The emergence of new plant diseases is an increasingly important concern. Climate change is likely to be among the factors causing most of the emerging diseases endangering forest and tree heritage around the world. Such diseases may be caused by latent pathogens or microorganisms cryptically associated with plants. The shift from a non-pathogenic to a pathogenic stage may depend on physiological alterations of the host, environmental changes and/or stress factors. In some woods of the Salento peninsula (Apulia region, Italy) sudden declines of holm oak plants (Quercus ilex L.) have been observed since 2016. The morphological and molecular characterization of representative fungal isolates associated with canker and necrosis in declining plants indicated that these isolates belong to the Botryosphaeriaceae family, and the most frequent species were Diplodia corticola and Diplodia quercivora, followed by Neofusicoccum vitifusiforme. In artificially inoculated young holm oak plants, both D. corticola and D. quercivora species produced intense and severe subcortical and leaf margin necrosis. N. vitifusiforme, although less aggressive, induced the same symptoms. Our research in addition to confirm the involvement of D. corticola in olm oak decline, represents the first report of D. quercivora as a new pathogen on Quercus ilex in Italy. Furthermore, to the best of our knowledge, we also found N. vitifusiforme as a new pathogen on Q. ilex for the first time.

The performance of two bio inoculants either in single or in combined applications with organic fertilizer was tested to determine their effect on plant growth and yield under normal and unfavorable field conditions such as low pH value and low content of P. Arbuscular Mycorrhiza Fungi ((AMF; three species of Glomus) and the plant growth-promoting bacterial strain Kosakonia radicincitans DSM16656 were applied to barley in two years field experiment with different soil pH levels and available nutrients. Grain yield, content of P, N, K, Mg, and soil microbial parameters were measured. Grain yield and content of nutrients were significantly increased by the applications of mineral fertilizer, organic fertilizer, AMF, K. radicincitans, and combined application of organic fertilizer with AMF and with K. radicincitans over the control under normal growth conditions. Under low pH and low P conditions, only the combined application of the organic fertilizer with K. radicincitans and organic fertilizer with AMF could increase grain yield and content of nutrients of barley over the control.

Endophytic microbes are a ubiquitous group of plant-associated communities that colonize the intercellular or intracellular host tissues while giving numerous beneficial effects to the plants. All the plant species are thought to be associated with endophytes, majorly constituted with bacteria and fungi. During the last two decades, there has been a considerable movement toward the study of endophytes associated with coffee plants. In this review, the main consideration is given to address the coffee-associated endophytic bacteria and fungi, particularly their action on plant growth promotion and the biocontrol of pests. In addition, we sought to identify and analyze the gaps in available research. Additionally, the potential of endophytes to improve the quality of coffee seeds is briefly discussed. Even though there are limited studies on the subject, it has been well recognized the potentiality of coffee endophytes in plant growth promotion through enhancing nitrogen fixation, availability of minerals, nutrient absorption, secretion of phytohormones, and other bioactive metabolites. Further, the antagonistic effect against various coffee pathogenic bacteria, fungi, nematodes, and also insect pests lead to the protection of the crop. Furthermore, it is recognized that endophytes enhance the sensory characteristics of coffee as a new field of study.

A plant’s health and productivity is influenced by its associated microbes. Although the common microbiome is often thought to be the most influential, significant numbers of rare or uncommon microbes (eg. specialized endosymbionts) may also play an important role in the health and productivity of certain plants in certain environments. To help identify rare/specialized bacteria and fungi in the most important angiosperm plants, we contrasted microbiomes of the shoots, roots and rhizospheres of Arabidopsis, Brachypodium, maize, wheat, sugarcane, rice, tomato, coffee, common bean, cassava, soybean, switchgrass, sunflower, Brachiaria, barley, sorghum, and pea. Plants were grown inside sealed jars on sterile sand or field soil. About 95% and 86% of fungal and bacterial diversity inside plants was uncommon, however judging by read abundance, up to half of the mycobiome consists of uncommon fungal cells, while less than 11% of bacterial endophytes are rare. Uncommon seed transmitted microbiomes consisted mostly of Proteobacteria, Firmicutes, Bacteriodetes, Ascomycetes and Basidiomycetes that most heavily colonized shoots, to a lesser extent roots and least of all rhizospheres. Soil served as a more diverse source of rare microbes than seeds, replacing or excluding the majority of the uncommon seed transmitted microbiome. With the rarest microbes, their colonization pattern could either be the result of stringent biotic filtering by most plants, or uneven/stochastic inoculum distribution in seeds or soil. Several strong plant-microbe associations were observed such as seed transmission to shoots, roots and/or rhizospheres of Sarocladium zeae (maize), Penicillium (pea and Phaseolus), and Curvularia (sugarcane), while robust bacterial colonization from cassava field soil occurred with the cyanobacteria Leptolyngbya into Arabidopsis and Panicum roots, and Streptomyces into cassava roots. Some abundant microbes such as Sakaguchia in rice shoots or Vermispora in Arabidopsis roots appeared in no other samples, suggesting they were infrequent, stochastically deposited propagules from either soil or seed (impossible to know based on the available data). Future experiments with culturing and cross inoculation of these microbes between plants may help us better understand host preferences and their role in plant productivity, perhaps leading to their use in crop microbiome engineering and enhancement of agricultural production.

Apple replant disease is a severe problem in orchards and tree nurseries. Evidence for the involvement of a nematode-microbe disease complex was reported. To search for this complex, plots with a history of apple replanting, and control plots cultivated for the first time with apple were sampled in two fields in two years. Shoot weight drastically decreased with each replanting. Nematodes were extracted from soil samples by floatation-centrifugation, washed on a 20 µm-sieve, and used for DNA extraction. Nematode communities and co-extracted fungi and bacteria were analyzed by high-throughput sequencing of amplified ribosomal fragments. The nematode community and co-extracted fungal and bacterial communities significantly differed between replanted and control plots. Free-living nematodes of the genera Aphelenchus, Cephalenchus, and an unidentified Dorylaimida were associated with replanted plots, as indicated by linear discriminant analysis effect size. Among the co-extracted fungi and bacteria, Mortierella was most indicative of replanting. Some genera, mostly Rhabditis, indicated healthy control plots. Isolating and investigating the putative disease complexes will help to understand and alleviate stress-induced root damage of apple in replanted soil.

The gut microbiota has recently been associated with susceptibility/resistance to malaria in animal models and humans, yet the impact of the gut microbiota on the risk of a malaria attack remains to be assessed. This study aims at assessing the influence of the gut microbiota on malaria attacks and Plasmodium parasitæmia in children living in a malaria-endemic area in Mali. Three hundred healthy children were included in a 16-months cohort study in Bandiagara. Their gut bacteria and fungi community structures were characterised via 16S and ITS metabarcoding from stool samples collected at inclusion. Clinician team monitored the occurrence of malaria attacks. Asymptomatic carriage of Plasmodium was assessed by qPCR. Over the 16-month period, 107 (36%) children experienced at least one occurrence of malaria attacks, and 82 (27%) at least one asymptomatic Plasmodium parasitæmia episode. A higher gut bacteria richness was independently associated with susceptibility to asymptomatic parasitæmia episodes and malaria attacks; while the Shannon H diversity and Chao-1 richness index of gut fungi community structure was relatively homogeneous in children who were and were not infected with P. falciparum. Using a linear discriminant effect size analysis of operational taxonomic units assigned to the species level, 17 bacteria, including Clostridiaceae, Eubacteriaceae, Senegalimassilia sp., Atopobiaceae and Lachnosipraceae, and seven fungi, including Dioszegia fristigensis, Ogataea polymorpha and Cutaneotrichosporon cyanovorans, were associated with susceptibility; whereas eight bacteria, including, Bifidobacterium spp., Weissela confusa and Peptostreptococcacea, and 3 fungi, Malassezia sp., Niesslia exosporoides, and Didymocrea leucaenae, were associated with resistance to malaria. Moreover, 15 bacteria, including Coproccus eutactus, Terrisporobacter petrolearius, Klebsiella pneumoniae and Ruminococcaceae, and 13 fungi, including Wallemia mellicola, were associated with susceptibility, whereas 19 bacteria, including Bifidobacterium spp., Bacteroides fragilis, Peptostreptococcacea, and Lactobacillus ruminis, and three fungi, including Cryptococcus neoformans, were associated with resistance to asymptomatic Plasmodium parasitæmia episodes. Further studies are needed to confirm these findings that point the way towards strategies aiming to reduce the risk of malaria by modulating gut microbiota components in at-risk populations.

The present study evaluates mold fungal resistance of newly developed loose-fill thermal insulation materials from wheat straw, corn stalk and water reed. Three different processing methods of raw materials was performed by mechanical crushing (Raw, ≤ 20 mm), thermal-mechanical pulping (TMP) using 4% NaOH and steam explosion pulping (SEP). An admixture of boric acid (8%) and tetraborate (7%) was applied to all processed substrates due to their anti-fungal properties. Additionally, the fourth sample group was prepared from SEPs of all raw species without boric acid and tetraborate (SEP*) as control. Samples from all treatments were separately inoculated by 5 different fungal species and incubated in darkness for 28 days at 28 ℃ and RH >90%. The highest resistance to the colonization of mold fungi was achieved by TMP and SEP processing coupled with addition of boric acid and tetraborate, where molds infest only around 35% to 40% of the inoculated sample area. The lowest mold fungi resistance was detected for Raw and SEP* samples, each ~75% that was affected by rich amount of accessible nutrients, suggesting that boric acid and tetraborate additives alone did not prevent mold fungal growth as effective as in combination with TMP and SEP treatments. Together, the achieved fungal colonization scores after combined fungicide and pulping treatments are acceptable for the application of various renewable materials in future thermal insulation product development.

Global agriculture has been forced to increase food production to feed the growing human population, while confronting various environmental obstacles such as global warming, resistance to pathogens, and constraints on arable land caused by soil salinity, drought, rising sea level, saltwater intrusion, and urbanization. Regarding abiotic stresses, salinity is a worldwide problem for agricultural production. Many efforts, therefore, have been made to cope with the environmental challenges, however, the progress of salinization, which is mainly caused and accelerated by anthropogenic activities, is likely faster than our progress in finding ways to deal with this problem. In addition, drought represents a global threat to the production of major crops. In addition, pests and pathogens cause significant crop losses and diminish global food security. Among the various strategies that have been investigated and applied in plant science, antimicrobial peptides derived from plants have caught widespread attention from scientists since these peptides exhibit beneficial biological activities. In agricultural science, there have been reports on the roles of antimicrobial peptides with active properties against biotic and abiotic stresses. Non-specific plant lipid transfer proteins, thionins, systemins, defensins, cyclotides, and heveins-like antimicrobial peptides are common antimicrobial peptides that have been found to be involved in the defense system against fungi and insect pests. Based on their potential ability to protect crops from pests, bacteria, and pathogenic fungi, the use of antimicrobial peptide genes in creating transgenic plants has been largely conducted during the last decades, and these studies have obtained positive results against the growth of fungi and bacteria. This review will focus on the latest progress in studies of antimicrobial peptides related to biotic and abiotic stress tolerance in plants. We will also update the current progress in the development of antimicrobial peptide-based transgenic crops.

Trichoderma atroviride is a strong necrotrophic mycoparasite antagonizing and feeding on a broad range of fungal phytopathogens. It further beneficially acts on plants by enhancing growth in root and shoot and inducing systemic resistance. Volatile organic compounds (VOCs) are playing a major role in all those processes. To date, T. atroviride IMI 206040 and T. atroviride P1 are among the most frequently studied T. atroviride strains and hence are used as model organisms to study mycoparasitism and photoconidiation. However, there are no studies available, which systematically and comparatively analyzed putative differences between these strains regarding their light-dependent behavior. We therefore explored the influence of light on conidiation and the mycoparasitic interaction as well as the light-dependent production of VOCs in both strains. Our data show that in contrast to T. atroviride IMI 206040 conidiation in strain P1 is independent of light. Furthermore, significant strain-and light-dependent differences in the production of several VOCs between the two strains became evident, indicating that T. atroviride P1 could be a better candidate for plant protection than IMI 206040.

White-rot fungi (WRF) have specific enzymes to degrade lignocellulosic and phenolic compounds. Therefore, their direct application could be an alternative to biodegrade complex lignocellulosic biomass such as olive mill solid waste (OMSW). The aim of this study was to evaluate the capacity of A. discolor and S. hirsutum to grow in OMSW as the sole substrate under static conditions and evaluate the phenolic removal compounds and lignin degradation. The lignolytic enzyme activity was determined, as was the phenolic compound removal. At the same time, lignin degradation and structural changes were evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM), respectively. Both strains were able to grow using OMSW as the sole substrate without adding other nutrients, oxygen and/or agitation. The higher ligninolytic enzyme activity was found at day 8, and the highest phenolic removal (more than 80% with both strains) was reached after 24 days of incubation. The CLSM analysis confirmed lignin degradation through the drop in lignin fluorescence from 3967 for untreated OMSW to 235 and 221 RFU after 24 days of treatment by A. discolor and S. hirsutum respectively. The results indicate that both WRF could be suitable candidates to design an in-situ pretreatment step of OMSW, as long as in future research the WRFs have the same performance in non-sterile conditions.

The cytoplasmic membrane is the fundamental component of all living cells, which participates in various physiological processes, such as material exchange, stress response, cell recognition, signal transduction, cellular immunity, apoptosis, pathogenicity, etc. The normal function of a cytoplasmic membrane requires stable organization of transmembrane protein-lipid microdomains, transmembrane protein-cell wall microdomains, and cytoskeleton-transmembrane protein microdomains. Here, we review the mechanisms and functions of various membrane lipid components, fatty acid content and saturation, membrane curvature, and cell wall and cytoskeleton in plasma membrane homeostasis affecting the pathogenicity of pathogenic fungi. Pathogenic fungi maintains plasma membrane homeostasis and contributes to fungal virulence by maintaining plasma membrane assembly, structural and functional integrity of pathogenic fungi at various stages of cell development through interactions among lipid components of cytoplasmic membranes, transmembrane proteins, cytoskeleton and cell wall components, etc.