Colonial bentgrass transcripts-expression differences compared with creeping bentgrass in response to water-deficit stress

Authors: AMUNDSEN, KEENAN - University Of Nebraska; Warnke, Scott; Bushman, Shaun; Robbins, Matthew; Martin, Ruth; Harris-Shultz, Karen

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2020
Publication Date: 12/25/2020
Citation: Amundsen, K., Warnke, S.E., Bushman, B.S., Robbins, M.D., Martin, R.C., Harris-Shultz, K.R. 2020. Colonial bentgrass transcripts-expression differences compared with creeping bentgrass in response to water-deficit stress. 61(3):2135-2147. Crop Science. https://doi.org/10.1002/csc2.20437.
DOI: https://doi.org/10.1002/csc2.20437

Interpretive Summary: Natural stands of creeping bentgrass (Agrostis stolonifera) are often found in wetland areas and exhibit very poor tolerance to dry soils. Colonial bentgrass (A. capillaris) is frequently found in dryer habitats and has the ability to go dormant and recover quickly under water deficit stress. A better understanding of gene regulation under water deficit conditions of the two species could improve breeding strategies for water deficit tolerant bentgrasses. A team of scientist from ARS and the University of Nebraska compared water use rates in two creeping bentgrass clones with differing water use profiles and one colonial bentgrass clone. Water use rates were similar among all plants, with the creeping bentgrass exhibiting stress earlier and recovering more slowly than the colonial bentgrass. A comparison of the gene expression in these species revealed that the colonial bentgrass differentially expressed 975 genes in response to water deficit stress compared to an average 98 differentially expressed genes in creeping bentgrass. These unique changes in gene expression in colonial bentgrass compared to creeping bentgrass may explain why colonial bentgrass is more drought tolerant than creeping bentgrass.

Technical Abstract: Natural stands of creeping bentgrass (Agrostis stolonifera) are often found in wetland areas and exhibit very poor tolerance to dry soils. Colonial bentgrass (A. capillaris) is frequently found in dryer habitats and has the ability to go dormant and recover quickly under water deficit stress. Hybridization between creeping and colonial bentgrass is possible and a better understanding of gene regulation under water deficit conditions of the two species could improve breeding strategies for water deficit tolerant bentgrasses. A greenhouse dry-down study was conducted using two creeping bentgrass clones with differing water use profiles and one colonial bentgrass clone. The genotypes were exposed to water deficit stress and well-watered control genotypes were included. Gravimetric evapotranspiration (ET) was determined and control plants watered at 80% ET and deficit irrigation plants watered at 50% ET. Water use rates were similar among all plants with the creeping bentgrass genotypes exhibiting stress earlier and recovering more slowly than the colonial bentgrass. At the conclusion of the experiment RNA-seq analysis was conducted and there were 975 differentially expressed colonial bentgrass transcripts in response to water deficit stress compared to an average 98 differentially expressed creeping bentgrass transcripts. Among the colonial bentgrass up-regulated transcripts in response to water deficit stress were eight transcription factors previously shown to be involved in deficit water stress response, and several transposon-related transcripts. This study characterized several transcripts with unique expression changes in colonial bentgrass compared to creeping bentgrass, which may explain why colonial bentgrass is more drought tolerant than creeping bentgrass.