The cis-Golgi Gene, Syntaxin 31, Induces the Expression of LESION SIMULATING DISEASE1 (LSD1) which Functions in Glycine max Defense to the Root Parasite Heterodera glycines

The membrane fusion genes alpha soluble NSF attachment protein (a-SNAP) and cis-Golgi syntaxin 31 (Gm-SYP38) contribute to Glycine max defense to the plant parasitic nematode Heterodera glycines. Accompanying their expression is the transcriptional activation of the defense genes ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) and NONEXPRESSOR OF PR1 (NPR1) that function in salicylic acid (SA) signaling. These results implicate the added involvement of the antiapoptotic gene LESION SIMULATING DISEASE1 (LSD1). Roots engineered to overexpress Gm-a-SNAP, SYP38, EDS1, NPR1, BOTRYTIS INDUCED KINASE1 (BIK1) and xyloglucan endotransglycosylase/hydrolase (XTH) in the susceptible genotype G. max_{[Williams 82/PI 518671]} have induced Gm-LSD1 (Gm-LSD1-2) transcriptional activity. In reciprocal experiments, roots engineered to overexpress Gm-LSD1-2 in the susceptible genotype G. max_{[Williams 82/PI 518671]} have induced levels of SYP38, EDS1, NPR1, BIK1 and XTH, but not a-SNAP prior to infection. In tests examining the role of Gm-LSD1-2 in defense, its overexpression results in reduced nematode parasitism. In contrast, RNA interference (RNAi) of Gm-LSD1-2 in the resistant genotype G. max_{[Peking/PI 548402]} results in an 3.24-10.42 fold increase in parasitism. The results identify that Gm-LSD1-2 functions in the defense response. It is proposed that LSD1, as an antiapoptotic protein, may establish an environment whereby the protected, living plant cell could secrete materials in the vicinity of the parasitizing nematode to disarm it. After the targeted incapacitation of the nematode the parasitized cell succumbs to its targeted demise as the infected root region is becoming fortified.