scholarly journals Geographic Distribution, Genetic Variability and Biological Properties of Rice Orange Leaf Phytoplasma in Southeast Asia

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 169
Author(s):  
Socheath Ong ◽  
Gilda B. Jonson ◽  
Matteo Calassanzio ◽  
Soriya Rin ◽  
Cheythyrith Chou ◽  
...  

Rice orange leaf phytoplasma (ROLP) causes clear orange to yellowish leaf discoloration and severe stunting in rice seedlings. The ecological and biological characteristics of ROLP are largely unknown because the disease has not widely caused serious problems in rice cultivated areas, thereby leading to the low accumulation of research data. However, in the past decade, the disease became a threat to rice production, particularly in South China and India; it has also been recognised in other Asian countries, such as Vietnam, Thailand and the Philippines. Here, we observed the occurrence of ROLP in paddies of the Southeast Asian counties (Cambodia, Vietnam and the Philippines) and found that the isolates in the Philippines and Vietnam were monophyletic, while those in India, Thailand and Cambodia were more diverse, suggesting their potential origins. In Cambodia, it was revealed that following polymerase chain reaction (PCR) detection, the known ROLP-insect vectors, N. virescens Distant and Recilia dorsalis Motchulsky, were ROLP-positive, indicating their roles in pathogen dispersal. Moreover, fluorescent and scanning electron microscopy revealed the intensive accumulation of the phytoplasma in phloem tissues and massive accumulation of storage starch in vascular bundle sheath and parenchyma. Altogether, this study illustrated the genetic variability of global ROLP isolates and the pathogen’s biological impact on rice tissue.

2016 ◽  
Vol 8 (6) ◽  
pp. 8849 ◽  
Author(s):  
Marc Timothy C. Tan ◽  
Joycelyn C. Jumawan ◽  
Jonas P. Quilang

Clarias macrocephalus Günther, 1864 is a Near Threatened freshwater catfish found in the Philippines and other Southeast Asian countries.  Its numbers have dwindled over the past few years because of habitat loss and competition.  This study examined the genetic diversity of the remaining viable populations of C. macrocephalus in the Philippines.  Primers were designed to amplify via polymerase chain reaction (PCR) the complete mitochondrial DNA (mtDNA) control region (870-bp) in 120 specimens collected from three sites: (1) Buguey, Cagayan; (2) Camalaniugan, Cagayan; and (3) Agusan del Sur.  Of the 120 sequences generated, only three haplotypes and two polymorphic sites were found. Overall haplotype and nucleotide diversity (h=0.479, π=0.00058) were alarmingly low, consistent with populations of other freshwater fishes that have experienced a genetic bottleneck.  The overall FST value was 0.80050, indicative of large genetic differentiation between populations.  The very low genetic variation found in all three C. macrocephalus populations calls for conservation and management efforts for the protection of the remaining populations of this economically important species.


Plant Disease ◽  
2015 ◽  
Vol 99 (11) ◽  
pp. 1483-1487 ◽  
Author(s):  
Shu Li ◽  
Weijia Hao ◽  
Guanghua Lu ◽  
Jilei Huang ◽  
Chuanhe Liu ◽  
...  

Rice orange leaf disease (ROLD) is caused by rice orange leaf phytoplasma (ROLP) and occurs sporadically in rice-growing areas in countries of eastern and southeastern Asia. ROLD caused severe damage to rice production in South China in the 1980s. Although its impact subsequently declined in South China, it has reemerged as a serious threat recently. Our study showed that ROLD occurrence varies in different seasons and fields. It was more severe in summer-grown crops (from July to October) than in spring-grown crops (from March to July). In most fields, the incidence was less than 10%, and diseased plants were scattered throughout the fields. In 20% of fields, the incidence was between 10 and 30%. In some fields, over 90% of plants were affected, causing crop failure. Typical symptoms of ROLD include orange-colored leaves and poor growth. Diseased plants were determined as positive for ROLP but negative for Rice tungro bacilliform virus, Rice tungro spherical virus, and Rice transitory yellowing virus through polymerase chain reaction and reverse-transcription polymerase chain reaction. Phytoplasma bodies but not virus-like particles were observed by electron microscopy in phloem tissue of diseased leaves. The leafhopper Inazuma dorsalis, previously identified as the unique vector for ROLP, was rare in the affected fields. Another leafhopper, Nephotettix cincticeps, previously considered a nonvector for this phytoplasma, was very common. Transmission tests revealed that this insect could also transmit ROLP; therefore, it might represent a new vector responsible for the recent incidence of ROLD.


2021 ◽  
Vol 13 (23) ◽  
pp. 12952
Author(s):  
Haitham Esam Rababah ◽  
Azhar Ghazali ◽  
Mohd Hafizal Mohd Isa

Fossil fuel consumption for electricity generation in the building sector is at an all-time high in line with the country’s economic growth. This scenario will increase the global CO2 emissions and large carbon footprints, thus leading to global warming. In recent years, most of the research related to the building sector has focused on the development of new techniques to reduce buildings’ energy consumption through energy conservation, energy efficiency, and the implementation of renewable energy technologies. The introduction of photovoltaic (PV) technology has become the most prominent renewable energy (RE) that can be integrated into building components. Even though the Building Integrated Photovoltaic (BIPV) has been available for decades, but its implementation in Southeast Asian countries has not gained widespread acceptance compared to European countries and other parts of Asia. This paper aims to investigate the effects and challenges of BIPV implementation in Southeast Asian Countries (Cambodia, Indonesia, Laos, Malaysia, Singapore, Thailand, Vietnam, and the Philippines), focusing on climate effects, the initial cost of PV technology, government policies, and initiatives. An in-depth literature review from past research, policies, and reports taken between 2016 to 2021 has been conducted and found that the environmental parameters directly influence the performance of BIPV systems and affect efficiency. This study pointed at Feed-in Tariff (FiT), policies and initiatives offered by the government in Southeast Asian countries are not beneficial and discourage building owners to adopt the BIPV technology or any other RE technology. Governments should revise the current policies to promote and attract more building owners to take part in the efforts to minimize CO2 emissions from the building industry.


2019 ◽  
Vol 12 (6) ◽  
pp. 774-777 ◽  
Author(s):  
Adrian P. Ybañez ◽  
Orgil V. Arrabis ◽  
Dennis Justin M. Alvarez ◽  
Eloiza May S. Galon ◽  
Rhea Mae P. Jayag ◽  
...  

Background: Tick-borne diseases are caused by a wide variety of viruses, pathogens, and diseases. Anaplasma, Ehrlichia, and Babesia spp. are among the most known tick-borne pathogens in Asia. In the Philippines, these pathogens were already reportedly present in dogs and large ruminants, but no study has been reported yet evaluating their presence in goats. Aim: The present study aimed to evaluate the presence of Anaplasma, Ehrlichia, and Babesia spp. in goats in Cebu, the Philippines. Materials and Methods: A total of 100 blood samples from goats were collected in Cebu, the Philippines. Profile of sampled goats including age, body score, and sex was obtained. Peripheral blood smear examination and DNA extraction were performed. Nested polymerase chain reaction assay was used to evaluate the presence of Anaplasma, Ehrlichia, and Babesia spp. Results: None of the samples were found positive with Anaplasma, Ehrlichia, and Babesia spp. infection. Conclusion: Tested goats were negative with Anaplasma, Ehrlichia, and Babesia spp. and calls for continuous surveillance of these pathogens due to the reported detection of these pathogens in other livestock animals in the area.


2021 ◽  
Vol 65 (10) ◽  
pp. 91-102
Author(s):  
N. Rogozhina

The choice of the countries of Southeast Asia as an example for analyzing the nature of interaction between developing countries and China within the framework of the Belt and Road Initiative is not accidental. The very logic of China’s stated goals of gaining dominant positions in the world economy and politics makes it inevitable that the countries of Southeast Asia located in geographic proximity to it are included in its long-term economic and political plans. The question, however, is to what extent do they meet the interests of the Southeast Asian countries themselves? The solution to this question is the main subject of research in the article. There are objective prerequisites for mutually beneficial cooperation. The Belt and Road projects are viewed by China as a tool for economic expansion into the region with the prospect of taking a leading position there, using the interest of Southeast Asian countries in the inflow of foreign investment to create modern infrastructure, the lack of which narrows their opportunities for further economic growth, maintaining competitiveness and developing integration ties within ASEAN Community. Expert assessments made by international organizations confirm the positive impact of OBOR projects on the economic development of Southeast Asian countries and although today it is too early to draw any conclusions, since the initiative is only at the initial stage of its implementation in the region, nevertheless the case studies presented in the article indicate a mismatch in the positions of the parties on a number of issues related to the financing of projects, their lack of transparency. non-compliance with environmental and social requirements. The support of the initiative on the part of the Southeast Asian countries does not automatically mean their acceptance of the terms of the agreements proposed by China, which are far from always consistent with their national interests and give rise to fears in society about its expansionist intentions. Therefore, in many Southeast Asian countries, participation in OBOR projects is turning into a subject of political discourse, which reflects the presence of disagreements in society and confrontation of interests regarding the advisability of rapprochement with China, given the associated economic and political risks. The countries of Southeast Asia can be conditionally divided into two groups according to their relation to the Belt and Road initiative. The first group includes Indonesia, Malaysia, Singapore, the Philippines, Thailand, Vietnam and Myanmar, whose position can be described as national pragmatism. While supporting the Chinese initiative in general, they nevertheless assess the possible risks of their participation in projects and seek to reduce them. The second group is represented by Laos and Cambodia, whose leadership unconditionally supports the Chinese initiative, guided by the interests of their own survival, which largely depends on Chinese assistance. Therefore, the prospect of falling into a debt trap and increasing economic dependence on the PRC and even the threat of losing sovereignty does not deter them from participating in highly controversial projects from a commercial point of view. Based on the analysis made, the author comes to the conclusion that, given the existing alignment of political forces in Southeast Asia, China can count on promoting its initiative in the region, which, however, does not automatically lead to an increase in its political influence and to the creation of a China-centric model of regional order. Acknowledgements. The article was prepared within the project “Post-crisis world order: challenges and technologies, competition and cooperation” supported by the grant from Ministry of Science and Higher Education of the Russian Federation program for research projects in priority areas of scientific and technological development (agreement № 075-15-2020-783).


1997 ◽  
Vol 18 (3) ◽  
pp. 1-5 ◽  
Author(s):  
Corazon V. C. Barba ◽  
Lucila B. Rabuco

Two of the major demographic trends in the developing and transitional countries are urbanization (the growth of cities and metropolitan populations) and ageing (the increase in the number of persons over 70 years of age, due to extended life expectancy). These two trends are felt to present unresolved challenges regarding health, well-being, and quality of life. These uncertainties gave rise to the multicentre Reconnaissance project carried out in five Asian countries (China, Indonesia, Malaysia, the Philippines, and Thailand) and three Latin American countries (Brazil, Guatemala, and Mexico), in collaboration with institutions in the Netherlands, Germany, and Italy, with financial support from the European Community. The findings, experience, and lessons from the preliminary qualitative (community), and quantitative (individual) surveys were shared among the investigators at a conference held at Wageningen, Netherlands.


Parasitology ◽  
2020 ◽  
Vol 147 (14) ◽  
pp. 1718-1722
Author(s):  
Oyime P. Aula ◽  
Donald P. McManus ◽  
Kosala G. Weerakoon ◽  
Remigio Olveda ◽  
Allen G. Ross ◽  
...  

AbstractHookworms are some of the most widespread of the soil-transmitted helminths (STH) with an estimated 438.9 million people infected. Until relatively recently Ancylostoma ceylanicum was regarded as a rare cause of hookworm infection in humans, with little public health relevance. However, recent advances in molecular diagnostics have revealed a much higher prevalence of this zoonotic hookworm than previously thought, particularly in Asia. This study examined the prevalence of STH and A. ceylanicum in the municipalities of Palapag and Laoang in the Philippines utilizing real-time polymerase chain reaction (PCR) on stool samples previously collected as part of a cross-sectional survey of schistosomiasis japonica. Prevalence of hookworm in humans was high with 52.8% (n = 228/432) individuals positive for any hookworm, 34.5% (n = 149/432) infected with Necator americanus, and 29.6% (n = 128/432) with Ancylostoma spp; of these, 34 were PCR-positive for A. ceylanicum. Considering dogs, 12 (n = 33) were PCR-positive for A. ceylanicum. This is the first study to utilize molecular diagnostics to identify A. ceylanicum in the Philippines with both humans and dogs infected. Control and elimination of this zoonotic hookworm will require a multifaceted approach including chemotherapy of humans, identification of animal reservoirs, improvements in health infrastructure, and health education to help prevent infection.


2006 ◽  
Vol 39 ◽  
pp. 77-88 ◽  
Author(s):  
S.C. Mehta ◽  
B.P. Mishra ◽  
M.S. Sahani

SummaryThe camel population in India is facing a severe decline which demands that immediate steps are taken to ensure its conservation. Characterisation is an integral part of the conservation program. The Polymerase Chain Reaction-Randomly Amplified Polymorphic DNA profile of unrelated camels of the Bikaneri (29), Jaisalmeri (30) and Kachchhi (18) breeds were analyzed. Reproducible polymorphic bands with varying frequencies among the three breeds of camel were obtained with five oligonucleotide primers. A total of 75 bands were amplified, of which 27 (36%) were polymorphic. The probability of obtaining identical fingerprints was observed to be the lowest in primer GC-10 (5.7%) followed by OP-08 (8.7%), GT-10 (11.3%), G-2 (15.5%) and G-1 (80%). Breed informative bands were amplified. The maximum genetic variability was observed in the Bikaneri (0.80±0.05) followed by the Kachchhi (0.84±0.06) and the Jaisalmeri (0.87±0.05) breeds. The inter-breed genetic distance estimates indicated a closer relationship in the Bikaneri-Kachchhi camels, (0.075), followed by the Jaisalmeri-Kachchhi (0.106) and Bikaneri-Jaisalmeri (0.132) breeds. A similar genetic relationship was observed when the degree of population subdivision was measured between the Bikaneri-Kachchhi (0.529), Jaisalmeri-Kachchhi (0.558) and Bikaneri-Jaisalmeri (0.566) breeds.


1987 ◽  
Vol 15 (3) ◽  
pp. 357-363
Author(s):  
Violeta Lopez-Gonzaga

Filipino women have traditionally enjoyed greater equality than women in other Southeast Asian countries, and women have played an important role in keeping families together despite impoverished conditions. One such woman is Rufina, who grew up amid poverty, and began working at the age of 14 to help support her family. More recently, due to military conflict in the countryside, she was forced to flee with her six children to the city of Bacolod, where she lived in an abandoned storage building with five other refugee families. Amid the crisis her two youngest children died, but through the seemingly hopeless circumstances, Rufina found hope through the ministry of a Christian evangelist, who was able to offer her medical aid and food supplies through a local congregation of believers.


2016 ◽  
Vol 144 (11) ◽  
pp. 2268-2275 ◽  
Author(s):  
M. M. NGWE TUN ◽  
S. INOUE ◽  
K. Z. THANT ◽  
N. TALEMAITOGA ◽  
A. ARYATI ◽  
...  

SUMMARYChikungunya virus (CHIKV) and Ross River virus (RRV) of the genusAlphavirus, family Togaviridae are mainly transmitted byAedesmosquitoes and the symptoms they cause in patients are similar to dengue. A chikungunya (CHIK) outbreak re-emerged in several Asian countries during 2005–2006. This study aimed to clarify the prevalence of CHIKV infection in suspected dengue patients in six countries in South Asia and Southeast Asia. Seven hundred forty-eight serum samples were from dengue-suspected patients in South Asia and Southeast Asia, and 52 were from patients in Fiji. The samples were analysed by CHIKV IgM capture ELISA, CHIKV IgG indirect ELISA and focus reduction neutralization test against CHIKV or RRV. CHIK-confirmed cases in South Asia, particularly Myanmar and Sri Lanka, were 4·6%, and 6·1%, respectively; and in Southeast Asia, particularly Indonesia, the Philippines and Vietnam, were 27·4%, 26·8% and 25·0%, respectively. It suggests that CHIK was widely spread in these five countries in Asia. In Fiji, no CHIK cases were confirmed; however, RRV-confirmed cases represented 53·6% of suspected dengue cases. It suggests that RRV is being maintained or occasionally entering from neighbouring countries and should be considered when determining a causative agent for dengue-like illness in Fiji.


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