The Philippine Rice Research Institute, with support from the DA’s Biotechnology Program, is developing a fast, efficient and accurate method to detect viruses in rice and insect vectors that aims to enable farmers know if their crops are in danger of damage or loss due to viral disease—even before any symptoms appear.

“It’s a good thing that recent advances in biotechnology have led to the development of the loop-mediated isothermal amplification (LAMP) assay by Natomi and his team of Eiken, Japan,” said Dr. Emmanuel Tiongco, research fellow at the Philippine Rice Research Institute, who heads the study on using LAMP as a virus detection method in the rice plant and their associated vectors.

“It has already been successful in diagnosing for pathogens in animals and humans, so why not plants?” he added.

The procedure for LAMP is known to be user friendly and relatively faster compared to previous biotechnological methods employed to detect rice viruses.

Together with Dr. Rubigilda Paraguison-Alili, Dr. Xuan Hoai Truong, and Ms. Ma. Johna Duque, Tiongco’s team has focused on the rice tungro bacilliform virus (RTBV), rice tungro spherical virus (RTSV), rice grassy stunt virus (RGSV), and rice ragged stunt virus (RRSV). Shortly, they will work on the rice dwarf virus (RDV) and its green leafhopper vector.

Initiated in August 2012, the project is expected to be completed within the year or early next year. Preliminary results have been very promising.

“LAMP assay results reveal that RTBV can be detected at 1 day after inoculation (DAI),” according to Tiongco. This is in stark contrast to the three DAIs required for symptoms to appear.

“We have bested ELISA, the previously established biotechnological method for detecting viruses in rice, by a full two DAIs. Further, RRSV was detected in the brown planthopper (BPH) by LAMP,” he added, meaning LAMP can detect the virus even before disease actually happens.

With the successful RRSV detection by LAMP in the BPH vector by Tiongco’s team, an operational virus detection system in the insect can be achieved and can be done even without a standing rice crop.

This may prevent a repeat of the devastating damage by RRSV in Vietnam and Thailand in 2005-2006 to happen in the Philippines. LAMP assay is, therefore, poised to become the ideal diagnostic tool for detecting RRSV in both the rice plant and the insect vectors.

“As long as we have stringent molecular lab conditions, LAMP assay is ideal,” Tiongco said.

Many stakeholders are already waiting for the final results of the study which could mean reduced misdiagnosis of rice diseases and timely delivery of pest management systems for farmers that would eventually translate to the reduction of costs from misuse and expenditure of pesticides.

Rice is the main staple food in the Philippines and its neighboring countries. It is by and large the biggest agricultural industry in the Philippines with 3.2 million hectares of land planted to rice season after season annually producing up to 19 million metric tons of grains.

However, its yield stability has been constantly threatened by insect pests and the viruses that they transmit.

Conventionally, assessment of rice virus disease incidence is done by visually inspecting the plants for symptoms, which happen when the disease is already prevalent.

Consequently, this impacts the efficacy of subsequent control measures. Conventional assessment is not very reliable because symptoms are, in some cases, due to other factors such as nutrient or water deficiency.

The common biotechnological methods being used are expensive and time-consuming. In some occasions, detection methods are unable to detect viral infections when the aggregate of viruses is very low. (DA-Biotechnology Program)

Posted By: Lynne Pingoy


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