Location: Soybean and Nitrogen Fixation ResearchTitle: An RNA-Seq study reveals genetic responses of diverse wild soybean accessions to increased ozone levels
|WALDECK, NATHAN - North Carolina State University|
|DICKEY, DAVID - North Carolina State University|
Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2017
Publication Date: 6/29/2017
Citation: Waldeck, N., Taliercio, E.W., Burkey, K.O., Carter Jr, T.E., Song, Q., Dickey, D. 2017. An RNA-Seq study reveals genetic responses of diverse wild soybean accessions to increased ozone levels. BMC Genomics. 18:498.
Interpretive Summary: Ozone is an air pollutant known to damage soybean productivity and ozone levels are increasing. Current ozone levels are thought to reduce soybean yields and rising ozone is expected to further impair crop productivity. To deal with this threat to soybean production, 66 wild soybean accessions have been screened for ozone tolerance and several have been identified that are tolerant of elevated ozone. A genetic marker was identified that is associated with ozone resistance in wild soybean. Analyses of gene expression data has shown that one target of ozone is the photosynthetic apparatus. The photosynthetic apparatus of one accession appears to be protected from ozone. Experiments are underway to transfer this trait into domesticated soybean to determine if this trait improves yield in the face of increasing ozone levels.
Technical Abstract: Ozone is a pollutant widely known to cause decrease in productivity in many plant species, including soybean. While cultivated soybean response to ozone has been studied, less work has been done to identify sources of resistance from wild relatives. This study presents a putative SNP marker on Chromosome 19 associated with response to elevated ozone in a genetically diverse group of 66 wild soybean (Glycine soja Zucc. and Sieb.) accessions subjected to ozone stress under growth chamber conditions and also uses RNA-Seq to identify changes in gene expression following exposure to ozone in selected pairs of sensitive and resistant wild soybean accessions. Results indicated many more genes responded to elevated ozone in the two selected accessions displaying an ozone-sensitive phenotype with many of the same genes responding. Fewer genes responded in the two selected resistant accessions and the responses were less correlated, indicating two possible different resistant response mechanisms to ozone exposure. Defense response genes were up regulated in both sensitive wild soybean accessions and down regulated in resistant accessions. A depletion of expression of genes involved in photosynthetic activity was observed for both sensitive accessions as well as for one resistant accession. Resistant accession PI 507656 did not show a significant decrease in expression of genes connected to photosynthetic activity. Fewer genes responded to ozone in resistant accessions. Ozone response was also evaluated for three leaf positions on each of the selected accessions, and unique responses to ozone were noted. Older leaf tissue displayed a consistent depletion of genes involved in photosynthesis, while younger leaf tissue had a pattern of more defense genes responding. Leaf tissues examined responded by altering oxidoreductase transcription regardless of ozone sensitivity. This study demonstrates the importance of examining wild soybean for ozone response and identifies a potential marker related to ozone response in the soybean gene pool.