Dry Rot Disease Research Articles

Lab and Field Level Potential of Endophytic Bacteria in Managing the Dry Root Rot Disease in Black Gram Incited by Rhizoctonia bataticola (Taubenh) Butler

Background: The plant growth promotion and efficacy against phytopathogens by the endophytic bacteria are being focused now due to their ecofriendly nature. Methods: Endophytic bacteria (24 nos) isolated from the roots, stems and leaves of black gram plants collected from different locations were tested for their potential to inhibit the growth of R. bataticola under in vitro and in vivo conditions. Result: The leaf endophyte BLE 4 exhibited maximum inhibition (79.6%) of R. bataticola followed by BSE 4 (77.4%), BSE 7 (77.0%) and BLE 1 (74.0%). Among these 4 isolates tested as seed treatment and soil application, there was significant increase in dry weight (7.1 g), plant height (37.7 cm), number of branches (13.2) and number of pods (26.2) in BLE 4 treated plots. Whereas, the incidence of dry root rot and yield were insignificant. In the screening study of isolates for their phosphate solubilization potential, protease activity, siderophore and HCN production, no single isolate possessed all the properties, but siderophore production, protease activity and phosphate solubilization were found in BSE 4, BRE 3, BRE 5 and BRE 10 isolates.

Low soil moisture predisposes field-grown chickpea plants to dry root rot disease: evidence from simulation modeling and correlation analysis

Rhizoctonia bataticola causes dry root rot (DRR), a devastating disease in chickpea (Cicer arietinum). DRR incidence increases under water deficit stress and high temperature. However, the roles of other edaphic and environmental factors remain unclear. Here, we performed an artificial neural network (ANN)-based prediction of DRR incidence considering DRR incidence data from previous reports and weather factors. ANN-based prediction using the backpropagation algorithm showed that the combination of total rainfall from November to January of the chickpea-growing season and average maximum temperature of the months October and November is crucial in determining DRR occurrence in chickpea fields. The prediction accuracy of DRR incidence was 84.6% with the validation dataset. Field trials at seven different locations in India with combination of low soil moisture and pathogen stress treatments confirmed the impact of low soil moisture on DRR incidence under different agroclimatic zones and helped in determining the correlation of soil factors with DRR incidence. Soil phosphorus, potassium, organic carbon, and clay content were positively correlated with DRR incidence, while soil silt content was negatively correlated. Our results establish the role of edaphic and other weather factors in chickpea DRR disease incidence. Our ANN-based model will allow the location-specific prediction of DRR incidence, enabling efficient decision-making in chickpea cultivation to minimize yield loss.

Fusarium oxysporum strains from wilting potato plants : Potential causal agents of dry rot disease in potato tubers

The present study focused on the isolation, identification and assessment of the dry rot-causing ability of Fusarium spp. associated with potato wilt in the Middle Volga region of Russia. A total of 14 Fusaria were isolated from the root necks of wilting potato plants. One isolate was identified as Fusarium solani, while the remaining thirteen of the isolates related to the species Fusarium oxysporum. Artificial inoculation of potato tubers with fungal spores showed that tubers of the cultivar Reggi exhibited the highest resistance [cultivar resistance index (CRI) = 0.78] to the tested isolates, while susceptibility (CRI = -0.44) was registered in tubers of the Zhukovskij rannij cultivar. The manifestation of dry rot during artificial inoculation with the spores of vascular-associated Fusaria was significantly influenced by pathogen virulence [H (9, N = 300) = 60.630, p <0.000001] and plant cultivar type [H (2, N = 210) = 17.201, p =0.00018]. However, not all isolates inhabiting occluded vessels caused dry rot in tubers.

Dry Root Rot Disease Assays in Chickpea: a Detailed Methodology.

Dry root rot (DRR) disease is an emerging biotic stress threat to chickpea cultivation around the world. It is caused by a soil-borne fungal pathogen, Rhizoctonia bataticola. In the literature, comprehensive and detailed step-by-step protocols on disease assays are sparse. This article provides complete details on the steps involved in setting up a blotting paper technique for quickly screening genotypes for resistance to DRR. The blotting paper technique is easy and less expensive. Another method, based on the sick pot approach, is a mimic of natural infection and can be applied to study the interacting components-plant, pathogen, and environment-involved in the disease triangle. Moreover, in nature, DRR occurs mostly in rainfed chickpea cultivation areas, where soil moisture recedes as crop growth advances. Drought stress is known to predispose chickpea plants to DRR disease. Pathomorphological and molecular understanding of plant-pathogen interaction under drought stress can pave the way for the identification of elite DRR-resistant varieties from the chickpea germplasm pool. This article provides a stepwise methodology for the preparation of a sick pot and subsequent disease assay. Overall, the information presented herein will help researchers prepare R. bataticola fungal inoculum, maintain this pathogen, set up the blotting paper technique, prepare sick culture and sick pot, and assess pathogen infection in chickpea plants.

STUDIES ON SOME POTATO TUBER ROT DISEASES DURING STORAGE

The dry rot disease incidence was affected by the different storage temperature degrees of both cultivations (Nili and Summer) during two tested seasons. The least periods of storage with least temperature degrees of storage (15 days at 3 – 5°C) decreased dry rot disease incidence % in both lasted seasons. Significant differences were notice between periods of storage which combined with different temperature degrees. Eight plant extracts were tested against dry rot disease in potato tubers. Three concentrations of each plant extract were used i.e. 3, 5 and 10%. Garlic and cinnamon extracts were tested against the most aggressive fungal isolates, under storage conditions on potato tubers cv. Spunta. Both plant extracts were effective on disease index and minimized potato dry rot disease symptoms. Biological control using biological agents were effective in disease control both in laboratory and under storage conditions. Also, Tachigaren plus 600 SL fungicide at 100 ppm was the most effective one in controlling the dry rot disease incidence.

Management on biotic stress to improve the nutmeg quality in North Moluccas, Indonesia

Indonesia dominates about 76% of nutmeg production and export in the world, where around 28.26% is produced in North Moluccas and 24.25% of its from North Halmahera. The objectives of this study were to reduce the biotic stress, increase the yield and improve the quality of the nutmeg produced by Tarakani Farmer Group in Galela District. (1) the Morphology of dry fruit rot disease in each stratum and (2) nutmeg cultivation system collected through interviews; and (3) climatic data, including temperature, and rainfall obtained from the Meteorology, Climatology, and Geophysics Agency of Galela District. This study was conducted at west Galela District and Tarakani Farmer Group. The farmers implemented the sanitation techniques of the crops; i.e.: pruning, collection and pile up/bury of the dropped fruits and fumigation by burning some leaves of local trees and biotic stress be controlled. During one year a grade A of nutmeg increased from 5.7 tons to 37.6 tons or increased from 17.6% to 38.2%. Nutmeg grade C reduced from 40% to 25%%. This effort will still be forwarded by utilizing biological agents to reduce biotic stress, such as Trichoderma spp. to control fungal pathogens and Bacillus thurigiensis to pest control.

Combined Influence of Chitosan and Calcium Chloride on Fusarium Dry Rot Disease Under Field Conditions

Background: Fusarium dry rot disease caused by Fusarium sambucinum Fuckel (F. sambucinum) can infect the potato tubers in the field and during storage. Yield losses by F. sambucinum reach 60%. Traditional methods to control Fusarium dry rot are fungicides application, which led to developing many isolates resistant to these fungicides. Objective: The aim of this study is to evaluate the effect of calcium chloride (CaCl2) and chitosan, alone or in combination, on plant development, tuber yield, and Fusarium dry rot disease incidence under field conditions. Methods: Soil inoculated with F. sambucinum before planting. We treated the seed tubers with CaCl2 (0.5 or 1%), chitosan 0.5%, or both. The foliage was sprayed twice with CaCl2 (0.5 or 1%), 0.1% chitosan, or both. During the vegetation period, growth parameters, such as germination (%), plant height (cm), and branches number per plant, were measured. At harvest, we calculated the total and the marketable number of tubers and tuber yield. In addition, during storage, we assessed the incidence of Fusarium dry rot disease on tubers. Results: Results revealed that combined pre-planting application with 1% CaCl2 and 0.5% chitosan with 2 hours intervals, then spraying foliar with 1% CaCl2 and 0.1% chitosan twice with ten days intervals starting at 40 days after planting resulted in: a) increasing the germination, enhancing the growth parameters such as plant height and branches number per plant; b) enhancing the marketable tuber yield by 75.2 and 97.6% in Sante and Kolobok varieties, respectively; c) reducing Fusarium dry rot disease incidence by 61.9-72.7%. Conclusion: The work highlighted that the combined pre-planting and foliar application of CaCl2 and chitosan might be recommended for potato producers to reduce the incidence of Fusarium dry rot disease and augment yields.

CONTROL OF POTATO TUBER DRY ROT DISEASE DURING STORAGE

The dry rot disease incidence was affected by the different storage temperature degrees of both cultivations (Nili and Summer) during two tested seasons. The least periods of storage with least temperature degrees of storage (15 days at 3 – 5°C) decreased dry rot disease incidence % in both lasted seasons. Significant differences were notice between periods of storage which combined with different temperature degrees. Eight plant extracts were tested against dry rot disease in potato tubers. Three concentrations of each plant extract were used i.e. 3, 5 and 10%. Garlic and cinnamon extracts were tested against the most aggressive fungal isolates, under storage conditions on potato tubers cv. Spunta. Both plant extracts were effective on disease index and minimized potato dry rot disease symptoms. Biological control using biological agents were effective in disease control both in laboratory and under storage conditions. Also, Tachigaren plus 600 SL fungicide at 100 ppm was the most effective one in controlling the dry rot disease incidence.

Role of resistance inducing chemicals against soybean dry root rot (R. bataticola) disease

Role of resistance inducing chemicals against soybean dry root rot (R. bataticola) disease

Potato dry rot disease: current status, pathogenomics and management.

Potato dry rot disease caused by Fusarium species is a major threat to global potato production. The soil and seed-borne diseases influence the crop stand by inhibiting the development of potato sprouts and cause severe rots in seed tubers, table and processing purpose potatoes in cold stores. The symptoms of the dry rot include sunken and wrinkled brown to black tissue patches on tubers having less dry matter and shriveled flesh. Fungal infection accompanied by toxin development in the rotten tubers raises more concern for consumer health. The widespread dry rot causing fungal species (Fusarium graminearum) is reported to have a hemibiotrophic lifestyle. A cascade of enzymes, toxins and small secreted proteins are involved in the pathogenesis of these hemibiotrophs. With the availability of the genome sequence of the most devastating species Fusarium sambucinum, it is important to identify the potential pathogenicity factors and small secreted proteins that will help in designing management strategies. Limited resistant cultivars and the emergence of fungicide-resistant strains have made it more threatening for potato cultivation and trade. Several novel fungicide molecules (Azoxystrobin, chlorothalonil and fludioxonil), are found very effective as tuber treatment chemicals. Besides, many beneficial bioagents and safer chemicals have shown antibiosis and mycoparasitism against this pathogen. Germplasm screening for dry rot resistance is important to assist the resistance breeding program for the development of resistant cultivars. This review aims to draw attention to the symptomatology, infection process, pathogenomics, the role of toxins and management approaches for potato dry rot disease, which is very much critical in designing better management strategies.

Characterization of Fusarium species causing dry root rot disease of citrus trees in Morocco

Citrus have been grown as a commercial fruit crop in Morocco for a decade. The area dedicated to growing and producing citrus has increased from 2006 to 2018 throughout the country. The rapid decline of citrus trees has been observed in many locations. Therefore, this study aimed to identify and characterize fungal pathogens associated with dry root rot (DRR) disease of citrus from diseased trees and soil collected from different citrus-growing plantations. Isolation and morphological identification of pathogens were performed using PDA-SC medium. Thirty-four Fusarium isolates were recovered from symptomatic plants. These isolates were identified based on morphological traits and the sequence of the internal transcribed spacer (ITS) region. Four Fusarium species were identified. Fusarium solani (Martius) was most frequently identified (70.60%), followed by F. oxysporum (17.65%), F. equiseti (8.82%) and F. brachygibbosum (2.94%). The two latter species have recently been associated with DRR in Morocco. Two separate pathogenicity trials were conducted to test the effect of the pathogens on young citrus seedlings. Results indicated that, with the exception of F. equiesti, Fusarium isolates were aggressive pathogens of citrange-Troyer and sour orange seedlings 2 months postinoculation. Citrus trees displayed key symptoms of DRR such as root rot, discolored and necrotic roots, purple wood discoloration, plant yellowing and general weakness. Further, all four species were able to induce lesions when they were used to inoculate citrus branches. This is the first detailed report of Fusarium species associated with DRR in Morocco.

Application of isomelezitose as an osmoprotectant for biological control agent preservation during drying and storage

ABSTRACT Isomelezitose (IMZ) is of interest as a potential osmoprotectant, but it has not been previously characterised even though the structurally similar trisaccharide melezitose has been previously shown to have excellent protective qualities. The recent discovery that sucrose can be converted to IMZ during glucansucrase reactions suggests that IMZ might become an economical choice as an osmoprotectant for microbial inoculants, such as biological control agents (BCAs). Because of this opportunity, its osmoprotective function was explored in this work using two strains of Pseudomonas fluorescens that are BCAs used to control maladies of potatoes stored postharvest. BCA cell viability and growth recovery rate after drying and storage at 25 oC were assessed. The data showed that IMZ and impure IMZ reaction products can function similarly to melezitose and trehalose to significantly reduce viable cell and activity losses during air drying and storage. Biocontrol treatments formulated with IMZ retained the ability to suppress Fusarium dry rot disease by up to 50% under severe disease challenge, even after storage 28 d at 25 oC in vacuum-sealed bags. Biocontrol treatments with IMZ suppressed disease by 15–35% more thancontrols without any added osmoprotectant. Neither IMZ nor two impure enzyme reaction products impacted germination of dry rot causative Fusarium sambucinum conidia or subsequent hyphal growth under gnotobiotic conditions. For the first time, the osmoprotective capability of IMZ has been demonstrated and shown to be potentially superior to others previously reported, including the structurally related compound melezitose and the currently marketed disaccharide trehalose.

Biological potential of Bacillus subtilis V26 for the control of Fusarium wilt and tuber dry rot on potato caused by Fusarium species and the promotion of plant growth

Fusariosis of potato caused by the Fusarium spp. is one of the most destructive soil-borne diseases throughout the world. This study aimed to investigate the growth-promoting and biocontrol potential of Bacillus subtilis V26 against the causal agents of Fusarium wilt and Fusarium dry rot diseases on potato. Characterization of plant growth promoting traits was assessed in vitro. The strain V26 was able to fix nitrogen, to produce indole-3-acetic acid, siderophore, hydrolytic enzymes and to solubilize inorganic phosphate. The PCR detection of ituC, fenA, fenB, fenD, srfAA, bmy, mnlA, bae and bac genes coding for iturin, fengycin, surfactin, bacyllomicin, macrolactin, bacillaene and bacilysin indicated a potential for lipopeptides, polyketides and dipeptide production, respectively by the strain V26. In vitro antagonism test showed that this strain can effectively inhibit F. oxysporum, F. solani, F. gramineaurum and F. sambucinum growth by 54.7 to 85.3% as compared to the untreated control, in a dual method. Antifungal activity was demonstrated against the dry rot potato tubers caused by Fusarium species. The preventive application of V26 significantly decreased the Fusarium dry rot disease severity at 42.8–63.8%, after 21 days of fungi inoculation. After 15 days of seedling emergence, plants were irrigated with V26 spore suspensions (108 CFU/mL), prior infection by Fusaium species, Fusarium wilt severity were reduced by 54.8 to 60.8% and plant growth parameters were improved, compared to the untreated ones, 60 days post-inoculation. Therefore, this strain could be a promising candidate to be developed as commercial biofertilizer and biocontrol formulation in sustainable agriculture.

Effect of different soil amendments and bio agents on development of dry root rot (DRR) diseases of chickpea caused by Rhizoctonia bataticola (M.phaseolina)

Chickpea (Cicer arietinum L.) is one of the important pulse crops of India. Occurrence of dry root rot (DRR) caused by Rhizoctonia bataticola (Taub.) Butler is emerging as a serious biotic constraint in recent years for successful and profitable cultivation of chickpea. The efficacy of various soil amendments and bio agents viz wheat straw @ 20g/kg of soil, bajra straw @ 20g/kg, mung bean straw @ 20g/kg, mustard cake @ 5g/kg, ground nut cake @ 5g/kg and farm yard manure @ 20g/kg of soil as mixture with soil and Trichoderma viride@ 4gm/kg seed, T. harzianum@4gm.kg seed, T. virens0.5 gm/ke seed & Bacillus subtilis@ 6gm/kg as seed treatment respectively were evaluated against Rhizoctonia bataticola causing root rot in Chickpea. Study of DRRin chickpea done under both pot and field conditionduring years 2018-2019 and 2019-2020. Soil amendment with mustard cake amendment was found most effective in reducing the disease incidence (33.33 & 38.33%) during both years (2018-2019 & 2019-2020) of study followed by wheat straw, bajra straw and FYM. Among the bio agents Trichoderma viride (24.44 & 26.66%) was found most effective in minimizing DRR incidence and mean pathogen propagules g-1 soil (1.16 x 103) during both years of study.

Management of wilt and dry root rot diseases of redgram [Cajanus cajan (L.) Millsp.] by using actinomycetes

Actinomycetes were tested for their antagonistic activity against Fusarium udum and Macrophomina phaseolina under in vitro condition. Among the tested isolates of Actinomycetes AC (5) reported highest 82.85 per cent reduction of mycelial growth of Fusarium udum and 85.13 per cent reduction of mycelial growth of Macrophomina phaseolina. In the field experiment, five treatments were tested for the management of wilt and dry root rot disease, T3- ST+ SA with Actinomycetes (AC 5) significantly recorded 71.92 and 70.38 per cent reduction of the wilt and dry root rot diseases, respectively. These biocontrol agents were used an alternative to the chemical fungicide for controlling the wilt and dry root rot incidence and enhanced the plant growth parameters and there by increased yield in redgram.

Effect of soil moisture regimes and soil types on incidence of Rhizoctonia bataticola causing dry root rot of chickpea

Effect of different soil moisture regimes and soil types on incidence of Rhizoctoniabataticola causing dry root of chickpea (Cicerarietinum L.). crop were studied during 2018-19 at VNMKV, Parbhani. In present studiesdry root rot disease incidence was higher (range: 80.00 to 74.45 per cent) at the soil moisture level of 55 to 60 per cent. Whereas it was noticed that sandy soil showed highest dry root rot disease incidence followed by sandy loam soil and than the other soil types.

Autophagy Related Gene (ATG3) is a Key Regulator for Cell Growth, Development, and Virulence of Fusarium oxysporum.

Fusarium oxysporum is the most important pathogen of potatoes which causes post-harvest destructive losses and deteriorates the market value of potato tubers worldwide. Here, F. oxysporum was used as a host pathogen model system and it was revealed that autophagy plays a vital role as a regulator in the morphology, cellular growth, development, as well as the pathogenicity of F. oxysporum. Previous studies based upon identification of the gene responsible for encoding the autophagy pathway components from F. oxysporum have shown putative orthologs of 16 core autophagy related-ATG genes of yeast in the genome database which were autophagy-related and comprised of ubiquitin-like protein atg3. This study elucidates the molecular mechanism of the autophagy-related gene Foatg3 in F. oxysporum. A deletion (∆) mutants of F. oxysporum (Foatg3∆) was generated to evaluate nuclear dynamics. As compared to wild type and Foatg3 overexpression (OE) strains, Foatg3∆ strains failed to show positive MDC (monodansylcadaverine) staining which revealed that Foatg3 is compulsory for autophagy in F. oxysporum. A significant reduction in conidiation and hyphal growth was shown by the Foatg3∆ strains resulting in loss of virulence on potato tubers. The hyphae of Foatg3∆ mutants contained two or more nuclei within one hyphal compartment while wild type hyphae were composed of uninucleate hyphal compartments. Our findings reveal that the vital significance of Foatg3 as a key target in controlling the dry rot disease in root crops and potato tubers at the postharvest stage has immense potential of disease control and yield enhancement.

OCCURRENCE OF ALTERNARIA LEAF SPOT DISEASE ON ALOE VERA AND ITS MANAGEMENT

Aloe vera is a valuable medicinal crop of the world. It suffers from several diseases but among them alternaria leaf spot and dry rot is most serious fungal disease which effects the commercial production and quality losses to Aloe vera. A survey was conducted to estimate the prevalence of dry rot disease in different nurseries located in urban areas of Faisalabad. During this survey maximum disease incidence was recorded in Horti club nursery (100%) and minimum disease incidence recorded at Faiz baho nursery and Qadir baksh form (13.8%). Among in-vitro tested fungicides Score gives maximum mycelial growth inhibition (89.5%) and maximum disease control (17.7%) as compared to control and other tested chemicals. Among in-vitro tested plant extracts Neem gives maximum mycelial growth inhabitation (41.2%) and in green house gives 14.2% disease control. Out of four tested fungicides and plant extracts Score and Neem gives best results against A. alternata mycelial growth and disease control.

Role of Autophagy-Related Gene atg22 in Developmental Process and Virulence of Fusarium oxysporum.

Autophagy is a universal catabolic process preserved in eukaryotes from yeast to plants and mammals. The main purpose of autophagy is to degrade cytoplasmic materials within the lysosome/vacuole lumen and generate an internal nutrient pool that is recycled back to the cytosol during nutrient stress. Here, Fusarium oxysporum was utilized as a model organism, and we found that autophagy assumes an imperative job in affecting the morphology, development, improvement and pathogenicity of F. oxysporum. The search of autophagy pathway components from the F. oxysporum genome database recognized putative orthologs of 16 core autophagy-related (ATG) genes of yeast, which additionally incorporate the ubiquitin-like protein atg22. Present study elucidates the unreported role of Foatg22 in formation of autophagosomes. The deletion mutant of Foatg22 did not demonstrate positive monodansylcadaverine (MDC) staining, which exposed that Foatg22 is required for autophagy in F. oxysporum. Moreover, the ∆Foatg22 strains exhibited a decrease in hyphal development and conidiation, and reduction in pathogenicity on potato tubers and leaves of potato plant. The hyphae of ∆Foatg22 mutants were less dense when contrasted with wild-type (WT) and overexpression (OE) mutants. Our perceptions demonstrated that Foatg22 might be a key regulator for the control of dry rot disease in tuber and root crops during postharvest stage.

Biosynthesis and Characterization of Silver Nanoparticles Produced by Plant Extracts and Its Antimicrobial Activity

Solanum tubersum is the fourth most challenging plant in Egypt, affected by several fungi, viral and bacterial diseases. Bacterial and fungal isolates (Brown rot disease (Ralstonia solaniserum), soft root disease (Pectobacterium carotovora) and dry rot disease (Fusarium oxisporum) were collected. The green extracts of silver nanoparticles were prepared by means of aqueous extracts of three wild plants, Physalis peruviana (leaves, red and green fruits) (N1, N2 and N3), Solanum nigrum (fruit) (N4) and Moringa oliefera (leaves) (N5). SEM, TEM, FT-IR and X-RD obtained the characterization of the biosynthesis of silver nanoparticles. The results indicated that nanoparticles were spherical, smooth and the sizes varied between 12 and 33 nm. The activity of the nanoparticle formulations was tested against the bacterial isolates using agar diffusion method and one fungus using mycelial growth method. The results also elucidated that N5 formulation showed a significantly potent antibacterial activity against R. solanacearum. However, N1 formulation was the highest active one against P. carotovra. In addition, the antifungal activity indicated that N1 had the highest effect (EC50 = 687.03 mg/L) followed by N3 (EC50 = 981.61 mg/L) against F. oxysporium. Nanoparticles synthesized by wild plants could be used as safe alternatives to harmful microbicides.