Search Results (3)

Areca Palm Velarivirus 1 (Velarivirus arecae, APV1), Areca palm necrotic ringspot virus (Arepavirus arecae, ANRSV), and Areca palm necrotic spindle-spot virus (Arepavirus arecamaculatum, ANSSV) are major viral pathogens that cause significant economic losses in areca palm cultivation. Rapid and reliable detection methods are essential for the early diagnosis and management of these viruses in affected regions. Specific primers were designed based on the Coat Protein (CP) gene sequences of the three target viruses: APV1. A specific primer pair targeting the coat protein (CP) region was designed for APV1, while primer pairs for ANRSV and ANSSV were designed based on conserved sequences surrounding the Nla-VPg/Nla-Pro protease cleavage sites. A multiplex reverse transcription-polymerase chain reaction (multiplex RT-PCR) assay was subsequently developed to simultaneously amplify the target sequences. The multiplex RT-PCR detection system was optimized by adjusting critical parameters, including the annealing temperature, extension time, and number of cycles, to ensure high specificity and sensitivity. The optimized multiplex reverse transcription-polymerase chain reaction (multiplex RT-PCR) successfully yielded distinct amplification products for all three target viruses: 938 bp for APV1, 527 bp for ANRSV, and 250 bp for ANSSV. The size differences among the amplicons allowed them to be clearly distinguishable by 2% agarose gel electrophoresis. The optimal reaction conditions were determined to be an annealing temperature of 53.4 °C and 35 cycles. Applying the optimized multiplex RT-PCR method, we analyzed 414 field samples collected from Hainan province. APV1 was identified as the most prevalent virus, detected in 22.71% of the total samples. ANRSV and ANSSV were detected at significantly lower rates, in 3.86% and 0.2% of the samples, respectively. Virus detection in areca samples from Hainan Island revealed clear regional differences in disease incidence, with higher rates in the eastern and central regions—particularly Baoting, Lingshui, Wanning, and Qionghai—averaging 46.73%. Together, these results demonstrate that the developed multiplex RT-PCR is a sensitive and practical tool for the routine molecular diagnosis and epidemiological investigation of APV1, ANRSV, and ANSSV in areca palms. Full article

Yellow leaf disease (YLD) has been the most severe disease threatening areca palm, commonly known in areca palm cultivation. However, it has not yet been systematically studied in terms of the relationship between infected plants and the structure of rhizosphere microbial communities. In order to systematically study the impact of YLD on the rhizosphere fungi of the areca palm, we implemented high-throughput sequencing technology to analyze the microbial community structure and diversity under different disease conditions. The results indicate that as the severity of the disease increases, the diversity of the fungal community diminishes, with species abundance and richness initially decreasing before subsequently increasing, while phylogenetic diversity increases, and significant changes occur in the structure of the soil fungal community. At the phylum level, the dominant fungal phyla in the rhizosphere of areca palm are Ascomycota and Basidiomycota. At the genus level, the dominant genera are Sarocladium, Roussoella, Penicillium, etc., and their relative abundance increases with the severity of the disease. LEfSe analysis revealed that Archaeorhizomyces, Codinaea, and Albifimbria serve as indicator species for healthy areca palms, with their relative abundance trends consistent with changes in Alpha diversity. FUNGuild prediction results indicated that the fungal nutrient type structures of the three rhizosphere samples were highly similar, with saprotrophs being the absolutely dominant type. With the increase in the severity of the disease, the number of harmful fungi in the soil (such as Plectosphaerella, Fusarium, etc.) increases, thereby limiting the sustainable development of the soil. Network analysis indicates that beneficial microbial communities such as Stachybotrys and Roussoella exhibit extensive negative interactions. Therefore, the YLD of areca palm significantly alters the structure and diversity of the rhizosphere fungal community. Simultaneously, some beneficial microorganisms may be recruited by the areca rhizosphere to resist the invasion of YLD by improving the rhizosphere environment and enhancing plant immunity, such as Trechispora, Saitozyma, and Marasmiellus. This experiment is expected to provide a theoretical basis for the study of the rhizosphere microecology of the areca palm, the exploration of excellent biocontrol resources, and the green control of YLD in the areca palm. Full article

Areca palm velarivirus 1 (APV1), the causal agent of yellow leaf disease (YLD), poses a serious threat to the economically important areca palm industry in the Hainan Province, China, yet its evolutionary dynamics remain poorly understood. Here, we performed a large-scale molecular survey by sequencing the coat protein (CP) gene from 364 APV1-infected samples collected across major cultivation regions of Hainan. Population genetic analyses revealed extremely high haplotype diversity (H_d = 0.997) but very low nucleotide diversity (π = 0.017). Neutrality tests (Tajima’s D = −2.266; Fu’s F_S = −23.697) and a unimodal mismatch distribution supported a scenario of recent demographic expansion from a restricted ancestral pool. Evolutionary analyses indicated that the CP gene is subject to strong purifying selection, although eight codons exhibited episodic positive selection, suggesting ongoing viral adaptation. Furthermore, we identified three distinct genetic clusters with significant geographic structuring, indicating that viral dissemination is shaped by local factors. Together, these results reveal a recent explosive invasion of APV1 characterized by rapid island-wide expansion and emerging local differentiation. This work provides novel insights into the evolutionary trajectory of APV1 and establishes a genomic basis for improved surveillance and management of YLD. Full article