Virus-Mediated Chemical Changes in Rice Plants Impact the Relationship between Non-Vector Planthopper Nilaparvata lugens Stål and Its Egg Parasitoid Anagrus nilaparvatae Pang et Wang

Abstract

In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae.

Plant infection by two different viruses induce contrasting changes of vectors fitness and behavior

“…Although those differences between responses of vectors and nonvectors to viral infection have been poorly studied until now, some studies have shown similar patterns. The PT circulative SRBSDV infection on rice plants had no effect on a planthopper nonvector (He et al ., ) but affected its vector (Tu et al ., ). A positive correlation was also highlighted between the NPT noncirculative PVY transmission efficiency by five aphid species (from nonvector to efficient ones) and the duration of their phloem sap ingestion phases (Boquel et al ., , ).…”

“…Some studies have investigated the relationship between alteration of colonization by the vector on infected plants and vector virus‐transmission efficiency. For example, the PT circulative Southern rice black‐streaked dwarf virus (SRBSDV, Fijivirus ) infection on rice plants had no effects on a nonvector brown planthopper (BPH, Nilaparvata lugens ) (He et al ., ) but affected its vector, the white‐backed planthopper (WBPH, Sogatella furcifera ) (Tu et al ., ). Boquel et al .…”

Virus altered rice attractiveness to planthoppers is mediated by volatiles and related to virus titre and expression of defence and volatile-biosynthesis genes

“…The healthy plants become their main food source and habitat. Some studies have indicated that the lifespans of female BPHs are shortened in SRBSDV-infected rice plants44. The lifespan of WBPHs carrying SRBSDV is less than 15 days at 25 °C45.…”

Quantification of southern rice black streaked dwarf virus and rice black streaked dwarf virus in the organs of their vector and nonvector insect over time

“…However, planthoppers and leafhoppers of the family Delphacidae are highly specific as to which viruses they acquire and/or transmit (Milne et al, 2005). For example, the brown planthopper has been found to feed on SRBSDV-infected plants without any impact on insect biology, and the virus could not be detected by RT-PCR (Pu et al, 2012;He et al, 2014). Similarly, corn stunt spiroplasm has not been detected in Peregrinus maidis after feeding on infected corn plants (Vega et al, 1995).…”