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Title: Beta vulgaris root genes and their potential role in insect resistance: functional genomics analysis of a serine proteinase inhibitor gene

Author
item Smigocki, Anna
item IVIC-HAYMES, SNEZANA - TOWSON UNIV TOWSON MD
item PUTHOFF, DAVID - MPPL
item ZUZGA, SABINA - WARSAW POLAND

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Abstract Only
Publication Acceptance Date: 5/9/2007
Publication Date: 7/21/2007
Citation: Smigocki, A.C., Ivic-Haymes, S., Puthoff, D.P., Zuzga, S. 2007. Beta vulgaris root genes and their potential role in insect resistance: functional genomics analysis of a serine proteinase inhibitor gene. Proceedings Molecular Plant-Microbe Interactions, Sorrento, Italy, p. 247.

Interpretive Summary:

Technical Abstract: To gain knowledge of root defense response mechanisms, an area of plant defense research that lacks much information, more than 150 sugar beet (Beta vulgaris L.) root ESTs responding to infestations by the sugar beet root maggot (SBRM, Tetanops myopaeformis von Röder) were identified using suppressive subtractive hybridization enrichment. The largest number of identified ESTs from both a susceptible (F1010) and moderately resistant (F1016) genotype grouped into the defense and stress response classes. Additional functional categories of the cloned genes included those involved in secondary metabolism and signal transduction. Using macroarrays, gene expression profiles of cloned F1016 genes indicated that the greatest number were regulated by methyl jasmonate and salicylic acid suggesting these signaling pathways may be involved in sugar beet root defense responses to SBRM. A gene of particular interest that encodes a serine (trypsin) protease inhibitor (BvSTI) was identified. Given serine proteases comprise the major digestive enzymes in root maggot midguts, this finding suggests that BvSTI may be involved in the resistance mechanism of F1016. BvSTI was fused to the CaMV 35S promoter for expression in sugar beet hairy roots to elucidate its functional role(s) in resistance and root biology. About a two- to four-fold increase in trypsin inhibitory activity was observed in the hairy roots transformed with the BvSTI construct. Insect feeding assays are currently in progress to examine the effects of the inhibitor on insect mortality and growth rates. Further characterization of the identified root ESTs will provide new knowledge in the field of plant defense. Additionally, more broadly applicable control strategies for the management of the sugar beet root maggot and other insect pests will be developed using this information.