Leaf area measurements of the allotetraploid somatic hybrids between OLL8 sweet orange and the fi... more Leaf area measurements of the allotetraploid somatic hybrids between OLL8 sweet orange and the finger lime and the diploid parents.</p
Relative expression of PR1 (A) and PR2 (B) transcripts in OLL8, finger lime (FL) and four selecte... more Relative expression of PR1 (A) and PR2 (B) transcripts in OLL8, finger lime (FL) and four selected OLL8+FL allotetraploids. Bars represent means ± standard error. Means separation by Tukey’s honestly significant difference test (P≤ 0.05).</p
The cybrids plants are carrying the finger lime nuclear genotype. Two cybrids (1 and 3) inherited... more The cybrids plants are carrying the finger lime nuclear genotype. Two cybrids (1 and 3) inherited the finger lime plastids, while cybrid 2 inherited the ‘Page’ mandarin plastid genome. All finger lime cybrids inherited the ‘page’ mitochondrial genome. The top right tree represents one of the cybrids in the field. Figure was created in BioRender.com.</p
Relative expression of 20G-Fe (A), ABF3 (B), ZIP10 (C) and CAM8 (D) transcripts in OLL8, finger l... more Relative expression of 20G-Fe (A), ABF3 (B), ZIP10 (C) and CAM8 (D) transcripts in OLL8, finger lime (FL) and four selected OLL8+FL allotetraploids. Bars represent means ± standard error. Means separation by Tukey’s honestly significant difference test (P≤ 0.05).</p
Fruit morphological characteristics of tetraploid finger lime and the diploid finger lime, extern... more Fruit morphological characteristics of tetraploid finger lime and the diploid finger lime, external (A) and internal (B) characteristics. Left (OLL8, 2X), Middle (finger lime, 2X), right (OLL8+FL, 4X).</p
Use of expressed sequence tag–simple sequence repeat (EST-SSR) to detect alleles and confirm allo... more Use of expressed sequence tag–simple sequence repeat (EST-SSR) to detect alleles and confirm allotetraploid somatic hybrids between OLL8 sweet orange and the finger lime (C. australasica).</p
Top panel (A-C) are Scanning Electron Microscopy (SEM) images demonstrating differences in stomat... more Top panel (A-C) are Scanning Electron Microscopy (SEM) images demonstrating differences in stomata numbers in A) OLL8, (B) finger lime and a (C) tetraploid somatic fusion. Lower panel are bar graphs comparing stomata number (D) and average stomatal area (E) in diploid parents and the tetraploid somatic fusion.</p
Relative expression of EXP-A4 (A) and ABC transporter C (B) transcripts in OLL8, finger lime (FL)... more Relative expression of EXP-A4 (A) and ABC transporter C (B) transcripts in OLL8, finger lime (FL) and four selected OLL8+FL allotetraploids. Bars represent means ± standard error. Means separation by Tukey’s honestly significant difference test (P≤ 0.05).</p
Ct values of CaLas detected in the 6-year-old allotetraploid somatic hybrids between OLL8 sweet o... more Ct values of CaLas detected in the 6-year-old allotetraploid somatic hybrids between OLL8 sweet orange and the finger lime and the diploid parents.</p
A) Morphological changes in leaves of the diploid parents (left, OLL8; middle; FL) and an OLL8+FL... more A) Morphological changes in leaves of the diploid parents (left, OLL8; middle; FL) and an OLL8+FL allotetraploid (right). B) and C) Ploidy analysis using flow cytometry. Diploid (B) and tetraploid (C) peaks derived from control and OLL8 + finger lime somatic fusion lines. D) A chromatogram of EST-SSR marker CX0010 labeled with 6-FAM generated from ABI trace files by GeneMarker® software (SoftGenetics). Top panel; OLL8 sweet orange (2X), Middle panel; finger lime (2X) Third and fourth panel; two independent OLL8 + FL (4X) lines.</p
Citrus canker and Huanglongbing (HLB) remain scourges of the citrus industry. While citrus canker... more Citrus canker and Huanglongbing (HLB) remain scourges of the citrus industry. While citrus canker largely affects the physical appearance of the fruit, it blemishes the fruit such that it becomes unmarketable. Huanglongbing, or citrus greening disease, is lethal to trees in the long term, and while the tree is in decline produces malformed and bitter fruits. Genetic analyses of citrus have shown that the pummelo (Citrus maxima Burm.) is one of the ancestors of the grapefruit as well as other citrus varieties. Identifying a disease resistant variety of pummelo would be useful to breed new, disease resistant varieties of grapefruit or other citrus. Mature, seed grown pummelo trees were examined in the field for evidence of disease in groves where both citrus canker and HLB are present. Trees found to be symptom free of HLB and citrus canker were replicated and subjected to canker inoculation under greenhouse conditions. Kumquats (Fortunella sp.), which are generally regarded as resist...
The Australian finger lime is a unique citrus species that has gained importance due to its uniqu... more The Australian finger lime is a unique citrus species that has gained importance due to its unique fruit characteristics and perceived tolerance to Huanglongbing (HLB), an often-fatal disease of citrus trees. In this study, we developed allotetraploid finger lime hybrids and cybrids by utilizing somatic cell fusion techniques to fuse diploid ‘OLL8’ sweet orange or ‘Page’ tangelo callus-derived protoplasts with finger lime (FL) mesophyll-derived protoplasts. Six somatic fusions were regenerated from the ‘OLL8’ + FL fusion, while three putative cybrids were regenerated from the ‘Page’ + FL fusion. Ploidy levels and nuclear-expressed sequence tag derived simple sequence repeat (EST-SSR) markers confirmed the somatic hybrid production, and mitochondrial DNA primer sets confirmed the cybrid nature. Several trees produced by the somatic fusion remained HLB negative even after 6 years of growth in an HLB-endemic environment. Pathogenesis related (PR) and other genes that are often upregula...
Leaf area measurements of the allotetraploid somatic hybrids between OLL8 sweet orange and the fi... more Leaf area measurements of the allotetraploid somatic hybrids between OLL8 sweet orange and the finger lime and the diploid parents.</p
Relative expression of PR1 (A) and PR2 (B) transcripts in OLL8, finger lime (FL) and four selecte... more Relative expression of PR1 (A) and PR2 (B) transcripts in OLL8, finger lime (FL) and four selected OLL8+FL allotetraploids. Bars represent means ± standard error. Means separation by Tukey’s honestly significant difference test (P≤ 0.05).</p
The cybrids plants are carrying the finger lime nuclear genotype. Two cybrids (1 and 3) inherited... more The cybrids plants are carrying the finger lime nuclear genotype. Two cybrids (1 and 3) inherited the finger lime plastids, while cybrid 2 inherited the ‘Page’ mandarin plastid genome. All finger lime cybrids inherited the ‘page’ mitochondrial genome. The top right tree represents one of the cybrids in the field. Figure was created in BioRender.com.</p
Relative expression of 20G-Fe (A), ABF3 (B), ZIP10 (C) and CAM8 (D) transcripts in OLL8, finger l... more Relative expression of 20G-Fe (A), ABF3 (B), ZIP10 (C) and CAM8 (D) transcripts in OLL8, finger lime (FL) and four selected OLL8+FL allotetraploids. Bars represent means ± standard error. Means separation by Tukey’s honestly significant difference test (P≤ 0.05).</p
Fruit morphological characteristics of tetraploid finger lime and the diploid finger lime, extern... more Fruit morphological characteristics of tetraploid finger lime and the diploid finger lime, external (A) and internal (B) characteristics. Left (OLL8, 2X), Middle (finger lime, 2X), right (OLL8+FL, 4X).</p
Use of expressed sequence tag–simple sequence repeat (EST-SSR) to detect alleles and confirm allo... more Use of expressed sequence tag–simple sequence repeat (EST-SSR) to detect alleles and confirm allotetraploid somatic hybrids between OLL8 sweet orange and the finger lime (C. australasica).</p
Top panel (A-C) are Scanning Electron Microscopy (SEM) images demonstrating differences in stomat... more Top panel (A-C) are Scanning Electron Microscopy (SEM) images demonstrating differences in stomata numbers in A) OLL8, (B) finger lime and a (C) tetraploid somatic fusion. Lower panel are bar graphs comparing stomata number (D) and average stomatal area (E) in diploid parents and the tetraploid somatic fusion.</p
Relative expression of EXP-A4 (A) and ABC transporter C (B) transcripts in OLL8, finger lime (FL)... more Relative expression of EXP-A4 (A) and ABC transporter C (B) transcripts in OLL8, finger lime (FL) and four selected OLL8+FL allotetraploids. Bars represent means ± standard error. Means separation by Tukey’s honestly significant difference test (P≤ 0.05).</p
Ct values of CaLas detected in the 6-year-old allotetraploid somatic hybrids between OLL8 sweet o... more Ct values of CaLas detected in the 6-year-old allotetraploid somatic hybrids between OLL8 sweet orange and the finger lime and the diploid parents.</p
A) Morphological changes in leaves of the diploid parents (left, OLL8; middle; FL) and an OLL8+FL... more A) Morphological changes in leaves of the diploid parents (left, OLL8; middle; FL) and an OLL8+FL allotetraploid (right). B) and C) Ploidy analysis using flow cytometry. Diploid (B) and tetraploid (C) peaks derived from control and OLL8 + finger lime somatic fusion lines. D) A chromatogram of EST-SSR marker CX0010 labeled with 6-FAM generated from ABI trace files by GeneMarker® software (SoftGenetics). Top panel; OLL8 sweet orange (2X), Middle panel; finger lime (2X) Third and fourth panel; two independent OLL8 + FL (4X) lines.</p
Citrus canker and Huanglongbing (HLB) remain scourges of the citrus industry. While citrus canker... more Citrus canker and Huanglongbing (HLB) remain scourges of the citrus industry. While citrus canker largely affects the physical appearance of the fruit, it blemishes the fruit such that it becomes unmarketable. Huanglongbing, or citrus greening disease, is lethal to trees in the long term, and while the tree is in decline produces malformed and bitter fruits. Genetic analyses of citrus have shown that the pummelo (Citrus maxima Burm.) is one of the ancestors of the grapefruit as well as other citrus varieties. Identifying a disease resistant variety of pummelo would be useful to breed new, disease resistant varieties of grapefruit or other citrus. Mature, seed grown pummelo trees were examined in the field for evidence of disease in groves where both citrus canker and HLB are present. Trees found to be symptom free of HLB and citrus canker were replicated and subjected to canker inoculation under greenhouse conditions. Kumquats (Fortunella sp.), which are generally regarded as resist...
The Australian finger lime is a unique citrus species that has gained importance due to its uniqu... more The Australian finger lime is a unique citrus species that has gained importance due to its unique fruit characteristics and perceived tolerance to Huanglongbing (HLB), an often-fatal disease of citrus trees. In this study, we developed allotetraploid finger lime hybrids and cybrids by utilizing somatic cell fusion techniques to fuse diploid ‘OLL8’ sweet orange or ‘Page’ tangelo callus-derived protoplasts with finger lime (FL) mesophyll-derived protoplasts. Six somatic fusions were regenerated from the ‘OLL8’ + FL fusion, while three putative cybrids were regenerated from the ‘Page’ + FL fusion. Ploidy levels and nuclear-expressed sequence tag derived simple sequence repeat (EST-SSR) markers confirmed the somatic hybrid production, and mitochondrial DNA primer sets confirmed the cybrid nature. Several trees produced by the somatic fusion remained HLB negative even after 6 years of growth in an HLB-endemic environment. Pathogenesis related (PR) and other genes that are often upregula...
Uploads
Papers by Ethan Nielsen