elevations. Phylogenetic principal component analysis clearly distinguished spring‐flowering species from autumn‐flowering species, suggesting that flowering time differentiation is related to the difference in ecological niches. Nucleotide substitution rates of 80 common genes showed slow evolutionary pace and low nucleotide variations, all genes being subjected to purifying selection.

Flower and fruit morphological characteristics of different crabapple genotypes of ornamental value

Crabapples (Malus spp.) are frequently used as ornamental trees. However, selections differ in decorative impact through blossoming and fruiting traits, growth habit, disease tolerance, ecological adaptability and fruit litter, so that there can be other valuable benefits. The aim of the present investigation was to determine morphometric characteristics of flowers, fruits and seeds within 15 different genotypes of crabapples studied at M.M. Grishko National Botanical Garden in Kyiv, Ukraine. Their main morphometric parameters were as follows: the highest number of flowers in the inflorescence was recorded within trees of ‘Professor Sprenger’ with 5.78 flowers, whereas the corolla was mostly decorative for ‘Royalty’ cultivar, with 5.7 petals; fruit weight varied from 1.49 g (‘Adirondak’) to 20.56 g (‘Era’), length from 12.87 mm (‘Van Ezeltine’) to 25.11 mm (‘Ola’), diameter from 12.0 mm (‘Batterball’) to 26.74 mm (‘Rayka Rozeva’), fruits number 1.0 (‘Era’) to 5.5 (‘Evereste’). The relationships between flowers, fruit and seed traits, accounting 16 traits and 15 cultivars investigated was highlighted by Pearson correlation and were clustered by unweighted pair group method with arithmetic mean (UPGMA). The variability observed in the apple crab genotypes offers the possibility to choose and use some valuable ornamental cultivars for the beautification of the landscape, as well as for possible future Malus breeding projects.

Parasitisation of Yponomeuta malinellus feeding on Crataegus monogyna in the allotment gardens in the city of Poznań, Poland

The apple ermine moth (Yponomeuta malinellus Zeller) is an economically important pest of apple trees and apple orchards. It is also a pest of ornamental trees and shrubs in urban habitats. The aim of our study was to determine the degree of parasitisation of the apple ermine moth pupae collected from the common hawthorn (Crataegus monogyna Jacquin) in the allotment gardens in Poznań, Poland, by parasitoids from the Ichneumonidae family, to determine parasitoid species and the dates when they start flying. Judged from the parasitisation of pupae, the parasitoids reduced the apple ermine moth population by 9.1% over the period 2014–2016. The apple ermine moth pupae were parasitised by the following six parasitoid species: Gelis areator (Panzer), Herpestomus brunnicornis (Gravenhorst), Itoplectis alternans (Gravenhorst), I. maculator (Fabricius), I. tunetana (Schmiedeknecht), and Pimpla turionushtana (Linnaeus). The most effective entomophages H. brunnicornis and I. tunetana reduced the apple ermine moth population by 3.2% and 2.7%, respectively. Our results suggest that the apple ermine population in urban allotment gardens exposed to heavy anthropogenic pressure can be reduced by parasitoids of the Ichneumonidae family. The degree of parasitisation of the moth in this particular urban habitat may be comparable to the degree of its parasitisation in orchards.

Calonectria in the age of genes and genomes: Towards understanding an important but relatively unknown group of pathogens.

The genus Calonectria includes many aggressive plant pathogens causing diseases on various agricultural crops as well as forestry and ornamental tree species. Some species have been accidentally introduced into new environments via international trade of putatively asymptomatic plant germplasm or contaminated soil, resulting in significant economic losses. This review provides an overview of the taxonomy, population biology, and pathology of Calonectria species, specifically emerging from contemporary studies that have relied on DNA‐based technologies. The growing importance of genomics in future research is highlighted. A life cycle is proposed for Calonectria species, aimed at improving our ability to manage diseases caused by these pathogens.

A Barcode-Based Phylogenetic Characterization of Phytophthora cactorum Identifies Two Cosmopolitan Lineages with Distinct Host Affinities and the First Report of Phytophthora pseudotsugae in California.

A collection of 30 Phytophthora cactorum and 12 P. pseudotsugae (subclade 1a) strains isolated from several recent surveys across California was phylogenetically compared to a worldwide collection of 112 conspecific strains using sequences from three barcoding loci. The surveys baited P. cactorum from soil and water across a wide variety of forested ecosystems with a geographic range of more than 1000 km. Two cosmopolitan lineages were identified within the widespread P. cactorum, one being mainly associated with strawberry production and the other more closely associated with apple orchards, oaks and ornamental trees. Two other well-sampled P. cactorum lineages, including one that dominated Californian restoration outplantings, were only found in the western United States, while a third was only found in Japan. Coastal California forest isolates of both Phytophthora species exhibited considerable diversity, suggesting both may be indigenous to the state. Many isolates with sequence accessions deposited as P. cactorum were determined to be P. hedraiandra and P. ×serendipita, with one hybrid lineage appearing relatively common across Europe and Asia. This study contains the first report of P. pseudotsugae from the state of California and one of the only reports of that species since its original description.

A New Disease for Europe of Ficus microcarpa Caused by Botryosphaeriaceae Species.

The Indian laurel-leaf fig (Ficus microcarpa) is an important ornamental tree widely distributed in the urban areas of Italy. Surveys conducted in 2019 and 2020 on several tree-lined streets, squares, and public parks in Catania and Siracusa provinces (Sicily, southern Italy) revealed the presence of a new disease on mature trees. About 9% of approximately 450 mature plants showed extensive branch cankers and dieback. Isolations from woody tissues obtained from ten symptomatic plants consistently yielded species belonging to the Botryosphaeriaceae family. The identification of the recovered fungal isolates was based on a multi-loci phylogenetic (maximum parsimony and maximum likelihood) approach of the ITS, tef1-α, and tub2 gene regions. The results of the analyses confirmed the presence of three species: Botryosphaeria dothidea, Neofusicoccum mediterraneum, and N. parvum. Pathogenicity tests were conducted on potted, healthy, 4-year-old trees using the mycelial plug technique. The inoculation experiments revealed that all the Botryosphaeriaceae species identified in this study were pathogenic to this host. Previous studies conducted in California showed similar disease caused by Botryosphaeriaceae spp., and the pathogenic role of these fungi was demonstrated. To our knowledge, this is the first report of Botryosphaeriaceae affecting Ficus microcarpa in Europe.

Overexpression of the Salix matsudana SmAP2-17 gene improves Arabidopsis salinity tolerance by enhancing the expression of SOS3 and ABI5

BackgroundSalix matsudana (Koidz.) is a widely planted ornamental allotetraploid tree species. Genetic engineering can be used to enhance the tolerance of this species to soil salinization, endowing varieties with the ability to grow along coastlines, thereby mitigating afforestation and protecting the environment. The AP2/ERF family of transcription factors (TFs) plays multidimensional roles in plant biotic/abiotic stress tolerance and plant development. In this study, we cloned the SmAP2-17 gene and performed functional analysis of its role in salt tolerance. This study aims to identify key genes for future breeding of stress-resistant varieties of Salix matsudana.ResultsSmAP2-17 was predicted to be a homolog of AP2-like ethylene-responsive transcription factor ANT isoform X2 from Arabidopsis, with a predicted ORF of 2058 bp encoding an estimated protein of 685 amino acids containing two conserved AP2 domains (PF00847.20). SmAP2-17 had a constitutive expression pattern and was localized to the nucleus. The overexpression of the native SmAP2-17 CDS sequence in Arabidopsis did not increase salt tolerance because of the reduced expression level of ectopic SmAP2-17, potentially caused by salt-induced RNAi. Transgenic lines with high expression of optimized SmAP2-17 CDS under salt stress showed enhanced tolerance to salt. Moreover, the expression of general stress marker genes and important salt stress signaling genes, including RD29A, ABI5, SOS3, AtHKT1, and RBohF, were upregulated in SmAP2-17-overexpressed lines, with expression levels consistent with that of SmAP2-17 or optimized SmAP2-17. Promoter activity analysis using dual luciferase analysis showed that SmAP2-17 could bind the promoters of SOS3 and ABI5 to activate their expression, which plays a key role in regulating salt tolerance.ConclusionsThe SmAP2-17 gene isolated from Salix matsudana (Koidz.) is a positive regulator that improves the resistance of transgenic plants to salt stress by upregulating SOS3 and ABI5 genes. This study provides a potential functional gene resource for future generation of salt-resistant Salix lines by genetic engineering.