Submitted to: Plant Physiology and Biochemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/29/2009
Publication Date: 10/27/2009
Citation: Williams, C.E., Saltzmann, K.D., Giovanini, M., Ohm, H. 2009. Transcript Profiles of Two Wheat Lipid Transfer Protein-encoding Genes are Altered During Attach by Hessian Fly Larvae. Plant Physiology and Biochemistry. 48:54-61. Interpretive Summary: Little is known about genes that play a role in plant resistance and susceptibility to insects. Two lipid transfer protein genes are silenced when virulent Hessian fly larvae attack susceptible wheat plants. These same genes are slightly stimulated during a resistance response. These genes appear to help maintain integrity of wheat cells and prevent larvae from obtaining nutrients. These results are important because these genes may be good candidates for transgenic approaches to strengthen plant cells during insect attack.
Technical Abstract: ‘GeneCalling’, an mRNA profiling technology, was used to identify a candidate lipid transfer protein (LTP) sequence that showed decreased mRNA abundance in wheat (Triticum aestivum L. em Thell) plants following attack by virulent Hessian fly (Mayetiola destructor Say) larvae (compatible interaction). Hfr-LTP (Hessian fly responsive lipid transfer protein), a near full-length cDNA corresponding to this putative LTP sequence, was cloned and is a proposed new member of the gene family encoding type 1 lipid transfer proteins. Following feeding by virulent Hessian fly larvae, Hfr-LTP mRNA levels were down-regulated as much as 196-fold below uninfested controls in susceptible wheat plants (compatible interaction) and suppression of Hfr-LTP was influenced by the number of larvae attacking a plant. Hfr-LTP transcript levels were not affected by other biotic factors (feeding by bird cherry-oat aphid, Rhopalosiphum padi L., and fall armyworm larvae, Spodoptera frugiperda Smith) or abiotic factors tested (mechanical wounding and treatment with abscisic acid, methyl jasmonate, or salicylic acid). Utilizing the same plant tissue used to measure Hfr-LTP transcript levels, expression of a previously described Hessian fly-responsive LTP, TaLTP3 (Triticum aestivum lipid transfer protein 3) was examined and showed that TaLTP3 transcripts increased early in the incompatible interaction (resistant plants) and decreased at later time points in the compatible interaction (susceptible plants). Similar to Hfr-LTP, TaLTP3 transcript levels were influenced by the number of Hessian fly larvae infesting a plant. The biological role of LTPs in plants is not well understood and possible functions of proteins encoded by Hfr-LTP are discussed.