Spatio-Temporal Dynamics of Lettuce Metabolome: A Framework for Targeted Nutritional Quality Improvement.

Lettuce ( L.) is a popular leafy vegetable valued for its dietary fiber, antioxidants, and beneficial vitamins. This study presents a comprehensive spatio-temporal analysis of the lettuce metabolome, revealing complex dynamics in metabolite accumulation influenced by plant age, leaf position, proximodistal distribution within a leaf, and head closure.

QTL mapping and transcriptome analysis of seed germination under PEG-induced water stress in Lactuca spp.

The impact of limited water availability on lettuce growth has been well documented. However, the mechanisms by which lettuce controls seed germination under water stress remain unknown. Germination percentage was evaluated in the cv.

Differential Sources of Resistance from Against Three Races of pathovar (Brown, 1918) Morinière et al. 2020 Causing Bacterial Leaf Spot of Lettuce.

Bacterial leaf spot (BLS) of lettuce ( L.) is caused by the bacterium pv. which is hypothesized to have at least three races of the pathogen present in North America as defined by their differential resistance phenotypes in lettuce cultivars/accessions.

Host cell wall composition and localized microenvironment implicated in resistance to basal stem degradation by lettuce drop (Sclerotinia minor).

Background: Sclerotinia spp. are generalist fungal pathogens, infecting over 700 plant hosts worldwide, including major crops. While host resistance is the most sustainable and cost-effective method for disease management, complete resistance to Sclerotinia diseases is rare.

Distribution of Three Races in Coastal California and Evaluation of Resistance in Lettuce.

Verticillium wilt, caused by , is one of the most devastating soilborne diseases of lettuce ( L.). There are three races of , and each race has been characterized by markers representing race-specific effectors.

Phenotypic characterization, plant growth and development, genome methylation, and mineral elements composition of neotetraploid lettuce ( L.).

Stable neotetraploid lines of lettuce ( L.) were produced from three phenotypically distinct cultivars (Annapolis, Eruption, Merlot) and an advanced breeding line (SM13-L2) using colchicine treatment of seeds or young seedlings. When tested under the greenhouse and field conditions, neotetraploids initially grew more rapidly than their diploid progenitors, however they reached their reproductive stage (bolting, flower bud formation, and flowering) substantially later.

Phytochemical and Agronomic Characterization of High-Flavonoid Lettuce Lines Grown under Field Conditions.

Flavonoids are antioxidant phytochemicals that confer a beneficial effect on human health. We have previously developed and characterized eight lettuce ( L.) lines that accumulated high levels of diverse flavonoids and their precursors in controlled environment conditions.

Differentially methylated genomic regions of lettuce seeds relate to divergence across morphologically distinct horticultural types.

Heritable cytosine methylation plays a role in shaping plant phenotypes; however, no information is available about DNA methylation in cultivated lettuce (), one of the most important leafy vegetables. Whole-genome bisulfite sequencing (WGBS) performed on seeds of 95 accessions from eight morphologically distinct horticultural types (Batavia, butterhead, iceberg, Latin, leaf, oilseed, romaine and stem) revealed a high level of methylation in lettuce genome with an average methylation of 90.6 % in the CG context, 72.

Genetic determinants of lettuce resistance to drop caused by Sclerotinia minor identified through genome-wide association mapping frequently co-locate with loci regulating anthocyanin content.

GWAS identified 19 QTLs for resistance to Sclerotinia minor, 11 of them co-locating with red leaf color. Lower disease incidence was observed in red and dark red accessions. Lettuce (Lactuca sativa L.

Dataset on the single nucleotide variation in diversity panel of 500 lettuce accessions genotyped with tunable genotyping-by-sequencing (tGBS) method.

Lettuce ( L.) is an important leafy vegetable cultivated in moderate climates around the world. Based on phenotypic characteristics, such as formation and size of 'heads' (leaves arranged in a dense rosette), size, and texture of leaves, length of stems, and size and composition of seeds, lettuce cultivars can be classified into several distinct horticultural types (Batavia, butterhead, iceberg, Latin, leaf, oilseed, romaine, and stem).

Genetic and physiological determinants of lettuce partial resistance to Impatiens necrotic spot virus.

Introduction: Impatiens necrotic spot virus (INSV) is a major pathogen currently threatening lettuce ( L.) production in the coastal areas of California. The virus is transmitted by the western flower thrips (Frankliniella occidentalis Pergande).

Extending lettuce shelf life through integrated technologies.

Lettuce, a leafy vegetable used in cuisines worldwide, is a highly perishable product sensitive to postharvest losses caused by biotic and abiotic factors. The existing technologies and approaches used during plant cultivation, harvest, processing, transportation, and storage can limit the postharvest issues, but further improvements are needed to meet a growing demand for excellent product appearance, combined with superb quality, biosafety, and low economic and environmental cost. This review summarizes our current understanding of lettuce postharvest physiology and genetics with focus on enzymatic discoloration of wounded surfaces and rapid tissue deterioration.

Weather factors, soil microbiome, and bacteria-fungi interactions as drivers of the epiphytic phyllosphere communities of romaine lettuce.

Lettuce is associated with seasonal outbreaks of Shiga toxin-producing Escherichia coli (STEC) infections. Little is known about how various biotic and abiotic factors affect the lettuce microbiome, which in turn impacts STEC colonization. We characterized the lettuce phyllosphere and surface soil bacterial, fungal, and oomycete communities at harvest in late-spring and -fall in California using metagenomics.

We are the champions. The index for evaluating concentration of championships using a sliding window approach.

The concept of competitive balance is considered to be an essential aspect in the field of sport economics. This work describes a novel approach for measuring and evaluating competitive balance through concentration of championships. The concentration of championships was assessed using a sliding window approach with the length of five consecutive competitions (years) and a single competition (year) increment over the whole evaluated period.

Insights into nitrogen metabolism in the wild and cultivated lettuce as revealed by transcriptome and weighted gene co-expression network analysis.

Large amounts of nitrogen fertilizers applied during lettuce (Lactuca sativa L.) production are lost due to leaching or volatilization, causing severe environmental pollution and increased costs of production. Developing lettuce varieties with high nitrogen use efficiency (NUE) is the eco-friendly solution to reduce nitrogen pollution.

Genome-wide association mapping reveals genomic regions frequently associated with lettuce field resistance to downy mildew.

GWAS identified 63 QTLs for resistance to downy mildew. Though QTLs were distributed across all chromosomes, the genomic regions frequently associated with resistance were located on chromosomes 4 and 5. Lettuce downy mildew is one of the most economically important diseases of cultivated lettuce worldwide.

Identification of Quantitative Trait Loci Associated with Bacterial Leaf Spot Resistance in Baby Leaf Lettuce.

Spring mix is a popular packaged salad that contains lettuce ( L.) as one of its main ingredients. Plants for baby leaf lettuce (BLL) production are grown at very high densities, which enhances the occurrence of bacterial leaf spot (BLS) caused by pv.

Seasonality, shelf life and storage atmosphere are main drivers of the microbiome and E. coli O157:H7 colonization of post-harvest lettuce cultivated in a major production area in California.

Background: Lettuce is linked to recurrent outbreaks of Shiga toxin-producing Escherichia coli (STEC) infections, the seasonality of which remains unresolved. Infections have occurred largely from processed lettuce, which undergoes substantial physiological changes during storage. We investigated the microbiome and STEC O157:H7 (EcO157) colonization of fresh-cut lettuce of two cultivars with long and short shelf life harvested in the spring and fall in California and stored in modified atmosphere packaging (MAP) at cold and warm temperatures.

Mapping and identification of genetic loci affecting earliness of bolting and flowering in lettuce.

Photoperiod and temperature conditions elicit different genetic regulation over lettuce bolting and flowering. This study identifies environment-specific QTLs and putative genes and provides information for genetic marker assay. Bolting, defined as stem elongation, marks the plant life cycle transition from vegetative to reproductive stage.

Molecular Mapping of Water-Stress Responsive Genomic Loci in Lettuce ( spp.) Using Kinetics Chlorophyll Fluorescence, Hyperspectral Imaging and Machine Learning.

Deep understanding of genetic architecture of water-stress tolerance is critical for efficient and optimal development of water-stress tolerant cultivars, which is the most economical and environmentally sound approach to maintain lettuce production with limited irrigation. Lettuce ( L.) production in areas with limited precipitation relies heavily on the use of ground water for irrigation.

Identification of Major Quantitative Trait Loci Controlling Field Resistance to Downy Mildew in Cultivated Lettuce ().

Lettuce downy mildew, caused by Regel, is the most economically important foliar disease of lettuce ( L.). The deployment of resistant cultivars carrying dominant resistance genes ( genes) plays a crucial role in integrated downy mildew disease management; however, high variability in pathogen populations leads to the defeat of plant resistance conferred by genes.

Genetics of Partial Resistance Against Race 2 in Wild and Cultivated Lettuce.

Lettuce () is one of the most economically important vegetables in the United States, with approximately 50% of the domestic production concentrated in the Salinas Valley of California. Verticillium wilt, caused by races 1 and 2 of the fungal pathogen , poses a major threat to lettuce production in this area. Although resistance governed by a single dominant gene against race 1 has previously been identified and is currently being incorporated into commercial cultivars, identification of resistance against race 2 has been challenging and no lines with complete resistance have been identified.

Genome Sequence of Race 1 Isolate VdLs.16 From Lettuce.

is a widespread fungal pathogen that causes Verticillium wilt on many economically important crops and ornamentals worldwide. Populations of have been divided into two distinct races based upon differential host responses in tomato and lettuce. Recently, the contemporary race 2 isolates were further divided into an additional race in tomato.