My lab is interested in the interaction between grapevine (Vitis vinifera L.) and its powdery mildew pathogen Erysiphe necator Schwein. In addition to being an intriguing biological phenomenon, this parasitic interaction is of great economic importance. Although E. necator can be effectively controlled by a range of fungicides, these chemicals can harm the environment, pose risk to human health, and/or become ineffective by the pathogen's ability to develop fungicide resistance. Dependence on chemical-based disease control can be alleviated by the cultivation of grape varieties that are innately resistant to the pathogen. My lab is working toward this goal by studying the interaction between E. necator and V. vinifera in both a compatible and incompatible interaction.

Recently, my lab has begun studies on V. vinifera varieties that have partial but economically significant resistance to powdery mildew. These varieties, originally from Central Asia, offer resistance against the pathogen after it has successfully penetrated grapevine epidermal cells. This trait is controlled by the dominant gene REN1, a novel resistance gene that is located on chromosome 13 and that is different from R genes previously found in wild North American Vitis species. Current efforts, led by my colleagues at the University of Udine, are being made to fine-map the location of REN1 and to clone it from the grapevine genome. The microsatellite markers generated for REN1 mapping can also be used to introgress the locus into hybrid grapevines using marker-assisted selection. This breeding method will enable us to combine REN1 with several other resistance genes that direct different defense mechanisms to fend off the powdery mildew disease. This approach, referred to as gene pyramiding, leads to hybrid grapes with durable resistance against powdery mildew. REN1 is particularly valuable for breeding because it is from a V. vinifera genotype, and its introduction to cultivated grapes will not result in linkage drag of undesired non-vinifera characteristics.

To better understand grapevine's susceptibility to powdery mildew, my lab also studies powdery mildew induced changes at the level of the entire transcriptome in the V. vinifera cultivar Cabernet Sauvignon. Despite the susceptibility interaction, we detected a major defense-related restructuring of the transcriptome upon powdery mildew inoculation. These changes were associated with an increase in salicylic acid (SA) levels, suggesting that a SA-mediated signal transduction system was activated. To determine if other signal transduction pathways were also activated, we performed comparative microarray studies in both SA and powdery mildew treated grapevines. We found many genes that were up- or down-regulated in response to powdery mildew but not SA treatment. We are currently studying the promoter of one of the genes that encodes an NAC-type transcription factor.

• Center for Grapevine Biotechnology hunts for breakthroughs (Aug. 2009)
• A very special grape: MU researchers use Norton grape to understand innate immune systems of grapevines against fungal pathogens (2008)
• Fruit Experiment Station (parts 1-3) (2007)
• Wine researchers using biotechnology (2006)
• Researchers seek out mysteries of grapes (2005)

• Outstanding Thesis Advisor Award, Southwest Missouri State University, 2004
• Excellence in Research Award, Southwest Missouri State University, 2003

Ali MB, Howard S, Chen S, Wang Y, Yu O, Kovacs LG, Qiu W. Berry skin development in Norton grape: Distinct patterns of transcriptional regulation and flavonoid biosynthesis. BMC Plant Biology 2011;11: art. no. 7.

Marsh E, Alvarez S, Hicks LM, Barbazuk WB, Qiu W, Kovacs L, Schachtman D. Changes in protein abundance during powdery mildew infection of leaf tissues of Cabernet Sauvignon grapevine (Vitis vinifera L.). Proteomics 2010;10(10):2057-2064.

Katula-Debreceni D, Lencsas AK, Szoke A, Veres A, Hoffmann S, Kozma P, Kovacs LG, Heszky L, Kiss E. Marker-assisted selection for two dominant powdery mildew resistance genes introgressed into a hybrid grape population. Scientia Horticulturae 2009;126(4):448-453.

Olah R, Zok A, Pedryc A, Howard S, Kovacs LG. Somatic embryogenesis in a broad spectrum of grape genotypes. Scientia Horticulturae 2009;120(1):134-137.

Zhang J, Ma H, Chen S, Ji M, Perl A, Kovacs L. Stress response proteins' differential expression in embryogenic and non-embryogenic callus of Vitis vinifera L. cv. Cabernet Sauvignon-A proteomic approach. Plant Science 2009;177:103-113.

Olah R, Zok A, Pedryc A, Howard S, Kovacs LG. Somatic embryogenesis in a broad spectrum of grape genotypes. Scientia Horticulturae 2009;120:134-137.

Galbacs Z, Molnar S, Halasz G, Hoffmann S, Kiss E, Kozma P, Kovacs LG, Veres A, Galli Z, Szoke A, Heszky L. Identification of grapevine cultivars using microsatellite-based DNA barcodes. Vitis - Journal of Grapevine Research 2009;48:17-24.

Fekete C, Fung RWM, Szabo Z, Qiu W, Chang L, Schachtman DP, Kovacs LG. Up-regulated transcripts in a compatible powdery mildew-grapevine interaction. Plant Physiology and Biochemistry 2009;47:732-738.

Coleman C, Copetti D, Cipriani G, Hoffmann S, Kozma P, Kovacs LG, Morgante MM, Testolin R, Di Gaspero G. The powdery mildew resistance gene REN1 co-segregates with an NBS-LRR gene cluster in two Central Asian grapevines. BMC Genetics 2009;10:89.

Winterhagen P, Howard SF, Qiu W, Kovacs LG. Transcriptional up-regulation of grapevine MLO genes in response to powdery mildew infection. American Journal of Enology and Viticulture 2008;59:159-168.

Fung RWM, Gonzalo M, Fekete C, Kovacs LG, Marsh E, McIntyre L, Schachtman DP, Qiu W. Powdery mildew induces defense-oriented reprogramming of the transcriptome in a susceptible but not in a resistant grapevine. Plant Physiology 2008;146:236-249.

Fung RWM, Qiu W, Su Y, Schachtman DP, Huppert K, Fekete C, Kovacs LG. Gene expression variation in grapevine species Vitis vinifera L. and Vitis aestivalis Michx. Genetic Resources and Crop Evolution 2007;54:1541-1553.

Qiu W, Fekete S, Todd T, Kovacs L. Facilitation of microshoot tip propagation of Vitis aestivalis var. Norton by combined application of an antioxidant and cytokinins. American Journal of Enology and Viticulture 2004;55:112-114.

Kovacs LG, Byers PL, Kaps ML, Saenz J. Dormancy, cold hardiness, and spring frost hazard in Vitis amurensis hybrids under continental climatic conditions. American Journal of Enology and Viticulture 2003;54:8-14.

Kovacs LG, Du G, Ding P. Tissue moisture loss during sample preparation lowers exotherm temperatures in dormant grape buds. HortScience 2002;37:701-704.

Hou H, Fekete S, Kovacs LG. \New members of the stilbene synthase gene family from the Vitis aestivalis-derived grape cultivar Norton. American Journal of Enology and Viticulture 2002;53:289-293.

Kovacs LG, Hanami H, Fortenberry M, Kaps ML. Latent infection by leafroll agent GLRaV-3 is linked to lower fruit quality in French-American hybrid grapevines Vidal blanc and St. Vincent. American Journal of Enology and Viticulture 2001;52:254-259.

Kovacs LG, Balatti PA, Krishnan HB, Pueppke SG. Transcriptional organization and expression of nolXQBTUV, a locus that regulates cultivar-specific nodulation of soybean by Rhizobium fredii USDA257. Molecular Microbiology 1995;17:923-933.