Poster: Plant Insect/Nematode Interactions

Abs # 679: C6 volatile-induction of defense genes and metabolites in maize seedlings

Presenter:	Farag, Mohamed A, mfarag73@yahoo.com
Authors	Farag, Mohamed A (A)   Pare, Paul W (B)
Affiliations:	(A): Texas Tech University, department of chemistry and biochemistry

In response to insect feeding, corn seedlings (Zea mays cv. Delprim) release elevated levels of volatile organic compounds (VOCs) including the C6 volatile (Z)-3-hexenol. With the exogenous application of (Z)-3-hexenol (0.5 and 0.05 mM) to undamaged seedlings, the level of mRNA accumulation for a series of defense genes was monitored by reverse transcriptase-mediated PCR. The induction of transcripts for Pal, Lox, Igl (indole-3-glycerol phosphate lyase) and Mpi (maize proteinase inhibitor) were compared with metabolites generated from the respective pathways. While head space VOC analysis showed an increase in (Z)-3-hexenyl acetate and methyl salicylate with Lox and Pal induction respectively, indole accumulation was not observed with an increase in Igl transcripts. Select transcripts and final products that accumulated in maize with C6-alcohol treatment were compared with corresponding responses activated by insect damage and methyl jasmonate exposure. (Z)-3-hexenol doses applied to the plant were comparable to amounts detected from maize seedlings with severe insect damage. These data indicate that (Z)-3-hexenol can serve as a signal molecule triggering plant defense responses.