Analysis of the Glycine max role of Syntaxin (SYP22) in resistance to Rotylenchulus reniformis

Syntaxin proteins are involved in the process of membrane fusion. G. max syntaxin genes (Gm-SYP22-3, and GmSYP22-4) that were similar in amino acid composition have been found to contribute to the ability of Glycine max to defend itselffrom infection by the plant- parasitic nematode Rotylenchulus reniformis. The Gm-SYP22-3and Gm-SYP22-4 genes were expressed in root cells (syncytia) undergoing a resistant reaction while not being expressed in control cells. The Gm-SYP22-3 and Gm-SYP22-4 genes have been isolated from genetically engineered in G. max [Williams 82/PI518671], a genotype typically susceptible to R. reniformis parasitism. Genetically engineered plants in G. max [Williams 82/PI 518671] that lack the overexpression of Gm-SYP22-3 or Gm-SYP22-4 genes have also been produced to serve as a control. The transgenic Gm-SYP22-3 or Gm-SYP22-4 overexpression lines with their pRAP15 control have then been infected with R. reniformis. Infection was allowed to proceed for 30 days. At the end of the 30-day life span, R. reniformisstages were extracted from the soil and eggs from the roots, enumerated and compared to control plants. Plants overexpressing Gm-SYP22-3 or Gm-SYP22-4 had suppressed R. reniformis. In contrast, the gene expression levels of Gm-SYP22-3 and Gm-SYP22-4 were reduced in transgenic lines engineered for their RNA interference (RNAi) in G. max [Peking/PI 548402], a genotype normally resistant to R. reniformis. In comparison to genetically engineered control G. max [Peking/PI 548402] lines, RNAi of Gm-SYP22-3 or Gm-SYP22-4 resulted in an increase in parasitism in the normally R. reniformis resistant G. max [Peking/PI 548402].

Soybean Resistance to Field Populations of Heterodera glycines in Selected Geographic Areas

Data were collected 2006 through 2008 from 527 soil samples to determine the current effectiveness of PI 88788 and other sources of Heterodera glycines resistance in three geographically separated areas of soybean production: Tennessee and Indiana/Illinois, USA, and Ontario, Canada. In Tennessee where PI 88788 source of resistance has been used since 1978, 93% of field populations reproduced on PI 88788 (≥10% of susceptible cultivar), and no HG Type 0 populations were found. In Indiana and Illinois, where resistance was used since the mid-1980s, from 56 to 88% of the populations reproduced on PI 88788 (≥10%). PI 548402 (Peking), PI 90763, and PI 437654 had low reproduction (≤10%) unlike Tennessee where 78% of the populations reproduced on PI 548402 (≥10%) and 93% reproduced on PI 90763 (≥10%). In Ontario, where cultivars with PI 88788 resistance were used after 1989, PI 88788 in 73% of the field populations had ≤10% reproduction. But 15% of Ontario populations reproduced on PI 548402 (≥10%) and 6% reproduced on PI 90763 (≥10%), two sources of resistance not generally present in commercial cultivars grown in Ontario. Accepted for publication 9 March 2010. Published 26 April 2010.