Tall Fescue Expressed Sequence Tag and Simple Sequence Repeats: Important Resources for Grass Species

Expressed sequence tag (EST) databases have been growing exponentially. The simple sequence repeat (SSR) has become one of the most useful molecular marker systems in plant breeding and is widely used in cultivar fingerprinting, genetic diversity assessment, molecular mapping and marker-assisted selection. ESTs are a potential source for SSRs. The EST-SSR markers are of high quality and have versatile applications in molecular breeding (Bughrara et al., 2003; Saha et al., 2004 a, b, c). Here, we present an overview of our efforts to develop SSRs from tall fescue ESTs and their application for the genetic improvement of forage and turf grass species

Hepatitis B virus total core antibody status in unvaccinated general population in a community of Bangladesh

Background: Hepatitis B virus (HBV) infection poses a significant health challenge in Bangladesh, with the hepatitis B core antibody (anti-HBc) being a crucial marker due to its lifelong presence in the bloodstream. This study aimed to evaluate the prevalence of anti-HBc (total) positivity among unvaccinated adults in Northeastern Bangladesh. Methods: This cross-sectional observational study was conducted in the Sobhanighat area of Sylhet, Bangladesh, in collaboration with the department of gastroenterology, Sylhet MAG Osmani Medical College, from November 2022 to August 2023. A total of 216 participants were selected using consecutive sampling. HBsAg, anti-HBs, and anti-HBc (total) were tested for all subjects, and data were collected using a pre-formed questionnaire and analyzed using statistical package for the social sciences (SPSS) version 24. Results: Among the participants, 16 (7.4%) tested positive for anti-HBc (total), while HBsAg was positive in 6 (2.77%) individuals. Anti-HBs was detectable in 23 (10.6%) participants, with 3 (1.38%) showing isolated anti-HBc positivity. Notably, 20% of HBsAg-positive cases exhibited heterotypic anti-HBs. Moreover, 56.25% of respondents with anti-HBc (total) positivity had detectable anti-HBs (p<0.001). Gender did not show significant associations with HBsAg, anti-HBc (total), anti-HBs, or isolated anti-HBc (p>0.05). Conclusions: The study underscores a notable prevalence of anti-HBc (total) positivity among unvaccinated individuals in Bangladesh, indicative of past HBV exposure. It underscores the necessity for enhanced vaccination coverage and robust infection control measures to mitigate HBV transmission in this demographic

An Efficient Brome mosaic virus-Based Gene Silencing Protocol for Hexaploid Wheat (Triticum aestivum L.)

Virus-induced gene silencing (VIGS) is a rapid and powerful method to evaluate gene function, especially for species like hexaploid wheat that have large, redundant genomes and are difficult and time-consuming to transform. The Brome mosaic virus (BMV)-based VIGS vector is widely used in monocotyledonous species but not wheat. Here we report the establishment of a simple and effective VIGS procedure in bread wheat using BMVCP5, the most recently improved BMV silencing vector, and wheat genes PHYTOENE DESATURASE (TaPDS) and PHOSPHATE2 (TaPHO2) as targets. Time-course experiments revealed that smaller inserts (~100 nucleotides, nt) were more stable in BMVCP5 and conferred higher silencing efficiency and longer silencing duration, compared with larger inserts. When using a 100-nt insert and a novel coleoptile inoculation method, BMVCP5 induced extensive silencing of TaPDS transcript and a visible bleaching phenotype in the 2nd to 5th systemically-infected leaves from nine to at least 28 days post inoculation (dpi). For TaPHO2, the ability of BMVCP5 to simultaneously silence all three homoeologs was demonstrated. To investigate the feasibility of BMV VIGS in wheat roots, ectopically expressed enhanced GREEN FLUORESCENT PROTEIN (eGFP) in a transgenic wheat line was targeted for silencing. Silencing of eGFP fluorescence was observed in both the maturation and elongation zones of roots. BMVCP5 mediated significant silencing of eGFP and TaPHO2 mRNA expression in roots at 14 and 21 dpi, and TaPHO2 silencing led to the doubling of inorganic phosphate concentration in the 2nd through 4th systemic leaves. All 54 wheat cultivars screened were susceptible to BMV infection. BMVCP5-mediated TaPDS silencing resulted in the expected bleaching phenotype in all eight cultivars examined, and decreased TaPDS transcript was detected in all three cultivars examined. This BMVCP5 VIGS technology may serve as a rapid and effective functional genomics tool for high-throughput gene function studies in aerial and root tissues and in many wheat cultivars

HIV Transmission Potential Among Local and Migrant Factory Workers in Kolkata, India

Migrant workers in India play a key role in the spread of HIV. Kolkata is a common destination for workers, who may acquire infection and transmit it to their wives and/or other sexual partners. We investigated sexual relations and condom use by factory workers. Migrant and local factory workers were randomly selected from five wards of Kolkata. Information was collected about demographic and socio-economic characteristics, sexual relationships, condom usage, and perceptions and intent to use condoms. Condom use was very low in both groups of workers, particularly among migrants. Many married workers visited female sex workers but never used condoms. Few intended to use condoms, and if they did, it did not always translate into actual usage. There is great potential for transmission of HIV/sexually transmitted infections by these workers. Carefully designed intervention and education programs in the context of low literacy and cultural norms are urgently needed

Toward Genomics-Based Breeding in C3 Cool-Season Perennial Grasses

Most important food and feed crops in the world belong to the C3 grass family. The future of food security is highly reliant on achieving genetic gains of those grasses. Conventional breeding methods have already reached a plateau for improving major crops. Genomics tools and resources have opened an avenue to explore genome-wide variability and make use of the variation for enhancing genetic gains in breeding programs. Major C3 annual cereal breeding programs are well equipped with genomic tools; however, genomic research of C3 cool-season perennial grasses is lagging behind. In this review, we discuss the currently available genomics tools and approaches useful for C3 cool-season perennial grass breeding. Along with a general review, we emphasize the discussion focusing on forage grasses that were considered orphan and have little or no genetic information available. Transcriptome sequencing and genotype-by-sequencing technology for genome-wide marker detection using next-generation sequencing (NGS) are very promising as genomics tools. Most C3 cool-season perennial grass members have no prior genetic information; thus NGS technology will enhance collinear study with other C3 model grasses like Brachypodium and rice. Transcriptomics data can be used for identification of functional genes and molecular markers, i.e., polymorphism markers and simple sequence repeats (SSRs). Genome-wide association study with NGS-based markers will facilitate marker identification for marker-assisted selection. With limited genetic information, genomic selection holds great promise to breeders for attaining maximum genetic gain of the cool-season C3 perennial grasses. Application of all these tools can ensure better genetic gains, reduce length of selection cycles, and facilitate cultivar development to meet the future demand for food and fodder

Molecular discrimination of tall fescue morphotypes in association with <i>Festuca</i> relatives

<div><p>Tall fescue (<i>Festuca arundinacea</i> Schreb.) is an important cool-season perennial grass species used as forage and turf, and in conservation plantings. There are three morphotypes in hexaploid tall fescue: Continental, Mediterranean and Rhizomatous. This study was conducted to develop morphotype-specific molecular markers to distinguish Continental and Mediterranean tall fescues, and establish their relationships with other species of the <i>Festuca</i> genus for genomic inference. Chloroplast sequence variation and simple sequence repeat (SSR) polymorphism were explored in 12 genotypes of three tall fescue morphotypes and four <i>Festuca</i> species. Hypervariable chloroplast regions were retrieved by using 33 specifically designed primers followed by sequencing the PCR products. SSR polymorphism was studied using 144 tall fescue SSR primers. Four chloroplast (NFTCHL17, NFTCHL43, NFTCHL45 and NFTCHL48) and three SSR (nffa090, nffa204 and nffa338) markers were identified which can distinctly differentiate Continental and Mediterranean morphotypes. A primer pair, NFTCHL45, amplified a 47 bp deletion between the two morphotypes is being routinely used in the Noble Research Institute’s core facility for morphotype discrimination. Both chloroplast sequence variation and SSR diversity showed a close association between Rhizomatous and Continental morphotypes, while the Mediterranean morphotype was in a distant clade. <i>F</i>. <i>pratensis</i> and <i>F</i>. <i>arundinacea</i> var. <i>glaucescens</i>, the P and G1G2 genome donors, respectively, were grouped with the Continental clade, and <i>F</i>. <i>mairei</i> (M1M2 genome) grouped with the Mediterranean clade in chloroplast sequence variation, while both <i>F</i>. <i>pratensis</i> and <i>F</i>. <i>mairei</i> formed independent clade in SSR analysis. Age estimation based on chloroplast sequence variation indicated that the Continental and Mediterranean clades might have been colonized independently during 0.65 ± 0.06 and 0.96 ± 0.1 million years ago (Mya) respectively. The findings of the study will enhance tall fescue breeding for persistence and productivity.</p></div

Classification of tall fescue germplasms collected from Greece based on four selected morphotype-specific chloroplast primers.

<p>The horizontal scale at bottom shows the Nei and Li/dice coefficients.</p