1a. Objectives (from AD-416):
The long-term objectives of this project are the following: 1) Develop improved varieties of pea, chickpea, and lentil that have enhanced resistance to diseases and abiotic stresses along with improved nutritional and processing traits; 2) Characterize the genetic basis for agronomically important traits in pea, lentil and chickpea; 3) Identify and characterize the genetic domains in pathogens of these crops that are responsible for disease, and 4) Develop improved methods for detecting pathogens and screening for disease resistance.
1b. Approach (from AD-416):
Identify and select improved germplasm and cultivars for pea, lentil, and chickpea through systematic evaluation under biotic and abiotic stress conditions to identify tolerant or resistant types for release to stakeholders.Identify genetic factors through classical breeding methods contributing to cold tolerance and winter hardiness in pea and lentil germplasm. Saturate genetic maps for the genomic regions that control Ascochyta blight resistance (ABR) in chickpea for fine mapping and identification of molecular markers for selection. Saturate genetic maps to identify markers linked to a broad range of agronomically important traits in pea, lentil, and chickpea. Increase mechanistic understanding of host-pathogen interactions to improve breeding and selection strategies for disease resistance in pea, lentil, and chickpea by challenging plants with respective pathogens and studying disease responses and pathogen biology.
3. Progress Report:
In 2011, 19 café kabuli chickpea breeding lines and six check varieties were tested at three locations in Washington and Idaho. A total of 61 advanced lentil breeding lines and 14 check varieties were planted in 2011 at four locations in Washington and Idaho. A total of 33 pea breeding lines (22 green and 11 yellow) and eight check varieties were evaluated at four locations in WA and ID in 2011. Advanced breeding lines that exhibit consistently high yield and seed quality were also evaluated in trials conducted at six locations in Washington and Idaho. Breeding lines were also evaluated for reaction to several diseases under greenhouse and field conditions. Peas and lentils were evaluated in the field for reaction to Aphanomyces root rot at two locations in Washington and Idaho. Chickpeas were evaluated for reaction to Ascochyta blight in the field in Washington. Several pea varieties and breeding lines, along with other wild relatives of pea, were screened in the greenhouse for resistance to white mold disease caused by Sclerotinia sclerotiorum, and several tolerant lines were identified. All advanced pea, lentil, and chickpea breeding lines were evaluated during 2012 for seed concentrations of 14 different minerals from plots harvested at three locations in Washington and Idaho. High yielding lines of pea, lentil, and chickpea were identified that have elevated concentrations of specific seed minerals. Laboratory research efforts have focused on developing and optimizing DNA markers for detecting genetic differences between chickpea lines. We also developed several tools for helping to improve the accuracy of experiments that study gene expression in peas and lentils. Molecular probes were developed for studying a group of nearly 40 genes that are thought to be involved in resistance in pea to Aphanomyces root rot. We studied changes in the expression (production of RNA from a DNA sequence) of 15 genes in pea lines inoculated with Aphanomyces and identified several genes that are expressed at higher levels in resistant plants.
1. New tools for studying gene expression in pea and lentil. The ability to precisely detect differences in gene expression between plants requires the use of “reference” genes, which should be stably expressed across different lines and treatments, and serve to normalize data for other genes. ARS scientists in Pullman, Washington identified five different genes in pea and lentil that can be used as reference genes. The reference genes (TIF, 18S rRNA, actin, B-tubulin 2 and B-tubulin 3) were used to normalize data from pea seedlings that were inoculated with the root rot pathogen Aphanomyces euteiches. Several genes, including callose synthase and B-1-3 glucanase, were identified that were expressed at higher levels in tolerant peas, suggesting these genes have a role in defense against disease. PCR primers and protocols developed during this study are useful tools for amplifying reference genes that can be applied to gene expression studies across a broad range of plant materials and growing conditions.
Fortuna, A., Honeycutt, C.W., Vandemark, G.J., Griffin, T.S., Larkin, R.P., He, Z., Wienhold, B.J., Sistani, K.R., Albrecht, S.L., Woodbury, B.L., Torbert III, H.A., Powell, J.M., Hubbard, R.K., Eigenberg, R.A., Wright, R.J., Allredge, R.J. 2012. Links among nitrification, nitrifier communities and edaphic properties in contrasting soils receiving dairy slurry. Journal of Environmental Quality. 41:262-272.