As a tropical fruit of considerable economic importance, passionfruit (Passiflora edulis Sims) is extensively cultivated in the tropical and subtropical regions of China; however, the widespread incidence of viral diseases has significantly hampered the safety of its production. Rapid, sensitive, and visual detection of plant viruses is essential to effectively prevent and manage these viral diseases. In this study, we developed a visual detection system (displaying under blue light or UV) utilizing reverse transcription recombinase-aided amplification (RT-RAA) in conjunction with CRISPR/Cas12a to detect three viruses harmful to passionfruit production: telosma mosaic virus (TelMV), East Asian passiflora virus (EAPV), and passiflora mottle virus (PaMoV). Within this system, the optimal primer concentration for the RT-RAA reaction was determined to be 0.4 μM for all three viruses, with an optimal reaction temperature of 37 °C. The optimal reaction times were established as 20 min for TelMV, 15 min for EAPV, and 30 min for PaMoV. The entire detection process could be completed within 30 min without the need for sophisticated equipment or instruments. For TelMV and EAPV, the detection system demonstrated the capability to detect samples at a dilution of 10⁶, representing an approximately 10⁴-fold improvement over RT-PCR, while for PaMoV, it could identify samples at a dilution of 10⁶, representing an approximately 10²-fold improvement over traditional RT-PCR methods. These results confirm the successful development of the CRISPR/Cas12a-based detection systems. Subsequently, the system was applied for in situ detection of the three target viruses in field settings, yielding results that were fully consistent with laboratory-based RT-PCR assays, a consistency which underscores the system’s strong potential for field application in detecting important crop viruses.

In Guangxi, China, winter ratoon tissues of perennial rice provide overwintering habitats for the migratory crop pest Mythimna separata (Walker, 1865) (Lepidoptera: Noctuidae). To understand the overwintering potential and fitness of this pest in perennial rice cropping systems, we evaluated the life history, population parameters, and flight performance of M. separata cohorts initiated in November, December, January, and February using group rearing and age-stage, two-sex life tables. The November cohort showed the highest intrinsic rate of increase (r_m = 0.1009 d⁻¹), while the February cohort exhibited the greatest fecundity (752.88 eggs/female) and flight capacity (7.61 h of flight during the 12 h flight period). In contrast, prolonged exposure to deep-winter cold severely suppressed survival, reproduction, population growth, and adult flight performance. These findings demonstrate that overwintering success depends strongly on the timing of cold exposure: gradual autumn cooling and late-winter warming can support population persistence, whereas sustained deep-winter cold is associated with reduced fitness. Perennial rice ratoon tissues may therefore facilitate pest carry-over between cropping cycles, and the overlap between spring ratoon regrowth and reproduction of late-winter cohorts may increase the risk of early-season outbreaks. Monitoring overwintering cohort dynamics together with ratoon phenology could improve early warning and support timely management of M. separata in perennial rice systems.

Southem rice black-streaked dwarf virus (SRBSDV), a fijivirus with a double-stranded RNA genome of 10 segments and 13 proteins, severely impairs rice growth and development. The functions of P8, one of the major coat proteins of SRBSDV, are still poorly understood. In this study, the SRBSDV-encoded P8 protein was used as bait in a yeast two-hybrid screen of a rice cDNA library, which identified an interaction between P8 and auxin response factor 15 (OsARF15). The interaction was then confirmed by GST pull-down (in vitro) and co-immunoprecipitation (Co-IP) (in vivo) assays. Truncated protein analysis further revealed that P8 primarily binds to the C-terminal region of OsARF15. Over-expression and knockout of OsARF15 rice plants were constructed and then inoculated by SRBSDV. The results showed that over-expression of OsARF15 promoted SRBSDV infection whereas its knockout enhanced virus resistance. Meanwhile, the effect of OsARF15 on root development was observed and found that knocking out OsARF15 significantly promoted the growth of rice roots at the seeding stage. These results demonstrate that the SRBSDV P8 protein facilitates viral infection by interacting with the C-terminal region of OsARF15. Our findings have further strengthened the role of P8 in the viral infection process.