**6. Carbohydrates**

Nematodes require carbohydrates for energy, usually in the form of glycogen. One study showed that several different carbohydrates were sufficient to provide a carbon, or energy source for *C. elegans*, and that glucose was more effective than fructose or sucrose [76]. For *C. elegans*, glucose along with cytochrome c and β-sitosterol were sufficient to sustain a healthy population.

One of the most striking features of soybean chemistry is the abundance of pinitol [77-79]. Pinitol is a carbohydrate with unusual nutritional properties [77]. Figure 2 shows a total ion chromatogram of a derivatized extract of soybean roots. It is unusual for a plant to have so much pinitol. The levels shown in this study indicate pinitol is present at a concentration of 26 mg/g (dry weight) compared to peanuts with only 4.7 mg/g or clover with 14 mg/g [79]. However, there is no evidence that pinitol, or any of the related inositols are needed for SCN survival [79].

Studying biochemical pathways would be a valuable approach, and could also help identify pathways that could be blocked to help minimize SCN survival. Our laboratory began by examining the chemistry of the plant to identify unique nutrients necessary for SCN survival, but that approach was not immediately successful. Another approach is to continue to use DNA mapping to better understand potential plant and parasite pathways. While this approach is less direct, it is currently a very active area of investigation, and can reveal more

Nutritional Requirements of Soybean Cyst Nematodes

http://dx.doi.org/10.5772/54247

11

Details of the SCN host-parasite responses during infection and feeding site establishment have been more extensively investigated than nutritional requirements. Relationships between the available nutrients from host plants compared to non-hosts could provide valuable clues on these requirements. And, once an adequate media for SCN survival has been well defined,

and Patricia Donald2

[1] Munn, E.A. Munn, P. D. Feeding and digestion in Lee, D. L. (ed). The Biology of

[2] Davis, E. L., Hussey, R. S., Baum, T. J. Getting to the roots of parasitism by nemato‐

[3] Hussey, R. S., Mims, C. W. Ultrastructure of esophageal glands and their secretory granules in the root-knot nematode, *Meloidogyne incognita*. *Protoplasma*. 1990; 156:

[4] Wyss, U. Feeding behavior of plant-parasitic nematodes.. In: Lee, D. L. (ed.). The Bi‐

ology of Nematodes. Taylor and Francis: New York; 2002. p233-259.

information than simply nutritional requirements.

The authors acknowledge support from the USDA and Battelle.

, James A. Campbell1

des. *Trends in Parasitology*. 2004; 20:134-141.

1 Pacific Northwest National Laboratory, Richland, Washington, USA

2 U. S. Department of Agriculture/ARS, Jacksonville, Tennessee, USA

Nematodes. Taylor and Frances. New York; 2002. p211-232.

methods to control this pest should follow.

**Acknowledgements**

**Author details**

Steven C. Goheen1

**References**

9-18.

**Figure 2.** A total ion chromatogram of derivatized soybean root extract is shown. A = D-(-)-Fructose, B = D-Pinitol, C = D-(+)-Glucose, D = D-*chiro*-inositol, E = β-D-(+)-Glucose, F = *Myo*-inositol. Reproduced with permission from [79].

### **7. Other nutrients or feeding requirements**

The nematode *Rhabditis maupasi* requires hemin or another iron porphyrin for survival [62]. Similarly, *C elegans* also requires a heme source for survival [34]. It is likely that many other nematodes require heme, or a closely related hemin. There is also good evidence that SCN requires a heme source [80].

#### **8. Discussion**

In comparison to our knowledge of human nutrition, our understanding of nutritional requirements of SCN is in its infancy. Limited information is available for members of the Nematoda Phyllum, but such a small amount of information is available that extrapolation across trophic groups and even within genera may be misleading. Finding a successful artificial diet would be a reasonable first step in defining the nutritional needs of SCN. But, this data needs to be coupled with a good understanding of feeding site establishment and plant responses to SCN infections.

Studying biochemical pathways would be a valuable approach, and could also help identify pathways that could be blocked to help minimize SCN survival. Our laboratory began by examining the chemistry of the plant to identify unique nutrients necessary for SCN survival, but that approach was not immediately successful. Another approach is to continue to use DNA mapping to better understand potential plant and parasite pathways. While this approach is less direct, it is currently a very active area of investigation, and can reveal more information than simply nutritional requirements.

Details of the SCN host-parasite responses during infection and feeding site establishment have been more extensively investigated than nutritional requirements. Relationships between the available nutrients from host plants compared to non-hosts could provide valuable clues on these requirements. And, once an adequate media for SCN survival has been well defined, methods to control this pest should follow.
