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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETIC ENHANCEMENT FOR RESISTANCE TO BIOTIC AND ABIOTIC STRESSES IN HARD WINTER WHEAT

Location: Hard Winter Wheat Genetics Research Unit

Title: Association of candidate genes with drought tolerance traits in diverse perennial ryegrass accessions

Authors
item Yu, X-Q -
item BAI, GUIHUA
item Liu, S-W -
item Luo, N -
item Wang, Y -
item Richmond, D -
item Pijut, Paula -
item Jackson, S -
item Yu, J-M -
item Jiang, Yw -

Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 9, 2013
Publication Date: February 6, 2013
Citation: Yu, X., Bai, G., Liu, S., Luo, N., Wang, Y., Richmond, D., Pijut, P.M., Jackson, S., Yu, J., Jiang, Y. 2013. Association of candidate genes with drought tolerance traits in diverse perennial ryegrass accessions. Journal of Experimental Botany. doi:10.1093/jxb/ert018.

Interpretive Summary: Drought is a major environmental stress limiting growth of perennial grasses in temperate regions. We conducted association mapping to identify putative candidate genes associated drought tolerance using 192 perennial ryegrass accessions from 43 countries. Significant variations in leaf wilting, leaf water content, canopy and air temperature, and chlorophyll fluorescence were identified under well-watered and drought conditions. The 192 accessions can be classified into five groups based on genome-wide DNA markers. Analysis of a set of selected candidate genes involved in antioxidant metabolism, dehydration, water-movement across membranes, and signal transduction identified 346 DNA marker differences across 192 accessions. Significant associations were identified between genes encoding late embryogenesis abundant protein and iron superoxide dismutase and leaf water content, and between cytosolic copper-zinc superoxide dismutase and chlorophyll fluorescence under drought conditions. These results indicate that genetic variation in these genes may affect whole-plant response to drought stress in perennial ryegrass.

Technical Abstract: Drought is a major environmental stress limiting growth of perennial grasses in temperate regions. Plant drought tolerance is a complex trait that is controlled by multiple genes. Candidate gene association mapping provides a powerful tool for dissection of complex traits. Candidate gene association mapping of drought tolerance traits was conducted in 192 diverse perennial ryegrass (Lolium perenne L.) accessions from 43 countries. The panel showed significant variations in leaf wilting, leaf water content, canopy and air temperature difference, and chlorophyll fluorescence under well-watered and drought conditions across six environments. Analysis of 109 simple sequence repeat markers revealed five population structures in the mapping panel. A total of 2520 expression-based sequence readings were obtained for a set of candidate genes involved in antioxidant metabolism, dehydration, water movement across membranes, and signal transduction, from which 346 single nucleotide polymorphisms were identified. Significant associations were identified between a putative LpLEA3 encoding late embryogenesis abundant group 3 protein and a putative LpFeSOD encoding iron superoxide dismutase and leaf water content, as well as between a putative LpCyt Cu-ZnSOD encoding cytosolic copper-zinc superoxide dismutase and chlorophyll fluorescence under drought conditions. Four of these identified significantly associated single nucleotide polymorphisms from these three genes were also translated to amino acid substitutions in different genotypes. These results indicate that allelic variation in these genes may affect whole-plant response to drought stress in perennial ryegrass.

Last Modified: 7/28/2014
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