2013 Annual Report
1a.Objectives (from AD-416):
To understand the genetic complexity of field populations of the emerging species of potato cyst nematode (PCN) and to develop novel control tools to aid the eradication of PCN in Idaho. Specific objectives include:
1. Use the chorismate mutase gene as a genetic marker to evaluate genetic variations among G. pallida field populations.
2. Develop novel nematode resistance in potato through a plant-delivered RNAi technology.
1b.Approach (from AD-416):
Globodera pallida, one of the two species of potato cyst nematode (PCN), has been found in nine fields in the eastern part of the state of Idaho. The discovery of this devastating potato pest poses threat to the potato industry of the U.S. Understanding the genetic complexity of field populations of this emerging nematode species and developing novel control tools are necessary to aid the eradication of G. pallida in Idaho.
We will use the chorismate mutase gene as a genetic marker to evaluate genetic variations among G. pallida field populations; and, we will develop novel nematode resistance in potato through a plant-delivered RNAi technology.
There are no potato varieties with broad-spectrum resistance to different species of potato cyst nematode (PCN; Globodera rostochiensis and G. pallida). We have utilized a plant-delivered RNAi technology targeting nematode effector genes to generate transgenic potatoes resistant to PCN. We cloned several effector genes including the chorismate mutase (CM) gene, CLAVATA3/ESR-like (CLE) genes and ubiquitin carboxyl extension protein (UBCEP) gene from G. rostochiensis and G. pallida and found that these effector genes are relatively conserved between the two PCN species. We generated transgenic potato lines expressing RNAi construct targeting each of these effector genes and tested these transgenic lines for PCN infection. We found that these transgenic lines showed dramatically reduced susceptibility to nematode infection. This research has led to 3 patent applications. In addition, we have found that the two advanced potato clones NY121 and NY140 developed from the potato breeding program at Cornell University confer complete resistance to G. rostochiensis and partial resistance to G. pallida. These advanced clones are valuable germplasm for developing novel types of potatoes with broad-spectrum resistance to diverse PCN species and populations.