Reviewed by Jared Jensen
Primary Review: Transcript profiling of Nematode and Aphid Infectome on Soybean
Together, the soybean aphid and the soybean cyst nematode account for up to 50% in annual
yield reduction of the soybean crop. This proposal aims to look at the interaction between the
aboveground soybean aphid and the belowground soybean cyst nematodes and how they each
may play a role in successful feeding, and ultimately yield loss on the soybean plant. More
specifically, they aim to look at how the mRNA transcripts are comparable when aphids and
nematodes are feeding on the same plant versus individual feedings. The basic setup for this
proposal is to grow two different soybean varieties, aphid-SCN resistant and aphid-SCN
susceptible, in field strip trials. There will be three different treatments, SCN only, aphid only,
and SCN + aphid; plus a no treatment control. With this setup come two main objectives. 1)
Identify physical attributes affected by soybean-soybean cyst nematode-soybean aphid
interaction as compared with single or no infection. And 2) Identify and characterize host genes
and pathogen effectors.
Looking closer at the physical attributes due to this interaction, the researcher hypothesizes
that the combination infection will reduce yield compared to singular infections, the
combination infection will lead to reduced cumulative aphid days compared to singular
infections, and lastly the nematode egg density and female counts will be increased in the
combination trial. For the characterization of host genes and pathogen effectors, the researcher
hypothesizes effectors responsible for successful infection are differentially expressed,
effectors from SCN and aphids co-operate to increase plant susceptibility, and finally interacting
host genes and pathogen effectors have correlated expression patterns.
This proposal seems to be a combination of two large projects that have been sized down in
order to get funding for both. The first aim could be a graduate student project in and of itself,
and the same could be said for the second aim. There are questions not probed in the first aim
but discussed as future directions that I feel are necessary for this study, specifically looking at
the order of introducing the SCN and the aphids and if there should be any delay for the second
introduction and secondly if the type of resistance used makes a difference (which rag and rhg
genes). Furthermore, the specifics for Aim 1 are not as well composed as aim 2. A preliminary
greenhouse study would be beneficial for this project before fieldwork to hash out some more
specifics, ie. Initial soil egg density, number of aphids, and water management.
The broader impacts of some individual aim listed are fairly vague: will lead to further
hypothesis generation. The overall impact is loosely tied to the objectives. The researcher lists
better understanding of control of the pests but does not propose anything that would lead to
such, the experiments in this proposal are more basic research and are less applied research.
Score: good
The vagueness of objective 1 and the lax description of pitfalls and future directions gave this
proposal a good rating. Objective 2 was much better thought out and would be a great follow
up study after objective one is better understood.