Explore the vast range of titles available.

Powdery mildew, caused by Blumeria graminis f. sp. tritici ( Bgt ), is one of the most destructive diseases that pose a great threat to wheat production. Wheat landraces represent a rich source of powdery mildew resistance. Here, we report the map-based cloning of powdery mildew resistance gene Pm24 from Chinese wheat landrace Hulutou. It encodes a tandem kinase protein (TKP) with putative kinase-pseudokinase domains, designated WHEAT TANDEM KINASE 3 (WTK3). The resistance function of Pm24 was validated by transgenic assay, independent mutants, and allelic association analyses. Haplotype analysis revealed that a rare 6-bp natural deletion of lysine-glycine codons, endemic to wheat landraces of Shaanxi Province, China, in the kinase I domain (Kin I) of WTK3 is critical for the resistance function. Transgenic assay of WTK3 chimeric variants revealed that only the specific two amino acid deletion, rather than any of the single or more amino acid deletions, in the Kin I of WTK3 is responsible for gaining the resistance function of WTK3 against the Bgt fungus. Powdery mildew is a major threat to world wheat yields. Here the authors describe the map-based cloning of Pm24 , a gain-of-function powdery mildew resistance allele that encodes a tandem kinase-pseudokinase protein with a deletion in a kinase domain that is endemic to certain wheat landraces.

The wheat Pm3 resistance gene against the powdery mildew pathogen occurs as an allelic series encoding functionally different immune receptors which induce resistance upon recognition of isolate-specific avirulence (AVR) effectors from the pathogen. Here, we describe the identification of five effector proteins from the mildew pathogens of wheat, rye, and the wild grass Dactylis glomerata , specifically recognized by the PM3B, PM3C and PM3D receptors. Together with the earlier identified AVRPM3 A2/F2 , the recognized AVRs of PM3B/C, (AVRPM3 B2/C2 ), and PM3D (AVRPM3 D3 ) belong to a large group of proteins with low sequence homology but predicted structural similarities. AvrPm3 b2/c2 and AvrPm3 d3 are conserved in all tested isolates of wheat and rye mildew, and non-host infection assays demonstrate that Pm3b , Pm3c , and Pm3d are also restricting the growth of rye mildew on wheat. Furthermore, divergent AVR homologues from non-adapted rye and Dactylis mildews are recognized by PM3B, PM3C, or PM3D, demonstrating their involvement in host specificity. The wheat Pm3 immune receptors confer resistance against powdery mildew by recognizing isolate-specific avirulence (AVR) effectors of the pathogen. Here, the authors identify and characterize two new AVR genes and demonstrate that Pm3 receptors are determinants of host-specificity for grass mildews.

The brown planthopper, Nilaparvata lugens, is a pest that threatens rice (Oryza sativa) production worldwide. While feeding on rice plants, planthoppers secrete saliva, which plays crucial roles in nutrient ingestion and modulating plant defense responses, although the specific functions of salivary proteins remain largely unknown. We identified an N. lugens-secreted mucin-like protein (NlMLP) by transcriptome and proteome analyses and characterized its function, both in brown planthopper and in plants. NlMLP is highly expressed in salivary glands and is secreted into rice during feeding. Inhibition of NlMLP expression in planthoppers disturbs the formation of salivary sheaths, thereby reducing their performance. In plants, NlMLP induces cell death, the expression of defense-related genes, and callose deposition. These defense responses are related to Ca²⁺ mobilization and the MEK2 MAP kinase and jasmonic acid signaling pathways. The active region of NlMLP that elicits plant responses is located in its carboxyl terminus. Our work provides a detailed characterization of a salivary protein from a piercing-sucking insect other than aphids. Our finding that the protein functions in plant immune responses offers new insights into the mechanism underlying interactions between plants and herbivorous insects.

Crop wild relatives offer natural variations of disease resistance for crop improvement. Here, we report the isolation of broad-spectrum powdery mildew resistance gene Pm36 , originated from wild emmer wheat, that encodes a tandem kinase with a transmembrane domain (WTK7-TM) through the combination of map-based cloning, PacBio SMRT long-read genome sequencing, mutagenesis, and transformation. Mutagenesis assay reveals that the two kinase domains and the transmembrane domain of WTK7-TM are critical for the powdery mildew resistance function. Consistently, in vitro phosphorylation assay shows that two kinase domains are indispensable for the kinase activity of WTK7-TM. Haplotype analysis uncovers that Pm36 is an orphan gene only present in a few wild emmer wheat, indicating its single ancient origin and potential contribution to the current wheat gene pool. Overall, our findings not only provide a powdery mildew resistance gene with great potential in wheat breeding but also sheds light into the mechanism underlying broad-spectrum resistance. Powdery mildew is a fungal leaf disease that reduces yield and grain quality in susceptible wheat varieties. Here, the authors report the cloning of the wild emmer wheat originated powdery mildew resistance gene Pm36 as a membrane associated tandem kinase and its possible resistance mechanism.

H62 copper alloy is a commonly used material in engineering, and stress cracking of copper alloys has always been concerned. In this paper, a two-dimensional model of H62 copper alloy was established by COMSOL electrochemical module, and the stress corrosion of H62 copper alloy was analyzed by using measured engineering stress-strain curve. The results show that the tensile stress has a serious effect on the stress corrosion, and the excessive tensile stress will lead to the fracture failure of the contact.

Pueraria thomsonii Benth is an important medicinal plant. Transcriptome sequencing, unigene assembly, the annotation of transcripts and the study of gene expression profiles play vital roles in gene function research. However, the full-length transcriptome of P. thomsonii remains unknown. Here, we obtained 44,339 nonredundant transcripts of P. thomsonii by using the PacBio RS II Isoform and Illumina sequencing platforms, of which 43,195 were annotated genes. Compared with the expression levels in the plant roots, those of transcripts with a |fold change| ≥ 4 and FDR < 0.01 in the leaves or stems were assigned as differentially expressed transcripts (DETs). In total, we found 9,225 DETs, 32 of which came from structural genes that were potentially involved in isoflavone biosynthesis. The expression profiles of 8 structural genes from the RNA-Seq data were validated by qRT-PCR. We identified 437 transcription factors (TFs) that were positively or negatively correlated with at least 1 of the structural genes involved in isoflavone biosynthesis using Pearson correlation coefficients (r) (r > 0.8 or r < -0.8). We also identified a total of 32 microRNAs (miRNAs), which targeted 805 transcripts. These miRNAs caused enriched function in 'ATP binding', 'defense response', 'ADP binding', and 'signal transduction'. Interestingly, MIR156a potentially promoted isoflavone biosynthesis by repressing SBP, and MIR319 promoted isoflavone biosynthesis by repressing TCP and HB-HD-ZIP. Finally, we identified 2,690 alternative splicing events, including that of the structural genes of trans-cinnamate 4-monooxygenase and pullulanase, which are potentially involved in the biosynthesis of isoflavone and starch, respectively, and of three TFs potentially involved in isoflavone biosynthesis. Together, these results provide us with comprehensive insight into the gene expression and regulation of P. thomsonii.

Cereal powdery mildews, which are caused by Blumeria graminis , are economically important diseases that are distributed throughout the world. To successfully evade the host defence mechanism, the wheat powdery mildew pathogen known as B. graminis f. sp. tritici ( Bgt ) secretes an array of effectors into plant cells to interfere with host immunity and promote fungal invasion and colonisation during the infection process. However, little is known about the functions of the vast majority of these effectors in immune manipulation. In this study, we identified an effector-coding gene known as BgtE-20069a from Bgt . This gene encodes a short protein carrying an N-terminal signal peptide with a secretory function and is highly upregulated in the early stage of Bgt infection in wheat. We observed that transient expression of BgtE-20069a in Nicotiana benthamiana suppressed programmed cell death (PCD) induced by both the proapoptotic protein Bax and the elicitor PAMP INF1 from Phytophthora infestans. The mature form of BgtE-20069a (which lacks a signal peptide) is localised to the cytoplasm and nucleus of plant cells. Moreover, the knockdown of BgtE-20069a resulted in reduced virulence towards wheat, with significantly decreased conidia production and a decreased haustorial formation rate being observed. Together, these results suggest that BgtE-20069a is a vital virulence factor that is required for Bgt infection in wheat; moreover, the results indicate that it can suppress plant immunity and increase Bgt virulence. Our findings broaden the current understanding of the role of effectors in promoting Bgt infection by manipulating host immunity, thereby providing new insights into the molecular mechanism of Bgt pathogenesis.

Pepper root rot is a serious soil-borne disease that hinders pepper production, and efforts are being made to identify biological agents that can prevent and control pepper root rot. Our group recently discovered and produced a biological agent, named G15, which reduces the diversity and richness of fungi and bacteria when applied to pepper fields. In the soil of the G15-treatment condition, the pathogenic fungus Fusarium was inhibited, while the richness of beneficial bacteria Rhodanobacter was increased. Also, the ammonia nitrogen level was decreased in the G15-treatment soil, and the pH, total carbon, and total potassium levels were increased. Compared to the control condition, pepper yield was increased in the treatment group (by 16,680 kg acre −1 ). We found that G15 could alter the microbial community structure of the pepper rhizosphere. These changes alter the physical and chemical properties of the soil and, ultimately, improve resistance to pepper root rot and increase pepper yield.

This study investigates the influence of magnetic fields on the electrochemical corrosion behavior of aerospace-grade H62 brass alloy in 3.5 wt% NaCl solution and its underlying 10 mechanisms. Employing electrochemical testing techniques combined with surface characterization methods, we explored the effects of magnetic field intensity (25–100 mT) and orientation (parallel and perpendicular to electrode surface) on the corrosion kinetics and corrosion product evolution of H62 brass alloy. Results demonstrate that magnetic fields significantly accelerate the corrosion process of H62 brass alloy. Under parallel magnetic field (100 mT), the corrosion current density increased from 0.49 μA/cm2 to 3.66 μA/cm2, approximately 7.5 times that of the non-magnetic condition, while perpendicular magnetic field increased it to 1.73 μA/cm2, approximately 3.5 times the baseline value. The charge transfer resistance decreased from 3382 Ω·cm2 to 1335 Ω·cm2. Magnetic field orientation determines the fundamental differences in corrosion acceleration mechanisms. Parallel magnetic fields primarily enhance mass transfer processes through Lorentz force-driven magnetohydrodynamic (MHD) effects, resulting in intensified uniform corrosion; perpendicular magnetic fields alter interfacial ion distribution through magnetic gradient forces, inducing localized corrosion tendencies. Magnetic fields promote the transformation of protective Cu2O films into porous Cu2(OH)3Cl, reducing the protective capability of corrosion product layers.

There is a large diversity of genetically defined resistance genes in bread wheat against the powdery mildew pathogen Blumeria graminis (B. g.) f. sp. tritici. Many confer race-specific resistance to this pathogen, but until now only the mildew avirulence gene AvrPm3 a2/f2 that is recognized by Pm3a/f was known molecularly. We performed map-based cloning and genome-wide association studies to isolate a candidate for the mildew avirulence gene AvrPm2. We then used transient expression assays in Nicotiana benthamiana to demonstrate specific and strong recognition of AvrPm2 by Pm2. The virulent AvrPm2 allele arose from a conserved 12 kb deletion, while there is no protein sequence diversity in the gene pool of avirulent B. g. tritici isolates. We found one polymorphic AvrPm2 allele in B. g. triticale and one orthologue in B. g. secalis and both are recognized by Pm2. AvrPm2 belongs to a small gene family encoding structurally conserved RNase-like effectors, including Avr a13 from B. g. hordei, the cognate Avr of the barley resistance gene Mla13. These results demonstrate the conservation of functional avirulence genes in two cereal powdery mildews specialized on different hosts, thus providing a possible explanation for successful introgression of resistance genes from rye or other grass relatives to wheat.