Development of a Host-Induced RNAi System in the Wheat Stripe Rust Fungus Puccinia striiformis f. sp. tritici

Rust fungi cause devastating diseases of wheat and other cereal species globally. Genetic resistance is the preferred method to control rusts but the effectiveness of race-specific resistance is typically transient due to the genetic plasticity of rust populations. The advent of RNA interference (RNAi) technology has shown promise for the engineering of resistance to some biotrophic pathogens in plants by altering the expression of essential pathogens\u27 genes. Gene fragments from the rust fungi Puccinia striiformis f. sp. tritici or P. graminis f. sp. tritici were delivered to plant cells through the Barley stripe mosaic virus system, and some reduced the expression of the corresponding genes in the rust fungus. The ability to detect suppression was associated with the expression patterns of the fungal genes because reduction was only detected in transcripts with relatively high levels of expression in fungal haustoria. The results indicate that an in planta RNAi approach can be used in functional genomics research for rust fungi and that it could potentially be used to engineer durable resistance. © 2011 The American Phytopathological Society

Approximation to Hadamard Derivative via the Finite Part Integral

In 1923, Hadamard encountered a class of integrals with strong singularities when using a particular Green’s function to solve the cylindrical wave equation. He ignored the infinite parts of such integrals after integrating by parts. Such an idea is very practical and useful in many physical models, e.g., the crack problems of both planar and three-dimensional elasticities. In this paper, we present the rectangular and trapezoidal formulas to approximate the Hadamard derivative by the idea of the finite part integral. Then, we apply the proposed numerical methods to the differential equation with the Hadamard derivative. Finally, several numerical examples are displayed to show the effectiveness of the basic idea and technique

Forgery face detection method based on multi-domain temporal features mining

Financial technology has greatly facilitated people’s daily life with the continuous development of computer technology in the financial services industry.However, digital finance is accompanied by security problems that can be extremely harmful.Face biometrics, as an important part of identity information, is widely used in payment systems, account registration, and many other aspects of the financial industry.The emergence of face forgery technology constantly impacts the digital financial security system, posing a threat to national asset security and social stability.To address the security problems caused by fake faces, a forgery face detection method based on multi-domain temporal features mining was proposed.The tampering features were distinguished and enhanced based on the consistency of statistical feature data distribution and temporal action trend in the temporal features of videos existing in the spatial domain and frequency domain.Temporal information was mined in the spatial domain using an improved LSTM, while in the frequency domain, temporal information existing in different frequency bands of the spectrum was mined using 3D convolution layers.The information was then fused with the tampering features extracted from the backbone network, thus effectively distinguishing forged faces from real ones.The effectiveness of the proposed method was demonstrated on mainstream datasets

Molecular cloning and expression analysis of turnip (Brassica rapa var. rapa) sucrose transporter gene family

In higher plants, sugars (mainly sucrose) are produced by photosynthetically assimilated carbon in mesophyll cells of leaves and translocated to heterotrophic organs to ensure plant growth and development. Sucrose transporters, or sucrose carriers (SUCs), play an important role in the long-distance transportation of sucrose from source organs to sink organs, thereby affecting crop yield and quality. The identification, characterization, and molecular function analysis of sucrose transporter genes have been reported for monocot and dicot plants. However, no relevant study has been reported on sucrose transporter genes in Brassica rapa var. rapa, a cruciferous root crop used mainly as vegetables and fodder. We identified and cloned 12 sucrose transporter genes from turnips, named BrrSUC1.1 to BrrSUC6.2 according to the SUC gene sequences of B. rapa pekinensis. We constructed a phylogenetic tree and analyzed conserved motifs for all 12 sucrose transporter genes identified. Real-time quantitative polymerase chain reaction was conducted to understand the expression levels of SUC genes in different tissues and developmental phases of the turnip. These findings add to our understanding of the genetics and physiology of sugar transport during taproot formation in turnips

Characterization of a tryptophan 2-monooxygenase gene from Puccinia graminis f. sp. tritici involved in auxin biosynthesis and rust pathogenicity

The plant hormone indole-3-acetic acid (IAA) is best known as a regulator of plant growth and development but its production can also affect plant-microbe interactions. Microorganisms, including numerous plant-associated bacteria and several fungi, are also capable of producing IAA. The stem rust fungus Puccinia graminis f. sp. tritici induced wheat plants to accumulate auxin in infected leaf tissue. A gene (Pgt-IaaM) encoding a putative tryptophan 2-monooxygenase, which makes the auxin precursor indole-3-acetamide (IAM), was identified in the P. graminis f. sp. tritici genome and found to be expressed in haustoria cells in infected plant tissue. Transient silencing of the gene in infected wheat plants indicated that it was required for full pathogenicity. Expression of Pgt-IaaM in Arabidopsis caused a typical auxin expression phenotype and promoted susceptibility to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000

Lesion Activity on Brain MRI in a Chinese Population with Unilateral Optic Neuritis.

Longitudinal studies have shown that brain white matter lesions are strong predictors of the conversion of unilateral optic neuritis to multiple sclerosis (MS) in Caucasian populations. Consequently brain MRI criteria have been developed to improve the prediction of the development of clinically definite multiple sclerosis (CDMS). In Asian populations, optic neuritis may be the first sign of classical or optic-spinal MS. These signs add to the uncertainty regarding brain MRI changes with respect to the course of unilateral optic neuritis. The aim of this study was to examine the association between brain lesion activity and conversion to CDMS in Chinese patients with unilateral optic neuritis. A small prospective cohort study of 40 consecutive Chinese patients who presented with unilateral optic neuritis was conducted. Brain lesion activity was recorded as the incidence of Gd-enhanced lesions and new T2 lesions. Brain lesions on MRI that were characteristic of MS were defined according to the 2010 revisions of the McDonald criteria. The primary endpoint was the development of CDMS. We found that nineteen patients (48%) had brain lesions that were characteristic of MS on the initial scan. One of these patients (3%) had Gd-enhanced brain lesions. A significantly lower percentage of the patients (10%, p<0.001) presented with new T2 brain lesions on the second scan. During a median of 5 years of follow-up, seven patients (18%) developed CDMS. There was no significant difference in the conversion rate to CDMS between patients with and without brain lesions that were characteristic of MS (4/19 and 3/21, respectively; Fisher exact test, one-sided, p = 0.44). We conclude that brain lesions characteristic of MS are common in Chinese patients with unilateral optic neuritis; however, these patients exhibit low lesion activity. The predictive value of brain lesion activity for CDMS requires investigation in additional patients

Generation and analysis of expression sequence tags from haustoria of the wheat stripe rust fungus Puccinia striiformis f. sp. Tritici

BACKGROUND: Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. In spite of its agricultural importance, the genomics and genetics of the pathogen are poorly characterized. Pst transcripts from urediniospores and germinated urediniospores have been examined previously, but little is known about genes expressed during host infection. Some genes involved in virulence in other rust fungi have been found to be specifically expressed in haustoria. Therefore, the objective of this study was to generate a cDNA library to characterize genes expressed in haustoria of Pst. RESULTS: A total of 5,126 EST sequences of high quality were generated from haustoria of Pst, from which 287 contigs and 847 singletons were derived. Approximately 10% and 26% of the 1,134 unique sequences were homologous to proteins with known functions and hypothetical proteins, respectively. The remaining 64% of the unique sequences had no significant similarities in GenBank. Fifteen genes were predicted to be proteins secreted from Pst haustoria. Analysis of ten genes, including six secreted protein genes, using quantitative RT-PCR revealed changes in transcript levels in different developmental and infection stages of the pathogen. CONCLUSIONS: The haustorial cDNA library was useful in identifying genes of the stripe rust fungus expressed during the infection process. From the library, we identified 15 genes encoding putative secreted proteins and six genes induced during the infection process. These genes are candidates for further studies to determine their functions in wheat-Pst interactions

Genome Sequence Resources for the Wheat Stripe Rust Pathogen (Puccinia striiformis f. sp. tritici) and the Barley Stripe Rust Pathogen (Puccinia striiformis f. sp. hordei)

Puccinia striiformis f. sp. tritici causes devastating stripe (yellow) rust on wheat and P. striiformis f. sp. hordei causes stripe rust on barley. Several P. striiformis f. sp. tritici genomes are available, but no P. striiformis f. sp. hordei genome is available. More genomes of P. striiformis f. sp. tritici and P. striiformis f. sp. hordei are needed to understand the genome evolution and molecular mechanisms of their pathogenicity. We sequenced P. striiformis f. sp. tritici isolate 93-210 and P. striiformis f. sp. hordei isolate 93TX-2, using PacBio and Illumina technologies and RNA sequencing. Their genomic sequences were assembled to contigs with high continuity and showed significant structural differences. The circular mitochondria genomes of both were complete. These genomes provide high-quality resources for deciphering the genomic basis of rapid evolution and host adaptation, identifying genes for avirulence and other important traits, and studying host-pathogen interactions

Disease-Induced Assemblage of the Rhizosphere Fungal Community in Successive Plantings of Wheat

Plant is one of the primary drivers of microbial communities in the rhizosphere. The consistent presence of the same plant species over time such as monocropping in agriculture can drive significant changes in plant-associated microbiomes. Most of the studies with monocropping have focused on bacteria, which are involved in the natural suppression of a number of soilborne diseases, including Rhizoctonia root rot and take-all. However, few studies have examined how monocropping and root rot pathogens jointly affect the structure of fungal communities in the rhizosphere. In this greenhouse study, rhizosphere fungal communities from successive wheat plantings infected with the fungal pathogen Rhizoctonia solani AG8 were characterized using MiSeq sequencing targeting the internal transcribed spacer 1 region of the ribosomal RNA gene. Sequence analyses revealed that distinct fungal groups clustered by planting cycles with or without strain AG8 inoculation but infection with strain AG8 enhanced the separation of fungal communities. Clusters of fungal communities were also observed in strain-AG8-infected and noninfected rhizospheres, whereas there was no difference in fungal communities between the rhizospheres with the least root disease and those with the worst root disease. Planting cycles significantly reduced fungal α diversity. The most abundant fungal genus was Mortierella which increased in relative abundance with planting cycles in strain-AG8-infected samples. In contrast, fungal genera that included Pseudogymnoascus, Gibberella, Fusarium, Fusicolla, Exophiala, and Waitea were reduced in relative abundance with successive plantings and strain AG8 infection. Together, this study revealed how fungal communities change with successive wheat growth under the pressure of a soilborne fungal pathogen

Genomic insights into host adaptation between the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici) and the barley stripe rust pathogen (Puccinia striiformis f. sp. hordei)

Abstract Background Plant fungal pathogens can rapidly evolve and adapt to new environmental conditions in response to sudden changes of host populations in agro-ecosystems. However, the genomic basis of their host adaptation, especially at the forma specialis level, remains unclear. Results We sequenced two isolates each representing Puccinia striiformis f. sp. tritici (Pst) and P. striiformis f. sp. hordei (Psh), different formae speciales of the stripe rust fungus P. striiformis highly adapted to wheat and barley, respectively. The divergence of Pst and Psh, estimated to start 8.12 million years ago, has been driven by high nucleotide mutation rates. The high genomic variation within dikaryotic urediniospores of P. striiformis has provided raw genetic materials for genome evolution. No specific gene families have enriched in either isolate, but extensive gene loss events have occurred in both Pst and Psh after the divergence from their most recent common ancestor. A large number of isolate-specific genes were identified, with unique genomic features compared to the conserved genes, including 1) significantly shorter in length; 2) significantly less expressed; 3) significantly closer to transposable elements; and 4) redundant in pathways. The presence of specific genes in one isolate (or forma specialis) was resulted from the loss of the homologues in the other isolate (or forma specialis) by the replacements of transposable elements or losses of genomic fragments. In addition, different patterns and numbers of telomeric repeats were observed between the isolates. Conclusions Host adaptation of P. striiformis at the forma specialis level is a complex pathogenic trait, involving not only virulence-related genes but also other genes. Gene loss, which might be adaptive and driven by transposable element activities, provides genomic basis for host adaptation of different formae speciales of P. striiformis