[Infection status and Molecular types of Rhinovirus among Cases of Acute Respiratory Tract Infections in Luohe City, Henan Province, from 2017 to 2022]

Objective: To understand the infection status and molecular types of rhinovirus (RV) among cases of Acute Respiratory Infections (ARIs) in Luohe City, Henan Province, from 2017 to 2022. Methods: From October 2017 to June 2022, clinical and epidemiological data were collected from 2 270 cases of ARIs at Luohe Central Hospital in Henan Province. Throat swab specimens were obtained from these cases. Real-time quantitative polymerase chain reaction (qPCR) was used to screen for RV-positive specimens. Subsequently, the positive samples were subjected to nested reverse transcription polymerase chain reaction (nested RT-PCR) to amplify the full-length VP1 region. Using the MEGA software, along with 169 RV reference strains recommended by the International Committee on Taxonomy of Viruses, a phylogenetic tree was constructed to determine RV types. Results: Among the 2 270 cases of ARIs, there were 1 283 male cases (56.52%). The median age (Q1, Q3) was 3 (1, 6) years, with the population under 5 years old accounting for 68.59% (1 557/2 270). RV was detected in 137 cases (6.04%), of which 68 cases (49.64%) showed co-detection with other viruses, with the most common being co-detection with enterovirus, accounting for 14.60% (20/137). The RV detection rates in the age groups of 0~4 years, 5~14 years, 15~59 years, and≥60 years were 6.42% (100/1 557), 4.69% (21/448), 3.80% (6/158), and 9.35% (10/107), respectively, with no statistically significant differences (χ2=5.310, P=0.150). The overall detection rates of RV before (2017-2019) and during (2020-2022) the COVID-19 pandemic showed no statistically significant difference (χ2=1.823, P=0.177). A total of 109 VP1 sequences were obtained, including 62 types. Among them, RV-A, RV-B, and RV-C had 42, 3, and 17 types respectively. Conclusion: RV is one of the predominant pathogens in ARIs cases in Luohe City, Henan Province, from 2017 to 2022. Multiple types of RV co-circulate without any apparent dominant type.

[Analysis of safety and factors influencing the surgical efficacy of benign biliary stenosis treated with autologous gastric flap repair with the vascular tip]

Objective: To investigate the complication rate and risk factors associated with using autologous gastric flap tissue with a vascular tip to treat benign biliary strictures. Methods: A retrospective analysis was conducted on clinical data of 92 patients with benign biliary stenosis who applied autologous gastric flap tissue to repair the stenosis at the PLA General Hospital from January 2006 to May 2022. Among them, there were 40 males and 52 females, aged from 25 to 79 (50.5±12.9) years. The perioperative clinical data of the patients were recorded(Body Mass Index、preoperative platelets et.), and a multivariate logistic regression model was used to analyze the factors influencing postoperative complications. Long-term follow-up was conducted to evaluate the long-term efficacy of autologous gastric flap tissue with vascular tissues for benign biliary stenosis surgery. Results: The incidence of recent postoperative complications in patients was 26.1%, and univariate analysis showed that preoperative bile-intestinal anastomosis, positive intraoperative bile bacterial culture, low preoperative hemoglobin, and low preoperative platelet count were significantly associated with the occurrence of postoperative complications after biliary stenosis repair with a vascularized gastric flap (P<0.05). Multifactorial analysis showed that low preoperative platelets (OR=0.990, 95%CI: 0.982-0.998, P=0.015), low preoperative hemoglobin (OR=4.953, 95%CI: 1.405-15.010, P=0.012) and positive intraoperative bile bacterial culture (OR=19.338, 95%CI: 3.618-103.360, P<0.001) were independent risk factors for the development of postoperative complications. The excellent long-term follow-up rate of patients was 92.0%. Conclusions: The procedure of repairing benign biliary stenosis with a vascularized gastric flap preserves the function of the sphincter of Oddi and reconstructs the normal physiological passage of the bile duct. This procedure is safe and feasible and provides a reliable option for the surgical treatment of bile duct injury and bile duct stenosis.

FHB resistance conferred by Fhb1 is under inhibitory regulation of two genetic loci in wheat (Triticum aestivum L.)

KEY MESSAGE

Two loci inhibiting Fhb1 resistance to Fusarium head blight were identified through genome-wide association mapping and validated in biparental populations. Fhb1 confers Fusarium head blight (FHB) resistance by limiting fungal spread within spikes in wheat (type II resistance). However, not all lines with Fhb1 display the expected resistance. To identify genetic factors regulating Fhb1 effect, a genome-wide association study for type II resistance was first performed with 72 Fhb1-carrying lines using the Illumina 90 K iSelect SNP chip. Of 84 significant marker-trait associations detected, more than half were repeatedly detected in at least two environments, with the SNPs distributed in one region on chromosome 5B and one on chromosome 6A. This result was validated in a collection of 111 lines with Fhb1 and 301 lines without Fhb1. We found that these two loci caused significant resistance variations solely among lines with Fhb1 by compromising the resistance. In1, the inhibitory gene on chromosome 5B, was in close linkage with Xwgrb3860 in a recombinant inbred line population derived from Nanda2419 × Wangshuibai and a double haploid (DH) population derived from R-43 (Fhb1 near isogenic line) × Biansui7 (with Fhb1 and In1); and In2, the inhibitory gene on chromosome 6A, was mapped to the Xwgrb4113-Xwgrb4034 interval using a DH population derived from R-43 × PH8901 (with Fhb1 and In2). In1 and In2 are present in all wheat-growing areas worldwide. Their frequencies in China's modern cultivars are high but have significantly decreased in comparison with landraces. These findings are of great significance for FHB resistance breeding using Fhb1.

Fine mapping of KLW1 that conditions kernel weight mainly through regulating kernel length in wheat (Triticum aestivum L.)

KLW1 was localized to a 0.6 cM interval near the centromere of chromosome 4B and found to be dominant in conditioning longer kernels and higher kernel weight. Kernel weight is a major wheat yield component and affected by kernel dimensions, filling process and kernel density. Because of this complexity, the mechanism underlying kernel weight is still far from clear. Qtgw.nau-4B or KLW1 was a major kernel weight QTL identified in the Nanda2419 × Wangshuibai population. We showed that introduction of the Nanda2419 allele into elite cultivar Wenmai6 resulted in longer kernels as well as higher kernel weight, without affecting other traits such as spike number per plant, plant height, spike length, spikelet number per spike, and kernel number per spike. KLW1 was dominant in conditioning higher kernel weight and functioned mainly through affecting kernel length. Using F₂ plants derived from KLW1 NIL, a high-density genetic map covering the QTL was constructed. KLW1 was consequently confined to the 0.6 cM Xwgrc4219-Xwgrc4067 interval by evaluating the recombinant lines in three field trials. KLW1 is complementary to KT1, the QTL on chromosome 5A of Nanda2419 for thicker and heavier kernels, in producing larger kernels with higher commercial value, augmenting its usefulness in wheat breeding.

Fine mapping KT1 on wheat chromosome 5A that conditions kernel dimensions and grain weight

KT1 was validated as a novel thickness QTL with major effects on wheat kernel dimensions and weight and fine mapped to a 0.04 cM interval near the chromosome-5A centromere. Kernel size, the principal grain weight determining factor of wheat and a target trait for both domestication and artificial breeding, is mainly defined by kernel length (KL), kernel width (KW) and kernel thickness (KT), of which KW and KT have been shown to be positively related to grain weight (GW). Qkt.nau-5A, a major QTL for KT, was validated using the QTL near-isogenic lines (NILs) in three genetic backgrounds. Genetic analysis using two F₂ populations derived from the NILs showed that Qkt.nau-5A was dominant for thicker kernel and inherited like a single gene and therefore was designated as Kernel Thickness 1 (KT1). With 77 recombinant lines identified from a total of 19,160 F₂ plants from the two NIL-derived F₂ populations, KT1 was mapped to the 0.04 cM Xwgrb1356-Xwgrb1619 interval, which was near the centromere and displayed strong recombination suppression. The KT1 interval showed positive correlation with KW and GW and negative correlation with KL and therefore could be used in breeding for cultivars with round-shaped kernels that are beneficial to higher flour yield. KT1 candidate identification could be achieved through combination of sequence variation analysis with expression profiling of the annotated genes in the interval.

Genetic control of Fusarium head blight resistance in two Yangmai 158-derived recombinant inbred line populations

Stably expressed type I and type II resistance QTL were identified using two Yangmai 158-derived RIL populations, and plant-height and flowering-time QTL intervals detected did not contribute to the FHB resistance variations. Yangmai 158 (Y158) is an elite wheat cultivar widely grown in China with stable Fusarium head blight (FHB) resistance. To enrich the genetic basis underlying FHB resistance, QTL mapping was conducted using two recombinant inbred line (RIL) populations derived from crosses of Y158 with susceptible lines Annong 8455 and Veery. Survey with makers linked to Fhb1, Fhb2, Fhb4 and Fhb5 in resistance cultivar Wangshuibai indicated that both Y158 and the susceptible lines do not contain these QTL. The RIL populations were surveyed with 65 PCR markers and 55 K chip, which generated 23,159 valid marker data, to produce genetic maps for whole genome scanning of quantitative trait loci (QTL). A total of six QTL, all with the Y158 alleles for better resistance and including one stably expressed QTL for type I resistance (Qfhi.nau-2D) and one stably expressed QTL for type II resistance (Qfhs.nau-2A), were identified. Moreover, taking advantage of the great genetic variations in plant height and flowering time, QTL conditioning these two traits were determined. Of six plant-height QTL and three flowering-time QTL intervals detected, none were associated with FHB resistance. The FHB resistance QTL in Y158 were shown to be useful alternatives in FHB resistance breeding programs. The SNP markers flanking Qfhs.nau-2A and Qfhi.nau-2D have been converted to breeder-friendly PCR-based markers to facilitate their applications.

Pyramiding of Fusarium Head Blight Resistance Quantitative Trait Loci, Fhb1, Fhb4, and Fhb5, in Modern Chinese Wheat Cultivars

Wheat production is increasingly threatened by the fungal disease, Fusarium head blight (FHB), caused by Fusarium spp. The introduction of resistant varieties is considered to be an effective measure for containment of this disease. Mapping of FHB-resistance quantitative trait locus (QTL) has promoted marker-assisted breeding for FHB resistance, which has been difficult through traditional breeding due to paucity of resistance genes and quantitative nature of the resistance. The lab of Ma previously cloned Fhb1, which inhibits FHB spread within spikes, and fine mapped Fhb4 and Fhb5, which condition resistance to initial infection of Fusarium spp., from FHB-resistant indigenous line Wangshuibai (WSB). In this study, these three QTLs were simultaneously introduced into five modern Chinese wheat cultivars or lines with different ecological adaptations through marker-assisted backcross in early generations. A total of 14 introgression lines were obtained. All these lines showed significantly improved resistance to the fungal infection and disease spread in 2-year field trials after artificial inoculation. In comparison with the respective recipient lines, the Fhb1, Fhb4, and Fhb5 pyramiding could reduce the disease severity by 95% and did not systematically affect plant height, productive tiller number, kernel number per spike, thousand grain weight, flowering time, and unit yield (without Fusarium inoculation). These results indicated the great value of FHB-resistance QTLs Fhb1, Fhb4, and Fhb5 derived from WSB, and the feasibility and effectiveness of early generation selection for FHB resistance solely based on linked molecular markers.

Germplasms, genetics and genomics for better control of disastrous wheat Fusarium head blight

Fusarium head blight (FHB), or scab, for its devastating nature to wheat production and food security, has stimulated worldwide attention. Multidisciplinary efforts have been made to fight against FHB for a long time, but the great progress has been achieved only in the genomics era of the past 20 years, particularly in the areas of resistance gene/QTL discovery, resistance mechanism elucidation and molecular breeding for better resistance. This review includes the following nine main sections, (1) FHB incidence, epidemic and impact, (2) causal Fusarium species, distribution and virulence, (3) types of host resistance to FHB, (4) germplasm exploitation for FHB resistance, (5) genetic control of FHB resistance, (6) fine mapping of Fhb1, Fhb2, Fhb4 and Fhb5, (7) cloning of Fhb1, (8) omics-based gene discovery and resistance mechanism study and (9) breeding for better FHB resistance. The advancements that have been made are outstanding and exciting; however, judged by the complicated nature of resistance to hemi-biotrophic pathogens like Fusarium species and lack of immune germplasm, it is still a long way to go to overcome FHB.

Cloning of a COBL gene determining brittleness in diploid wheat using a MapRseq approach

Plant tissue brittleness is related to cellular structure and lodging. MED0031 is a mutant identified previously from ethyl methane sulfonate treatment of diploid wheat accession TA2726, showing brittleness in both stem and leaf. In microscopic and histological observations, the mutant was found to have less large vascular bundles per unit area, a thinner sclerenchyma cell wall, and a broader parenchyma, compared with the wild type. The mutated gene, TmBr1, was mapped to a 0.056 cM interval on chromosome 5A^m. This gene was cloned using a MapRseq approach that searched the candidate gene through combination of the prior target gene mapping information with SNP calling and discovery of differentially expressed genes from RNA_seq data of the wild type and a BC₃F₂ bulk showing the mutant phenotype. TmBr1 encodes a COBL protein and a nonsense mutation within the region coding for the conserved COBRA domain caused premature translation termination. Introduction of TmBr1 to Arabidopsis AtCOBL4 mutant rescued the phenotype, demonstrating their functional conservation. Apart from the effect on cellulose content, the TmBr1 mutation might modulate synthesis of noncellulosic polysaccharide pectin as well. Application of the MapRseq approach to isolation of genes present in recombination cold spots and complicated genomes was discussed.

Mutation of a histidine-rich calcium-binding-protein gene in wheat confers resistance to Fusarium head blight

Head or ear blight, mainly caused by Fusarium species, can devastate almost all staple cereal crops (particularly wheat), resulting in great economic loss and imposing health threats on both human beings and livestock^1-3. However, achievement in breeding for highly resistant cultivars is still not satisfactory. Here, we isolated the major-effect wheat quantitative trait locus, Qfhs.njau-3B, which confers head blight resistance, and showed that it is the same as the previously designated Fhb1. Fhb1 results from a rare deletion involving the 3' exon of the histidine-rich calcium-binding-protein gene on chromosome 3BS. Both wheat and Arabidopsis transformed with the Fhb1 sequence showed enhanced resistance to Fusarium graminearum spread. The translation products of this gene's homologs among plants are well conserved and might be essential for plant growth and development. Fhb1 could be useful not only for curbing Fusarium head blight in grain crops but also for improving other plants vulnerable to Fusarium species.

HL2 on chromosome 7D of wheat (Triticum aestivum L.) regulates both head length and spikelet number

A major QTL QSpl.nau-7D, named HL2, was validated for its effects on head length and kernel number per spike using NIL, and mapped to a 0.2 cM interval using recombinants. Improvement in wheat inflorescence traits such as spike or head length and spikelet number provides an important avenue to increase grain yield potential. In a previous study, QSpl.nau-7D, the major QTL for head length on chromosome 7D, was identified in the recombinant inbred lines derived from Nanda2419 and Wangshuibai. To validate and precisely map this QTL, the Wangshuibai allele was transferred to elite cultivar Yangmai15 through marker-assisted selection. Compared with the recurrent parent, the resultant near-isogenic line (NIL) yielded not only 28% longer spikes on the average but also more spikelets and kernels per spike. Moreover, the NIL had a lower spikelet density and did not show significant kernel weight change. In the F₂ population derived from the NIL, QSpl.nau-7D acted like a single semi-dominant gene controlling head length and was therefore designated as Head Length 2 (HL2). With this population, a high-density genetic map was constructed mainly using newly developed markers, and 100 homozygous recombinants including 17 genotypes were obtained. Field experiments showed that the recombinants carrying the 0.2-cM interval flanked by Xwgrb1588 and Xwgrb1902 from Wangshuibai produced longer spikes than those without this Wangshuibai allele. Comparative mapping of this interval revealed a conserved synteny among cereal grasses. HL2 is beneficial to wheat breeding for more kernels per spike at a lower spikelet density, which is a favored morphological trait for Fusarium head blight resistance.

Fine mapping of powdery mildew resistance gene Pm4e in bread wheat (Triticum aestivum L.)

Fine mapping of wheat powdery mildew-resistance gene Pm4e to a 0.19 cM interval with sequence-based markers provides the foundation for map-based cloning and marker-assisted selection with breeder-friendly markers. Powdery mildew caused by Blumeria graminis f. sp. tritici is a wheat foliar disease that poses a serious threat to global wheat production. Pm4 is a resistance gene locus that has played a key role in controlling this disease in wheat production and a few resistance alleles of this locus have been identified. We have previously mapped the Pm4e allele to a 6.7 cM interval on chromosome 2AL. In this study, Pm4e was delimited to a 0.19 cM interval flanked by Xwgrc763 and Xwgrc865, through employment of a larger segregating population, derived from the cross of resistant parent D29 with susceptible parent Yangmai 158 (Y158), and enrichment of the genetic interval with markers developed on Chinese Spring (C.S.) survey sequence. In this interval, Pm4e co-segregated with a few markers, some of which were either D29-dominant or Y158-dominant, implying great sequence variation in the interval between D29 and Y158. Most of these co-segregation markers could not differentiate the Pm4 alleles from each other. Survey of 55 wheat cultivars with four co-dominant markers showed that the Pm4e-co-segregating loci always co-exist. Annotation of the Pm4e interval-corresponding C.S. sequence revealed more than a dozen resistance gene analogs clustered in a 2.4 Mb region, although C.S. is susceptible to the Pm4e-avirulent isolate Bgt2. This study has established the foundation for map-based cloning of Pm4e. Moreover, some of the co-dominant markers developed in this study could help in marker-assisted transfer of Pm4e into elite cultivars.

Correction to: Fine mapping of powdery mildew resistance gene Pm4e in bread wheat (Triticum aestivum L.)

Unfortunately, the style of the units was incorrectly published ("cm" instead of "cM") throughout the original article.

Mapping QTLs controlling kernel dimensions in a wheat inter-varietal RIL mapping population

Seven kernel dimension QTLs were identified in wheat, and kernel thickness was found to be the most important dimension for grain weight improvement. Kernel morphology and weight of wheat (Triticum aestivum L.) affect both yield and quality; however, the genetic basis of these traits and their interactions has not been fully understood. In this study, to investigate the genetic factors affecting kernel morphology and the association of kernel morphology traits with kernel weight, kernel length (KL), width (KW) and thickness (KT) were evaluated, together with hundred-grain weight (HGW), in a recombinant inbred line population derived from Nanda2419 × Wangshuibai, with data from five trials (two different locations over 3 years). The results showed that HGW was more closely correlated with KT and KW than with KL. A whole genome scan revealed four QTLs for KL, one for KW and two for KT, distributed on five different chromosomes. Of them, QKl.nau-2D for KL, and QKt.nau-4B and QKt.nau-5A for KT were newly identified major QTLs for the respective traits, explaining up to 32.6 and 41.5% of the phenotypic variations, respectively. Increase of KW and KT and reduction of KL/KT and KW/KT ratios always resulted in significant higher grain weight. Lines combining the Nanda 2419 alleles of the 4B and 5A intervals had wider, thicker, rounder kernels and a 14% higher grain weight in the genotype-based analysis. A strong, negative linear relationship of the KW/KT ratio with grain weight was observed. It thus appears that kernel thickness is the most important kernel dimension factor in wheat improvement for higher yield. Mapping and marker identification of the kernel dimension-related QTLs definitely help realize the breeding goals.

Characterization of three wheat grain weight QTLs that differentially affect kernel dimensions

The QGw.nau - 2D, QGw.nau - 4B and QGw.nau - 5A intervals were investigated for their effects on weight, length, width, and thickness of kernels and their differential roles in determining kernel size and shape were demonstrated. Grain weight (GW) contributes greatly to wheat yield and is directly related to kernel size and shape. Although over 100 quantitative trait loci (QTLs) for GW have been reported in the literatures, few have been well characterized for their association with kernel traits. In this study, three GW QTLs identified in elite cultivar 'Nanda2419' ('Mentana'), including QGw.nau-2D, QGw.nau-4B and QGw.nau-5A, were investigated through near isogenic line (NIL) development and evaluation. NILs for all three QTLs and one NIL with both QGw.nau-4B and QGw.nau-5A were developed with the help of marker-assisted selection after two to three generations of backcross using cultivar 'Wangshuibai' as the recurrent parent. One NIL with QGw.nau-4B in the background of cultivar 'Wenmai6' was also obtained. In four different field trials, these NILs consistently produced heavier kernels than the recurrent parents. QGw.nau-4B showed the largest effect on GW; its presence resulted in 0.4-0.5 g increase of hundred-grain weight, depending on genetic backgrounds. QGw.nau-4B and QGw.nau-5A functioned additively in conditioning GW. These three QTL intervals showed pleiotropic effects on, or close linkage with genes for, spike length, plant height and flag leaf width, respectively, and acted differentially in determining the kernel dimensions that are the major GW determinants. They all conditioned wider kernels with QGw.nau-5A displaying the largest effect. QGw.nau-4B and QGw.nau-5A also conditioned thicker kernels but had opposite effects on kernel length. This study demonstrated that marker-assisted selection is effective for GW improvement. The availability of GW NILs could facilitate cloning of GW genes and unraveling of kernel development mechanisms.

Effects of different exercise durations on Keap1-Nrf2-ARE pathway activation in mouse skeletal muscle

The purpose of this study was to investigate the effects of acute exercise stress on the nuclear factor-erythroid2 p45-related factor 2 (Nrf2)/antioxidant response element (ARE) transactivation, Kelch-like ECH-associated protein 1 (Keap1) cytosolic protein and Nrf2 nucleoprotein expressions, Nrf2 target genes mRNA expressions, and glutathione redox (GSH/GSSG) ratio level; with a particular focus on the changes in Keap1-Nrf2-ARE pathway activation following different durations of exercise. Wild-type mice (C57BL/6J, two months old) were separated into one-hour and six-hour treadmill running groups, as well as a non-exercise control group (n = 10 in each group). Measurements of Nrf2/ARE transactivation, Nrf2 nucleoprotein expressions, Keap1 cytosolic protein expression, Nrf2 target genes' mRNA expressions (superoxide dismutase-1 [SOD1], superoxide dismutase-2 [SOD2], γ-glutamyl cysteine ligase-modulatory [GCLm], γ-glutamyl cysteine ligase-catalytic [GCLc], glutathione reductase [GR], glutathione peroxidase-1 [Gpx1], catalase [CAT], and hemoxygenase-1 [Ho-1]), and GSH/GSSG ratio were carried out immediately after exercise. The results showed significant increases in Keap1-Nrf2-ARE pathway activation and the mRNA expressions of six measured enzymes in skeletal muscle after six hours of exercise; while in the one-hour exercise group, there was no change in Keap1-Nrf2-ARE pathway activation and only two enzymes' mRNA expressions were increased. It is suggested that the changes in Keap1-Nrf2-ARE pathway activation and its target genes' mRNA expressions were dependent on the exercise duration, with longer duration associated with higher responses.

Genetic dissection of yield-related traits in a recombinant inbred line population created using a key breeding parent in China's wheat breeding

Understanding the genetics underlying yield formation of wheat is important for increasing wheat yield potential in breeding programs. Nanda2419 was a widely used cultivar for wheat production and breeding in China. In this study, we evaluated yield components and a few yield-related traits of a recombinant inbred line (RIL) population created by crossing Nanda2419 with the indigenous cultivar Wangshuibai in three to four trials at different geographical locations. Negative and positive correlations were found among some of these evaluated traits. Five traits had over 50 % trial-wide broad sense heritability. Using a framework marker map of the genome constructed with this population, quantitative trait loci (QTL) were identified for all traits, and epistatic loci were identified for seven of them. Our results confirmed some of the previously reported QTLs in wheat and identified several new ones, including QSn.nau-6D for effective tillers, QGn.nau-4B.2 for kernel number, QGw.nau-4D for kernel weight, QPh.nau-4B.2 and QPh.nau-4A for plant height, and QFlw.nau-5A.1 for flag leaf width. In the investigated population, Nanda2419 contributed all QTLs associated with higher kernel weight, higher leaf chlorophyll content, and a major QTL associated with wider flag leaf. Seven chromosome regions were related to more than one trait. Four QTL clusters contributed positively to breeding goal-based trait improvement through the Nanda2419 alleles and were detected in trials set in different ecological regions. The findings of this study are relevant to the molecular improvement of wheat yield and to the goal of screening cultivars for better breeding parents.

Fine mapping TaFLW1, a major QTL controlling flag leaf width in bread wheat (Triticum aestivum L.)

INTRODUCTION

Flag leaf width (FLW) is directly related to photosynthetic capacity and yield potential in wheat. In a previous study, Qflw.nau-5A controlling FLW was detected on chromosome 5A in the interval possessing Fhb5 for type I Fusarium head blight (FHB) resistance using a recombinant inbred line population derived from Nanda2419 × Wangshuibai.

MATERIALS AND METHODS

Qflw.nau-5A near-isogenic line (NIL) with the background of Mianyang 99-323 and PH691 was developed and evaluated. FLW inheritance was investigated using two F2 populations developed from crossing the Qflw.nau-5A NILs with their recurrent parents. One hundred ten and 28 recombinants, which included 10 and 5 types of recombinants, were identified from 2816 F2 plants with Mianyang 99-323 background and 1277 F2 plants with PH691 background, respectively, and phenotyped in field trials for FLW and type I FHB resistance. Deletion bin mapping was applied to physically map Qflw.nau-5A.

RESULTS AND CONCLUSIONS

The introduction of Wangshuibai Qflw.nau-5A allele reduced the FLW up to 3 mm. In the F2 populations, Qflw.nau-5A was inherited like a semi-dominant gene, and was therefore designated as TaFLW1. The FLW of the recombinant lines displayed a distinct two-peak distribution. Recombinants with wider leaves commonly have Mianyang 99-323 or PH691 chromatin in the 0.2 cM Xwmc492-Xwmc752 interval that resided in the 5AL12-0.35-0.57 deletion bin, and recombinants with narrow leaves were Wangshuibai genotype in this interval. Phenotypic recombination between FLW and type I FHB resistance was identified, implying TaFLW1 was in close linkage with Fhb5. These results should aid wheat breeders to break the linkage drag through marker-assisted selection and assist in the map-based cloning of TaFLW1.

PmX: a recessive powdery mildew resistance gene at the Pm4 locus identified in wheat landrace Xiaohongpi

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most devastating foliar diseases of wheat and imposes a constant challenge on wheat breeders. Xiaohongpi, a Chinese landrace of wheat (Triticum aestivum L.), shows resistance to powdery mildew during the entire growth stage in the field and under controlled conditions. The F1 plants from cross of the powdery mildew susceptible cultivar Yangmai158 with Xiaohongpi were susceptible to isolate Bgt19, the locally most prevalent Bgt isolate. In the derived F2 population and F3 progenies, the resistance segregation deviated significantly from the one-gene Mendelian ratio. However, marker analysis indicated that only one recessive gene conferred the resistance, which co-segregated with Xsts-bcd1231 that showed co-segregation with Pm4a in different studies. Allelism test indicated that this recessive resistance gene, designated as pmX, is either allelic or tightly linked to Pm4a. The pmX gene was different from Pm4 alleles in resistance spectrum. Examination of the genotype frequencies at pmX and the linked marker loci in the F2 population showed that a genetic variation favoring the transmission of Xiaohongpi alleles could be the cause of deviated segregation. Mapping of the pmX-linked markers using Chinese Spring deletion lines indicated that it resides in the 0.85-1.00 bin of chromosome 2AL.

Identification and mapping of a new powdery mildew resistance gene on chromosome 6D of common wheat

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most serious wheat diseases. The rapid evolution of the pathogen's virulence, due to the heavy use of resistance genes, necessitates the expansion of resistance gene diversity. The common wheat line D57 is highly resistant to powdery mildew. A genetic analysis using an F(2) population derived from the cross of D57 with the susceptible cultivar Yangmai 158 and the derived F(2:3) lines indicated that D57 carries two dominant powdery mildew resistance genes. Based on mapping information of polymorphic markers identified by bulk segregant analysis, these two genes were assigned to chromosomes 5DS and 6DS. Using the F(2:3) lines that segregated in a single-gene mode, closely linked PCR-based markers were identified for both genes, and their chromosome assignments were confirmed through linkage mapping. The gene on chromosome 5DS was flanked by Xgwm205 and Xmag6176, with a genetic distance of 8.3 cM and 2.8 cM, respectively. This gene was 3.3 cM from a locus mapped by the STS marker MAG6137, converted from the RFLP marker BCD1871, which was 3.5 cM from Pm2. An evaluation with 15 pathogen isolates indicated that this gene and Pm2 were similar in their resistance spectra. The gene on chromosome 6DS was flanked by co-segregating Xcfd80 and Xmag6139 on one side and Xmag6140 on the other, with a genetic distance of 0.7 cM and 2.7 cM, respectively. This is the first powdery mildew resistance gene identified on chromosome 6DS, and plants that carried this gene were highly resistant to all of the 15 tested pathogen isolates. This gene was designated Pm45. The new resistance gene in D57 could easily be transferred to elite cultivars due to its common wheat origin and the availability of closely linked molecular markers.

Precise mapping Fhb5, a major QTL conditioning resistance to Fusarium infection in bread wheat (Triticum aestivum L.)

Qfhi.nau-5A is a major quantitative trait locus (QTL) against Fusarium graminearum infection in the resistant wheat germplasm Wangshuibai. Genetic analysis using BC(3)F(2) and BC(4)F(2) populations, derived from selfing two near-isogenic lines (NIL) heterozygous at Qfhi.nau-5A that were developed, respectively, with Mianyang 99-323 and PH691 as the recurrent parent, showed that Qfhi.nau-5A inherited like a single dominant gene. This QTL was thus designated as Fhb5. To fine map it, these two backcross populations and a recombinant inbred line (RIL) population derived from Nanda2419 × Wangshuibai were screened for recombinants occurring between its two flanking markers Xbarc56 and Xbarc100. Nineteen NIL recombinants were identified from the two backcross populations and nine from the RIL population. In the RIL recombinant selection process, selection against Fhb4 present in the RIL population was incorporated. Genotyping these recombinant lines with ten markers mapping to the Xbarc56-Xbarc100 interval revealed four types of Mianyang 99-323-derived NIL recombinants, three types of PH691-derived NIL recombinants, and four types of RIL recombinants. In different field trials, the percentage of infected spikes of these lines displayed a distinct two-peak distribution. The more resistant class had over 55% less infection than the susceptible class. Common to these resistant genotypes, the 0.3-cM interval flanked by Xgwm304 and Xgwm415 or one of these two loci was derived from Wangshuibai, while none of the susceptible recombinants had Wangshuibai chromatin in this interval. This interval harboring Fhb5 was mapped to the pericentromeric C-5AS3-0.75 bin through deletion bin mapping. The precise localization of Fhb5 will facilitate its utilization in marker-assisted wheat breeding programs.

Resistance to hemi-biotrophic F. graminearum infection is associated with coordinated and ordered expression of diverse defense signaling pathways

Fusarium species cause serious diseases in cereal staple food crops such as wheat and maize. Currently, the mechanisms underlying resistance to Fusarium-caused diseases are still largely unknown. In the present study, we employed a combined proteomic and transcriptomic approach to investigate wheat genes responding to F. graminearum infection that causes Fusarium head blight (FHB). We found a total of 163 genes and 37 proteins that were induced by infection. These genes and proteins were associated with signaling pathways mediated by salicylic acid (SA), jasmonic acid (JA), ethylene (ET), calcium ions, phosphatidic acid (PA), as well as with reactive oxygen species (ROS) production and scavenging, antimicrobial compound synthesis, detoxification, and cell wall fortification. We compared the time-course expression profiles between FHB-resistant Wangshuibai plants and susceptible Meh0106 mutant plants of a selected set of genes that are critical to the plants' resistance and defense reactions. A biphasic phenomenon was observed during the first 24 h after inoculation (hai) in the resistant plants. The SA and Ca(2+) signaling pathways were activated within 6 hai followed by the JA mediated defense signaling activated around 12 hai. ET signaling was activated between these two phases. Genes for PA and ROS synthesis were induced during the SA and JA phases, respectively. The delayed activation of the SA defense pathway in the mutant was associated with its susceptibility. After F. graminearum infection, the endogenous contents of SA and JA in Wangshuibai and the mutant changed in a manner similar to the investigated genes corresponding to the individual pathways. A few genes for resistance-related cell modification and phytoalexin production were also identified. This study provided important clues for designing strategies to curb diseases caused by Fusarium.

Characterization of a single recessive yield trait mutant with elevated endogenous ABA concentration and deformed grains, spikelets and leaves

The characterization of yield trait mutants is important for understanding the regulation of grain yield formation in staple food crops. Meh0239 is a yield trait-related mutant identified from a mutant library of the common wheat cultivar Wangshuibai created by ethylmethyl sulfide (EMS) treatment of dry seeds. To shed some light on the nature of this mutation, it was investigated morphologically, physiologically, anatomically and genetically. The mutant plant showed obvious phenotypic differences in comparison with the wild type, starting at the seedling stage, including reduced plant height, wider and shorter leaves, shortened spikes, spikelets and grains and a more compact spikelet distribution. Also, seeds produced in the mutant germinated more slowly. Meh0239 contained a significantly higher level of abscisic acid (ABA) but lower levels of indole-3-acetic acid (IAA), methyl jasmonate (MeJA) and zeatin riboside (ZR) in flag leaves. Cells of all types in the leaf epidermis appeared shorter along the axial direction. The bulliform cells and long cells on the adaxial leaf surface were abnormal in shape. A genetic analysis using two F₂ segregating populations indicated that a single recessive mutation in wheat chromosome 7DS, about 3.1cM distal from Xwmc506, caused these variations. Because of the pleiotropic nature of this gene and its relation with yield trait formation, we named it Yt1 for yield trait related 1.

Fine mapping Fhb4, a major QTL conditioning resistance to Fusarium infection in bread wheat (Triticum aestivum L.)

Qfhi.nau-4B is a major quantitative trait locus (QTL) against Fusarium graminearum infection identified in the Fusarium head blight-resistant germplasm Wangshuibai. To fine map this QTL, a recombinant inbred line (RIL) population of 530 lines derived from Nanda2419 x Wangshuibai and the BC(3)F(2) population derived from the cross of a Qfhi.nau-4B near isogenic line (NIL) with susceptible cultivar Mianyang 99-323 as the recurrent parent were screened for recombinants occurred between microsatellite markers Xbarc20 and Xwmc349 that flank Qfhi.nau-4B. A total of 95 recombinants were obtained, including 45 RIL recombinants obtained through reverse-selection of Qfhi.nau-5A and 50 NIL recombinants from the BC(3)F(2) population. Genotyping these recombinant lines with 22 markers mapping to the Xbarc20 and Xwmc349 interval revealed fourteen genotypes of the RIL recombinants as well as of the NIL recombinants. Two-year field evaluation of their resistance to Fusarium infection showed that these lines could be clearly classified into two groups according to percentage of infected spikes. The more resistant class had over 60% less infection than the susceptible class and were common to have Wangshuibai chromatin in the 1.7-cM interval flanked by Xhbg226 and Xgwm149. None of the susceptible recombinants had this Wangshuibai chromatin. Qfhi.nau-4B was thus confined between Xhbg226 and Xgwm149 and named Fhb4. The interval harboring Fhb4 was mapped to 4BL5-0.86-1.00 bin using Chinese Spring deletion lines, a region with about 5.7 times higher recombination rate than the genome average. This study established the basis for map-based cloning of Fhb4.

A high-density intervarietal map of the wheat genome enriched with markers derived from expressed sequence tags

Bread wheat (Triticum aestivum L.) is a hexaploid species with a large and complex genome. A reference genetic marker map, namely the International Triticeae Mapping Initiative (ITMI) map, has been constructed with the recombinant inbred line population derived from a cross involving a synthetic line. But it is not sufficient for a full understanding of the wheat genome under artificial selection without comparing it with intervarietal maps. Using an intervarietal mapping population derived by crossing Nanda2419 and Wangshuibai, we constructed a high-density genetic map of wheat. The total map length was 4,223.1 cM, comprising 887 loci, 345 of which were detected by markers derived from expressed sequence tags (ESTs). Two-thirds of the high marker density blocks were present in interstitial and telomeric regions. The map covered, mostly with the EST-derived markers, approximately 158 cM of telomeric regions absent in the ITMI map. The regions of low marker density were largely conserved among cultivars and between homoeologous subgenomes. The loci showing skewed segregation displayed a clustered distribution along chromosomes and some of the segregation distortion regions (SDR) are conserved in different mapping populations. This map enriched with EST-derived markers is important for structure and function analysis of wheat genome as well as in wheat gene mapping, cloning, and breeding programs.

Molecular genetic analysis of five spike-related traits in wheat using RIL and immortalized F2 populations

Kernel number per spike is one of the most important yield components of wheat. To map QTLs related to kernel number including spike length (SPL), spikelet number per spike (SPN), fertile spikelet number (FSPN), sterile spikelet number (SSPN) and compactness, and to characterize the inheritance modes of the QTLs and two-locus interactions, 136 recombinant inbred lines (RILs) derived from 'Nanda2419' x 'Wangshuibai' and an immortalized F(2 )population (IF(2)) generated by randomly permutated intermating of these RILs were investigated. QTL mapping made use of the previously constructed over 3300 cM linkage map of the RIL population. Three, five, two, two and six chromosome regions were identified, respectively, for their association with SPL, SPN, FSPN, SSPN, and compactness in at least two of the three environments examined. All compactness QTLs but one shared the respective intervals of QSpn.nau-5A and the SPL QTLs. Xcfd46-Xwmc702 interval on chromosome 7D was related to all traits but SSPN and had consistently the largest effects. The fact that not all the compactness QTL intervals were related to both SPL and SPN indicates that compactness is regulated by different mechanisms. Interval coincidence between QTLs of SPL and SPN and between QTLs of FSPN and SSPN was minimal. For all the traits, favorable alleles exist in both parents. Inheritance modes from additiveness to overdominance of the QTLs were revealed and two-locus interactions were detected, implying that the traits studied are under complex genetic control. The results could contribute to wheat yield improvement and better use of Wangshuibai and Nanda2419 the two special germplasms in wheat breeding program.

Molecular genetic analysis of five spike-related traits in wheat using RIL and immortalized F2 populations

Kernel number per spike is one of the most important yield components of wheat. To map QTLs related to kernel number including spike length (SPL), spikelet number per spike (SPN), fertile spikelet number (FSPN), sterile spikelet number (SSPN) and compactness, and to characterize the inheritance modes of the QTLs and two-locus interactions, 136 recombinant inbred lines (RILs) derived from 'Nanda2419' x 'Wangshuibai' and an immortalized F(2 )population (IF(2)) generated by randomly permutated intermating of these RILs were investigated. QTL mapping made use of the previously constructed over 3300 cM linkage map of the RIL population. Three, five, two, two and six chromosome regions were identified, respectively, for their association with SPL, SPN, FSPN, SSPN, and compactness in at least two of the three environments examined. All compactness QTLs but one shared the respective intervals of QSpn.nau-5A and the SPL QTLs. Xcfd46-Xwmc702 interval on chromosome 7D was related to all traits but SSPN and had consistently the largest effects. The fact that not all the compactness QTL intervals were related to both SPL and SPN indicates that compactness is regulated by different mechanisms. Interval coincidence between QTLs of SPL and SPN and between QTLs of FSPN and SSPN was minimal. For all the traits, favorable alleles exist in both parents. Inheritance modes from additiveness to overdominance of the QTLs were revealed and two-locus interactions were detected, implying that the traits studied are under complex genetic control. The results could contribute to wheat yield improvement and better use of Wangshuibai and Nanda2419 the two special germplasms in wheat breeding program.

Treatment of volatile organic compounds in a biotrickling filter under thermophilic conditions

The objectives of this research were to investigate the potential to biologically treat volatile organic compounds emitted by the forest products industry at thermophilic conditions and to examine the microbial community developed at high temperatures. Three biotrickling filters were run in parallel at temperatures ranging from 40 degrees C (mesophilic control) to 70 degrees C. The first phase involved treatment of methanol, for a 3-month run, and the second phase involved a 260-day run on the treatment of alpha-pinene. Methanol removal rates over 100 g m(-3) h(-1) where achieved at temperatures up to 70 degrees C. Alpha-pinene removal was achieved at temperatures up to 60 degrees C with optimal treatment occurring at 55 degrees C at rates up to 60 g m(-3) h(-1). The time for acclimation increased with increasing temperature and was longer for pinene than for methanol. Filter performance was also able to quickly recover from a shutdown period of up to 2 weeks due to the robustness of the microbial communities as determined by DNA fingerprinting analysis. The high-temperature communities treating methanol or pinene were more similar to each other than the mesophilic communities (i.e., 40 degrees C). The mesophilic methanol community had a high degree of functional redundancy, while the mesophilic pinene community was more unique and very distinct from the others. These results show that biofiltration at high temperatures is achievable and opens up a range of possibilities for applying biofiltration to hot gas streams.

Oldest playable musical instruments found at Jiahu early Neolithic site in China

Excavations at the early Neolithic site of Jiahu in Henan Province, China have produced what may be the earliest complete, playable, tightly-dated multinote musical instruments. Jiahu was occupied from 7000 BC to 5700 BC, considerably antedating the well known Peiligang culture. Here we describe six exquisitely made complete flutes which were found in radiocarbon-dated excavation layers, along with fragments of perhaps 30 more. The flutes are made from the ulnae of the red-crowned crane (Grus japonensis Millen) and have 5, 6, 7 and 8 holes. The best preserved flute has been played and tonally analysed. In addition to early musical artefacts, the archaeological record at Jiahu contains important information on the very foundations of Chinese society. We describe the archaeological characteristics of the Jiahu site, details concerning its dating, its place in the prehistory of the Chinese Neolithic, the ethnicity of its population and the results of a tonal analysis of a nearly 9,000-year-old musical instrument found there.

[Analysis of 9 cases of pulmonary tuberculosis complicated with legionnaires disease]

OBJECTIVE

To study the characteristics of pulmonary tuberculosis complicated with legionnaires disease (LD) to avoid misdiagnosis and incorrect treatment.

METHOD

Nine cases of pulmonary tuberculosis complicated with LD were retrospectively analyzed.

RESULT

The clinical and chest X-ray manifestations varied, and no characteristics were found in these cases. Because cross antibodies existed between Legionella pneumophila and other causal bacteria, it was found difficult to differentiate LD, pulmonary tuberculosis and other causal bacteria infection. Efficacy of erythromycin combined with rifampicin, and decrease of serum titres of Legionella pneumophila four times after treatment were found helpful for definite diagnosis of LD.

CONCLUSION

Only paying much attention to LD, and detecting the serum antibody as early as possible can provide evidence for diagnosing of the disease.

[Treatment of congenital glaucoma with trabeculotomy]

OBJECTIVE

To investigate the method of localization of Schlemm's canal during trabeculotomy to evaluate the successful rate of trabeculotomy.

METHOD

The author treated 38 cases (46 eyes) of congenital glaucoma with trabeculotomy. Harms trabeculotomy knife was introduced into the Schlemm's canal through the cutting end of an external collecting channel. The follow-up period was over 6 months in 37 eyes.

RESULTS

The intraocular pressure, C/D ratio were significantly improved after surgery compared to the preoperative ones (P < 0.05). But no significant differences were found in the corneal diameter, the depth of the anterior chamber, the length of ocular axis before and after surgery (P > 0.05). The intraocular pressure of 27 eyes (73.0%) was less than or equal to 2.8 kPa (1 kPa = 7.5 mmHg), showing good control of glaucoma.

CONCLUSION

During trabeculotomy, the trabeculotomy knife introduced in to the Schlemm's canal through an external collecting channel is a better and accurate method of localization of Schlemm's canal. The method is relatively simple, reliable and has certain value in clinical application.

Study on the antimutagenic effect of pine needle extract

The micronucleus test and sister-chromatic exchange (SCE) test were used to research the antimutagenic effect of pine needle extract. The results showed that the mutagenic effect of cyclophosphamide (CP) was inhibited by the pine needle extract. The micronucleus frequencies (MNF) of mouse bone marrow and human lymphocytes from peripheral blood were decreased with the effect of the extract (the dose was 2000 mg/kg or 5 mg/ml); the frequency of SCE in human lymphocytes was also reduced significantly, which indicated that the MNF and the SCE frequencies were negatively correlated with the dose of pine needle extract (r = -0.9782, -0.9587, -0.9765, respectively). This suggested that the pine needle extract was an effective antimutagen and it is important to choose the proper doses of pine needle extract for antitumor effect.

An activated sludge-based biosensor for rapid IC50 estimation and on-line toxicity monitoring

The RODTOX (Rapid Oxygen Demand and TOXicity tester), an activated sludge-based respirographic biosensor, is a device for on-line monitoring of the short-term biochemical oxygen demand (stBOD) and potential toxicity of incoming wastewater on the basis of on-line interpretation of respirograms resulting from pulse additions of either calibration substrate or sample. The principle of toxicity detection is based on the comparison of calibration respirograms before and after receiving a potential toxicant. In this paper, the results of the RODTOX as an on-line toxicity monitor are presented. In addition, a simple and fast procedure to estimate the IC50 of a toxicant has been developed, and its validity and good repeatability demonstrated. The performance of this procedure is compared with that of the Microtox test.

Mitomycin C-induced meiotic crossing-over on the interstitial segments in the Chinese hamster heterozygous for a reciprocal translocation

Using Chinese hamsters heterozygous for T(2;10)3Idr and T(1;3)8Idr reciprocal translocations, the authors studied mitomycin C (MMC)-induced crossing-over on the interstitial segments. Marker chromosomes with unequal-length chromatids resulting from crossing-over were clearly detectable, and the frequencies of such marker chromosomes were constant among individual males which were heterozygous for the same reciprocal translocation. The frequency of MMC-induced crossing-over on the interstitial segments increased roughly with increase in dose. These findings, therefore, indicated that marker chromosomes with unequal-length chromatids in translocation heterozygotes may be a useful indicator for detection of the cytogenetic effects of environmental mutagens on germ cells.