Transgenic expression of lactoferrin imparts enhanced resistance to head blight of wheat caused by Fusarium graminearum

<p>Abstract</p> <p>Background</p> <p>The development of plant gene transfer systems has allowed for the introgression of alien genes into plant genomes for novel disease control strategies, thus providing a mechanism for broadening the genetic resources available to plant breeders. Using the tools of plant genetic engineering, a broad-spectrum antimicrobial gene was tested for resistance against head blight caused by <it>Fusarium graminearum </it>Schwabe, a devastating disease of wheat (<it>Triticum </it><it>aestivum </it>L.) and barley (<it>Hordeum vulgare </it>L.) that reduces both grain yield and quality.</p> <p>Results</p> <p>A construct containing a bovine lactoferrin cDNA was used to transform wheat using an <it>Agrobacterium</it>-mediated DNA transfer system to express this antimicrobial protein in transgenic wheat. Transformants were analyzed by Northern and Western blots to determine lactoferrin gene expression levels and were inoculated with the head blight disease fungus <it>F</it>. <it>graminearum</it>. Transgenic wheat showed a significant reduction of disease incidence caused by <it>F. graminearum </it>compared to control wheat plants. The level of resistance in the highly susceptible wheat cultivar Bobwhite was significantly higher in transgenic plants compared to control Bobwhite and two untransformed commercial wheat cultivars, susceptible Wheaton and tolerant ND 2710. Quantification of the expressed lactoferrin protein by ELISA in transgenic wheat indicated a positive correlation between the lactoferrin gene expression levels and the levels of disease resistance.</p> <p>Conclusions</p> <p>Introgression of the lactoferrin gene into elite commercial wheat, barley and other susceptible cereals may enhance resistance to <it>F. graminearum</it>.</p

Synthesis, Characterisation, Structure, and Magnetic Properties of [Ni{H 2 NCH(CH 3 )CH 2 NH 2 } 3 ][Fe(CN) 5 NO]·H 2 O

The complex [Ni(pn

Transgenic expression of lactoferrin imparts enhanced resistance to head blight of wheat caused by \u3ci\u3eFusarium graminearum\u3c/i\u3e

Background: The development of plant gene transfer systems has allowed for the introgression of alien genes into plant genomes for novel disease control strategies, thus providing a mechanism for broadening the genetic resources available to plant breeders. Using the tools of plant genetic engineering, a broad-spectrum antimicrobial gene was tested for resistance against head blight caused by Fusarium graminearum Schwabe, a devastating disease of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) that reduces both grain yield and quality. Results: A construct containing a bovine lactoferrin cDNA was used to transform wheat using an Agrobacterium-mediated DNA transfer system to express this antimicrobial protein in transgenic wheat. Transformants were analyzed by Northern and Western blots to determine lactoferrin gene expression levels and were inoculated with the head blight disease fungus F. graminearum. Transgenic wheat showed a significant reduction of disease incidence caused by F. graminearum compared to control wheat plants. The level of resistance in the highly susceptible wheat cultivar Bobwhite was significantly higher in transgenic plants compared to control Bobwhite and two untransformed commercial wheat cultivars, susceptible Wheaton and tolerant ND 2710. Quantification of the expressed lactoferrin protein by ELISA in transgenic wheat indicated a positive correlation between the lactoferrin gene expression levels and the levels of disease resistance. Conclusions: Introgression of the lactoferrin gene into elite commercial wheat, barley and other susceptible cereals may enhance resistance to F. graminearum

Genetic transformation of \u3ci\u3eFusarium oxysporum\u3c/i\u3e f.sp. \u3ci\u3egladioli\u3c/i\u3e with \u3ci\u3eAgrobacterium\u3c/i\u3e to study pathogenesis in \u3ci\u3eGladiolus\u3c/i\u3e

Fusarium rot caused by Fusarium oxysporum f.sp. gladioli (Fog) is one of the most serious diseases of Gladiolus, both in the field and in bulbs in storage. In order to study the mechanisms of pathogenesis of this fungus, we have transformed Fog with Agrobacterium tumefaciens binary vectors containing the hygromycin B phosphotransferase (hph) gene and fluorescence reporter genes EGFP (green), EYFP (yellow) or ECFP (cyan) using the AGL-1 strain of A. tumefaciens. Hygromycin B (100 μg/ml) resistant colonies were observed only when acetosyringone was added to the co-cultivation medium. Transformed colonies are more clearly visible when co-cultivated on cellophane membrane than on Hybond -N+ membrane. Transformed lines were stably maintained through four serial passages on medium containing hygromycin B, and they expressed green, yellow or cyano fluorescence. PCR with hph-specific primers and Southern blotting with an hph-specific probe were positive for HygR lines but not for the untransformed isolate. The cyano fluorescence of the ECFP-transformed isolate was clearly distinguishable from the green autofluorescence of Gladiolus roots, signifying the potential of these lines for further histopathological investigations. Transformed lines will be useful for identifying pathogenicity related genes, screening transgenic resistance, and in studies of host-pathogen interactions

Gene expression profiling of the plant pathogenic basidiomycetous fungus \u3ci\u3eRhizoctonia solani\u3c/i\u3e AG 4 reveals putative virulence factors

Rhizoctonia solani is a ubiquitous basidiomycetous soilborne fungal pathogen causing damping- off of seedlings, aerial blights and postharvest diseases. To gain insight into the molecular mechanisms of pathogenesis a global approach based on analysis of expressed sequence tags (ESTs) was undertaken. To get broad gene-expression coverage, two normalized EST libraries were developed from mycelia grown under high nitrogen-induced virulent and low nitrogen/methylglucose-induced hypovirulent conditions. A pilot-scale assessment of gene diversity was made from the sequence analyses of the two libraries. A total of 2280 cDNA clones was sequenced that corresponded to 220 unique sequence sets or clusters (contigs) and 805 singlets, making up a total of 1025 unique genes identified from the two virulence-differentiated cDNA libraries. From the total sequences, 295 genes (38.7%) exhibited strong similarities with genes in public databases and were categorized into 11 functional groups. Approximately 61.3% of the R. solani ESTs have no apparent homologs in publicly available fungal genome databases and are considered unique genes. We have identified several cDNAs with potential roles in fungal pathogenicity, virulence, signal transduction, vegetative incompatibility and mating, drug resistance, lignin degradation, bioremediation and morphological differentiation. A codon-usage table has been formulated based on 14 694 R. solani EST codons. Further analysis of ESTs might provide insights into virulence mechanisms of R. solani AG 4 as well as roles of these genes in development, saprophytic colonization and ecological adaptation of this important fungal plant pathogen

Histopathological Features Of Deep Fungal Infections : An Analysis Of Sixteen Skin Biopsies

In the present study, skin biopsies in suspected cases of deep fungal infections were subjected to H &amp;E and special stainings. In 2 of the 5 cases of sporotrichosis and in both cases of chromomycosis and of histoplasmosis, PAS positive fungal elements could be demonstrated. In both the cases of histoplasmosis, the fungi were also demonstrated by GMS staining. In 3 cases of sporotrichosis, 2 cases of mycetoma and 3 cases of subcutaneous phycomycosis, fungus could not be demonstrated by PAS staining. However, the histopathological features were corroborative

Soybean Nodule-Associated Non-Rhizobial Bacteria Inhibit Plant Pathogens and Induce Growth Promotion in Tomato

The root nodules are a unique environment formed on legume roots through a highly specific symbiotic relationship between leguminous plants and nodule-inducing bacteria. Previously, Rhizobia were presumed to be the only group of bacteria residing within nodules. However, recent studies discovered diverse groups of bacteria within the legume nodules. In this report soybean nodule-associated bacteria were studied in an effort to identify beneficial bacteria for plant disease control and growth promotion. Analysis of surface-sterilized single nodules showed bacterial diversity of the nodule microbiome. Five hundred non-rhizobial colonies from 10 nodules, 50 colonies per nodule, were tested individually against the tomato wilt causing bacterial pathogen Clavibacter michiganensis subsp. michiganensis (Cmm) for inhibition of pathogen growth. From the initial screening, 54 isolates were selected based on significant growth inhibition of Cmm. These isolates were further tested in vitro on another bacterial pathogen Pseudomonas syringae pv. tomato (Pst) and two fungal pathogens Rhizoctonia solani and Sclerotinia sclerotiorum. Bacterial metabolites were extracted from 15 selected isolates with ethanol and tested against pathogen Cmm and Pst. These isolates were identified by using MALDI-TOF mass spectrometry and 16S rRNA gene sequencing. Pseudomonas spp. were the dominant soybean nodule-associated non-rhizobial bacterial group. Several isolates imparted significant protection against pathogens and/or plant growth promotion on tomato seedlings. The most promising nodule-associated bacterial isolate that suppressed both Cmm and Pst in vitro and Pst in tomato seedlings was identified as a Proteus species. Isolation and identification of beneficial nodule-associated bacteria established the foundation for further exploration of potential nodule-associated bacteria for plant protection and growth promotion

Soybean Nodule-Associated Non-Rhizobial Bacteria Inhibit Plant Pathogens and Induce Growth Promotion in Tomato

The root nodules are a unique environment formed on legume roots through a highly specific symbiotic relationship between leguminous plants and nodule-inducing bacteria. Previously, Rhizobia were presumed to be the only group of bacteria residing within nodules. However, recent studies discovered diverse groups of bacteria within the legume nodules. In this report soybean nodule-associated bacteria were studied in an effort to identify beneficial bacteria for plant disease control and growth promotion. Analysis of surface-sterilized single nodules showed bacterial diversity of the nodule microbiome. Five hundred non-rhizobial colonies from 10 nodules, 50 colonies per nodule, were tested individually against the tomato wilt causing bacterial pathogen Clavibacter michiganensis subsp. michiganensis (Cmm) for inhibition of pathogen growth. From the initial screening, 54 isolates were selected based on significant growth inhibition of Cmm. These isolates were further tested in vitro on another bacterial pathogen Pseudomonas syringae pv. tomato (Pst) and two fungal pathogens Rhizoctonia solani and Sclerotinia sclerotiorum. Bacterial metabolites were extracted from 15 selected isolates with ethanol and tested against pathogen Cmm and Pst. These isolates were identified by using MALDI-TOF mass spectrometry and 16S rRNA gene sequencing. Pseudomonas spp. were the dominant soybean nodule-associated non-rhizobial bacterial group. Several isolates imparted significant protection against pathogens and/or plant growth promotion on tomato seedlings. The most promising nodule-associated bacterial isolate that suppressed both Cmm and Pst in vitro and Pst in tomato seedlings was identified as a Proteus species. Isolation and identification of beneficial nodule-associated bacteria established the foundation for further exploration of potential nodule-associated bacteria for plant protection and growth promotion

Differential regulation of miRNAs involved in the susceptible and resistance responses of wheat cultivars to wheat streak mosaic virus and Triticum mosaic virus

Abstract Background Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are components of the wheat streak mosaic virus disease complex in the Great Plains region of the U.S.A. and elsewhere. Co-infection of wheat with WSMV and TriMV causes synergistic interaction with more severe disease symptoms compared to single infections. Plants are equipped with multiple antiviral mechanisms, of which regulation of microRNAs (miRNAs) is a potentially effective constituent. In this investigation, we have analyzed the total and relative expression of miRNA transcriptome in two wheat cultivars, Arapahoe (susceptible) and Mace (temperature-sensitive-resistant), that were mock-inoculated or inoculated with WSMV, TriMV, or both at 18 °C and 27 °C. Results Our results showed that the most abundant miRNA family among all the treatments was miRNA166, followed by 159a and 168a, although the order of the latter two changed depending on the infections. When comparing infected and control groups, twenty miRNAs showed significant upregulation, while eight miRNAs were significantly downregulated. Among them, miRNAs 9670-3p, 397-5p, and 5384-3p exhibited the most significant upregulation, whereas miRNAs 319, 9773, and 9774 were the most downregulated. The comparison of infection versus the control group for the cultivar Mace showed temperature-dependent regulation of these miRNAs. The principal component analysis confirmed that less abundant miRNAs among differentially expressed miRNAs were strongly correlated with the inoculated symptomatic wheat cultivars. Notably, miRNAs 397-5p, 398, and 9670-3p were upregulated in response to WSMV and TriMV infections, an observation not yet reported in this context. The significant upregulation of these three miRNAs was further confirmed with RT-qPCR analysis; in general, the RT-qPCR results were in agreement with our computational analysis. Target prediction analysis showed that the miRNAs standing out in our analysis targeted genes involved in defense response and regulation of transcription. Conclusion Investigation into the roles of these miRNAs and their corresponding targets holds promise for advancing our understanding of the mechanisms of virus infection and possible manipulation of these factors for developing durable virus resistance in crop plants