Identifying the earliest citrus responses to Liberibacter asiaticus infection: a temporal metabolomics study.

The global citrus industry faces a great threat from Huanglongbing (HLB), a destructive disease caused by ' Liberibacter asiaticus' (Las) that induces significant economic losses without any known cure. Understanding how citrus plants defend against HLB, particularly at the early stages of infection, is crucial for developing long-term solutions. This study investigated the earliest metabolic responses of fresh citrus leaves to Las infection using untargeted metabolomics and machine learning models.

Uncovering Interactions between Plant Metabolism and Plant-Associated Bacteria in Huanglongbing-Affected Citrus Cultivars Using Multiomics Analysis and Machine Learning.

Huanglongbing (HLB) is a highly destructive disease that inflicts significant economic losses on the citrus industry worldwide but with no cure available. However, microbiomes formulated by citrus plants may serve as disease antagonists, increasing the level of HLB tolerance. This study established an integrated analysis of untargeted metabolomics and microbiomics data for different citrus cultivars, providing critical insights into the interactions between plant metabolism and plant-associated bacteria in the development of HLB.

Plant mitochondrial introns as genetic markers - conservation and variation.

Plant genomes are comprised of nuclear, plastid and mitochondrial components characterized by different patterns of inheritance and evolution. Genetic markers from the three genomes provide complementary tools for investigations of inheritance, genetic relationships and phenotypic contributions. Plant mitochondrial genomes are challenging for universal marker development because they are highly variable in terms of size, gene order and intergenic sequences and highly conserved with respect to protein-coding sequences.

Role of long non-coding RNA in regulatory network response to Liberibacter asiaticus in citrus.

Long non-coding RNAs (lncRNAs) serve as crucial regulators in plant response to various diseases, while none have been systematically identified and characterized in response to citrus Huanglongbing (HLB) caused by Liberibacter asiaticus (Las) bacteria. Here, we comprehensively investigated the transcriptional and regulatory dynamics of the lncRNAs in response to L. Samples were collected from leaf midribs of Las- and mock-inoculated HLB-tolerant rough lemon () and HLB-sensitive sweet orange () at week 0, 7, 17, and 34 following inoculation using Las+ budwood of three biological replicates in the greenhouse.

Highly efficient hairy root genetic transformation and applications in citrus.

Highly efficient genetic transformation technology is greatly beneficial for crop gene function analysis and precision breeding. However, the most commonly used genetic transformation technology for woody plants, mediated by , is time-consuming and inefficient, which limits its utility for gene function analysis. In this study, a simple, universal, and highly efficient genetic transformation technology mediated by K599 is described.

Genome-Wide Association Study of Healthful Flavonoids among Diverse Mandarin Accessions.

Mandarins have many unique flavonoids with documented health benefits and that help to prevent chronic human diseases. Flavonoids are difficult to measure and cannot be phenotyped without the use of specialized equipment; consequently, citrus breeders have not used flavonoid contents as selection criteria to develop cultivars with increased benefits for human health or increased tolerance to diseases. In this study, peel, pulp, and seed samples collected from many mandarin accessions and their hybrids were analyzed for the presence of selected flavonoids with documented human health benefits.

Histone Acetyltransferases and Deacetylases Are Required for Virulence, Conidiation, DNA Damage Repair, and Multiple Stresses Resistance of .

Histone acetylation, which is critical for transcriptional regulation and various biological processes in eukaryotes, is a reversible dynamic process regulated by HATs and HDACs. This study determined the function of 6 histone acetyltransferases (HATs) (, , , , , ) and 6 histone deacetylases (HDACs) (, , , , , ) in the phytopathogenic fungus by analyzing targeted gene deletion mutants. Our data provide evidence that HATs and HDACs are both required for mycelium growth, cell development and pathogenicity as many gene deletion mutants (Δ, Δ, Δ, Δ, Δ, Δ, and Δ) displayed reduced growth, conidiation or virulence at varying degrees.

Comparative Leaf Volatile Profiles of Two Contrasting Mandarin Cultivars against Liberibacter asiaticus Infection Illustrate Huanglongbing Tolerance Mechanisms.

Huanglongbing (HLB), presumably caused by Liberibacter asiaticus (Las), is a devastating citrus disease worldwide. While all citrus are affected by HLB, some cultivars display greater tolerance; however, the underlying mechanisms are not fully understood. Here, volatile changes in HLB-tolerant LB8-9 Sugar Belle (SB) and HLB-sensitive Murcott mandarins after Las infection were comprehensively compared to determine if specific volatiles are associated with HLB responses and to discern the underlying tolerance mechanisms.

The Mechanism of Citrus Host Defense Response Repression at Early Stages of Infection by Feeding of Transmitting Liberibacter asiaticus.

Citrus Huanglongbing (HLB) is the most devastating disease of citrus, presumably caused by " Liberibacter asiaticus" (Las). Although transcriptomic profiling of HLB-affected citrus plants has been studied extensively, the initial steps in pathogenesis have not been fully understood. In this study, RNA sequencing (RNA-seq) was used to compare very early transcriptional changes in the response of Valencia sweet orange (VAL) to Las after being fed by the vector, (Asian citrus psyllid, or ACP).

Metabolic Profiling of Hybrids Generated from Pummelo and in Relation to Their Attraction to , the Vector of Huanglongbing.

The citrus industry at present is severely affected by huanglongbing disease (HLB). HLB is caused by the supposed bacterial pathogen " Liberibacter asiaticus" and is transmitted by the insect vector, the Asian citrus psyllid, Kuwayama. Developing new citrus hybrids to improve HLB management is much needed.

Effect of fruit maturity on volatiles and sensory descriptors of four mandarin hybrids.

Mandarins (or tangerines) are mainly consumed as fresh fruits due to the ease of peeling and desirable flavor. Sweetness, acidity, and flavor of mandarin are the most important criteria for consumer preference. The objective of this study was to evaluate the effects of harvest date on sensory and chemical components of four mandarin cultivars (Murcott, 411, Temple, and 'LB8-9' Sugar Belle®).

Novel assembly strategy cracks open the mysteries of walnut genome evolution.

High quality chromosome-scale assemblies from an interspecific hybrid between walnut and a wild relative reveal the persistence of asymmetric fractionation between the sub-genomes and suggest a late-Miocene origin for the genus .

Phloem Regeneration Is a Mechanism for Huanglongbing-Tolerance of "Bearss" Lemon and "LB8-9" Sugar Belle Mandarin.

Huanglongbing (HLB) is an extremely destructive and lethal disease of citrus worldwide, presumably caused by phloem-limited bacteria, Liberibacter asiaticus (Las). The widespread invasiveness of the HLB pathogen and lack of natural HLB-resistant citrus cultivars have underscored the need for identifying tolerant citrus genotypes to support the current citrus industry's survival and potentially to lead to future natural HLB resistance. In this study, transverse sections of leaf lamina and midribs were examined with light and epifluorescence microscopy to determine anatomical characteristics that underlie HLB-tolerant mechanisms operating among "Bearss" lemon, "LB8-9" Sugar Belle mandarin, and its sibling trees compared with HLB-sensitive "Valencia" sweet orange.

Juice volatile composition differences between Valencia orange and its mutant Rohde Red Valencia are associated with carotenoid profile differences.

A targeted approach using HS-SPME-GC-MS was performed to investigate volatile compounds of ordinary Valencia (VAL) and its more deeply colored mutant Rohde Red Valencia orange (RRV) at different developmental stages. Fifty-six volatile components classified into six chemical groups were quantified. The individual volatile compounds in each group were significantly influenced by the genotype and harvest date.

Genome resequencing and transcriptome profiling reveal structural diversity and expression patterns of constitutive disease resistance genes in Huanglongbing-tolerant and its hybrids.

Huanglongbing (HLB) is the most destructive bacterial disease of citrus worldwide. While most citrus varieties are susceptible to HLB, a close relative of , and some of its hybrids with are tolerant to HLB. No specific HLB tolerance genes have been identified in but recent studies have shown that constitutive disease resistance genes were expressed at much higher levels in HLB-tolerant hybrids and the expression of genes was modulated by Liberibacter asiaticus (Las), the pathogen of HLB.

Metabolically speaking: Possible reasons behind the tolerance of 'Sugar Belle' mandarin hybrid to huanglongbing.

Huanglongbing (HLB) is currently considered the most destructive disease of citrus. Since its spread to the Americas, HLB has killed millions of trees and caused a sharp decline in production in many citrus growing regions. With the continuous spread of HLB disease in Florida and worldwide, there is an urgent need for the development of commercial citrus cultivars with a strong tolerance to HLB.

Effect of Low-Furanocoumarin Hybrid Grapefruit Juice Consumption on Midazolam Pharmacokinetics.

The objectives of this study were to investigate the effect of grapefruit juice low in furanocoumarins on CYP3A activity and to summarize previous findings of enzyme inhibition measured by the metabolism of midazolam after intake of grapefruit juice. Twelve healthy volunteers participated in a prospective, randomized, double-blinded, 3-way crossover clinical study to determine the effect of regular grapefruit juice (RGJ) and a novel, low-furanocoumarin hybrid grapefruit juice (HGJ) on the metabolism of oral midazolam, used as a probe for in vivo CYP3A activity, compared with water as a control. The RGJ was 100% hand-squeezed "Hudson" grapefruit juice, and the HGJ contained low amounts of furanocoumarin constituents.

Construction of citrus gene coexpression networks from microarray data using random matrix theory.

After the sequencing of citrus genomes, gene function annotation is becoming a new challenge. Gene coexpression analysis can be employed for function annotation using publicly available microarray data sets. In this study, 230 sweet orange (Citrus sinensis) microarrays were used to construct seven coexpression networks, including one condition-independent and six condition-dependent (Citrus canker, Huanglongbing, leaves, flavedo, albedo, and flesh) networks.

Comprehensive meta-analysis, co-expression, and miRNA nested network analysis identifies gene candidates in citrus against Huanglongbing disease.

Background: Huanglongbing (HLB), the most devastating disease of citrus, is associated with infection by Candidatus Liberibacter asiaticus (CaLas) and is vectored by the Asian citrus psyllid (ACP). Recently, the molecular basis of citrus-HLB interactions has been examined using transcriptome analyses, and these analyses have identified many probe sets and pathways modulated by CaLas infection among different citrus cultivars. However, lack of consistency among reported findings indicates that an integrative approach is needed.

Identification of genes associated with low furanocoumarin content in grapefruit.

Some furanocoumarins in grapefruit (Citrus paradisi) are associated with the so-called grapefruit juice effect. Previous phytochemical quantification and genetic analysis suggested that the synthesis of these furanocoumarins may be controlled by a single gene in the pathway. In this study, cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis of fruit tissues was performed to identify the candidate gene(s) likely associated with low furanocoumarin content in grapefruit.

Surface barriers of mandarin 'okitsu' leaves make a major contribution to canker disease resistance.

Field evaluations have shown that Satsuma mandarin (Citrus unshiu) 'Okitsu' is one of the mandarin cultivars that shows substantial resistance to Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus bacterial canker disease.

Mining of haplotype-based expressed sequence tag single nucleotide polymorphisms in citrus.

Background: Single nucleotide polymorphisms (SNPs), the most abundant variations in a genome, have been widely used in various studies. Detection and characterization of citrus haplotype-based expressed sequence tag (EST) SNPs will greatly facilitate further utilization of these gene-based resources.

Results: In this paper, haplotype-based SNPs were mined out of publicly available citrus expressed sequence tags (ESTs) from different citrus cultivars (genotypes) individually and collectively for comparison.

Cytological and molecular characterization of three gametoclones of Citrus clementina.

Background: Three gametoclonal plants of Citrus clementina Hort. ex Tan., cv.

Aroma characterization of tangerine hybrids by gas-chromatography-olfactometry and sensory evaluation.

Background: Tangerines have a distinct flavor among citrus fruit. However, information on tangerine volatiles remains limited. Volatile compounds from a breeding population of tangerines were earlier identified by gas chromatography-mass spectrometry.