Several new sweet oranges have been approved for release by UF-IFAS; these include several from Brazil believed to have canker tolerance, as well as new Valencia types with earlier and later maturity. The former will be generally available, but the latter will be patented and available through license agreements; together, they give industry new options to produce distinctive, high-quality juice. Canker tolerance of the Brazilian selections is currently being assessed under controlled greenhouse conditions, and preliminary results indicate that some of them are, in fact, significantly more canker-tolerant than ordinary sweet oranges. Additional data was collected from other advanced sweet orange selections in replicated field trials, and the best performing of these are being cleaned of pathogens and indexed, to provide certified budwood sources following approval for their release. These include a range of Valencia-types with improved color, yield, and juice quality attributes, as well as some very productive, seedless Midsweet clones; fruit and juice of these selections have been included in several commercial taste panels and assessments, and have been shown to be superior in their quality attributes. Hybrid plants have been produced for rootstock improvement from the previous season, and new crosses were made this spring 2009, that utilized germplasm with potential canker and HLB resistance or tolerance. Previous work to develop rootstocks tolerant of or resistant to other maladies (such as CTV, blight, Phytophthora/Diaprepes, calcareous soils, etc.) continues, as we collected data from replicated trials and other plantings. New rootstock trials were planned, with plants being propagated or already planted, to test the suitability of experimental rootstocks for advanced production technologies; tree size control and broad-spectrum disease resistance and tolerance of adverse environmental conditions are critical to these efforts. Some trials include the recently released UF cultivar Sugar Belle (Tm), but most are with sweet orange. New transgenes have been developed or acquired, and experiments have been established to introduce them into HLB and canker susceptible citrus. Previously developed transgenic plants have been inoculated with HLB, and those thus far showing no symptoms and negative qPCR tests (after more than 18 months) are being propagated for further testing. Several newly developed transgenic lines are being propagated for canker inoculations and evaluation, as well. New pummelo-grapefruit hybrids, some of which were previously found to be significantly more tolerant of canker than grapefruit, are being propagated for canker challenges. Several of these hybrids also have been found to contain little or no furanocoumarin compounds, suggesting that they might not result in harmful grapefruit-drug interactions; further, some of them produce seedless fruit. A series of experiments have been established to provide materials needed for research aimed at further characterization of gene expression differences resulting when susceptible citrus are challenged with HLB. RNA and DNA samples have been prepared at regular intervals to follow gene expression changes over time. These experiments may provide genetic targets to induce resistance to HLB, or at least to develop markers for early detection of disease. Previous research revealed several target genes in kumquat associated with its canker resistance (hypersensitivity). Microarray experiments were analyzed and have revealed more information on the defense machinery within kumquat cells. Several of the target genes have been fully cloned for further experiments including genetic transformation, following a more careful study of their gene expression patterns. Publicly available citrus genome resources are being mined for genes that may be used to hasten development of citrus plants resistant to HLB, canker, and other production-limiting diseases. Additional molecular markers have been developed and mapped in collaboration with colleagues in Spain and France, in support of the International Citrus Genome Consortium sequencing project. We are well on our way to meeting project objectives and goals.
Since the funding period started, one laboratory technician was added to the staff of CCTF. He was trained in all procedures employed in the lab and presently is capable of performing duties with very little supervision. Organization of the work in the lab was set to allow for higher influx of orders through different assignment of chores. The list of transgenic plants that were produced and confirmed by the presence of reporter gene and appropriate PCR reaction: LIMA gene: 3 Flame; LIMA(SN) gene: 5 Flame; CIT108 gene: 12 Valencia; CIT108p gene: 7 Flame; CIT108p3 gene: 14 Flame; CIT108p17 gene: 6 Flame; CL1 gene: 1 Valencia; 2 Duncan; CL2 gene: 1 Valencia, 1 Duncan; PITA gene: 40 Duncan, 3 Valencia; C5* gene: 3 Duncan; CN1 gene: 1 Duncan; N1* gene: 2 Duncan; F3* gene: 8 Duncan. Presently, there are about 90 plants in the soil that were picked as positive for presence of reporter gene but not tested by PCR.
Main goal – Analysis of transcriptome of sweet orange Hamlin during the infection of Candidatus Liberibacter spp. Main activities Experiment set up Ð From February to June 60 plants of sweet orange Hamlin were grafted into Rangpur lime and established at screen house. They will be grafted with infected budwoods in vegetative development of the plants and grafting of the budwoods. I have a pure source of Candidatus Liberibacter asiaticus (CLas) kept under screen house but source of Ca. Liberibacter americanus (CLam) has been difficult to keep, because the bacteria have low transmission efficiency with infected budwoods. Infected plants in the field have decreased in the last years, and CLas seems to be more pathogenic than CLam. The experiments will be changed from the original version in order to improve the quality of results. Besides the time course for sampling of infected and health leaves, tissue of bark (enriched with phloem tissue) in the infected branches will also be collected and compared with leaves. A concern in the experiments is regard with time of infection that can really be associated to the interaction plant with the bacteria. Preliminary we consider 0, 2, 6, 12, 18,24, 30, 45, 60, and 90 days after grafting. I am evaluating to consider three main pools. One before the bacteria can be detected by RT-qPCR (0, 2, 6, 12, 18 days); other pool of samples collected at 24, 30, 45 and 60 days. Sample after 90 days will be considered alone, since at that time severe damages caused by the disease could disturb the results. Thus the experiments could be conduced with three pools of leaves + control, three of bark + control, with tissue infected with both bacteria individually. Array design – The arrays and the hybridization will be conduced as service by Nimblegen / Roche. A set of arrays was already tested in other experiment with suitable quality. The database was 32,000 unigenes of sweet orange (CitEST). Each unigene was represented 6 times with oligo probes of 50 to 60 bases. Therefore, an array has a density of 180,000 spots. Procedure for RNA isolation with high quality is established. RT-qPCR Ð Although the experiments with arrays were not finished, we are looking for good candidates as house keeping genes in citrus. Among them .-tubulina, expansin-like B1, and ankirin. Some troubles Ð Although FCPRAC sent a check with part of financial support in Abril 2009, until now the check could not be paid. The bank cannot explain what is going on, but they promised in August the funds would be available. Actually all activities were until now conduced with funds of other projects.
The HLB pathogen is acquired by the Asian citrus psyllid during the feeding process, which indicates that the alimentary canal is the first organ of the transmission cycle. Our first task in this collaboration has been completed by stockpiling this organ for mRNA analysis. 1000 adult, noninfective psyllids were submerged, one at a time, in 50% RNAse Later¨ (Ambion), a general protease that destroys transcript degrading enzymes. The alimentary canals of each were extirpated in this solution and transferred with a pinpoint to 0.5ml of 100% TRIzol¨ (Invitrogen), a powerful phenolic that allows for deep freezing and long-term storage. The same low volume of phenolic and high number of guts has been shown with whiteflies to yield an outstanding 28 nanograms mRNA per microliter final concentration. As an aside, alimentary canals were dissected and pooled from two adult psyllids confined to an infective orchard tree branch for three days, to see if a qPCR signal could be had in so small a sample. Results were a Ct value of 35, where 40 is no signal and 20 is a high-titer signal. This first test run indicates that quantification of titer in individual guts is a highly feasible approach to quality control when stockpiling of organs from infective psyllids commences. The laboratory rearing system is under construction and excellent progress has been made once psyllids began reproducing at high levels (June onward) and some adults and immatures, as well as samples from different portions of the plants on which colonies are being reared have been collected for qPCR analysis (in progress).
The project has two objectives: (1) Over-express MAP kinase kinase 7 (MKK7) gene in citrus to increase disease resistance (Transgenic approach). (2) Select for citrus mutants with increased disease resistance (Non-transgenic approach). For objective 1, the Arabidopsis MKK7 gene has been cloned into the CTV-based expression vector and transition expression of MKK7 in citrus leaves is underway. The Arabidopsis MKK7 gene has also been cloned into the plant binary vector pBI1.4T (a pBI121 derivative) and transformed into citrus using the Agrobacterium-mediated approach. Characterization of the MKK7 transgenic citrus plants is underway. For objective 2, citrus cell suspension culture has been established and the concentration of sodium iodoacetate that will be used for the selection has been experimentally determined. Two citrus cell suspension cultures were obtained, one Navel orange cell suspension culture and one Hamlin cell suspension culture. Both cell suspension cultures were established using soft, friable callus derived from nucellar tissues. After subculturing for several generations in the Murashige and Tucker (MT) liquid medium, the cell aggregates in the Navel orange culture formed large clumps and very few single cells could be visualized (data not shown). In contrast, the cell aggregates in the Hamlin culture were dispersed and very small clumps and single cells were equally distributed throughout the liquid media. When placed on the MT solid embryogenic callus-inducing medium, the cells quickly propagated and formed calli. Therefore, the Hamlin suspension cells were used as starting materials for the selection. The Hamlin cell suspension culture has been scaled up in the MT liquid medium. Several flasks of the culture are maintained for subculture. Since different plant species and different starting materials require different concentrations of sodium iodoacetate to completely inhibit their growth (data not shown), the concentration that could completely inhibit the growth of the Hamlin suspension cells was experimentally determined. The Hamlin cells from the suspension culture were grown on the MT medium plates supplemented with different concentrations of sodium iodoacetate ranged from 0 to 0.2 mM. Hamlin suspension cells were found to be highly sensitive to the inhibitor. A concentration of 0.1 mM of sodium iodoacetate could completely arrest their growth. Therefore, 0.1 mM of sodium iodoacetate will be used in the selection.
This project has three objectives: 1) gap closure of Ca. Liberibacter asiaticus (Las) found in Florida; 2) complete genomic sequencing to closure of Ca. L. americanus (Lam) strain S’o Paulo from Brazil, and 3) comparative genome analysis of Las and Lam to attempt to determine common factors enabling pathogenicity to citrus. This project is complementary and synergistic to work that was recently published (Duan et al. 2009. MPMI 22:1011-1020), in which the nearly complete genomic sequence of Las strain psy62, extracted from infected psyllids, was obtained. Within psy62, many unique genes of unknown function are found and it is difficult to establish which genes among the many unique unknowns might be important to enable pathogenicity on citrus. If the same unknown genes are found in a different species that causes the same disease (Huanglongbin, or HLB) on citrus, this information can considerably focus the research priorities for candidate genes that may be investigated as possible targets for chemical or genetic control of HLB. Our approach is to obtain the complete genomic sequence of a different Liberibacter species, Lam, that also causes HLB, and compare it to psy62. In collaboration with Fundecitrus in Brazil, DNA samples extracted from citrus midribs infected with Lam were purified on pulsed-field gels by Dr. Nelson Wulff and brought to UF. We used multiple displacement amplification (MDA) to obtain sufficient DNA for sequencing. Two trial shotgun libraries were constructed, one from each sample, and tested for quality by 454 sequencing. After bioinformatics filtering, Sample 1 yielded 1.6 Mb of sequence, of which 13 kb (0.8%) was new Lam DNA sequence. Sample 2 yielded 9.2 Mb of sequence, of which 41 kb (0.4%) was new Lam DNA sequence, resulting in 54 kb of new Lam DNA sequence to date. More importantly, the principle contaminating DNA from these trial runs was identified as citrus mitochondrial DNA, which guided modification of our extraction method so that this contaminating DNA has now been greatly reduced from a third DNA sample, which has been sent for full scale sequencing. In anticipation of a draft Lam genome, subsequent Las/Lam genome comparisons, and also to help close remaining gaps in the psy62 genome, two fosmid libraries were constructed using DNA extracted from HLB infected citrus, one from Lam strain S’o Paulo and one from Las strain UF506. Each library consisted of 1100 fosmid clones, both with an average insert size of ca. 31 kb, cloned in fosmid vector pCC2FOS. The Las UF506 library was used to close gaps surrounding 8 unjoined contigs of psy62, all containing phage-related genes. DNA probes were made as PCR products amplified from Las infected citrus and used to probe nylon blots of the UF506 fosmid library. Eight fosmids were identified and partially sequenced to join 7 previously unjoined psy62 contigs to form one complete 40,048 bb circular phage genome (named SC-1) plus one 31 kb contig, potentially representing a highly related but separate phage SC-2. SC-1 has 28 direct repeat regions. Both SC-1 and the SC-2 supercontig were validated by PCR amplification of HLB infected citrus along 89% of their entire lengths.
Due to the recent arrival of the funds on campus, experimental aspects of the project are still in the early stages and limited to preparation of primers and the cloning of the promoters and resistance protein genes that will be evaluated in the project as follows: 1-A series of phloem-specific promoters from Arabidopsis and other plants are in the process of being cloned for evaluation in transformed plants. Initial assessment of the constructs will be evaluated in transient assays and suitable candidate clones will be transformed into Arabidopsis and citrus plants to test for phloem-specific expression. These promoters will be used to express resistance proteins (R proteins) and R protein mutants in an attempt to confer resistance to Liberibacter infection. Due to the potential of R proteins to interfere with normal growth and development of the plant, their expression will be limited to the phloem tissues, the site where the pathogen resides. 2- Several R proteins are being cloned for expression in Arabidopsis and citrus plants. Attenuated mutants of these proteins will be first expressed in the transient assay using Arabidopsis leaf mesophyll protoplasts to evaluate their effects on normal cellular function. Expression of these proteins will be driven by the phloem-specific promoters cloned in objective 1 above.
The goal of this project is to transform the Arabidopsis and citrus NPR1 genes (AtNPR1 and CtNPR1), and the rice XIN31 gene into citrus, and to evaluate their resistance to both citrus canker (caused by Xanthomonas axonopodis pv. citri (Xac)) and greening diseases. The first year objectives include: (1) Molecular characterization of the transgenic plants; (2) Inoculation of the transgenic plants with Xac. (3) Inoculation of the transgenic plants with the HLB pathogen and monitoring of the bacterium in planta with quantitative PCR; (4) Transformation of SUC2::NPR1 into citrus. (5) Plant maintenance. Overall the project is doing very well. To date, we have transformed AtNPR1, CtNPR1, XIN31, and XIN31K into the susceptible citrus cultivar ‘Duncan’ grapefruit. A total of seven lines for AtNPR1, 15 lines for CtNPR1, 12 lines for XIN31, and eight lines for XIN31K have been produced. All of these lines are maintained in green houses located at the Citrus Research and Education Center in Lake Alfred, Florida. More transgenic lines for each gene are to be available. A PCR system for identifying the presence of the transgenes has been established. A preliminary screening of part of the transgenic population has led to the identification of three, three, eight positive lines for the AtNPR1, CtNPR1, and XIN31 genes, respectively. Among them, the six PCR-positive lines for the NPR1 genes have been multiplied by grafting. Additionally, we have obtained the promoter construct of the Arabidopsis SUC2 gene from Dr. Jude Grosser’s lab. Construction of SUC2::NPR1 is in progress.
As proposed, a transgenic test site has been prepared at the USDA/ARS USHRL Picos Farm in Ft. Pierce. A new 8 acre site has been bedded, supplied with irrigation, and a ground cover established. Several acres in the far NE corner have been prepared for Dr. Dawson’s proposed field test of modified CTV expression vectors designed to produce anti-microbial peptides in citrus host plants. APHIS specified that Dr. Dawson’s site be as far from existing commercial citrus groves as possible, and recommended the NE corner of the Picos Farm. Answers have been provided to numerous questions from regulators to facilitate field testing approval. Cooperators have been made aware that the site is ready for planting.
The diseases Huanglongbing (HLB) and Citrus Bacterial Canker (CBC) present serious threats to the future success of citrus production in the US. Insertion of genes conferring resistance to these diseases or the HLB insect vector is a promising way to solve these problems. Transformation vectors, suitable for incorporating genes into citrus trees, have been prepared for five antimicrobial peptides (AMPs) with several promoters and are being used to generate transformants of rootstock and scion genotypes. Many thousands of putatively transformed shoots have been developed to produce citrus resistant to HLB and CBC or citrus psyllid. Many have been micrografted to grow shoots for propagation and further evaluation. Large numbers of D4E1 transformed rootstocks are being challenged with HLB and citrus canker. Initial trials indicate significantly reduced susceptibility to citrus canker from about 20% of the D4E1 transformed citrus. The first steps have been taken to use information from Liberibacter sequence data to develop a transgenic solution for HLB-resistance. In addition, collaboration has been initiated with a molecular biology team at the Western Regional Research Center in Albany, CA to develop constructs which minimize commercial IP conflicts, regulatory problems, and consumer concerns in transgenic citrus resistant to HLB and CBC. The strategy is called ÒcisgenicsÓ and uses genes from citrus. The genes are identified from citrus genomic data. A total of 39 antimicrobial peptides (AMPs) have been assessed in-vitro for activity in suppressing growth of the bacteria causing CBC and two surrogates for Liberibacter that are closely related alpha-proteobacters. In the initial studies, the synthetic AMPs D4E1 and D2A21 were among the most active, with minimum inhibitory concentrations at 1 µM or less across all test bacteria. Following these studies, an agreement was developed with AgroMed (the producers of these peptides) and a citrus industry partner, Southern Gardens Citrus. An additional 20 synthetic AMPs have been assessed as part of this agreement, revealing several AMPs that were highly active against all test species; transformation constructs will soon be prepared to produce transgenic citrus. Hemolysis assays have been conducted with 36 of the AMPs to gauge potential for human health risks: most of the AMPs showed slight or negligible hemolytic activity. The tomato cultivar ÔM82Õ was transformed with the AMP D4E1 and Garlic Lectin as a model system for more quickly assessing resistance than is possible using citrus. D4E1-transformed tomatoes were challenged by inoculations with Agrobacterium tumefaciens: no immune plants were identified, but some produced only very small galls and overall gall mass was 30% lower in D4E1-transformed vs. control ÔM82Õ. Transformed plants have been propagated and D4E1- transformed vs. control plants will also be challenged with Xanthomonas campestris pv. vesicatoria to assess resistance. Garlic-lectin-transformed tomatoes vs. control ÔM-82Õ will be tested for effects on populations of the phloem-feeding whitefly pest (Bemisia species). High throughput evaluation of HLB resistance will require the ability to efficiently assess resistance in numerous plants. Graft-inoculation, controlled psyllid-inoculation, and ÒnaturalÓ psyllid inoculation in the field are being compared. A material transfer agreement has been established with Texas A&M University to permit lab and greenhouse comparisons with the Spinach Defensin expressing grapefruit and ‘Hamlin’. Since this material is well down the regulatory pathway, it makes no sense to move forward with any transformed citrus which is not markedly superior to this benchmark material.
New hybrids between citrus relatives and citrus cultivars were studied for tolerance to HLB disease in greenhouse testing. Some new hybrids that were studied remain healthy and vigorous despite HLB infection and have been selected for further field and greenhouse testing. These hybrids will be used as parental material for breeding high quality rootstock and scion cultivars with tolerance. In this quarter, yield, fruit quality, tree size, and other performance information were collected from existing USDA/cooperative rootstock and scion field trials. Trees were propagated to establish new field trials for new rootstock and scion cultivars. Studies continue to assess rootstock tolerance of Huanglongbing (HLB) under field conditions using existing trials that have become infected with HLB through natural spread. Some differences among rootstocks for HLB response were noted and are being examined more carefully. A field experiment continued to identify rootstocks with resistance to the Phytophthora-Diaprepes Complex. Crosses were completed for development of improved citrus rootstocks focused on developing an improved sour orange (Supersour) rootstock and introgressing HLB resistance from exotic citrus relatives. In a coordinated effort between this grant and the FCATP transgenic citrus grant to USDA, selected anti-microbial and insect resistance genes were inserted into outstanding rootstock and scion cultivars to develop new cultivars with resistance to HLB and Citrus Bacterial Canker (CBC). An early flowering gene, FT, was transformed into outstanding citrus breeding material to facilitate rapid introgression of favorable traits, such as disease resistance, into new cultivars and increase early productivity of scion cultivars. Research is continuing to follow leads generated by the HLB gene expression study completed last year, including cloning of selected genes and promoters strongly expressed in response to HLB infection. These sequences are being used as targets for novel exotic genes, to help identify endogenous resistance genes, and to selectively express transgenes when and where the tree is infected by HLB. Work was continued to study the inheritance of fruit quality factors in sweet orange-type material using more than 1000 trees from populations of hybrids between high quality pummelo and mandarin parents. Work was initiated to study gene expression in seedless cultivars and identify genes that may be specifically associated with seedlessness. One promising new seedless scion cultivar, ‘Early Pride’, was released for commercial use. One highly productive dwarfing rootstock, US-942, is in the final stages of official release.
One of the major problems in genetically transforming mature citrus tissue in the hot and humid conditions of Florida and Brazil is obtaining clean explant material to initiate uncontaminated tissue cultures. Therefore initial efforts on this project are focused on methods to produce mature citrus tissue that is uncontaminated by bacteria, fungi, or insects. USDA scientists are developing in vitro systems for the continuous and semi-continuous production of mature tissue. Mature tissue derived from in vitro shoots is aseptic and will require little or no disinfestation. In addition, such tissue may respond well to tissue culture manipulations and be highly suitable for genetic transformation. UF and Brazilian scientists are growing trees under very clean conditions that prevent infestation by pests. Tissue derived from these trees should be better suited for transformation since the duration and intensity of disinfestation required should be minimal. In both the in vitro and in vivo systems, the 1) addition of compounds such as disinfectants, biocides, and antibiotics for control of pests without harm to the citrus tissue and, 2) the pretreatments, medium constituents, and environmental conditions required to effectively grow and manipulate this material is being investigated.
The objective of this project is to determine if Carrizo rootstocks, either wild type or overexpressing the Arabidopsis NPR1 gene, and so having an enhanced, inducible defense response, have any effect on gene expression and/or the defense response of wild type (non transgenic) grapefruit scions to HLB. It has long been recognized in the traditional growing of citrus that rootstock selection has a large effect on scion phenotype. However, it is not understood at the molecular level how rootstocks provide their advantages or disadvantages. For this purpose we have propagated transgenic Carrizo rootstock plants (lines 776, 854 and 857) that express the AtNPR1 gene. This gene is central in plant defense and these lines also show enhanced expression of the marker PR1 gene. Additionally, one transgenic line that lacks AtNPR1 expression and PR1 overexpression (line 884) and one transformed but nontransgenic line (i.e. lacks the AtNPR1 transgene, line 859) and wild type Carrizo planst were also propagated as negative controls. These lines have been grafted with wild type ÔDuncanÕ grapefruit. Other controls consist of nongrafted clones of AtNPR1 Carrizo (all lines mentioned above), wild type Carrizo, and non grafted grapefruit. The plants are being maintained in a containment facility at UF in Gainesville. We have also multiplied our HLB inoculum in ÔDuncanÕ grapefruit. The next step is to challenge the different graft combinations and to examine them for phenotype and gene expression with and without HLB challenge.
Juvenile sweet oranges were grafted to several rootstocks with potential to induce scion precosity. Trees will subsequently be transferred to our early fruiting structure to encourage precocious flowering and fruit set. Seed of the same clones were planted to provide juvenile seedlings for planned experiments. Transformation experiments comparing transformation efficiency of various selected sweet oranges were initiated, including several clones that have previously shown precocious bearing in field trials. In Arabidopsis and other plants, the overexpression of a FLOWERING LOCUS T (FT) gene in transgenic plants leads to accelerated flowering. In the Moore lab we have cloned and sequenced the three citrus FT genes and placed them individually in transformation vector plasmids. We have initiated Agrobacterium-mediated transformation experiments with Carrizo citrange, sweet orange, and grapefruit.
This project has two main objectives: 1) Development of genetic transformation systems for mature tissues of the most important sweet orange varieties of Florida, namely Hamlin and Valencia, using Pineapple as a control for which a transformation system already exists, and of the most important rootstock genotype, Carrizo citrange. Procedures would be first developed in Spain and then transferred to Florida, where a new greenhouse would be constructed and implemented for this purpose. 2) Overexpression of meristem-identity genes in Pineapple sweet orange to generate more compact and productive varieties. RNA interference-mediated downregulation of a gibberellin biosynthesis gene in Carrizo citrange to produce semidwarf/semidwarfing rootstocks. For the first objective, preparation of plant material for transformation was initiated about one year ago in Spain and this permitted us starting transformation experiments of the three sweet orange varieties 3 months ago. Both Hamlin and Valencia mature tissues are being highly responsive to organogenic regeneration. As we started to work with Valencia, the first GUS-positive mature Valencia transformants have been already generated and are growing in vitro. Due to space limitations, preparation of starting material of mature Carrizo citrange is a bit delayed. In Florida, we have provided to The University of Florida IFAS facilities all the specifications for the greenhouse and are in the planning stages. Moreover, we have to hire a manager for the mature transformation facility and allow this scientist to begin training in the Spanish laboratory. A job description has been written, a search committee selected, and the position is awaiting approval by University of Florida bureaucracy. We expect that this position will be filled by late summer. For the second objective, we have initiated experiments to ectopically over-express CsAP1 (AP1 from sweet orange) and CsFT (FT from sweet orange) in transgenic Pineapple sweet orange. The formalization of the master agreement between the IVIA and the Department of Citrus has suffered an unanticipated delay of several months mainly due to IVIA bureaucracy.
(863) 956-8817
(863) 956-5894
700 Experiment Station Road
Lake Alfred, FL 33850
Email Us
