Cochliobolus Heterostrophus Research Articles

Investigation of the antifungal activity of the dicarboximide fungicide iprodione against Bipolaris maydis

Southern corn leaf blight (SCLB), mainly caused by Bipolaris maydis, is a destructive disease of maize worldwide. Iprodione is a widely used dicarboximide fungicide (DCF); however, its antifungal activity against B. maydis has not been well studied until now. In this study, the sensitivity of 103 B. maydis isolates to iprodione was determined, followed by biochemistry and physiology assays to ascertain the fungicide's effect on the morphology and other biological properties of B. maydis. The results indicated that iprodione exhibited strong inhibitory activity against B. maydis, and the EC50 values in inhibiting mycelial growth ranged from 0.088 to 1.712 μg/mL, with a mean value of 0.685 ± 0.687 μg/mL. After treatment with iprodione, conidial production of B. maydis was decreased significantly, and the mycelia branches increased with obvious shrinkage, distortion and fracture. Moreover, the expression levels of the osmotic pressure-related regulation genes histidine kinase (hk) and Ssk2-type mitogen-activated protein kinase (ssk2) were upregulated, the glycerin content of mycelia increased significantly, the relative conductivity of mycelia increased, and the cell wall membrane integrity was destroyed. The in vivo assay showed that iprodione at 200 μg/mL provided 79.16% protective efficacy and 90.92% curative efficacy, suggesting that the curative effect was better than the protective effect. All these results proved that iprodione exhibited strong inhibitory activity against B. maydis and provided excellent efficacy in controlling SCLB, indicating that iprodione could be an alternative candidate for the control of SCLB in China.

Prevalence of Southern Leaf Blight of Maize in two major maize producing states of India

Southern corn leaf blight (SCLB) or Maydis leaf blight, caused by Bipolaris maydis, is an important disease of maize in the eastern and north-eastern part of India. Hence, to assess the severity and distribution of the disease in two distinct and major maize growing states i.e. Mizoram and West Bengal were selected. A roving survey was conducted under different agro-climatic conditions during the kharif season of 2019 and 2020 in three districts of West Bengal and as well as in Mizoram. The survey results revealed that SCLB was more prevalent in the plains of West Bengal in comparison to hilly areas of Mizoram. The mean SCLB incidence varied from 18.87% in Zemabawk, Mizoram to 63.22% in institutional farm, C-block, of BCKV, West Bengal. The mean disease severity ranged from 10.06 % in Muthi, Mizoram to 22.09% in Instructional Farm, Jaguli, BCKV, West Bengal. Both disease incidence and severity were highest at 99 DAS in all the locations surveyed. Successive surveys of SCLB in the maize growing belts across the country need to be conducted to develop a better understanding about the disease prevalence, intensity and severity under different agro-ecological conditions.

Benchmarking of different microbes for their biosurfactants antifungal action against plant pathogens

The biotic stress caused by phytopathogens (bacteria, fungus, yeast and insect pests) is a primary factor in yield loss of plants. Biocontrol agents and their active compounds are used to manage such plant pathogens. Here, in our study, we screened four bacterial isolates identified as Bacillus cereus, B. anthracis, B. velezensis and Serratia marcescens after morphological, biochemical and molecular characterization (16s rDNA sequencing) for production of biosurfactant by foam forming activity, oil spreading tests and emulsification activity. Highest foam stability (75 min) and maximum emulsification activity E24% (75%) was observed by B. velezensis strain. Among all the four isolates, Bacillus velezensis strain produced maximum biosurfactant (0.349±0.004 g/50 mL). Biosurfactant of all the four bacterial isolates were checked for fungal inhibiton on PDA plate(s). Bacillus velezensis showed comparatively the highest percent inhibition 58.82, 88.15, 78.45,72.68, 83.96, 75.47, 68.07 and 88.44% against Colletotrichum falcatum, Fusarium oxysporum f sp. ciceri, Helminthosporium maydis, F. oxysporum f. sp. lycopersici, Aspergillus niger, Mucor sp., Helminthosporium oryzae and Rhizoctonia solani, respectively. Bacillus velezensis biosurfactant among all the four bacterial isolates was found to be most effective against the tested phytopathogens.

The response of some genotypes of maize to downy mildew, maydis leaf blight, leaf rust, and stalk rot

Plant diseases in maize are still one of the limiting factors in efforts to increase maize production. The aims of this study were: (1) to obtain populations, lines, and candidate hybrid varieties that were resistant to downy mildew (Peronosclerospora spp.), maydis leaf blight (Bipolaris maydis), rust (Puccinia sp.), and bacterial stalk rot (Dikeya sp.); (2) to identify the causative pathogen using 16s rDNA analysis. In this study, a number of lines/populations of candidate varieties were tested against downy mildew, maydis leaf blight, rust, and stalk rot. The test results showed that all tested hybrid candidates showed resistance to downy mildew even JHD 03 showed a very resistant reaction. The average downy mildew attack ranged from 0.0-10.7%. All of the hybrid candidates tested showed a moderately resistant reaction to maydis leaf blight with an average attack percentage ranging from 18.0-24.7%. All tested hybrid candidates showed a sensitive to very sensitive reaction to rust disease with an average attack percentage ranging from 31.3-68.7%. There were five hybrid maize lines showing very resistant to moderately resistant to bacterial stem rot disease with an average attack percentage ranging from 4.67-24%.

Evaluation of Fungicides, Botanicals and Biocontrol Agents for Management of Southern Leaf Blight of Maize (Bipolaris maydis)with Effective Benefit Cost Ratio

Southern leaf blight of maize (Bipolaris maydis) is one of the major disease in many countries including India. An experiment was conducted for two consecutive years during rabi 2019 and 2020 to develop an integrated management of southern leaf blight of maize using fungicides, botanicals and bioagents under natural field conditions. Propiconazole was found to be the best and showed 100% mycelial growth inhibition in vitro at 0.1%. Among the botanicals, citronella showed 99.70% mycelial growth inhibition and Trichoderma harzianum was found to be the best with 84.26% mycelial growth inhibition among the biocontrol agents. The results of the field trials showed the highest yield performance (2601.71 kg ha-1) and percent reduction in disease severity over control of 61.70 % in the treatment comprising of seed treatment+spraying with propiconazole 25% EC @ 1% which was followed by treatment comprised of spraying with citronella @ 0.1% (2445.33 kg ha-1) and spraying with propiconazole 25% EC @ 0.1% (2349.26 kg ha-1). Highest BC ratio was obtained in seed treatment+spraying with propiconazole 25% EC @ 1% (4.05) followed by spraying with Trichoderma harzianum @ 4 g (3.71) and seed treatment+spraying with Trichoderma harzianum @ 4 g (3.69). The results showed that seed treatment+spraying with propiconazole 25% EC @ 1% was significantly superior over other treatments.

Distribution of Bipolaris maydis in southern Khyber Pakhtunkhwa (KP) – Pakistan and estimation of yield losses in maize crop

Maydis leaf blight, is an important disease of maize in Khyber Pakhtunkhwa (KP) – Pakistan. Knowledge about distribution pattern of a disease in an area is helpful for adoption of appropriate disease management strategy. Therefore, an extensive survey of the disease was conducted in southern districts of the province in 2020. Four union council in each district and five fields per union council were assessed in “X” shaped pattern. The highest disease incidence was found in district Bannu (78.05%) while least was detected in district Tank (39.84%). Similarly, the isolates of Bannu and Kohat districts exhibited larger colony diameter and spore size than other isolates. Yield losses were also assessed based on attainable and actual yield. The highest value of area under disease progress curve (AUDPC) was observed for cultivar Azam (229.7). Regression analysis indicated that a unit (1%) increase in AUDPC value increased yield loss by 7.6%.

Epicoccum spp. Causing Maize Leaf Spot in Heilongjiang Province, China.

Maize leaf spot occurs worldwide and affects maize production. Maize can be infected by several pathogens causing leaf spot, such as Bipolaris zeicola, Bipolaris maydis, Curvularia species, Alternaria species, etc. In the current study, 30 Epicoccum isolates recovered from symptomatic maize leaves were identified based on morphological characteristics, pathogenicity, and multilocus sequence analyses of nuLSU, ITS, tub2, and rpb2. These maize isolates were grouped into five Epicoccum species, including E. nigrum, E. layuense, E. sorghinum, E. latusicollum, and E. pneumoniae. Pathogenicity tests showed that all five Epicoccum species could produce small ellipse- and spindle-shaped spots on maize leaves. The lesion center was grayish yellow to dark gray and surrounded by a chlorotic area. Furthermore, the Epicoccum isolates exhibited high pathogenicity to 20 main maize varieties of Heilongjiang Province but showed different sensitivities to the commonly used fungicides carbendazim and tebuconazole. In addition, these Epicoccum isolates showed different production capacity of pectinase, cellulase, protease, amylase, laccase, and gelatinase, but all showed high lipase activity. This is the first report globally of E. layuense, E. latusicollum, and E. pneumoniae as causal agents of maize leaf spot. E. pneumoniae was first reported as a plant pathogen.

ZmGLP1, a Germin-like Protein from Maize, Plays an Important Role in the Regulation of Pathogen Resistance.

A gene encoding a protein similar to germin-like proteins (GLPs) was obtained from maize (Zea mays) and designated as ZmGLP1. Based on the ZmGLP1 conserved domain and phylogenetic status, ZmGLP1 was grouped into GLP subfamily b and has high similarity to OsGLP8-14 from Oryza sativa. ZmGLP1 is expressed in different maize tissues during different growth stages and is mainly expressed in the stems and leaves. The induced expression patterns confirmed that ZmGLP1 is differentially expressed under abiotic and hormone stress; it had an early response to jasmonic acid (JA) and ethephon (ET) but a late response to salicylic acid (SA) and was significantly upregulated under Bipolaris maydis infection. The overexpression of ZmGLP1 in Arabidopsis improved the resistance to biotrophic Pseudomonas syringae pv. tomato DC3000 (PstDC3000) and necrotrophic Sclerotinia sclerotiorum by inducing the expression of JA signaling-related genes. Moreover, the hydrogen peroxide (H2O2) content increased due to the overexpression of ZmGLP1 in Arabidopsis after pathogen infection. Compared to the wild-type control, the H2O2 content of ZmGLP1-overexpressing Arabidopsis infected by PstDC3000 increased significantly but was lower in transgenic plants infected with S. sclerotiorum. Furthermore, high-performance liquid chromatography-tandem mass (HPLC-MS/MS) spectrometry showed that the JA contents of ZmGLP1-overexpressing Arabidopsis markedly increased after pathogen infection. However, the improved resistance of ZmGLP1-overexpressing Arabidopsis pretreated with the JA biosynthetic inhibitor, sodium diethyldithiocarbamate trihydrate (DIECA), was suppressed. Based on these findings, we speculate that ZmGLP1 plays an important role in the regulation of Arabidopsis resistance to biotrophic PstDC3000 and necrotrophic S. sclerotiorum; the regulatory effects are achieved by inducing plant oxidative burst activity and activation of the JA signaling pathway.

Morphological and molecular characterization of Actinomycetes isolates and their metabolite fingerprinting

Two actinomycetes isolates RK-302 and RK-320 obtained from limestone rock of Dehradun, Uttarakhand were characterized morphologically, biochemically and by using 16S rDNA sequencing at Jaypee Institute of Information Technology, Noida during 2017-18. Differences in morphological/biochemical features showed that the isolates differed from each other as well as from the nearest matching strains in the GenBank database. Variation in dimension for spore size of both isolates was observed through transmission electron microscopy. Both isolates, RK-302 and RK-320 showed activity against phytopathogenic fungi, Fusarium graminearum and Bipolaris maydis using agar plugs in vitro. Metabolite fingerprinting with GC-MS revealed the presence of 37 and 31 compounds, respectively from RK-302 and RK-320. Combined analysis of phenotypic, biochemical and molecular studies showed that the isolates differed at strain level. From the metabolite fingerprint and antimicrobial activity data, it was concluded that the antimicrobial compounds identified in present study may be useful in developing novel bio control agents for plant pathogens.

Confirmation of physiological race of Bipolaris maydis causing maydis leaf blight of maize in India

Maydis leaf blight (MLB) incited by Bipolaris maydis occurs in most of the maize growing regions. Present study revealed morphological divergence among 74 isolates of B. maydis collected from geographically distant places of India. Based on morpho-cultural features clustered by R software, 25 representative isolates of B. maydis were used for race identification. The internal transcribed spacer (ITS) sequence further confirmed the isolates as B. maydis. In recent concept, variation in disease incidence and infectivity denotes genetic shift in the pathogen or introduction of new pathogenic race(s) through germplasm exchange. For unveiling Indian race(s) of B. maydis, present exploration was made. Four genetically divergent maize genotypes with cytoplasmic male sterility (CMS), viz. -C (MGU- 161QPV-C), -T (MGU- 345PV-T), -S (MGU-150Q-S) and CM-119 (fertile cytoplasm) were assessed using 25 isolates of B. maydis during kharif 2018-19 at ICAR-IARI, New Delhi. The genotype MGU-161QPV-C associated with CMS-C was highly resistant followed by MGU-345PV-T (CMS-T) and MGU-150Q-S (CMS-S), whereas CM-119 showed high susceptibility. Present outcome confirmed prevalence of race 'O' of B. maydis in India and eliminated uncertainty about occurrence of other races, i.e. T and C.

Endophytic Metarhizium robertsii suppresses the phytopathogen, Cochliobolus heterostrophusand modulates maize defenses.

Fungi in the genus Metarhizium (Hypocreales: Clavicipitaceae) are insect-pathogens and endophytes that can benefit their host plant through growth promotion and protection against stresses. Cochliobolus heterostrophus (Drechsler) Drechsler (Pleosporales: Pleosporaceae) is an economically-significant phytopathogenic fungus that causes Southern Corn Leaf Blight (SCLB) in maize. We conducted greenhouse and lab-based experiments to determine the effects of endophytic M. robertsii J.F. Bisch., Rehner & Humber on growth and defense in maize (Zea mays L.) infected with C. heterostrophus. We inoculated maize seeds with spores of M. robertsii and, at the 3 to 4-leaf stage, the youngest true leaf of M. robertsii-treated and untreated control plants with spores of C. heterostrophus. After 96 h, we measured maize height, above-ground biomass, endophytic colonization by M. robertsii, severity of SCLB, and expression of plant defense genes and phytohormone content. We recovered M. robertsii from 74% of plants grown from treated seed. The severity of SCLB in M. robertsii-treated maize plants was lower than in plants inoculated only with C. heterostrophus. M. robertsii-treated maize inoculated or not inoculated with C. heterostrophus showed greater height and above-ground biomass compared with untreated control plants. Height and above-ground biomass of maize co-inoculated with M. robertsii and C. heterostrophus were not different from M. robertsii-treated maize. M. robertsii modulated the expression of defense genes and the phytohormone content in maize inoculated with C. heterostrophus compared with plants not inoculated with C. heterostrophus and control plants. These results suggest that endophytic M. robertsii can promote maize growth and reduce development of SCLB, possibly by induced systemic resistance mediated by modulation of phytohormones and expression of defense and growth-related genes in maize.

Antifungal mechanism of isothiocyanates against Cochliobolus heterostrophus.

Isothiocyanates (ITCs) generated from the 'glucosinolates-myrosinase' defense system in the Brassicaceae exhibit broad antagonistic activity to various fungal pathogens. Nevertheless, the antifungal activity of ITCs to non-adapted fungi of Brassicaceae plants were seldom determined. The inhibitory effects of ITCs on Cochliobolus heterostrophus were evaluated and the antagonistic mechanism was explored. The mycelium growth of C. heterostrophus was hindered significantly by allyl, 4-(methylthio)-butyl, and phenyethyl ITCs, 4MTB-ITC exhibited the highest inhibitory effect on mycelium growth with an IC50 value of 53.4μmol L-1 . In addition, ITCs exhibited obvious inhibitory effect on conidia germination and pathogenicity of C. heterostrophus. Proteomic analysis indicated that the inhibition of C. heterostrophus by A-ITC downregulated the expression of genes related to energy metabolism, oxidoreductase activity, melanin biosynthesis, and cell wall-degrading enzymes. Furthermore, mutants ΔChtrx2 and ΔChnox1 showed increased sensitivity to ITCs, and melanin biosynthesis was inhibited significantly in C. heterostrophus in response to A-ITC. Interestingly, unlike other pathogens that infected Brassicaceae plants, the SaxA in C. heterostrophus displayed no function in ITC degradation. In addition, the ITCs also exhibited obvious inhibitory effect on mycelium growth of Setosphaeria turcica, Fusarium graminearum, and Magnaporthe oryzae. This study indicated that non-Brassicaceae-adapted pathogens are more sensitive to ITCs, and ITCs could have applications in protecting non-Brassicaceae crops in future. In addition, loss of ChNOX1 and ChTRX2 increased the sensitivity of C. heterostrophus to ITCs. Our results provided potential utilization of ITCs to control diseases caused by non-Brassicaceae pathogenic fungi. © 2022 Society of Chemical Industry.

Synthesis, phloem mobility and induced plant resistance of synthetic salicylic acid amino acid or glucose conjugates.

The growing demand for food, combined with a strong social expectation for a diet produced with fewer conventional agrochemical inputs, has led to the development of new alternatives in plant protection worldwide. Among different possibilities, the stimulation of the plant innate immune system by chemicals represents a novel and promising way. The vectorization strategy of an active ingredient that we previously developed with fungicides can potentially extend to salicylic acid (SA) or its halogenated analogues. Using the click chemistry method, six new conjugates combining SA or two mono- or di-halogenated analogues with L-glutamic acid or β-D-glucose via a 1,2,3-triazole nucleus have been synthesized. Conjugate 8a, which is derived from SA and glutamic acid, showed high phloem mobility in the Ricinus model, similar to that of SA alone despite a much higher steric hindrance. In vivo bioassays of the six conjugates against two maize pathogenic fungi Bipolaris maydis and Fusarium graminearum revealed that, unlike SA, the amino acid conjugate 8a with good phloem mobility exerted a protective effect not only locally at the application site, but also in distant stem tissues after foliar application. Moreover, compounds 8a and 8b induced up-regulation of both defense-related genes ZmNPR1 and ZmPR1 similar to their parent compounds upon challenge inoculation with B. maydis. The vectorization of salicylic acid or its halogenated derivatives by coupling them with an α-amino acid can be a promising strategy to stimulate SA-mediated plant defenses responses against pathogens outside the application site. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Identification of Early and Extra-Early Maturing Tropical Maize Inbred Lines with Multiple Disease Resistance for Enhanced Maize Production and Productivity in Sub-Saharan Africa.

Maize, a staple for millions across sub-Saharan Africa (SSA), faces major biotic constraints affecting production and safety of the crop. These include northern corn leaf blight (NCLB), southern corn leaf blight (SCLB), Curvularia leaf spot (CLS), and aflatoxin contamination by Exserohilum turcicum, Bipolaris maydis, Curvularia lunata, and Aspergillus flavus, respectively. Farmers in SSA would benefit tremendously if high-yielding maize hybrids with multiple disease resistance (MDR) were developed and commercialized. In all, 49 early-maturing (EM; 90 to 95 days to physiological maturity) and 55 extra-early-maturing (EEM, 80 to 85 days to physiological maturity) inbred lines developed by the International Institute of Tropical Agriculture were identified as resistant to NCLB in field evaluations in multiple agroecologies of Nigeria in 2017 and 2018. From each maturity group, the 30 most resistant inbreds were selected for evaluation for resistance to SCLB and CLS using a detached-leaf assay. Additionally, the inbreds were screened for resistance to kernel rot and aflatoxin contamination using a kernel screening assay. In all, 7 EM and 6 EEM maize inbreds were found to be highly resistant to the three foliar pathogens while 10 inbreds were resistant to the foliar pathogens and supported significantly less (P = 0.01) aflatoxin accumulation than other inbreds. Inbreds having MDR should be tested extensively in hybrid combinations and commercialized. Large-scale use of maize hybrids with MDR would (i) increase maize production and productivity and (ii) reduce losses caused by aflatoxin contamination. Overall, planting of EM and EEM maize hybrids with MDR would contribute to food security, reduced aflatoxin exposure, and increased incomes of maize farmers in SSA.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

The Sorting Nexin Genes ChSNX4 and ChSNX41 Are Required for Reproductive Development, Stress Adaption and Virulence in Cochliobolus heterostrophus.

Sorting nexins are a conserved protein family involved in many cellular processes in fungi, and the function of sorting nexin Snx4 (Atg24) and Snx41 (Atg20) in Cochliobolus heterostrophus was not clear. The ΔChsnx4 and ΔChsnx41 mutants were generated by a PCR-based marker method to determine the roles of Snx4 and Snx41 in reproductive development, stress adaption, and virulence in C. heterostrophus. Compared with the wild-type strain, the ΔChsnx4 and ΔChsnx41 mutants exhibited obvious changes in vegetative growth and in morphology of conidia. In addition, the conidiation, appressorium formation, and virulence of snx4 and snx41 mutants were dramatically reduced. Moreover, ΔChsnx4 and ΔChsnx41 mutants were more sensitive to oxidative stress (menadione and H2O2), cell wall integrity stress (Congo red and calcofluor white), fungicides, and isothiocyanates. All the phenotypes mentioned above were restored in complemented strains. In addition, ChSnx4 and ChSnx41 were proven to interact with each other through yeast two-hybrid. Taken together, these findings indicated that ChSNX4 and ChSNX41 were important for fungal growth, asexual development, stress adaption, and virulence in C. heterostrophus.

Synthesis and antifungal activity evaluation of novel pyridine derivatives as potential succinate dehydrogenase inhibitors

Two series of novel pyridine derivatives (1a−l, 2a−l) were synthesized and characterized by IR, 1H NMR, 13C NMR, and HRMS. The crystal structures of compounds 1 h and 2l were characterized by single crystal X-ray diffraction and crystallized in the monoclinic and orthorhombic system, respectively. The in vitro antifungal activity of synthesized compounds were determined against five plant pathogenic fungi namely Gibberella zeae, Helminthosporium maydis, Rhizoctonia solani, Botrytis cinerea, and Sclerotinia sclerotiorum and most of the target compounds revealed significant antifungal activity at 20 mg/L. Of these, the inhibitory rate and the median effect concentrations (EC50) of compounds 1 m, 2i, 2o, and 2p were more close to fluopyram against B. cinerea. Meanwhile, the half inhibitory concentrations (IC50) of compounds 1 m, 2i, 2o, and 2p against succinate dehydrogenase (SDH) and their score in molecular docking were also more close to fluopyram, indicating the stronger antifungal activities of the four compounds were well associated with the affinities of these compounds in interacting with SDH. Therefore, we concluded that compounds 1 m, 2i, 2o, and 2p might be potential succinate dehydrogenase inhibitors (SDHIs), which was been reported for the first time.

Inhibitory Potentialities of Bio-control Agents on Cochliobolus heterostrophus Inciting Maydis Leaf Blight of Maize in Manipur

The antagonistic potentialities of seven species of native Trichoderma viz., T. atroviride, T. koningiopsis, T. ovalisporum, Hypocrea lixii, T. harzianum, T. asperellum and T. harzianum were evaluated in vitro against Cochliobolus heterostrophus causing maydis leaf blight of maize. The current study of dual culture assay, revealed the percentages of mycelial growth inhibition of C. heterostrophus by Hypocrea lixii, T. harzianum, T. atroviridae, T. koningiopsis, T. ovalisporum, T. asperellu and T. harzianum were 80.4%, 83.80%, 83.80%, 82.85%, 85.23%, 83.33% and 82.38% respectively. Each species significantly slowed the Cochliobolus heterostrophus pathogen's expansion. The findings indicate that C. heterostrophus, a common pathogen associated with maize leaf blight, is capable of being inhibited to a significant degree by all seven species of Trichoderma, using them as effective potential antagonists.

Multi-Gene Phylogenetic Approach for Identification and Diversity Analysis of Bipolaris maydis and Curvularia lunata Isolates Causing Foliar Blight of Zea mays.

Bipolaris species are known to be important plant pathogens that commonly cause leaf spot, root rot, and seedling blight in a wide range of hosts worldwide. In 2017, complex symptomatic cases of maydis leaf blight (caused by Bipolaris maydis) and maize leaf spot (caused by Curvularia lunata) have become increasingly significant in the main maize-growing regions of India. A total of 186 samples of maydis leaf blight and 129 maize leaf spot samples were collected, in 2017, from 20 sampling sites in the main maize-growing regions of India to explore the diversity and identity of this pathogenic causal agent. A total of 77 Bipolaris maydis isolates and 74 Curvularia lunata isolates were screened based on morphological and molecular characterization and phylogenetic analysis based on ribosomal markers—nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) region, 28S nuclear ribosomal large subunit rRNA gene (LSU), D1/D2 domain of large-subunit (LSU) ribosomal DNA (rDNA), and protein-coding gene-glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Due to a dearth of molecular data from ex-type cultures, the use of few gene regions for species resolution, and overlapping morphological features, species recognition in Bipolaris has proven difficult. The present study used the multi-gene phylogenetic approach for proper identification and diversity of geographically distributed B. maydis and C. lunata isolates in Indian settings and provides useful insight into and explanation of its quantitative findings.

Undescribed specialised metabolites from the endophytic fungus Emericella sp. XL029 and their antimicrobial activities

The fungus Emericella sp. XL029 isolated from leaves of Panax notoginseng was investigated for agents with potential antibacterial and antifungal activities using a one strain-many compounds (OSMAC) strategy. Fifteen compounds, including seven undescribed structures, were obtained from this species. Their structures were confirmed by extensive spectroscopic data, single-crystal X-ray crystallography and quantum chemistry calculations. Emerlactam A exhibited better antibacterial activity against multidrug-resistant Enterococcus faecium and antifungal activity against Helminthosporium maydis, with an MIC value of 12.5 μg/mL. Quiannulatic acid displayed significant antibacterial activity against multidrug-resistant Enterococcus faecium and multidrug-resistant Enterococcus faecalis with MIC values of 1.56 μg/mL and 3.13 μg/mL, respectively. 5-alkenylresorcinol exhibited significant antifungal activity against all tested phytopathogenic fungi with MIC values ranging from 6.25 to 12.5 μg/mL.

Resistance to multiple leaf diseases in popcorn lines with potential for baby corn production

The cultivation of special corns, such as baby corn, has had a positive influence on the economy of the country. Despite its importance, there is still a need for studies aimed at increasing production and planting areas of the crop. Phytosanitary studies are of particular interest, as the cultivation of such crops is susceptible to a series of pathogens, such as Bipolaris maydis, Exserohilum turcicum, and Puccinia polysora. The use of resistant cultivars is the most effective way to prevent the occurrence of these diseases. Thus, the present study aimed to identify popcorn lines that have the potential for baby corn production and are resistant to the main leaf diseases that affect the crop. The experiment was conducted in randomized blocks with four replications of 30 lines in each area, during two planting seasons. The area was located at the Federal Institute of Espírito Santo (IFES) Campus of Alegre, situated in Rive district, Espírito Santo State, Brazil. Using the obtained data, the area under the disease progress curve was obtained. Subsequently, analysis of the joint variance of the data was conducted, and when a significant effect was found, a grouping of means test was conducted. The Mahalanobis distance for each pair of lines was also calculated, and the genetic distance matrix was used to construct a dendrogram using the UPGMA method. Considering the averages obtained for the three diseases (Southern corn leaf blight, Northern corn leaf blight, and Southern rust), lines L61, L63, L65, L683, L684, L685, L691, L694, and L695 were identified as possible donors of resistance alleles for multiple diseases. Multivariate analysis efficiently grouped the lines L61, L63, L684, L685, and L691, which are described as most resistant in the univariate analysis.