1a.Objectives (from AD-416):
Ethylene is an essential hormonal signal for soybean leaf and flower abscission and nematode infection of roots. In addition, other hormones, e.g., auxin, and peptide signals, e.g., IDA, modulate the plants response to ethylene. Gene expression and proteins involved in developmental mechanisms associated with abscission and nematode colonization of roots will be identified and characterized. The goal is to better understand shared signaling paths in soybean in order to genetically engineer soybean with higher productivity and improved resistance to nematode infection.
1b.Approach (from AD-416):
Several experimental approaches including RNA sequencing and proteomics will be used to identify genes and proteins linked to abscission and nematode infection. Their functional role in these processes will be determined by over-expression and suppression of selected genes in transgenic plants. Transformation protocols include viral induced gene silencing (VIGS), transformation and regeneration of mature plants, and hairy root transformation of axenic roots maintained on culture media.
We obtained seeds of Arabidopsis (a model plant) that possess mutated genes for the signaling proteins IDA, HAESA, and HAESA-LIKE2. We also obtained tomato seeds that include proteins that fluoresce when exposed to the plant hormone auxin. All of these seeds were planted to obtain additional seed stocks and analysis of the mutant plants was begun. Roots of Arabidopsis and tomato were infected with root-knot nematodes and fluorescence of the auxin reporter protein was monitored at the infection site.