BETA VULGARIS ROOT ESTS MODULATED BY SUGAR BEET ROOT MAGGOT FEEDING AND THEIR REGULATION BY WOUNDING AND DEFENSE SIGNALING MOLECULES

Authors: Puthoff, David; Smigocki, Anna

Submitted to: Planta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2006
Publication Date: 1/1/2006
Citation: Puthoff, D.P., Smigocki, A.C. 2006. Beta vulgaris root ests modulated by sugar beet root maggot feeding and their regulation by wounding and defense signaling molecules. Plant Cell Rep., online first (DOI 10.1007/s00299-006- 0201-y).

Interpretive Summary: Disease and pest problems are responsible for decreases in yield of sugar from sugar beet. The sugar beet root maggot is one of the most devastating insect pests of sugar beet. It is found in two-thirds of all U. S. sugar beet fields and accounts for 10-100% reduction in yields. Crop production practices and chemical insecticides are presently used to control the root maggot. These controls, however, are often either ineffective or in the case of insecticides, harmful to the environment. Therefore, a strong impetus exists for development of effective and environmentally friendly control measures. We identified sugar beet traits (genes) that are associated with root responses to root maggot feeding in both susceptible and moderately resistant sugar beet varieties. Information on the root responses will increase our knowledge of plant-insect interactions. Scientists will use this information to identify plant resistance mechanisms that will lead to new approaches for increasing root maggot resistance in economically important sugar beet varieties without the use of harmful pesticides.

Technical Abstract: Plant root responses to insect pests have been an area of plant defense lacking much information. Sugar beet root maggot, Tetanops myopaeformis von Röder, is the most important insect pest on sugar beet (Beta vulgaris) in the US and Canada. We have identified more than 150 sugar beet root ESTs responding to 24 and 48 hr infestations by the root maggot from both susceptible, F1010, and moderately resistant, F1016, sugar beet genotypes using suppressive subtractive hybridization. Identified genes break down into many functional categories including defense, stress response, secondary metabolism, signal transduction and senescence-related. The largest number of identified ESTs from both the susceptible and moderately resistant sugar beet genotypes grouped into the defense and stress response class. Using macroarrays, gene expression profiles from F1016 sugar beet roots were obtained following infestation by first-instars, mechanical wounding and treatment of roots with the signaling molecules methyl jasmonate, salicylic acid and ethylene. Of the examined root ESTs, 39% were regulated by methyl jasmonate suggesting this signaling pathway may be involved in regulating sugar beet root responses to the sugar beet root maggot. Identification of these sugar beet root ESTs provides knowledge in the field of plant root defense responses and will lead to the development of novel control strategies for control of the sugar beet root maggot.