Resistance to Ditylenchus destructor Infection in Sweet Potato by the Expression of Small Interfering RNAs Targeting unc-15, a Movement-Related Gene

Abstract

Stem nematode (Ditylenchus destructor) is one of most serious diseases that limit the productivity and quality of sweet potato (Ipomoea batatas), a root crop with worldwide importance for food security and nutrition improvement. Hence, there is a global demand for developing sweet potato varieties that are resistant to the disease. In this study, we have investigated the interference of stem nematode infectivity by the expression of small interfering RNAs (siRNAs) in transgenic sweet potato that are homologous to the unc-15 gene, which affects the muscle protein paramyosin of the pathogen. The production of double-stranded RNAs and siRNAs in transgenic lines with a single transgene integration event was verified by Northern blot analysis. The expression of unc-15 was reduced dramatically in stem nematodes collected from the inoculated storage roots of transgenic plants, and the infection areas of their storage roots were dramatically smaller than that of wild-type (WT). Compared with the WT, the transgenic plants showed increased yield in the stem nematode-infested field. Our results demonstrate that the expression of siRNAs targeting the unc-15 gene of D. destructor is an effective approach in improving stem nematode resistance in sweet potato, in adjunct with the global integrated pest management programs.

The Defense Response Involved in Sweetpotato Resistance to Root-Knot Nematode Meloidogyne incognita: Comparison of Root Transcriptomes of Resistant and Susceptible Sweetpotato Cultivars With Respect to Induced and Constitutive Defense Responses

“…However, the molecular mechanisms of nematode resistance in sweetpotato are poorly understood. Although multiple resistance genes involved in qualitative response to nematode infection have been discovered in sweetpotato through transcriptome, proteome and transgenic analyses, the exact function and mode of action of these genes remain unknown ( Fan et al, 2015 ; Zhai et al, 2016 ; Ha et al, 2017 ; Lee et al, 2019 ). Here, we performed a comprehensive analysis of gene expression in three RCs and three SCs of sweetpotato before and after infection with M. incognita infection to characterize induced and constitutive defense responses.…”

Multi-copy alpha-amylase genes are crucial for Ditylenchus destructor to parasitize the plant host

“…destructor , the relative infection area and reproduction of RNAi-treated worms in the storage roots of sweet potato were analyzed. Approximately 500 nematodes soaked with dsRNA for 24 h were inoculated into storage roots using the method of artificial inoculation described by Fan [ 9 ], with some modifications. The inoculated storage roots were maintained in an incubator in the dark at 25°C.…”

“…destructor are chemical nematicides, crop rotation, and resistant crop varieties. However, these strategies have certain limitations: most chemical nematicides are unfriendly to the environment, crop rotation fetches less profit to farmers, and the number of available resistant crop varieties is limited [ 9 ]. Hence, it is necessary to explore an effective and safe strategy against D .…”

“…In contrast, studies on the pathogenesis-related genes in D . destructor are relatively few [ 9 , 16 ]. D .…”

Genetic Engineering and Sustainable Crop Disease Management: Opportunities for Case-by-Case Decision-Making

“…These studies report partial to complete control of diseases caused by several of the most important pathogens worldwide. Likewise, gene silencing holds much promise for pesticide-free nematode management [92][93][94]. Diverse pathogenicity genes in nematodes present many molecular targets [95], highlighting the promise RNA silencing holds for sustainable, long-term nematode management.…”