Host-Derived Artificial MicroRNA as an Alternative Method to Improve Soybean Resistance to Soybean Cyst Nematode

Abstract

The soybean cyst nematode (SCN), Heterodera glycines, is one of the most important pests limiting soybean production worldwide. Novel approaches to managing this pest have focused on gene silencing of target nematode sequences using RNA interference (RNAi). With the discovery of endogenous microRNAs as a mode of gene regulation in plants, artificial microRNA (amiRNA) methods have become an alternative method for gene silencing, with the advantage that they can lead to more specific silencing of target genes than traditional RNAi vectors. To explore the application of amiRNAs for improving soybean resistance to SCN, three nematode genes (designated as J15, J20, and J23) were targeted using amiRNA vectors. The transgenic soybean hairy roots, transformed independently with these three amiRNA vectors, showed significant reductions in SCN population densities in bioassays. Expression of the targeted genes within SCN eggs were downregulated in populations feeding on transgenic hairy roots. Our results provide evidence that host-derived amiRNA methods have great potential to improve soybean resistance to SCN. This approach should also limit undesirable phenotypes associated with off-target effects, which is an important consideration for commercialization of transgenic crops.

Assembly and Annotation of Transcriptome Provided Evidence of miRNA Mobility between Wheat and Wheat Stem Sawfly

“…Wheat Stem Sawfly larva accommodates in wheat stem and feeds from there until pupae stage of its life cycle ( Delaney et al, 2010 ). Given the evidence of cross-kingdom regulation by miRNAs ( Zhang et al, 2012 ; Tian et al, 2016 ; Jia et al, 2017 ), the interaction between intracellular molecules of WSS larvae and wheat cannot be underestimated due to these two organisms being in contact and trying to defeat each other. To assess possible effects of larval miRNAs on wheat gene expression and its response to WSS pathogen, target analysis for larval miRNAs was performed against Triticum aestivum coding sequences deposited at ensemble plant database using psRNAtarget tool.…”

“…miRNAs from one species may function at interspecies level, targeting genes or genomes of organisms which they have physical contact. Very recently, independent studies have been reported several examples of trans -kingdom delivery of sRNAs from; plant to virion ( Iqbal et al, 2017 ), oomycetes to plant ( Jia et al, 2017 ), plant to nematodes ( Tian et al, 2016 ). Similar to what these studies suggested, miRNAs might also be effective in regulating insect–host interactions at WSS larval stages once larva gets into the stem of the host plant.…”

Genome-wide identification of soybean microRNA responsive to soybean cyst nematodes infection by deep sequencing

“…Two soybean genotypes ‘KS4607’ and ‘KS4313N’, which are susceptible and resistant to SCN HG type 7, respectively, were used in this study. All seeds were surface sterilized before germination as described by Tian et al [ 74 ]. Healthy germinated seeds were planted into brand new D40 Deepots (Stuewe and Sons, Inc., Corvallis, OR) with sterilized soil and SCN-infested sterilized soil containing approximately 3000 eggs per 100 cm 3 of an HG type 7 H. glycines population.…”

“…Three independent biological replicates per treatment were grown under the same conditions as described above, and soybean roots were collected seven days and 35 days post inoculation. Roots were cleaned up with high pressure tap water as standard SCN bioassay procedure as described by Tian et al [ 74 ], and flash frozen in liquid nitrogen and then stored at −80 °C until RNA extraction. Treatments were as follow: KS4607 non-inoculated at 7 dpe (S7C), KS4607 non-inoculated at 35 dpe (S35C), KS4607 SCN inoculated at 7 dpe (S7 N), KS4607 SCN inoculated at 35 dpe (S35 N), KS4313N non-inoculated at 7 dpe (R7C), KS4313N non-inoculated at 35 dpe (R35C), KS4313N SCN inoculated at 7 dpe (R7N), and KS4313N SCN inoculated at 35 dpe (R35N).…”

Engineering Artificial MicroRNAs for Multiplex Gene Silencing and Simplified Transgenic Screen

“…miRNA). amiRNA technology has been applied successfully to engineer a wide range of crop species to obtain desirable agronomic traits (Butardo et al, 2011;Toppino et al, 2011;Chi et al, 2014) or enhanced resistance to viruses (Niu et al, 2006;Duan et al, 2008;Kis et al, 2016), fungi (Wang et al, 2016;Zhang et al, 2016b), nematodes (Tian et al, 2016), and insects (Guo et al, 2014). Notably, the amiRNAmediated viral resistance remains effective even at low temperatures (e.g.…”