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The areca palm is one of the three important "trees" (hevea brasiliensis, areca palm, and coconut) of tropical agriculture in Hainan province, China. However, the areca palm is highly susceptible to yellow leaf disease--the mostcommon disease affecting the palm--which is highly destructive, spreads rapidly, andis difficult to control with comprehensive physical, chemical, and ecological measures. Eco-geochemical studies have focused on the elemental geochemical behavior and ecological effects of the soil-plant system, which may prevent yellow leaf disease in the areca palm. With the support of the People's Government of Wanning City, Hainan Province, an eco-geochemical study was conductedon the areca palm area of Wanning City. Thirty sets of geochemical samples were collected from the root soil, root system, and leaves of areca palms infected with yellow leaf disease, along with samples taken fromhealthy trees. Root soil samples were tested for 28 indicators--including Se, Cu, Pb, Zn, Cd, Hg, As, Cr, Ni, Fe, Mn, B, Mo, Cl, F, I, N, P, K, Ca, Mg, S, Co, Na, Si, Al, pH, and organic matter. Additionally, the plant samples were tested for 23 elements--including Se, Cu, Pb, Zn, Cd, Hg, As, Cr, Ni, Fe, Mn, B, Mo, F, I, N, P, K, Ca, Mg, S, Co, and Na. Binomial logistic regression analysisof whether areca palmswere infected with yellow leaf disease as the dependent variable showed that As, B, and Co in the root soil were the main characteristic elements for determining whether the areca palmwas infected. The coefficients of As were negative, while the coefficientsof B and Co were positive, indicatinga lower probability of areca palminfection when the As content is higher and the contents of B and Co are lower. N, Co, and Na in the rootsystemwere the main characteristic elements for determining whetherthe areca palmwas infected. The coefficients of As, N, and Na were negative, while the coefficients of Co were positive, indicating a lower probability of areca palmsbeing infected when the contents of As, N, and Na are higher, and the content of Co is lower. The elements Zn, Hg, Mg, and S in the leaveswere the main factors determining whether the areca palmswere infected. The coefficients of Zn, Hg, and S were negative, and the coefficientsof Mg were positive, indicating a lower probability of areca palminfection when the contents of Zn, Hg, and Sarehigher, and content of Mg content is lower. Statistical analysis also showed that the correct classification rate and chi-square test expressed leaf> root system> root soil, indicating that the differences in elemental contents in the leaveswere the most accurate reflection of whether the areca palmwas infected. Soil is the most important source of trace elements in leaves and roots. From an eco-geochemical perspective, changing the elemental composition of root soil can be prevented, and yellow leaf diseaseamong areca palmscan be controlled. The As indicator did not enter thestatistical model of leaves (but Hg did), indicating that As does not easily reach the leaves or even the fruit of the palm. As is well known, arsenic-containing pesticides and drugs are used for plant pest control and human disease treatment, which indicates that increasing arsenic elements in the root system may enhance the prevention of areca palm from developing yellow leaf disease. Thus, this study provides a new eco-geochemical approach for the prevention and control of yellow leaf disease in areca palms. However, arsenic, as a toxic element, is an important control indicator for soil environmental quality and agricultural food safety. Therefore, systematic field trial studies and evaluations of areca palm root soil and fruits should be conducted to avoid secondary contamination using As; this can prevent and control yellow leaf disease inareca palms. [ABSTRACT FROM AUTHOR]

Background: Areca palm (Areca catechu) is a woody perennial plant of both economical and medicinal importance grown in tropical and subtropical climates. Yet, the molecular biology study of areca palm is extremely impeded by its unavailability of a transformation method. An efficient protoplast isolation and transformation system could be highly desirable to overcome this barrier. Results: Here, we described a simple and efficient method for protoplast isolation and transformation from the perennial plant areca palm. A high yield of protoplasts (2.5 × 107 protoplasts per gram of fresh leaf tissues) was obtained from the fresh light green leaflet from the newly-emerged leaf digested overnight in the enzyme solution [2% (w/v) cellulase R10, 0.5% (w/v) macerozyme R10, 0.7 M mannitol, 10 mM CaCl2, 20 mM KCl, 20 mM MES and 0.1% (w/v) BSA, pH 5.7] by the direct leaf-peeling method. The isolated areca protoplasts maintain viability of 86.6% and have been successfully transformed with a green fluorescent protein (GFP)-tagged plasmid (pGreen0029-GFP, 6.0 kb) via the polyethylene glycol (PEG)-mediated transformation. Moreover, the mannitol concentration (optimal: 0.7 M) was determined as a key factor affecting areca protoplast isolation. We also demonstrated that the optimal density of areca protoplast for efficient transformation was at 1.0–1.5 × 106 cells/ml. With the optimization of transformation parameters, we have achieved a relatively high transformation efficiency of nearly 50%. Conclusion: We have established the first efficient protocol for the high-yield isolation and transformation of areca palm protoplasts. This method shall be applied in various biological studies of areca palm, such as gene function analysis, genome editing, protein trafficking and localization and protein–protein interaction. In addition, the protoplast system offers a great genetic transformation approach for the woody perennial plant-areca palm. Moreover, the established platform may be applied in protoplast isolation and transformation for other important species in the palm family, including oil palm and coconut. [ABSTRACT FROM AUTHOR]

Arecanut palm is a commercially important plantation crop valued for its nut. In this investigation, we report the discovery of a putative novel arepavirus, named areca palm necrotic ringspot virus 2 (ANRSV2), in necrotic ringspot diseased areca palms in Bantwal, Dakshina Kannada, Karnataka, India through RNA-sequencing and transmission electron microscopy. Further, the presence of ANRSV2 in the diseased samples was confirmed through reverse transcriptase-polymerase chain reaction assays. In addition, by mining public domain transcriptome data for arepaviral sequences, we identified a putative novel arepavirus in Psychotria rubra , a non-palm host. We recovered the genome sequences of the areca palm necrotic ringspot virus in honey bees, tomato, Onobrychis viciifolia, and Rhamnus heterophylla. These findings broaden our comprehension of arepaviral diversity and host range, and suggest an intriguing possibility of pollen-mediated arepaviral transmission that necessitates empirical validation. Further studies are needed to understand the biology of identified putative novel arepaviruses. • A putative novel arepavirus was identified in diseased areca palms in Karnataka, India through RNA-sequencing. • Presence of the identified virus was validated through RT-PCR in one of the diseased samples. • Through data-mining, genome of a putative novel arepavirus was identified in Psychotria rubra. • Areca palm necrotic ringspot virus genome was identified in transcriptomes of three dicot species and honey bees. [ABSTRACT FROM AUTHOR]

Tirathaba rufivena Walker (Lepidoptera: Pyralidae) is an important pest of areca palm, Areca catechu L. (Arecaceae), in China. The effects of azadirachtin on the development and mortality of T. rufivena were determined. All larval instars were susceptible to azadirachtin, but the stomach and contact toxicities diminished as the larvae matured. The LC25 and LC50 dosages had no effect on larval hatch when applied directly to the eggs on different days after deposition, but the LC90 treatment retarded hatch from eggs treated 1 to 3 d after deposition. The tested concentrations significantly affected the survival of neonate larvae from treated eggs, especially larvae that emerged from eggs treated 3 d after deposition. Azadirachtin also prolonged larval development and duration of the pupal stage. The percentage of adult emergence decreased, and longevity of the emerged adults was shortened, following treatment. Also, egg production and viability from females treated as larvae with azadirachtin were significantly affected. [ABSTRACT FROM AUTHOR]

Palms are an increasingly important element in landscapes in the subtropical and warm temperate regions of the United States. Unfortunately, palms have very high nutritional requirements and rarely can be found without at least one nutrient deficiency, especially on the sandy and calcareous soils of the southeastern United States. These deficiencies are conspicuous and unsightly, reduce canopy size and vigor, and can become fatal. Current maintenance fertilizer recommendations for landscape palms in Florida growing in these soils entail four applications per year of an 8N-0.9P-10K-4Mg plus micronutrients palm fertilizer. However, because phosphorus (P) and nitrogen (N) are considered pollutants of ground and inland and coastal surface waters, it is important to apply only as much of these elements as necessary for palm health. This study showed that areca palms (Dypsis lutescens) can be grown in a native sand soil or in a calcareous fill soil without supplemental P and with no N applied during the rainy summer months of June through September w hen application of these elements may be legally restricted. It also demonstrated that the negative effects caused by high N:potassium (K) ratio turf fertilizers can be mitigated by adding a controlled release palm fertilizer that contains no N or P. Because of strong dilution effects in this study, leaf nutrient concentrations were found to be poor indicators of palm quality and nutritional status. [ABSTRACT FROM AUTHOR]

Two reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assays were developed for the detection of areca palm necrotic ringspot virus (ANRSV) and areca palm necrotic spindle-spot virus (ANSSV), respectively. These two emerging viruses both induce necrotic symptoms in areca palms. The coat protein (CP) gene of ANRSV and the 9 K gene of ANSSV were used to design the respective RT-LAMP primers for the assays. Each set of four primers designed for each of these viruses was found to be highly specific in the detection of the respective targeted virus. The optimal incubation conditions for the RT-LAMP assays were 63 °C for 40 min for ANRSV and at 61 °C for 40 min for ANSSV. The sensitivity of the RT-LAMP method for each of these viruses was 10-fold greater than that of the corresponding conventional reverse-transcription polymerase chain reaction (RT-PCR). The RT-LAMP assays may be useful for the rapid early detection of ANSSV and ANRSV in commercial areca palm production. [ABSTRACT FROM AUTHOR]