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‘Aiea, Hawaii, United States

Tew T.L.,U.S. Department of Agriculture | Wu K.K.,Retired | Schnell R.J.,U.S. Department of Agriculture | Nagai C.,Hawaii Agricultural Research Center | And 4 more authors.
Sugar Tech | Year: 2010

Sugarcane (Saccharum hybrid spp.) breeders at the Hawaiian Sugar Planters' Association used biparental and melting pot (modified polycross) crossing methods concurrently from 1935 to 1985. While the annual effort expended to make biparental crosses exceeded the effort to make melting pot crosses over this 50-year period, annual viable seed yield from biparental crosses was usually less than 15% of that from melting pot crosses and hence, the numbers of seedlings planted to the field from those crosses usually accounted for less than 20% of the total seedling population. In 1985, nine of the 10 sugarcane cultivars listed in Hawaii's variety census originated from melting pot crosses; only one originated from a biparental cross. In the face of a shrinking sugar industry in Hawaii and a smaller work force in the breeding program, the decision was made in 1985 to rely primarily on melting pot crosses for the production of commercial cultivars. From 1985 to 2005, twelve additional clones that were bred prior to 1985 eventually attained "commercial cultivar" status by exceeding 1% of the total cane growing area. All twelve originated from melting pot crosses. Over the 50-year period that the two crossing methods were used, the melting pot method proved to be more labour efficient and ultimately contributed more than the biparental crossing procedure toward the development of new commercial cultivars for the Hawaiian sugar industry. From 1985 forward, the biparental crossing method was used more for introgressing desired traits from exotic germplasm than for the development of commercial cultivars. © 2010 Society for Sugar Research & Promotion.

Carlos-Hilario L.,University of Hawaii at Manoa | Porter B.W.,University of Hawaii at Manoa | Zhu Y.J.,Hawaii Agricultural Research Center | Christopher D.A.,University of Hawaii at Manoa
Tropical Plant Biology | Year: 2014

Promoters are essential upstream genetic switches that activate and repress gene expression. Promoter characterization is a key prerequisite before using in downstream biotechnology applications. The model system, Arabidopsis thaliana, was utilized here to efficiently hasten the time to verify and characterize the functionality and strength of promoters from the more complex tropical tree, Carica papaya. Four putative promoter regions and their 5’UTRs were isolated from the genes encoding peroxidase (Cp9), β-1,3-glucanase (Cp29), ferulate-5-hydroxylase (Cp35) and hypersensitive-induced response protein (Cp45) and fused to eGFP. In silico analysis predicted the presence of several cis-elements associated with regulatory functions in stress and defense responses. The Arabidopsis transcriptional machinery readily recognized the promoters, as determined by qualitative and quantitative measurements of eGFP expression (fluorescence, mRNA and protein levels). The eGFP was expressed in a variety of tissues of the transgenic plants (vasculature, shoot apex, cotyledon, cotyledon petioles, hypocotyls, and root). The Cp29 and Cp45 promoters showed the highest and most promising overall expression. Comparison of eGFP mRNA and protein levels indicated post-transcriptional regulation. Identifying the precise transcription start sites (TSSs) demonstrated transcription fidelity and mapped the length of the 5′-UTR. Predicted mRNA 5′-UTR secondary structures potentially affected the translational efficiency of the mRNAs during development, most notably for Cp9 and Cp35. This work demonstrates the utility of using Arabidopsis to quickly evaluate and identify useful promoters (Cp29, Cp45) from complex tropical plants for future biotechnology goals, and to analyze 5′UTR regulation, cis-elements, and trans-acting factors. © 2014, Springer Science+Business Media New York.

Dey K.K.,University of Hawaii at Manoa | Borth W.B.,University of Hawaii at Manoa | Melzer M.J.,University of Hawaii at Manoa | Wang M.-L.,Hawaii Agricultural Research Center | Hu J.S.,University of Hawaii at Manoa
Viruses | Year: 2015

Higher plants use RNA silencing to defend against viral infections. As a counter defense, plant viruses have evolved proteins that suppress RNA silencing. Mealybug wilt of pineapple (MWP), an important disease of pineapple, has been associated with at least three distinct viruses, Pineapple mealybug wilt associated virus -1, -2, and -3 (PMWaV-1, -2, and -3). Selected open reading frames (ORFs) of PMWaV-1 and PMWaV-2 were screened for their local and systemic suppressor activities in Agrobacterium-mediated transient assays using green fluorescent protein (GFP) in Nicotiana benthamiana. Results indicate that PMWaV-2 utilizes a multiple-component RNA silencing suppression mechanism. Two proteins, p20 and CP, target both local and systemic silencing in N. benthamiana, while the p22 and CPd proteins target only systemic silencing. In the related virus PMWaV-1, we found that only one of the encoded proteins, p61, had only systemic suppressor activity. Of all the proteins tested from both viruses, only the PMWaV-2 p20 protein suppressed local silencing induced by double-stranded RNA (dsRNA), but only when low levels of inducing dsRNA were used. None of the proteins analyzed could interfere with the short distance spread of silencing. We examined the mechanism of systemic suppression activity by investigating the effect of PMWaV-2-encoded p20 and CP proteins on secondary siRNAs. Our results suggest that the PMWaV-2 p20 and CP proteins block the systemic silencing signal by repressingproduction of secondary siRNAs. We also demonstrate that the PMWaV-2 p20 and p22 proteins enhanced the pathogenicity of Potato virus X in N. benthamiana. © 2015 by the authors; licensee MDPI, Basel, Switzerland.

Burbano E.G.,University of Hawaii at Manoa | Wright M.G.,University of Hawaii at Manoa | Gillette N.E.,U.S. Department of Agriculture | Mori S.,U.S. Department of Agriculture | And 3 more authors.
Environmental Entomology | Year: 2012

The black twig borer, Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae), is a pest of coffee and many endemic Hawaiian plants. Traps baited with chemical attractants commonly are used to capture ambrosia beetles for purposes of monitoring, studying population dynamics, predicting outbreaks, and mass trapping to reduce damage. The objectives of this research were to optimize trapping systems for X. compactus and other ambrosia beetles such as Xylosandrus crassiusculus (Motschulsky) and Xyleborinus saxesenii (Ratzeburg) by comparing efficacy of several attractants, repellents, and trap types. The ability of certain chemicals to act as beetle repellents and thus interfere with trap catch was tested for purposes of protecting host plants from attack. Potential attractants and application methods tested were as follows: ethyl alcohol pouch delivery system, ethyl alcohol vial delivery system, α-pinene in Eppendorf tubes, eugenol bubblecaps, ginger oil bubblecaps, manuka oil bubblecaps, phoebe oil bubblecaps, and an unbaited control. Potential repellents tested were limonene and verbenone. Ethyl alcohol vials were as attractive as ethyl alcohol sleeves, and were more effective than traps baited with eugenol and α-pinene. Japanese beetle traps were more effective for black twig borer trapping than Lindgren funnel traps, and were easier to deploy. Verbenone and limonene significantly reduced trap catch of Xylosandrus compactus and X. crassiusculus, suggesting that they may be effective for reducing attraction to host plants. These results show the importance of developing a combination of several monitoring techniques to enhance management procedures for the black twig borer. © 2012 Entomological Society of America.

Suzuki J.Y.,U.S. Department of Agriculture | Tripathi S.,U.S. Department of Agriculture | Tripathi S.,University of Hawaii at Manoa | Fermin G.A.,University of Los Andes, Venezuela | And 18 more authors.
Acta Horticulturae | Year: 2010

Transformation plasmid-derived insert number and insert site sequence in 55-1 line papaya derivatives Rainbow and SunUp was determined as part of a larger petition to allow its import into Japan (Suzuki et al., 2007, 2008). Three insertions were detected by Southern analysis and their corresponding sequences determined by clones (Fermín, 2002) or via the whole genome shotgun (WGS) sequence database of SunUp (Ming et al., 2008). All functional transgenes including the coat protein (CP) gene that confers resistance to PRSV, and visible and selectable marker genes, uidA encoding glucuronidase (GUS) and nptII encoding neomycin phosphotransferase II were found in a single 9,789 basepair (bp) insert referred to as the functional transgene. The two other insertion sites consisted of a 290 bp nonfunctional sequence of the nptII gene and a 1,533 bp plasmid-derived fragment containing a nonfunctional 222 bp segment of the tetA gene. Detection of the same three inserts in Rainbow and in samples of SunUp representing transgenic generations five to eight (R5 to R8) suggests that the inserts are stable. Five out of the six genomic DNA segments flanking the three inserts were nuclear plastid sequences (nupts). No changes to endogenous gene function based on sequence structure of the transformation plasmid DNA insertion sites could be determined and no allergenic or toxic proteins were predicted from analysis of the insertion site and flanking genomic DNA. These results should support a positive review of the petition to allow the import and consumption of Rainbow and its derivatives in Japan, which is currently in its final stages. Export of Rainbow papaya to Japan will greatly benefit the local papaya industry in Hawaii and will provide a case for testing consumer acceptance of genetically engineered fresh products in Japan.

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