Browsing by Author "Lovell, John T."

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    Biosynthesis and Emission of Stress-Induced Volatile Terpenes in Roots and Leaves of Switchgrass (Panicum virgatum L.)
    Muchlinski, Andrew; Chen, Xinlu; Lovell, John T.; Köllner, Tobias G.; Pelot, Kyle A.; Zerbe, Philipp; Ruggiero, Meredith; Callaway, LeMar, III; Laliberte, Suzanne; Chen, Feng; Tholl, Dorothea (2019-09-19)
    Switchgrass (Panicum virgatum L.), a perennial C4 grass, represents an important species in natural and anthropogenic grasslands of North America. Its resilience to abiotic and biotic stress has made switchgrass a preferred bioenergy crop. However, little is known about the mechanisms of resistance of switchgrass against pathogens and herbivores. Volatile compounds such as terpenes have important activities in plant direct and indirect defense. Here, we show that switchgrass leaves emit blends of monoterpenes and sesquiterpenes upon feeding by the generalist insect herbivore Spodoptera frugiperda (fall armyworm) and in a systemic response to the treatment of roots with defense hormones. Belowground application of methyl jasmonate also induced the release of volatile terpenes from roots. To correlate the emission of terpenes with the expression and activity of their corresponding biosynthetic genes, we identified a gene family of 44 monoterpene and sesquiterpene synthases (mono-and sesqui-TPSs) of the type-a, type-b, type-g, and type-e subfamilies, of which 32 TPSs were found to be functionally active in vitro. The TPS genes are distributed over the K and N subgenomes with clusters occurring on several chromosomes. Synteny analysis revealed syntenic networks for approximately 30-40% of the switchgrass TPS genes in the genomes of Panicum hallii, Setaria italica, and Sorghum bicolor, suggesting shared TPS ancestry in the common progenitor of these grass lineages. Eighteen switchgrass TPS genes were substantially induced upon insect and hormone treatment and the enzymatic products of nine of these genes correlated with compounds of the induced volatile blends. In accordance with the emission of volatiles, TPS gene expression was induced systemically in response to belowground treatment, whereas this response was not observed upon aboveground feeding of S. frugiperda. Our results demonstrate complex above and belowground responses of induced volatile terpene metabolism in switchgrass and provide a framework for more detailed investigations of the function of terpenes in stress resistance in this monocot crop.
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    JGI Plant Gene Atlas: an updateable transcriptome resource to improve functional gene descriptions across the plant kingdom
    Sreedasyam, Avinash; Plott, Christopher; Hossain, Md Shakhawat; Lovell, John T.; Grimwood, Jane; Jenkins, Jerry W.; Daum, Christopher; Barry, Kerrie; Carlson, Joseph; Shu, Shengqiang; Phillips, Jeremy; Amirebrahimi, Mojgan; Zane, Matthew; Wang, Mei; Goodstein, David; Haas, Fabian B.; Hiss, Manuel; Perroud, Pierre-Francois; Jawdy, Sara S.; Yang, Yongil; Hu, Rongbin; Johnson, Jenifer; Kropat, Janette; Gallaher, Sean D.; Lipzen, Anna; Shakirov, Eugene; Weng, Xiaoyu; Torres-Jerez, Ivone; Weers, Brock; Conde, Daniel; Pappas, Marilia R.; Liu, Lifeng; Muchlinski, Andrew; Jiang, Hui; Shyu, Christine; Huang, Pu; Sebastian, Jose; Laiben, Carol; Medlin, Alyssa; Carey, Sankalpi; Carrell, Alyssa A.; Chen, Jin-Gui; Perales, Mariano; Swaminathan, Kankshita; Allona, Isabel; Grattapaglia, Dario; Cooper, Elizabeth A.; Tholl, Dorothea; Vogel, John P.; Weston, David J.; Yang, Xiaohan; Brutnell, Thomas P.; Kellogg, Elizabeth A.; Baxter, Ivan; Udvardi, Michael; Tang, Yuhong; Mockler, Todd C.; Juenger, Thomas E.; Mullet, John; Rensing, Stefan A.; Tuskan, Gerald A.; Merchant, Sabeeha S.; Stacey, Gary; Schmutz, Jeremy (Oxford University Press, 2023-08-01)
    Gene functional descriptions offer a crucial line of evidence for candidate genes underlying trait variation. Conversely, plant responses to environmental cues represent important resources to decipher gene function and subsequently provide molecular targets for plant improvement through gene editing. However, biological roles of large proportions of genes across the plant phylogeny are poorly annotated. Here we describe the Joint Genome Institute (JGI) Plant Gene Atlas, an updateable data resource consisting of transcript abundance assays spanning 18 diverse species. To integrate across these diverse genotypes, we analyzed expression profiles, built gene clusters that exhibited tissue/condition specific expression, and tested for transcriptional response to environmental queues. We discovered extensive phylogenetically constrained and condition-specific expression profiles for genes without any previously documented functional annotation. Such conserved expression patterns and tightly co-expressed gene clusters let us assign expression derived additional biological information to 64 495 genes with otherwise unknown functions. The ever-expanding Gene Atlas resource is available at JGI Plant Gene Atlas (https://plantgeneatlas.jgi.doe.gov) and Phytozome (https://phytozome.jgi.doe.gov/), providing bulk access to data and user-specified queries of gene sets. Combined, these web interfaces let users access differentially expressed genes, track orthologs across the Gene Atlas plants, graphically represent co-expressed genes, and visualize gene ontology and pathway enrichments.