Cross-Kingdom Gene Coexpression Analysis Using a Stemphylium botryosum–Lens ervoides System Revealed Plasticity of Intercommunication Between the Pathogen Secretome and the Host Immune Systems

Necrotrophic pathogens are responsible for significant declines in crop yield and quality worldwide. During the infection process, a pathogen releases a series of secretory proteins to counteract the plant immune system, and this interaction of pathogen and host molecules determines whether the pathogen will successfully invade the host plant tissues. In this study, we adopted co-transcriptomic approaches to analyze the Lens ervoides–Stemphylium botryosum system, with a focus on 1,216 fungal genes coding for secretory proteins and 8,810 disease-responsive genes of the host 48, 96, and 144 h postinoculation, captured in two F9 recombinant inbred lines (RILs) displaying contrasting disease responses. By constructing in planta gene coexpression networks (GCNs) for S. botryosum, we found that the pathogen tended to co-upregulate genes regulating cell wall degradation enzymes, effectors, oxidoreductases, and peptidases to a much higher degree in the susceptible host LR-66-577 than in the resistant RIL LR-66-637, indicating that the promotion of these digestive enzymes and toxins increased S. botryosum virulence. Construction of cross-kingdom GCNs between pathogen and plant for the two RILs revealed that the co-upregulation of these fungal digestive enzymes and toxins simultaneously promoted a series of defense responses such as redox change, expression of membrane-related genes and serine/threonine kinase, and stress and disease responses in the susceptible RIL which was not observed in the resistant RIL, indicating that these activities exacerbated susceptibility to S. botryosum. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Potential of Pseudomonas stutzeri strains isolated from rhizospheric soil endowed with antifungal activities against phytopathogenic fungus Stemphylium botryosum

Mokrani S, Bejaoui B, Belabid L, Nabti E, Mokrani S. 2020. Potential of Pseudomonas stutzeri strains isolated from rhizospheric soil endowed with antifungal activities against phytopathogenic fungus Stemphylium botryosum. Biodiversitas 21: 47-54. In this present study, two Pseudomonas strains P4 and P5 isolated from rhizospheric soil were characterized for PGP (Plant Growth Promoting) traits production like HCN (Hydrogen Cyanid), siderophores and IAA (Indole Acetic Acid). Phylogenic tree based on 16S DNAr identification-related the two strains P4 and P5 to Pseudomonas stutzeri NR 116489 and NR 113652.1. One phytopathogenic fungus St-bt (Stemphylium botryosum) was isolated from Phaseolus vulgaris L. Macroscopic and microscopic identification attributed it to the genus Stemphylium. Antifungal activities of the two Pseudomonas strains P4 and P5 against fungus isolate St-bt had revealed very highly significant inhibition percentages of 38.46± 3.85% and 56.56± 2.22% for each strain, respectively.

Current Knowledge on Pathogenicity and Management of Stemphylium botryosum in Lentils (Lens culinaris ssp. culinaris Medik)

Stemphylium blight (SB) caused by Ascomycete, Stemphylium botryosum Wallr. has been a serious threat to lentil cultivation, mainly in Bangladesh, Nepal, India, and Canada since its first outbreak in Bangladesh in 1986. The genus Stemphylium Wallr., a dematiaceous hyphomycete, comprises up to 150 species, and is pathogenic on a wide range of plants infecting leguminous as well as nonleguminous crops. In recent years, studies indicated overlapping in morphological characters among the different species under the genus Stemphylium, making the identification and description of species difficult. This necessitates different molecular phylogenetic analysis in species delimitation. Therefore, a detailed understanding of spatial diversity and population structure of the pathogen is pertinent for producing source material for resistance breeding. The role of different weather variables as predisposing factors for the rapid spread of the pathogen necessitates devising a disease predictive model for the judicial application of fungicides. A dearth of information regarding spore biology, epidemiology, race diversity, host-pathogen interaction, and holistic disease management approach necessitates immediate attention towards more intensive research efforts. This is the first comprehensive review on the current state of knowledge and research efforts being made for a better understanding of the SB resistance through cognizing biology, ecology, and epidemiology of S. botryosum and effective disease management strategies to prevent widespread outbreaks of SB. The information regarding the biology and epidemiology of S. botryosum is also crucial for strengthening the “Integrated Disease Management” (IDM) programme. The need for a regional research network is advocated where the disease is becoming endemic.

Effect of incubation temperatures on mycelial growth, conidial features and density of Stemphylium botryosum Walr isolates

The cultural and morphological variability of Stemphylium botryosum Walr was studied with five isolates viz. isolate 1 (Stb-I1), isolate 2 (Stb-I2), isolate 3 (Stb- I3), isolate 4 (Stb-I4) and isolate 5 (Stb-I5) collected from Parsa, Rautahat, Dang, Banke and Chitwan districts of Nepal respectively during 2011-2012 crop season with Completely Randomized Design (CRD) maintaining 3 replications at Plant Pathology Laboratory of Grain Legumes Research Program (GLRP), Rampur, Chitwan. Single spore isolation technique was followed to isolate the pathogen. The pathogen was grow on Potato Dextrose Agar (PDA) and incubated with different temperatures in BOD incubator. The calibrated ocular micrometer was used to measure the length and breadth of the conidia while conidial count with sporulation intensity was attempted with hemocytometer. The mycelium color of the different isolates was varied from white, grey, brown and brownish black in peripheral part while mostly black pigmentation was noticed in lateral part of the culture plate. The shape and texture was regular and velvety for most isolates and in some isolate, roughly irregular shape with cottony texture was found. The higher colony diameter of 7.66 cm and conidial dimension of 29.42×18.12 μm (L/B ratio-1.62) with profuse sporulation intensity (46.67 conidia /0.01 ml) was observed at 25 °C after 15 days of incubation on PDA. However, 2.84 cm diameter, 19.58×9.81 μm (L/B ratio-2.00) with poor conidial density (7.60 conidia /0.01 ml) was noticed at 10 °C. The observation at 10 and 35 °C was at par in case of mycelial growth, conidial features and sporulation intensity. Mostly conidia of all isolates were brown in color at lower incubation temperature but they became dark grey brown at 25 and 30 °C and grey color was noticed when incubated at 35 °C on PDA after 15 days of incubation.Kathmandu University Journal of Science, Engineering and TechnologyVol. 12, No. I, June, 2016, page: 80-89

Efficacy of fungicides to control Stemphylium blight (Stemphylium botryosum) of lentil

A field experiment was carried out during Rabi seasons of 2011-12 and 2012-13 to evaluate the efficacy of fungicides in controlling Stemphylium blight (S. botryosum) of lentil. Five fungicides were evaluated under higher disease pressure (106 ml-1) of Stemphylium blight. Results revealed that Foliar spray (4 sequences) with Rovral 50WP (Iprodione) @ (0.2%) and Secure 600WG (Fenamidione+Mancozeb) @ (0.2%) at an interval of 7 days effectively controlled the disease and increased yield of lentil by 31.99% and 28.20%, respectively. The fungicides may be selected for control of the disease.Bangladesh J. Agril. Res. 40(2): 229-233 June 2015

Micromycetes on Pisum sativum var. arvense

Seeds of 11 Austrian winter pea genotypes, harvested at Radzików (CEP) in 1993 and 1994, were evaluated for fungi occurrence on Coon's agar medium in Petri plates. Number of species isolated depended on the genotype and year of collection. <i>Alternaria alternata, Stemphylium botryosum</i> were found on all the tested samples and <i>Phoma pinodella</i> and <i>Fusarium poae</i> were also common while <i>Botrytis cinerea, Sclerotinia sclerotiorum</i> and <i>Mycosphaerella pinodes</i> appeared to be common only in 1993. Three species occurred only once. The mycoflora was richer in 1993. The common seed inhabitants usually transmitted higher percentage of fungi than species occuring more seldom.

Yariability of dry seed mycobiota of Pisum sativum

Mycobiota of dry pea seeds of cv. Ramir and line R 429/87 harvested at Radzików, Oleśnica Mała and Łagiewniki in 1991—93 was investigated. Among twenty species <i>Alternaria aliernata</i> and <i>Stemphylium botryosum</i> occurred commonly each year. <i>Mycosphaerella pinodes, Ascochyta pisi, Fusarium poae</i> and <i>Cladosporium herbarum</i> were noted on most of the tested seed samples. Percentage of sccee transmitting the fungi varied depending on locations, time and genotypes, being the lowest for Łagiewniki and in 1992. The year 1991 was the most favourable for seed mycobiota development, especially for pathogenic fungi.