Hue University Journal of Science: Agriculture and Rural Development

Effect of AC4-null mutations on the infectivity of pepper yellow leaf curl Thailand virus in Nicotiana benthamiana

Ho Ngoc Han, Ho Thi Hoang Nhi, Huynh Thi Thanh Tuyen , Truong Thi Hong Hai — Mon, 01 Jun 2026 00:00:00 +0700

Begomoviruses are among the most devastating plant viruses. They have compact genomes that encode six to eight proteins important for viral replication and spread. Among these proteins, AC4 (C4 in monopartite begomoviruses) is a multifunctional protein with roles in host immunity suppression and disease symptom expression. Here, we investigated the role of AC4 in the infectivity of pepper yellow leaf curl Thailand virus, a begomovirus recently reported in central Vietnam. First, three AC4-null mutants were created from the infectious clones of DNA-A of PepYLCThV using QuikChange site-directed mutagenesis. The mutants were confirmed with PCR and DNA sequencing. The wild-type and mutants infectious clones were used to infect Nicotiana benthamiana via agroinoculation. Symptom expression was monitored for up to 28 days post inoculation. Disease onset started at five to six days post inoculation. Inoculation with AC4-null mutant infectious clones, similar to wild-type AC4 infectious clones, resulted in severe leaf distortion, mosaic, white patches on leaves and stunted growth in 100% of inoculated plants. Furthermore, the presence of DNA-A and DNA-B were confirmed in infected plants by PCR. These results suggested AC4 plays an insignificant role in the infectivity of PepYLCThV in the model plant N. benthamiana.

Livelihood diversification and transition among lagoon fishing households and White leg shrimp (Litopenaeus vannamei) farming expansion in Phu Dien Commune, Hue City, Vietnam

Duong Ngoc Phuoc , Le Thi Thanh Thuy, Nguyen Ngoc Truyen, Ho Le Phi Khanh — Mon, 01 Jun 2026 00:00:00 +0700

This study examines the expansion of white leg shrimp farming as a livelihood stressor shaping diversification and constraining transitions among small-scale lagoon fishing households in Phu Dien Commune, Hue City, Vietnam. Data were collected through a survey of 100 fishing households, complemented by focus group discussions and key informant interviews. The findings show that households are affected by multiple and overlapping pressures, including declining aquatic resources, lagoon pollution, market fluctuations, rising input costs, natural disasters, COVID-19, and the expansion of white-leg shrimp farming. Despite these pressures, most households continue to depend on fishing because of constraints related to capital, skills, and employment opportunities; only 7% of households exited fishing, while 11% adjusted their fishing gear, effort, or fishing grounds. The study suggests that livelihood diversification mainly takes the form of incremental and constrained adaptation rather than full livelihood transformation. Based on these findings, the study recommends strengthening environmental management in aquaculture, supporting livelihood transitions, and promoting co-management of lagoon resources to enhance community resilience.