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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Plant Genetic Resources and Disease Research » Research » Research Project #434947

Research Project: Genetic Improvement and Sustainable Production Systems for Sub-tropical and Tropical Crops in the Pacific Basin

Location: Tropical Plant Genetic Resources and Disease Research

2018 Annual Report

Objective 1: Develop papayas with superior disease resistance and value added traits. Subobjective 1A: Generate papaya lines with wide-spectrum resistance to papaya ringspot virus. Subobjective 1B: Breed new papaya cultivars with superior disease resistance, quality, flavor, and value added products. Objective 2: Devise integrated horticultural management practices and enhanced germplasm to improve plant health, yield, quality, and product value of coffee. Subobjective 2A: Evaluate coffee rootstocks to identify genotypes with resistance or tolerance to root-knot nematodes under field conditions. Subobjective 2B: Evaluate horticultural practices to identify those that yield optimal vegetative growth, flowering, fruiting, and quality of coffee. Subobjective 2C: Combine the preceding knowledge into an integrated package of genetic and horticultural management solutions to optimize coffee production in Hawai'i. Objective 3: Genetic improvement of disease and pest resistances and ornamental traits in anthuriums. Subobjective 3A: Identify and assess the efficacy of selected transgenes for controlling burrowing nematode, Radopholus similus in anthurium. Subobjective 3B: Identify metabolic pathways and molecular components governing novel flower color traits in anthurium. Subobjective 3C: Generate and assess anthurium plants with transgenes for enhanced resistance to plant-parasitic nematodes and bacterial diseases, and novel flower colors.

Objective 1: Focus on improving for disease resistance and improved appearance of papaya through both molecular and conventional breeding. Subobjective 1A: Utilize Clustered Regularly Short Palindromic Repeats (CRISPR)/Cas9 or alternatively Cas9/ subgenomic RNA (sgRNA) directed mutation of an endogenous papaya gene eIF4E or eIF(iso)4E gene to confer broad viral resistance resulting in commercial papaya cultivars with wide-spectrum resistance to papaya ringspot virus (PRSV) and related viruses using a combination of transformation and crossing. Subobjective 1B: Develop commercially acceptable papaya cultivars with PRSV resistance, blemish free skin, and improved flavor using conventional breeding and selection. Objective 2: Develop coffee management practices to facilitate coffee harvest and improve resistance to pests such as nematodes and CBB. Subobjective 2A: Use grafting techniques to test if yields of Arabica coffee will be higher when grafted on Coffea canephora 'Nemaya' rootstock in nematode (Meloidogyne konaensis) infested fields when compared to un-grafted trees. Subobjective 2B: Focus on a combination of pruning, fertilization, and applications of plant growth regulators to synchronize coffee flowering and subsequent fruit development to concentrate harvests and reduce the amount of immature berries at the end of the growing season. Subobjective 2C: Use the on farm site surveys to evaluate commercial strain of Beauveria bassiana GHA to help to mitigate damage caused by the coffee berry borer in commercial coffee farms. Objective 3: Utilize transient expression and functional analysis of genes to identify key effectors of nematode resistance and pigment production and use transformation to generate bacterial and nematode resistant anthurium varieties. Subobjective 3A: Use transient expression of genes involved with nematode resistance to identify potential transcripts for control of the burrowing nematode, Radopholus similis, and improve transformation efficiency for anthuriums. Subobjective 3B: Use molecular techniques for functional analysis of regulatory genes or biosynthetic genes for pigment pathways and identification of organ-specific promoters to prove that genes identified by sequence homology will function in anthurium color pathways similar to those reported in model systems. Subobjective 3C: Use molecular transformation to generate and assess anthurium plants with transgenes for resistance to plant-parasitic nematodes and bacterial diseases.

Progress Report
This project began in March 2018 and continues the research of 2040-2100-015-00D, "Molecular Resources for the Improvement of Tropical Ornamental and Fruit Crops". For additional information, see report for the previous project. Objective 1: Scientists continue to breed for improved papaya with a blemish-free appearance and papaya ringspot virus resistance. In addition, plantings of papaya to incorporate Phytophthora tolerance into the existing hybrids have been established. Objective 2: Propagation and evaluation of coffee rootstock resistant to root knot nematodes have been initiated. Ongoing efforts continue to monitor and implement horticultural practices such as pruning with applications of Beauveria bassiana to optimize coffee production in Hawaii. Objective 3: Construction of an expression library of Radopholus similis has been initiated. Collection of Xanthomonas axonopodis pv. dieffenbachiae isolates causing bacterial blight at cooperator farms commenced. Anthurium plants continue to be transformed for bacterial resistance and multiplied for further testing and will commence for floral color modifications.


Review Publications
Wraight, S.P., Galaini-Wraight, S., Howes, R.L., Castrillo, L.A., Carruthers, R.I., Smith, R.H., Matsumoto Brower, T.K., Keith, L.M. 2018. Prevalence of naturally-occurring strains of Beauveria bassiana in populations of coffee berry borer Hypothenemus hampei on Hawaii Island, with observations on coffee plant-H. hampei-B. bassiana interactions. Journal of Invertebrate Pathology.