Fungal Plant Diseases Research Articles

Assessment of the phytopathological state of ornamental forms of common pine (Pinus sylvestris L.) cultivars of the selection of the Central Botanical Garden of the National Academy of Sciences of Belarus

One of the ways to combat the penetration and spread of dangerous pathogens of fungal plant diseases on the territory of the republic may be the selection of domestic varieties resistant to fungal phytopathogens and a reduction of the import of planting material. Over the past decades, the Central Botanical Garden of the National Academy of Sciences of Belarus (CBG) has been working on the development of new cultivars of coniferous plants for landscaping purposes. The purpose of this study was to study of the composition of the mycobiota of needles and shoots of ornamental forms of Scotch pine of the CBS breeding.The article presents the results of the survey of Pinus sylvestris L. cultivars of CBG selection, carried out in the period 2020–2021 years in The Central Botanical Garden of NAS (Belarus, Minsk). As a result, it was found that among the 18 of Pinus sylvestris L. cultivars of CBG selection, the most stable were ‘Woshodjaschaia’ and ‘Minchanka’, the least stable were ‘Karolina’ and ‘Chupa Chups’.The species composition of the mycobiota of needles and shoots includes such dangerous pathogens as fungi from the genus Lophodermium, causing premature falling of needles, as well as Cyclaneusma minus, causing premature yellowing and falling of needles, and Gremmeniella abietina, the causative agent of scleroderriosis or pine shoot cancer. Among the less dangerous fungi, conditionally pathogenic species have been identified – Alternaria alternara, Auerobasidium pullulans, Cladosporium spp., Phoma spp., as well as the endophyte fungus Sydowia polyspora.

BioClay™ prolongs RNA interference-mediated crop protection against Botrytis cinerea.

One of the most promising tools for the control of fungal plant diseases is spray-induced gene silencing (SIGS). In SIGS, small interfering RNA (siRNA) or double-stranded RNA (dsRNA) targeting essential or virulence-related pathogen genes are exogenously applied to plants and postharvest products to trigger RNA interference (RNAi) of the targeted genes, inhibiting fungal growth and disease. However, SIGS is limited by the unstable nature of RNA under environmental conditions. The use of layered double hydroxide or clay particles as carriers to deliver biologically active dsRNA, a formulation termed BioClay™, can enhance RNA durability on plants, prolonging its activity against pathogens. Here, we demonstrate that dsRNA delivered as BioClay can prolong protection against Botrytis cinerea, a major plant fungal pathogen, on tomato leaves and fruit and on mature chickpea plants. BioClay increased the protection window from 1 to 3 weeks on tomato leaves and from 5 to 10 days on tomato fruits, when compared with naked dsRNA. In flowering chickpea plants, BioClay provided prolonged protection for up to 4 weeks, covering the critical period of poding, whereas naked dsRNA provided limited protection. This research represents a major step forward for the adoption of SIGS as an eco-friendly alternative to traditional fungicides.

Optimizing fermentation of Bacillus amyloliquefaciens 3–5 and determining disease suppression and growth in cucumber (Cucumis sativus)

Bacillus spp. have been extensively used as biocontrol agents for controlling fungal plant diseases. In the present study, a strain of Bacillus amyloliquefaciens (strain 3–5) with antagonistic activity against several plant pathogenic fungi was identified, determined optimal fermentation conditions, and explored its ability to control Fusarium wilt in cucumber. The optimal medium for solid-state fermentation (SSF) of strain 3–5 contained wheat bran (35 %), rice husk (40 %), corn meal (20 %), bean flour (15 %), maize starch (1.5 %), beef extract (2.5 %), and MgSO4 (1.5 %). The number of viable cells obtained on this medium was up to 4.577 × 1013 CFU/g under optimal fermentation conditions which included inoculum 6 %, solid content 36 g/L, material-sterile water ratio of 1.0:1.0 and fermentation for 44 h at 32 ℃ and pH 7.0 of the initial medium. The ability of B. amyloliquefaciens 3–5 to inhibit the growth of various fungal pathogens was determined by confrontation culture assays, and greenhouse pot experiments to determine the ability of 3–5 to decrease the incidence of wilt caused by Fusarium oxysporumf. sp.cucumerinum (FOC) in cucumber. Results indicated that 3–5 had an inhibitory effect on all ten of the pathogenic fungi tested, with a 60 % level of inhibition when the mass ratio of B. amyloliquefaciens 3–5 to nutrient soil of 10 %. The thickness of main stems, root length, and plant height of cucumber were significantly higher (P＜0.05) in 3–5 treated plants than control, which the growth rates were 77.5 %, 35.8 %, and 53.3 %, respectively in pot experiments. The application of 3–5 bio-agents is beneficial to reduce the incidence of cucumber Fusarium wilt that the preventive effect and therapeutic effect were 72.1 % and 48.8 %. In summary, a newly isolated strain ofB. amyloliquefaciens 3–5 was demonstrated to control Fusarium wiltin cucumber. The strain should be further evaluated for its commercial potential.

Biocontrol Potential and Mode of Action of Trichoderma Against Fungal Plant Diseases

Biocontrol Potential and Mode of Action of Trichoderma Against Fungal Plant Diseases

Isolation and identification of a new biocontrol bacteria against Salvia miltiorrhiza root rot and optimization of culture conditions for antifungal substance production using response surface methodology

BackgroundS. miltiorrhiza root rot is a soil-borne disease mainly caused by Fusarium solani and Fusarium oxysporum, which has spread rapidly in China in recent years. To reduce the amount of pesticides to control this plant fungal disease, biological control using endophytic bacteria is a promising method. Many endophytic bacteria show good biocontrol potential against various plant fungal diseases. The aims of this study were to isolate and identify endophytic bacteria with antifungal activity from Salvia miltiorrhiza plant tissue. In order to increase antifungal substances production, the culture conditions of the isolated DS-R5 strain were optimized through response surface methodology.ResultsThirteen endophytic bacteria with antifungal activity against the target pathogenic fungus were successfully screened. The DS-R5 strain that had the strongest antifungal activity was identified based on morphological, physiological and biochemical characteristics, 16S rRNA and gyrB sequence analysis.The results of response surface methodology experiments showed that the optimal values of the three significant factors were as follows: medium volume, 51.0 ml; initial pH, 6.7; fermentation temperature, 33.1 °C. Under these optimal culture conditions, the titer of antifungal substances produced by the DS-R5 strain was 77.6% higher than that under the initial culture conditions.ConclusionsThe antifungal activity of endophytic bacteria from Salvia miltiorrhiza has been demonstrated for the first time, which may benefit future crop quality and production. In addition, response surface methodology can be well applied the optimization of culture conditions for antifungal substance, which lays the foundation for further research on strain DS-R5.

Rhamnolipids and fengycins, very promising amphiphilic antifungal compounds from bacteria secretomes, act on Sclerotiniaceae fungi through different mechanisms.

Rhamnolipids (RLs) and fengycins (FGs) are amphiphilic lipid compounds from bacteria secretomes proposed to replace synthetic pesticides for crop protection. They both display plant defense triggering properties and direct antimicrobial activities. In particular, they have well reported antifungal effects against phytopathogenic fungi. RLs and FGs are considered to act through a direct interaction with membrane lipids and a destabilization of microorganism plasma membrane, thereby limiting the risk of resistance emergence. The main objective of this work was to gain insights in the antimycelial mode of action of these metabolites to promote them as environment and human health friendly biocontrol solutions. Their biocidal effects were studied on two Sclerotiniaceae fungi responsible for diseases in numerous plant species worldwide. We show here that different strains of Botrytis cinerea and Sclerotinia sclerotiorum have opposite sensitivities to RLs and FGs on plate experiments. Overall, B. cinerea is more sensitive to FGs while S. sclerotiorum is more sensitive to RLs. Electron microscopy observations demonstrated that RLs induce mycelial destructuring by asperities emergence and hyphal fusions whereas FGs promote swelling and formation of vesicle-like structures due to vacuole fusions and autophagy. Permeability studies, phosphatidylserine externalization and reactive oxygen species production assessments showed a programmed cell death triggering by RLs at medium concentrations (until 50 μg mL−1) and necrosis characteristics at higher concentration. Programmed cell death was always observed on hyphae treated with FGs. Quantifications of mycelial ergosterol content indicated that a higher ergosterol rate in S. sclerotiorum correlates with increasing sensitivity to RLs. Oppositely, a lower ergosterol rate in B. cinerea correlates with increasing sensitivity to FGs, which was confirmed by ergosterol biosynthesis inhibition with tebuconazole. This gain of knowledge will help to better understand the mode of action of RLs and FGs to fight specific plant fungal diseases.

Effect of triadimefon on rat placental morphology, function, and gene expression

Triadimefon is a fungicide that is broadly used to treat fungal diseases of plants. It causes developmental toxicity in the animal model. Whether triadimefon disrupts the placental function and the underlying mechanism remains unclear. Thirty-six female pregnant Sprague-Dawley rats were randomly assigned into four groups and were orally administered via gavage of triadimefon (0, 25, 50, and 100 mg/kg/day) for 10 days from gestational day (GD) 12–21. Triadimefon disrupted the structure of the placenta, leading to hypertrophy, abnormal hemodynamics, including fibrin exudation, edema, hemorrhage, infarction, and inflammation. RNA-seq analysis showed that triadimefon down-regulated the expression of developmental and metabolic genes, while up-regulating the immune/inflammatory genes. The qPCR showed that triadimefon markedly down-regulated the expression of Cpt1c, Scd2, Ldlr, Dvl1, Flt4, and Vwf and their proteins, while up-regulating the expression of Cyp1a1, Star, Ccl5, and Cx3cr1 and their proteins at 25–100 mg/kg. Western blot showed that triadimefon reduced the level of STAT3 at doses of 50 and 100 mg/kg and the phosphorylation of AMPK at 100 mg/kg. In conclusion, triadimefon severely damages the structure and function of the placenta, leading to placental hypertrophy, local blood circulation disorders, and inflammation and this may be associated with its down-regulation of genes related to metabolism and nutrient transport and the up-regulation of inflammatory genes via STAT3 and AMPK signals.

Evaluation of Septoria leaf spot (Septoria helianthi) alone and in combination with other foliar fungal spots on sunflower

Abstract In recent years, Septoria leaf spot has taken a strong place in the list of economically important diseases of sunflower. It may be a favorable factor for the development of other diseases on sunflower plants too. The aim of the research was to evaluate the frequency and degree of infection of sunflower plants with Septoria helianthi as well as possibility of simultaneous infection with this pathogen and other fungi which cause foliar spots, such as downy mildew, Alternaria leaf spot and Phoma black stem under conditions of stationary infectious nursery. The year 2021 turned out to be extremely favorable for the development of fungal leaf spots on sunflower. Assessment of fungal diseases of sunflower plants was performed in F2 families obtained after crossing ZL22A, ZL58A, ZL70A, ZL78A, and ZL169A lines of Zaporozhye breeding (Ukraine) with HAR7 line (originating from the USA). Each F2 family (sample) was obtained from self-pollination of one F1 plant with varying severity of Septoria disease. It was found that in the conditions of 2021, sunflower was quite affected by Septoria disease. The percentage of injured plants in F2 samples ranged from 41.0 to 100.0%. The severity of disease was different. Less resistant genotypes included plants with lesions on sunflower leaves of lower, middle, and upper tiers in approximately equal numbers, while more resistant genotypes had almost no plants with injured leaves of upper tiers. It was established that the development of Phoma disease occurred both on plants with Septoria leaf spot and on healthy plants. On average, among the plants infected with Phoma macdonaldii, the proportion of plants jointly affected by Phoma and Septoria diseases was 2/3. However, the frequency of simultaneous infection of plants with S. helianthi and P. macdonaldii in genotypes with different resistance to Septoria leaf spot differed significantly and ranged from 80% in less resistant to 40% in more resistant accessions. Most plants (about 90%) infected with Plasmopara halstedii were simultaneously infected with S. helianthi. That is, both of these pathogens can simultaneously develop on the same plant and lead to a decline in its basic physiological functions. The rate of simultaneous damage of sunflower by Alternaria and Septoria was quite low compared to plant damage by Alternaria alone and was less than 30%. This may mean that the pathogen of Alternaria leaf spot avoids plants with existing S. helianthi fungus.

Investigation of bioactive compounds from Bacillus sp. against protein homologs CDC42 of Colletotrichum gloeosporioides causing anthracnose disease in cassava by using molecular docking and dynamics studies.

Manihot esculenta, commonly called cassava, is an economically valuable crop and important staple food, grown in tropical and subtropical regions of the world. Demand for cassava in the food and fuel industry is growing worldwide. However, anthracnose disease caused by Colletotrichum gloeosporioides severely affects cassava yield and production. The bioactive molecules from Bacillus are widely used to control fungal diseases in several plants. Therefore, in this study, bioactive compounds (erucamide, behenic acid, palmitic acid, phenylacetic acid, and β-sitosterol) from Bacillus megaterium were assessed against CDC42, a key protein for virulence, from C. gloeosporioides. Structure of the CDC42 protein was generated through the comparative homology modeling method. The binding site of the ligands and the stability of the complex were analyzed through docking and molecular dynamics simulation studies, respectively. Furthermore, a protein interaction network was envisaged through the STRING database, followed by enrichment analysis in the WebGestalt tool. From the enrichment analysis, it is apparent that bioactive from B. megaterium chiefly targets the MAP kinase pathway that is essential for filamentous growth and virulence. Further exploration through experimental studies could be advantageous for cassava improvement as well as to combat against C. gloeosporioides pathogen.

In vivo and in vitro antifungal activities of five alkaloid compounds isolated from Picrasma quassioides (D. Don) Benn against plant pathogenic fungi

Highly active and novel antifungal compounds are continuously researched from natural products for pesticide development. Picrasma quassioides (D. Don) Benn, a species of Simaroubaceae, is used in traditional Chinese medicine to treat colds and upper respiratory infections. In this study, the active ingredients of P. quassioides and their antifungal activities against plant pathogenic fungi are investigated to explore the practical application of the plant in the agricultural field. The results showed that the extracts of P. quassioides exhibited highly significant preventive and curative effects on apple valsa canker (AVC) with a reduction of lesion diameter were 80.28% and 83.63%, respectively, and can improve the resistance of apple trees to a pathogen. Five antifungal compounds, namely, canthin-6-one (T1), nigakinone (T2), 4,5-dimethoxycanthin-6-one (T3), 1-methoxycarbonyl-β-carboline (T4), and 1-methoxycarbonyl-3-methoxyl-β-carboline (T5), are isolated from P. quassioides using the bioassay-guided method. This is the first report of 1-methoxycarbonyl-3-methoxyl-β-carboline as a natural product. Canthin-6-one shows strong in vitro inhibitory activity against 11 species of plant pathogenic fungi, and their EC50 values range from 1.49 to 8.80 mg/L. The control efficacy of canthin-6-one at 2000 mg/L are 87.88% and 94.37% against AVC and 80.10% and 84.73% against apple anthracnose (C. gloeosporioides), respectively. Additionally, V. mali is observed after treatment with cannin-6-one, although microscopic. This is the first study on the control of the secondary metabolites of P. quassioides against plant fungal diseases. The results show that P. quassioides is a potential resource for the development of botanical fungicides.

ПРОТИВОГРИБКОВАЯ АКТИВНОСТЬ ПРОИЗВОДНЫХ АНТРАХИНОНА (Сообщение 2)

Fungal infections are an increasingly recognized global threat to human, animal and plant health. The problem is acute in agriculture as well. The problems posed by fungal plant pathogens affect global food security by causing severe damage to many valuable crops. This is related to crop yields, post-harvest losses, and contamination of forage and consumer products.The purposeof the review is to analyze the problem of fungal diseases of plants and search for effective fungicides in the family of anthraquinone derivatives. Objects. Derivatives of 9,10-anthraquinone: chrysophanol, emodin, рhyscion, rhein, aloe-emodin.Results.Fungi are key components of global biogeochemical cycles and include numerous species with pathogenic potential that affect various plant species. Of particular concern is the impact of fungal pathogens on cultivated and commercial plant species on which the food security of the world population depends. Among natural compounds, 9,10-anthraquinone derivatives represent a group of quinones with biological activity and great structural diversity. This review presents the data on the main fungal plant pathogens and the analysis of the antifungal activity of the most abundant anthraquinone molecules, such as chrysophanol, emodin, physcion, rein and aloe-emodin, as well as some structurally related molecules, in order to analyze the influence of chemical structure of derivatives on their activity.Conclusion. Natural sources of antimicrobial agents, which can be regarded as an alternative to traditionally used drugs, have now begun to receive special attention. Natural sites contain a variety of biologically active secondary metabolites. Among them, derivatives of 9,10-anthraquinone, such as chrysophanol, emodin, physcion, rein, aloe-emodin, have shown activity against a variety of plant fungal pathogens and can be considered as promising structures for finding new antifungal agents.

Bacteria as Biological Control Agents of Plant Diseases.

Biological control is an effective and sustainable alternative or complement to conventional pesticides for fungal and bacterial plant disease management. Some of the most intensively studied biological control agents are bacteria that can use multiple mechanisms implicated in the limitation of plant disease development, and several bacterial-based products have been already registered and marketed as biopesticides. However, efforts are still required to increase the commercially available microbial biopesticides. The inconsistency in the performance of bacterial biocontrol agents in the biological control has limited their extensive use in commercial agriculture. Pathosystem factors and environmental conditions have been shown to be key factors involved in the final levels of disease control achieved by bacteria. Several biotic and abiotic factors can influence the performance of the biocontrol agents, affecting their mechanisms of action or the multitrophic interaction between the plant, the pathogen, and the bacteria. This review shows some relevant examples of known bacterial biocontrol agents, with especial emphasis on research carried out by Spanish groups. In addition, the importance of the screening process and of the key steps in the development of bacterial biocontrol agents is highlighted. Besides, some improvement approaches and future trends are considered.

Growth and development of transgenic peanut (Arachis hypogaea) lines containing chitinase 42 kDa gene from Trichoderma asperellum SH16

Peanut (Arachis hypogaea L.) is vulnerable to many diseases. Vietnam and other regions where peanut is widely cultivated have a high threat of fungal and other plant diseases. Various fungicides are available to control the fungal disease but these have various harmful effects on the natural flora, fauna, and environment. Transgenic peanut lines which possess antifungal activity provide a possible solution in managing fungal diseases apart from the traditional resistance and fungicide usage. Therefore, this study evaluated the probable growth and development of chitinase transgenic peanut lines against Sclerotium rolfsii, a pathogen that causes “southern blight” in plants, under greenhouse conditions. This study provided evidence that through Agrobacterium itumefaciens mediated transformation, 42 kDa chitinase genes from Trichoderma asperellum, which is under the regulation of 35S promoter, were successfully incorporated into the peanut’s (A. hypogaea L.) genome and expressed in their plants. This evidence also demonstrated that transgenic peanut lines were suitable for growing and developing in the greenhouse. Further, it was reported that transgenic peanut lines took approximately 133 to 145 days from planting to maturity. These results also revealed that various growth characteristics of transgenic peanut lines having two synthetic genes (syncod Chi42-2 i.e. S2-2, S2-4, S2-6, and syncod Chi42-1 i.e. S1-1, S1-2, S1-3) were greater than that from the wild-type Chi42 (WT-1, WT-2, and WT-3). In addition, yield-related parameters including the number of mature pods, 100 pods weight and 100 seeds weight for all the transgenic peanut lines were higher than that of the non-transformed plant. Among the transgenic lines, line S2-4 exhibited significantly higher growth and yield than the other transgenic lines. These results demonstrated that 42 kDa chitinase genes overexpressing peanut lines could be a candidate for improvement against plants to phytopathogenic fungus S. rolfsii and high yield.

Role of nanotechnology in improving quality of edible crop plants

Improving human health is the considered major concern in area of medical and agricultural sciences. It is achieved by providing good health supplements with balanced diet to people in the forms of cost effective and safe nano-biofortified or nano-bioengineered vegetable crop plants to fight against malnutrition and other various diseases. And these nano-based methodologies are involved the use of nanoparticles of essential nutrients like copper, iron, selenium, cobalt, and zinc being as fertilizers or stimulants in soils or waters to improve the qualities of vegetable crop plants and make them more enriched with major nutrients and diseased free. Hence, this strategic clinical and agro-practice based management should be considered to combat fungal and microbial diseases of crop plants through cost effective and green nanotechnology-based approach used in the form of nano-formulation and fortified bioagents and biostimulants.

Effect of Leaf Extract of Cassia fistula on the Growth and Development of Colletotrichum gloeosporioides and Cercospora bataticola

Because of the widespread and uncontrolled use of traditional fungicides, many plant pathogens have become resistant to them, making it more challenging to control most fungal plant diseases with these fungicides. Since the dawn of time, phytochemicals have contributed significantly to human welfare without causing any harm. Therefore, PFT method with different leaf extracts of Cassia fistula (Aqueous, methanol and acetone) and their three concentrations (250µl, 500µl and 1000µl per 15 ml of PDA) was used against Colletotrichum gloeosporioides and Cercospora bataticola, causing fruit rot and leaf spot of beet respectively. Results of this study showed that maximum inhibition (76.8%) of Colletotrichum gloeosporioides was found with1000µl concentration of methanolic extract of Cassia fistula leaves 3 DAI while maximum inhibition of Cercospora bataticola (68.7%) was found with the same concentration of acetone extract of Cassia fistula leaves 3 DAI. Considerable growth inhibition (68.7%) of Colletotrichum gloeosporioides and 50.5% of Cercospora bataticola were found with 1000µl concentration of methanolic and acetonic extracts of Cassia fistula leaves respectively 5 DAI. Acetonic extract of Cassia fistula leaves with 1000µl concentration was also found as a good antifungal for Colletotrichum gloeosporioides which inhibited 64.8% and 54.6% 3 and 5 DAI respectively.
 However, there was no considerable growth inhibition of both fungal plant pathogens with aqueous extract. The results of present study revealed that methanolic and acetonic leaf extracts of Cassia fistula can be used for fungal plant disease management with further extensive studies.

Plantago lagopus extract as a green fungicide induces systemic resistance against Rhizoctonia root rot disease in tomato plants.

Extensive use of chemical control agents and fungicides typically leads to numerous risks to human health and the environment. Using plant extracts as natural substances represents a dual key for the environment and sustainable food production, as it reduces the input of synthetic pesticides into the environment and/or controls plant pathogens. For the first time, a Plantago lagopus ethanolic extract has been characterized and evaluated for its protective and curative effects against Rhizoctonia solani in tomato plants. The results showed that P. lagopus extract (10 μg/ml) completely inhibited R. solani mycelial growth in vitro. At 20 days of post fungal inoculation, the results demonstrated that using P. lagopus extract (100 μg/ml) in vivo enhanced tomato plant growth by significantly increasing shoot and root parameters in protective and curative treatments. Furthermore, the protective and curative treatments significantly reduced the disease index by 18.66 and 38.66%, respectively. Induction of systemic resistance with upregulation of PR-1 and PR-2 and a significant increase in the transcriptional levels of PR-3 and CHS in all P. lagopus extract-treated tomato plants were reported compared to untreated plants. HPLC analysis showed that the most common polyphenolic components detected in P. lagopus extract were rutin (74206.3 mg/kg), naringenin (2388.74 mg/kg), quercetin (1249.13 mg/kg), and p-hydroxybenzoic acid (1035.87 mg/kg). In addition, the ellagic acid (798.47 mg/kg), vanillic acid (752.55 mg/kg), catechol (648.89 mg/kg), cinnamic acid (332.51 mg/kg), ferulic acid (296.32 mg/kg), benzoic acid (295.95 mg/kg), and chlorogenic acid (116.63 mg/kg) were also reported. Our study is the first to show that P. lagopus extract can help plants fight off R. solani fungal infection. Furthermore, the findings imply that using the P. lagopus extract as a natural biocontrol agent could be a sustainable strategy to manage plant fungal diseases.

Effects of Macroautophagy and Mitophagy on the Pathogenicity of Fusarium graminearum.

Fusarium graminearum is the main pathogen of Fusarium head blight (FHB), which causes huge economic losses every year. In this study, an attempt was made to control FHB from the point of view of the physiological behavior of the pathogen itself. Autophagic inhibitors and activators were used, and the pathogenicity-related indices of F.graminearum were measured. The results showed that under nitrogen-rich conditions, macroautophagy inhibition and activation greatly reduced the mycelium weight to 0.28 and 0.25 g/ml at 24 h, which were 17.82 and 24.77% lower than that of the control treatment, respectively. Mitophagy inhibition also significantly decreased the mycelium weight (P < 0.05). Conidial yield was found to be affected by factors related to autophagy occurrence. It was found that both autophagy inhibition and activation could reduce the conidiation of F.graminearum. The toxin contents in wheat medium of macroautophagy activation treatments were 0.678, 0.190, 0.402, and 0.195 μg/g when cultured for 8 and 24h under 0% N and 100% N conditions, respectively, which were significantly higher than those of the control treatments (P < 0.05). The infection length was measured to characterize the infectivity of F.graminearum, and we found that the length was short under macroautophagy activation conditions. However, mitophagy did not seem to affect the infectivity of F.graminearum. In summary, the above results indicate that macroautophagy and mitophagy inhibition could reduce the pathogenicity of F.graminearum, which may provide a new perspective for management of plant fungal diseases.

How to Feed an Empire?

Abstract In 1937—one year after the Fascist “conquest” of Ethiopia—the Italian East African Empire was on the brink of an economic and food crisis. In order to feed the newborn empire's growing Italian population, Mussolini's regime launched a call for agricultural mobilization meant to rapidly make the empire self-sufficient in wheat, the main staple of the Italian population. This article analyzes the scientific foundations of the program of imperial “wheat autarky” and its materialization during the “wheat campaigns” between 1938 and 1941, particularly focusing on the introduction of and experimentation with hybrid wheat seeds in the Ethiopian highlands. The article shows the key role played by Italian agronomists and plant breeders in the framing and implementation of wheat autarky in the Fascist empire. Contrary to the historical emphasis of Fascist propaganda on the technological and human colonization of Ethiopia by Italian agriculture, the article also argues for the crucial position of indigenous farming within the colonial project of wheat development. Finally, Ethiopia's environments and its nonhuman actors became essential protagonists in the unfolding of these agricultural plans. The article makes the case for viewing wheat rust—a fungal plant disease—as a key component of the evolution and demise of the Italian occupation of Ethiopia.

Interview with Shay Shaanan, STK Bio-Ag Technologies

STK was previously known as Stockton. It was started in 1994 by Peter Tirosh who left a 23-year career at Makhteshim-Agan (now ADAMA) to set up his own generic company buying solutions from China and selling them into Latin America where he had good connections from his previous jobs. In 2004, Peter met two people from an Israeli start-up who told him about an idea to take tea-tree oil (TTO) from Pharma where it was used as an anti-bacterial agent and develop it into a solution for crop protection. Peter cooperated with them and after two years acquired the company. With money from Stockton they investigated TTO in more detail, worked out which diseases it controlled, how to formulate and use it, and in 2012, discovered that TTO controlled black Sigatoka (Mycosphaerella fijiensis), a key disease in LATAM bananas at the time. In 2015 there was a change in company ownership when a new CEO was appointed from outside the family. Following a $90 million investment from a public Chinese company, a new strategy was implemented in 2016 to develop and market botanical crop solutions for sustainable agriculture and aquaculture, and a rebranding in 2018 changed the company name from Stockton to STK to reflect the company's transition from its legacy generic agrochemicals business to its new focus on bio-ag technology and botanical-based solutions. The biofungicide Timorex Gold is its flagship product and based on TTO derived from the Melaleuca alternifolia plant. It is a broad spectrum biofungicide with preventive and curative properties recommended for the control of many important plant fungal and bacterial diseases in a wide range of fruit and vegetable crops. It can be used in rotations with other products, in tank mixes and as a solo formulation. The TTO extract contains over 100 compounds, some of which work synergistically and some which offer diverse modes of action.

A Systematic Analysis of Machine Learning and Deep Learning Based Approaches for Plant Leaf Disease Classification: A Review

Crops’ production and quality of yields are heavily affected by crop diseases which cause adverse impacts on food security as well as economic losses. In India, agriculture is a prime source of income in most rural areas. Hence, there is an intense need to employ novel and accurate computer vision-based techniques for automatic crop disease detection and their classification so that prophylactic actions can be recommended in a timely manner. In literature, numerous computer vision-based techniques by utilizing divergent combinations of machine learning, deep learning, CNN, and various image-processing techniques along with their associated merits and demerits have already been discussed. In this study, we systematically reviewed recent research studies undertaken by a variety of scholars and researchers of fungal and bacterial plant disease detection and classification and summarized them based on vital parameters like type of crop utilized, deep learning/machine learning architecture used, dataset utilized for experiments, performance matrices, types of disease detected and classified, and highest accuracy achieved by the model. As per the analysis carried out, in the category of machine learning-based approaches, 70% of studies utilized real-field plant leaf images and 30% utilized laboratory condition plant leaf images for disease classification while in the case of deep learning-based approaches, 55% studied employed laboratory-conditioned images from the PlantVillage dataset, 25% utilized real-field images, and 20% utilized open image datasets. The average accuracy attained with deep learning-based approaches is quite higher at 98.8% as compared to machine learning-based approaches at 92.2%. In the case of deep learning-based methods, we also analyzed the performances of pretrained and training from scratch models that have been utilized in various studies for plant leaf disease classification. Pretrained models perform better with 99.64% classification accuracy compared to training from scratch models which achieved 98.64% average accuracy. We also highlighted some major issues encountered in the computer vision-based disease detection and classification approach used in literature and provided recommendations that will help and guide researchers to explore new dimensions in crop disease recognition.