Identification of the Coexisting Virus-Derived siRNA in Maize and Rice Infected by Rice Black-Streaked Dwarf Virus.

Area of Science:

• Plant pathology
• Molecular biology
• Virology

Background:

• Rice black-streaked dwarf virus (RBSDV) causes significant crop losses in maize and rice.
• Virus-derived small interfering RNAs (vsiRNAs) are crucial in the plant-virus coevolutionary arms race, modulating host immunity via RNA silencing.
• The ability of RBSDV to produce conserved vsiRNAs across different host species remained uninvestigated.

Purpose of the Study:

• To investigate whether RBSDV generates common vsiRNAs in distinct plant species, specifically maize (Zea mays) and rice (Oryza sativa).
• To characterize the vsiRNAs produced by RBSDV in these hosts and identify their potential targets.
• To explore the implications of these findings for developing novel antiviral strategies.

Main Methods:

• High-throughput sequencing of small RNA and degradome libraries from infected maize and rice.
• Bioinformatic analysis of vsiRNA characteristics, distribution, and hot spots on the viral genome.
• Stem-loop PCR and real-time quantitative PCR to validate the function of specific coexisting vsiRNAs (co-vsiRNAs).

Main Results:

• RBSDV infection produced vsiRNAs predominantly of 21 and 22 nt in both maize and rice.
• 73 co-vsiRNAs were identified in both hosts, with specific co-vsiRNAs (3.1 and 3.5) confirmed to inhibit host gene expression.
• Viral infection differentially impacted target genes related to ribosome function in maize and metabolism/biosynthesis in rice.

Conclusions:

• RBSDV can produce conserved vsiRNAs that function in multiple host species.
• These conserved vsiRNAs play a role in suppressing host gene expression, contributing to viral pathogenesis.
• The findings provide a foundation for developing cross-species antiviral therapies targeting conserved vsiRNAs.