Genome-Wide Comparative Analysis of the Cytochrome P450 Monooxygenase Family in 19 Aphid Species and Their Expression Analysis in 4 Cereal Crop Aphids.

Cytochrome P450 monooxygenases (CYP450s) play a variety of physiological roles, including pesticide resistance, plant allelochemical detoxification, and hormone metabolism catalysis. However, limited information is available on the classification and expression profiles of the CYP450 gene family in aphid species. This is the first study to identify the cytochrome P450 gene family in 19 aphid species at the whole genome level. A total of 1100 CYP450 genes were identified in 19 aphid species. Three hundred CYP450 genes belonged to six cereal crop aphid species, which were further classified into four subfamilies according to the phylogenetic relationship. The conserved motifs, exon-intron structures, and genomic organization of the same subfamilies were similar. Predictions of subcellular localization revealed that the endoplasmic reticulum harbored the majority of CYP450 proteins. In Sitobion avenae and Rhopalosiphum maidis, the increase in the CYP450 gene was primarily caused by segmental duplication events. However, only tandem duplication occurred in the CYP450 gene family of Diuraphis noxia, Rhopalosiphum padi, Schizaphis graminum, and Sitobion miscanthi. Synteny analysis found three continuous colinear CYP450 gene pairs among six cereal crop aphid species. Furthermore, we obtained the expression profiles of four cereal crop aphids, including R. padi, D. noxia, S. graminum, and S. avenae. Differential expression analysis provided growth stage specificity genes, tissue specificity genes, organ specificity genes and some detoxification metabolic genes among these four cereal crop aphids. Meanwhile, their expression patterns were showed. The related functions and pathways of CYP450s were revealed by GO and KEGG enrichment analysis. Above all, we picked the differentially expressed CYP450 genes from all of the differentially expressed genes (DEGs). These differentially expressed CYP450 genes provided some new potential candidates for aphid control and management. This work establishes the foundation for further investigations into the regulatory functions of the CYP450 gene family in aphid species and beyond.

Identification of nuclear membrane SUN proteins and components associated with wheat fungal stress responses.

In eukaryotes, the nuclear membrane that encapsulates genomic DNA is composed of an inner nuclear membrane (INM), an outer nuclear membrane (ONM), and a perinuclear space. SUN proteins located in the INM and KASH proteins in the ONM form the SUN-KASH NM-bridge, which functions as the junction of the nucleocytoplasmic complex junction. Proteins containing the SUN domain showed the highest correlation with differentially accumulated proteins (DAPs) in the wheat response to fungal stress. To understand the characteristics of SUN and its associated proteins in wheat responding to pathogen stress, here we investigated and comprehensive analyzed SUN- and KASH-related proteins among the DAPs under fungi infection based on their conserved motifs. In total, four SUN proteins, one WPP domain-interacting protein (WIP), four WPP domain-interacting tail-anchored proteins (WIT), two WPP proteins and one Ran GTPase activating protein (RanGAP) were identified. Following transient expression of Nicotiana benthamiana, TaSUN2, TaRanGAP2, TaWIT1 and TaWIP1 were identified as nuclear membrane proteins, while TaWPP1 and TaWPP2 were expressed in both the nucleus and cell membrane. RT-qPCR analysis demonstrated that the transcription of TaSUN2, TaRanGAP2 and TaWPP1 were strongly upregulated in response to fungal infection. Furthermore, using the bimolecular fluorescence complementation, the luciferase complementation and a nuclear and split-ubiquitin-based membrane yeast two-hybrid systems, we substantiated the interaction between TaSUN2 and TaWIP1, as well as TaWIP1/WIT1 and TaWPP1/WPP2. Silencing of TaSUN2, TaRanGAP2 and TaWPP1 in wheat leaves promoted powdery mildew infection and hyphal growth, and reduced the expression of TaBRI1, TaBAK1 and Ta14-3-3, indicating that these NM proteins play a positive role in resistance to fungal stress. Our study reveals the characteristics of NM proteins and propose the preliminary construction of SUN-WIP-WPP-RanGAP complex in wheat, which represents a foundation for detail elucidating their functions in wheat in future.

Crossed renal ectopia with rectal cancer: A case report.

BACKGROUND: Crossed renal ectopia (CRE) occurs when one kidney crosses the midline from the primary side to the contralateral side while the ureter remains on the primary side. Rectal cancer, one of the most common malignant tumors of the digestive tract, refers to cancer from the dentate line to the rectosigmoid junction. The concurrent presentation of CRE alongside rectal cancer is an uncommon clinical observation. CASE SUMMARY: Herein, we report a 69-year-old male patient with rectal cancer who was diagnosed with CRE via computed tomography during hospitalization. Following thorough preoperative evaluations, the patient underwent Dixon surgery. CONCLUSION: We performed laparoscopic radical resection of rectal cancer and adequate lymph node removal in a patient with CRE with no postoperative discomfort.

GenoBaits®WheatplusEE: a targeted capture sequencing panel for quick and accurate identification of wheat-Thinopyrum derivatives.

KEY MESSAGE: A total of 90,000 capture probes derived from wheat and Thinopyrum elongatum were integrated into one chip, which served as an economical genotype for explorating Thinopyrumspecies and their derivatives. Thinopyrum species play a crucial role as a source of new genetic variations for enhancing wheat traits, including resistance to both abiotic and biotic factors. Accurate identification of exogenous chromosome(s) or chromosome segments or genes is essential following the introduction of alien genetic material into wheat, but this task remains challenging. This study aimed to develop a high-resolution wheat-Thinopyrum elongatum array, named GenoBaits®WheatplusEE, to trace alien genetic information by genotyping using a target sequencing system. This GenoBaits®WheatplusEE array included 90,000 capture probes derived from two species and integrated into one chip, with 10,000 and 80,000 originating from wheat and Th. elongatum, respectively. The capture probes were strategically positioned in genes and evenly distributed across the genome, facilitating the development of a roadmap for identifying each alien gene. The array was applied to the high-throughput identification of the alien chromosomes or segments in Thinopyrum and distantly related species and their derivatives. Our results demonstrated that the GenoBaits®WheatplusEE array could be used for direct identification of the breakpoint of alien segments, determine copy number of alien chromosomes, and reveal variations in wheat chromosomes by a single round of target sequencing of the sample. Additionally, we could efficiently and cost-effectively genotype, supporting the exploration of subgenome composition, phylogenetic relationships, and polymorphisms in essential genes (e.g., Fhb7 gene) among Thinopyrum species and their derivatives. We hope that GenoBaits®WheatplusEE will become a widely adopted tool for exporting wild germplasm for wheat improvement in the future.

An intron-located single nucleotide variation of TaGS5-3D is related to wheat grain size through accumulating intron retention transcripts.

KEY MESSAGE: Thirty-three stable QTL for 13 yield-related traits across ten environments were identified in the PD34/MY47 RIL population, and a candidate gene TaGS5-3D in Qmt.nwafu.3D was preliminarily identified to affect grain-related traits through accumulation of specific transcripts. Dissecting the genetic basis of yield-related traits is pivotal for improvement of wheat yield potential. In this study, a recombinant inbred line (RIL) population genotyped by SNP markers was used to detect quantitative trait loci (QTL) related to yield-related traits in ten environments. A total of 102 QTL were detected, including 33 environmentally stable QTL and 69 putative QTL. Among them, Qmt.nwafu.3D was identified as a pleiotropic QTL in the physical interval of 149.77-154.11 Mb containing a potential candidate gene TaGS5-3D. An SNP (T > C) was detected in its ninth intron, and TaGS5-3D-C was validated as a superior allele associated with larger grains using a CAPS marker. Interestingly, we found that TaGS5-3D-C was closely related to significantly up-regulated expression of intron-retained transcript (TaGS5-3D-PD34.1), while TaGS5-3D-T was related to dominant expression of normal splicing transcript (TaGS5-3D-MY47.1). Our results indicated that alternative splicing associated with the SNP T/C could be involved in the regulation of grain-related traits, laying a foundation for the functional analysis of TaGS5-3D and its greater potential application in high-yield wheat breeding.

Molecular Cytological Analysis and Specific Marker Development in Wheat-Psathyrostachys huashanica Keng 3Ns Additional Line with Elongated Glume.

Psathyrostachys huashanica Keng (2n = 2x = 14, NsNs) is an excellent gene resource for wheat breeding, which is characterized by early maturity, low plant height, and disease resistance. The wheat-P. huashanica derivatives were created by the elite genes of P. huashanica and permeate into common wheat through hybridization. Among them, a long-glume material 20JH1155 was identified, with larger grains and longer spike than its parents. In the present study, the methods of cytological observation, GISH, and sequential FISH analysis showed that 20JH1155 contained 21 pairs of wheat chromosomes and a pair of P. huashanica. There were some differences in 5A and 7B chromosomes between 20JH1155 and parental wheat 7182. Molecular marker, FISH, and sequence cloning indicated 20JH1155 alien chromosomes were 3Ns of P. huashanica. In addition, differentially expressed genes during immature spikelet development of 20JH1155 and 7182 and predicted transcription factors were obtained by transcriptome sequencing. Moreover, a total of 7 makers derived from Ph#3Ns were developed from transcriptome data. Taken together, the wheat-P. huashanica derived line 20JH1155 provides a new horizon on distant hybridization of wheat and accelerates the utilization of genes of P. huashanica.

On improving the English language ability of Science Citation Index papers for medical postgraduates through flipped classroom teaching.

Medical postgraduates are the new force of scientific research groups in China. However, the limitation of their English language ability restricts their publication of high-level Science Citation Index (SCI) papers to a large extent. Measures to improve students' SCI language ability from macro, intermediate and micro aspects were discussed through flipped classroom teaching mode, such as students' reading papers before class, students' practicing paper writing after class, and teacher's making comments in class. The feedback from the questionnaire showed that 96.65% of the students were satisfied with the teaching mode and 93.57% of them had improved their confidence in SCI writing. For the problems mentioned in the feedback, it was suggested that colleges and universities should formulate policies to encourage teachers to engage in medical English teaching, meanwhile teachers should constantly improve their professional quality, so as to help students improve their SCI language ability rapidly.

Cytogenetic identification and molecular marker development of a novel wheat-Leymus mollis 4Ns(4D) alien disomic substitution line with resistance to stripe rust and Fusarium head blight.

Leymus mollis (Trin.) Pilg. (2n = 4x = 28, NsNsXmXm) potentially harbours useful genes that might contribute to the improvement of wheat. We describe M862 as a novel wheat-L. mollis alien disomic substitution line from a cross between wheat cv. 7182 and octoploid Tritileymus M47. Cytological observations indicate that M862 has a chromosome constitution of 2n = 42 = 21II. Two 4D chromosomes of wheat substituted by two L. mollis Ns chromosomes were observed, using the GISH and ND-FISH analyses. Molecular marker, 55K SNP array and wheat-P. huashanica liquid array (GenoBaits®WheatplusPh) analyses further indicate that the alien chromosomes are L. mollis 4Ns. Therefore, it was deduced that M862 was a wheat-L. mollis 4Ns(4D) alien disomic substitution line. There were also changes in chromosomes 1A, 1D, 2B and 5A detected by ND-FISH analysis. Transcriptome sequencing showed that the structural variation of 1D, 1A and 5A may have smaller impact on gene expression than that for 2B. In addition, a total of 16 markers derived from Lm#4Ns were developed from transcriptome sequences, and these proved to be highly effective for tracking the introduced chromosome. M862 showed reduced height, larger grains (weight and width), and was highly resistance to CYR32 and CYR34 stripe rust races at the seedling stage and mixed stripe rust races (CYR32, CYR33 and CYR34) at the adult stage. It was also resistance to Fusarium head blight (FHB). This alien disomic substitution line M862 may be exploited as an important genetic material in the domestication of stipe rust and FHB resistance wheat varieties.

Development and Molecular Cytogenetic Identification of Two Wheat-Aegilops geniculata Roth 7Mg Chromosome Substitution Lines with Resistance to Fusarium Head Blight, Powdery Mildew and Stripe Rust.

Fusarium head blight (Fhb), powdery mildew, and stripe rust are major wheat diseases globally. Aegilops geniculata Roth (UgUgMgMg, 2n = 4x = 28), a wild relative of common wheat, is valuable germplasm of disease resistance for wheat improvement and breeding. Here, we report the development and characterization of two substitution accessions with high resistance to powdery mildew, stripe rust and Fhb (W623 and W637) derived from hybrid progenies between Ae. geniculata and hexaploid wheat Chinese Spring (CS). Fluorescence in situ hybridization (FISH), Genomic in situ hybridizations (GISH), and sequential FISH-GISH studies indicated that the two substitution lines possess 40 wheat chromosomes and 2 Ae. geniculata chromosomes. Furthermore, compared that the wheat addition line parent W166, the 2 alien chromosomes from W623 and W637 belong to the 7Mg chromosomes of Ae. geniculata via sequential FISH-GISH and molecular marker analysis. Nullisomic-tetrasomic analysis for homoeologous group-7 of wheat and FISH revealed that the common wheat chromosomes 7A and 7B were replaced in W623 and W637, respectively. Consequently, lines W623, in which wheat chromosomes 7A were replaced by a pair of Ae. geniculata 7Mg chromosomes, and W637, which chromosomes 7B were substituted by chromosomes 7Mg, with resistance to Fhb, powdery mildew, and stripe rust. This study has determined that the chromosome 7Mg from Ae. geniculata exists genes resistant to Fhb and powdery mildew.

Genetic identification of the pleiotropic gene Tasg-D1/2 affecting wheat grain shape by regulating brassinolide metabolism.

Improving yield potential is a major goal of wheat breeding that depends on identifying key genetic loci. In this study, two residual heterozygous line RHL351- and RHL78-derived populations were employed for genetic linkage map construction and QTL detection. Two genetic populations indicated a robust grain-size QTL between Marker6 and Marker10. It covered a 95.54-99.38 Mb physical interval and was named Qpleio.nwafu.3D, containing the candidate gene Tasg (TraesCS3D02G137200). Intriguingly, RNA-seq analysis and sequencing revealed two different allelic variants in Tasg, named Tasg-D1 (G>A) and Tasg-D2 (C>G), respectively. Although the relationship between Tasg-D1 and grain size had been demonstrated previously, here we provided the first genetic evidence that C/G allelic variation in Tasg-D2 was associated with grain shape and size through a newly developed dCAPS marker. In addition, transcriptome comparison indicated that Tasg-D1/2 might primarily contribute to significant expression differences in brassinolide (BR) metabolism-related genes rather than those related to BR responses in developing grains and spikes. Our study provided new evidence and a breeder-friendly dCAPS marker for improving grain size through the selection of Tasg, as well as a basis to understand Tasg function in the future.

Identification of Differentially Expressed Genes in Resistant Tetraploid Wheat (Triticum turgidum) under Sitobion avenae (F.) Infestation.

The grain aphid Sitobion avenae (Fabricius) is one of the most destructive pests of wheat (Triticum aestivum). Deployment of resistant wheat germplasm appears as an excellent solution for this problem. Elite bread wheat cultivars only have limited resistance to this pest. The present study was carried out to investigate the potential of the tetraploid wheat (Triticum turgidum) variety Lanmai, which showed high resistance to S. avenae at both seedling and adult plant stages, as a source of resistance genes. Based on apterous adult aphids' fecundity tests and choice bioassays, Lanmai has been shown to display antixenosis and antibiosis. Suppression subtractive hybridization (SSH) was employed to identify and isolate the putative candidate defense genes in Lanmai against S. avenae infestation. A total of 134 expressed sequence tags (ESTs) were identified and categorized based on their putative functions. RT-qPCR analysis of 30 selected genes confirmed their differential expression over time between the resistant wheat variety Lanmai and susceptible wheat variety Polan305 during S. avenae infestation. There were 11 genes related to the photosynthesis process, and only 3 genes showed higher expression in Lanmai than in Polan305 after S. avenae infestation. Gene expression analysis also revealed that Lanmai played a critical role in salicylic acid and jasmonic acid pathways after S. avenae infestation. This study provided further insights into the role of defense signaling networks in wheat resistance to S. avenae and indicates that the resistant tetraploid wheat variety Lanmai may provide a valuable resource for aphid tolerance improvement in wheat.

Identification and DNA Marker Development for a Wheat-Leymus mollis 2Ns (2D) Disomic Chromosome Substitution.

Leymus mollis (2n = 4x = 28, NsNsXmXm), a wild relative of common wheat (Triticum aestivum L.), carries numerous loci which could potentially be used in wheat improvement. In this study, line 17DM48 was isolated from the progeny of a wheat and L. mollis hybrid. This line has 42 chromosomes forming 21 bivalents at meiotic metaphase I. Genomic in situ hybridization (GISH) demonstrated the presence of a pair chromosomes from the Ns genome of L. mollis. This pair substituted for wheat chromosome 2D, as shown by fluorescence in situ hybridization (FISH), DNA marker analysis, and hybridization to wheat 55K SNP array. Therefore, 17DM48 is a wheat-L. mollis 2Ns (2D) disomic substitution line. It shows longer spike and a high level of stripe rust resistance. Using specific-locus amplified fragment sequencing (SLAF-seq), 13 DNA markers were developed to identify and trace chromosome 2Ns of L. mollis in wheat background. This line provides a potential bridge germplasm for genetic improvement of wheat stripe rust resistance.

Molecular cytogenetics and development of St-chromosome-specific molecular markers of novel stripe rust resistant wheat-Thinopyrum intermedium and wheat-Thinopyrum ponticum substitution lines.

BACKGROUND: Owing to their excellent resistance to abiotic and biotic stress, Thinopyrum intermedium (2n = 6x = 42, JJJsJsStSt) and Th. ponticum (2n = 10x = 70) are both widely utilized in wheat germplasm innovation programs. Disomic substitution lines (DSLs) carrying one pair of alien chromosomes are valuable bridge materials for transmission of novel genes, fluorescence in situ hybridization (FISH) karyotype construction and specific molecular marker development. RESULTS: Six wheat-Thinopyrum DSLs derived from crosses between Abbondanza nullisomic lines (2n = 40) and two octoploid Trititrigia lines (2n = 8x = 56), were characterized by sequential FISH-genome in situ hybridization (GISH), multicolor GISH (mc-GISH), and an analysis of the wheat 15 K SNP array combined with molecular marker selection. ES-9 (DS2St (2A)) and ES-10 (DS3St (3D)) are wheat-Th. ponticum DSLs, while ES-23 (DS2St (2A)), ES-24 (DS3St (3D)), ES-25(DS2St (2B)), and ES-26 (DS2St (2D)) are wheat-Th. intermedium DSLs. ES-9, ES-23, ES-25 and ES-26 conferred high thousand-kernel weight and stripe rust resistance at adult stages, while ES-10 and ES-24 were highly resistant to stripe rust at all stages. Furthermore, cytological analysis showed that the alien chromosomes belonging to the same homoeologous group (2 or 3) derived from different donors carried the same FISH karyotype and could form a bivalent. Based on specific-locus amplified fragment sequencing (SLAF-seq), two 2St-chromosome-specific markers (PTH-005 and PTH-013) and two 3St-chromosome-specific markers (PTH-113 and PTH-135) were developed. CONCLUSIONS: The six wheat-Thinopyrum DSLs conferring stripe rust resistance can be used as bridging parents for transmission of valuable resistance genes. The utility of PTH-113 and PTH-135 in a BC1F2 population showed that the newly developed markers could be useful tools for efficient identification of St chromosomes in a common wheat background.

Fine mapping and distribution analysis of hybrid necrosis genes Ne1 and Ne2 in wheat in China.

KEY MESSAGE: Flanking markers useful for identifying hybrid necrosis alleles were identified by fine mapping Ne1 and Ne2 and the distribution of the two necrosis genes was investigated in Chinese elite wheat varieties. Hybrid necrosis of wheat is caused by the interaction of two dominant complementary genes Ne1 and Ne2 present separately in normal parents and is regarded as a barrier to gene transfer in wheat breeding. However, the necrosis alleles still occur at a high frequency in modern wheat varieties. In this study, we constructed two high-density genetic maps of Ne1 and Ne2 in winter wheat. In these cultivars, Ne1 was found to be located in a span interval of 0.50 centimorgan (cM) on chromosome 5BL delimited by markers Nwu_5B_4137 and Nwu_5B_5114, while Ne2 co-segregated with markers Lseq102 and TC67744 on 2BS. Statistical analysis confirmed that the dosage effect of Ne1 and Ne2 also existed in moderate and severe hybrid necrosis systems, and the symptoms of necrosis can also be affected by the genetic background. Furthermore, we clarified the discrete distribution and proportion of the Ne1 and Ne2 in the 10 China's agro-ecological production zones. We concluded that 26.2% and 33.2% of the 1364 cultivars (lines) were genotyped with Ne1Ne1ne2ne2 and ne1ne1Ne2Ne2, respectively and introduced modern cultivars should directly affect the frequencies of necrosis genes in modern Chinese cultivars (lines), especially that of Ne2. Taking investigations in spring wheat together, we proposed that hybrid necrosis alleles could positively affect breeding owing to their linked excellent genes such as Lr13. Additionally, based on the pedigrees and hybridization tests, we speculated that the Ne1 and Ne2 in winter wheat may directly originate from wild emmer and introduced cultivars or hexaploid triticale, respectively.

Molecular cytogenetics for a wheat-Aegilops geniculata 3Mg alien addition line with resistance to stripe rust and powdery mildew.

BACKGROUND: Aegilops geniculata Roth is closely related to common wheat (Triticum aestivum L.) and is a valuable genetic resource for improvement of wheat. RESULTS: In this study, the W19513 line was derived from the BC1F10 progeny of a cross between wheat 'Chinese Spring' and Ae. geniculata SY159. Cytological examination showed that W19513 contained 44 chromosomes. Twenty-two bivalents were formed at the first meiotic metaphase I in the pollen mother cellsand the chromosomes were evenly distributed to opposite poles at meiotic anaphase I. Genomic in situ hybridization demonstrated that W19513 carried a pair of alien chromosomes from the M genome. Fluorescence in situ hybridization confirmed detection of variation in chromosomes 4A and 6B. Functional molecular marker analysis using expressed sequence tag-sequence-tagged site and PCR-based landmark unique gene primers revealed that the alien gene belonged to the third homologous group. The marker analysis confirmed that the alien chromosome pair was 3Mg. In addition, to further explore the molecular marker specificity of chromosome 3Mg, based on the specific locus amplified fragment sequencing technique, molecular markers specific for W19513 were developed with efficiencies of up to 47.66%. The W19513 line was inoculated with the physiological race E09 of powdery mildew (Blumeria graminis f. sp. tritici) at the seedling stage and showed moderate resistance. Field inoculation with a mixture of the races CYR31, CYR32, CYR33, and CYR34 of the stripe rust fungus (Puccinia striiformis f. sp. triticii) revealed that the line W19513 showed strong resistance. CONCLUSIONS: This study provides a foundation for use of the line W19513 in future genetic research and wheat improvement.

A dominant spotted leaf gene TaSpl1 activates endocytosis and defense-related genes causing cell death in the absence of dominant inhibitors.

The spotted leaf lesion mimic trait simulates cell death in a plant responding to pathogen infection. Some spotted leaf genes are recessive, while others are dominant. A small number of plants with a lesion mimic phenotype appeared in a segregating population obtained by crossing two normal green wheat strains, XN509 and N07216. Here, we clarified the genetic model and its breeding value. Phenotyping of the consecutive progeny populations over six cropping seasons showed that the spotted leaf lesion mimic phenotype was controlled by a dominant gene designated TaSpl1, which was inhibited by two other dominant genes, designated TaSpl1-I1 and TaSpl1-I2. Using bulked segregant analysis RNA-seq (BSR-Seq) and newly developed KASP-PCR markers, the TaSpl1 and TaSpl1-I1 loci in N07216 were mapped to the end of chromosomes 3DS and 3BS, respectively. Plants with the spotted phenotype showed lower levels of stripe rust and powdery mildew than those with the normal green phenotype. Compared with normal leaves, the differentially expressed genes in spotted leaves were significantly enriched in plant-pathogen interaction and endocytosis pathways. There were no differences in the yield parameters of the F5 and F6 sister lines, N13039S with TaSpl1 and N13039 N without TaSpl1. These results provide a greater understanding of spotted leaf phenotyping and the breeding value of the lesion mimic allele in developing disease-resistance varieties.

Identification and expression analysis of heat-shock proteins in wheat infected with powdery mildew and stripe rust.

Heat-shock proteins (HSPs), which are encoded by conserved gene families in plants, are crucial for development and responses to diverse stresses. However, the wheat (Triticum aestivum L.) HSPs have not been systematically classified, especially those involved in protecting plants from disease. Here, we classified 119 DnaJ (Hsp40) proteins (TaDnaJs; encoded by 313 genes) and 41 Hsp70 proteins (TaHsp70s; encoded by 95 genes) into six and four groups, respectively, via a phylogenetic analysis. An examination of protein sequence alignment revealed diversity in the TaDnaJ structural organization, but a highly conserved J-domain, which was usually characterized by an HPD motif followed by DRD or DED motifs. The expression profiles of HSP-encoding homologous genes varied in response to Blumeria graminis f. sp. tritici (Bgt) and Puccinia striiformis f. sp. tritici (Pst) stress. A quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated a lack of similarity in the expression of DnaJ70b, Hsp70-30b, and Hsp90-4b in Bgt-infected resistant and susceptible wheat. Furthermore, a direct interaction between DnaJ70 and TaHsp70-30 was not detected in a yeast two-hybrid (Y2H) assay, but screening cDNA library and Y2H evidence supported that TaHsp70-30 not only interacts directly with heat-shock transcription factor (HSF) A9-like protein but also interacts with TaHsp90-4 by HSP organizing protein. This study revealed the structure and expression profiles of the HSP-encoding genes in wheat, which may be useful for future functional elucidation of wheat HSPs responses to fungal infections.

Chromosome karyotype and stability of new synthetic hexaploid wheat.

Synthetic hexaploid wheat offers breeders ready access to potentially novel genetic variation in wild ancestral species. In this study, we crossed MY3478 (2n = 4x = 28, AABB) as the maternal parent with the stripe rust-resistant SY41 (2n = 2x = 14, DD) as the paternal parent to construct the new hexaploid wheat line NA0928 through natural allopolyploidization. Agronomic traits and the cytology of the S8-S9 generations of NA0928 were analyzed. Abundant variation in agronomic traits was observed among each strain of NA0928 in the S8 generation. Agronomic traits were superior in strains resistant to stripe rust compared with those of highly susceptible strains. The rank order of the coefficients of variation were tiller number (55.3%) > spike length (15.3%) > number of spikelets (13.9%) > plant height (8.7). Number of tillers and spike length are important traits in wheat breeding to improve yield. Cytological observation and fluorescence in situ hybridization showed that the chromosome number and configuration showed rich variation among NA0928 strains in the S9 generation. Chromosome number ranged from 36 to 44. Variation in chromosome karyotype was detected in the A and B subgenomes. Meiotic chromosome behavior in pollen mother cells and multicolor genomic in situ hybridization revealed that two new synthetic hexaploid wheat strains showed genetic stability; one strain was resistant to stripe rust and developed multiple tillers, and the other strain was susceptible to stripe rust, but both showed improved thousand-kernel weight (TKW) weight and produced multiple tillers. The two strains will be valuable germplasm resources for use in wheat breeding.

Cytogenetic Analysis and Molecular Marker Development for a New Wheat-Thinopyrum ponticum 1Js (1D) Disomic Substitution Line With Resistance to Stripe Rust and Powdery Mildew.

Thinopyrum ponticum (2n = 10x = 70), a member of the tertiary gene pool of wheat (Triticum aestivum L.), harbors many biotic and abiotic stress resistance genes. CH10A5, a novel disomic substitution line from a cross of T. aestivum cv. 7182 and Th. ponticum, was characterized by cytogenetic identification, in situ hybridization, molecular marker analysis, and morphological investigation of agronomic traits and disease resistance. Cytological observations showed that CH10A5 contained 42 chromosomes and formed 21 bivalents at meiotic metaphase I. Genome in situ hybridization (GISH) analysis indicated that two of its chromosomes came from the Js genome of Th. ponticum, and wheat 15K array mapping and fluorescence in situ hybridization (FISH) revealed that chromosome 1D was absent from CH10A5. Polymorphic analysis of molecular markers indicated that the pair of alien chromosomes belonged to homoeologous group one, designated as 1Js. Thus, CH10A5 was a wheat-Th. ponticum 1Js (1D) disomic substitution line. Field disease resistance trials demonstrated that the introduced Th. ponticum chromosome 1Js was probably responsible for resistance to both stripe rust and powdery mildew at the adult stage. Based on specific-locus amplified fragment sequencing (SLAF-seq), 507 STS molecular markers were developed to distinguish chromosome 1Js genetic material from that of wheat. Of these, 49 STS markers could be used to specifically identify the genetic material of Th. ponticum. CH10A5 will increase the resistance gene diversity of wheat breeding materials, and the markers developed here will permit further tracing of heterosomal chromosome fragments in the future.