Project description:The Australian finger lime (Citrus australasica) is tolerant to Huanglongbing (HLB; Citrus greening). This species can be utilized to develop HLB tolerant citrus cultivars through conventional breeding and biotechnological approaches. In this report, we conducted a comprehensive analysis of transcriptomic data following a non-choice infection assay to understand the CaLas tolerance mechanisms in the finger lime. After filtering 3,768 differentially expressed genes (DEGs), 2,396 were downregulated and 1,372 were upregulated in CaLas-infected finger lime compared to CaLas-infected HLB-susceptible 'Valencia' sweet orange. Comparative analyses revealed several DEGs belonging to cell wall, β-glucanase, proteolysis, R genes, signaling, redox state, peroxidases, glutathione-S-transferase, secondary metabolites, and pathogenesis-related (PR) proteins categories. Our results indicate that the finger lime has evolved specific redox control systems to mitigate the reactive oxygen species and modulate the plant defense response. We also identified candidate genes responsible for the production of Cys-rich secretory proteins and Pathogenesis-related 1 (PR1-like) proteins that are highly upregulated in infected finger lime relative to noninfected and infected 'Valencia' sweet orange. Additionally, the anatomical analysis of phloem and stem tissues in finger lime and 'Valencia' suggested better regeneration of phloem tissues in finger lime in response to HLB infection. Analysis of callose formation following infection revealed a significant difference in the production of callose plugs between the stem phloem of CaLas+ 'Valencia' sweet orange and finger lime. Understanding the mechanism of resistance will help the scientific community design strategies to protect trees from CaLas infection and assist citrus breeders in developing durable HLB tolerant citrus varieties.

| S-EPMC9634478 | biostudies-literature

Citrus glauca strain:CRC3463 | isolate:PI 539717 | cultivar:Australian desert lime

Project description:Citrus glauca strain:CRC3463 | isolate:PI 539717 | cultivar:Australian desert lime Genome sequencing and assembly

| PRJNA924093 | ENA

Citrus glauca strain:CRC3463 | isolate:PI 539717 | cultivar:Australian desert lime

Project description:Citrus glauca strain:CRC3463 | isolate:PI 539717 | cultivar:Australian desert lime Genome sequencing and assembly

| PRJNA924091 | ENA

Citrus glauca strain:CRC3463 | isolate:PI 539717 | cultivar:Australian desert lime

Project description:Citrus glauca strain:CRC3463 | isolate:PI 539717 | cultivar:Australian desert lime Genome sequencing and assembly

| PRJNA924092 | ENA

Utilization of somatic fusion techniques for the development of HLB tolerant breeding resources employing the Australian finger lime (Citrus australasica).

Project description: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 upregulated in HLB-tolerant trees were also upregulated in our somatic fusions. These newly developed somatic fusions and cybrids could potentially be used as breeding parents to develop the next generation of improved HLB-tolerant rootstocks and scions.

| S-EPMC8354479 | biostudies-literature

Citrus australasica

Project description:Citrus australasica Assembly

| PRJNA1144587 | ENA

Citrus australasica

Project description:Citrus australasica Assembly

| PRJNA1144588 | ENA