By Cielito M. Reganit
MANILA, July 8 (PNA) — The Philippine Rice Research Institute (PhilRice), with support from the Department of Agriculture’s Biotechnology Program, is developing a fast, efficient and accurate method to detect viruses in rice and insect vectors in order to enable farmers know if their crops are in danger of damage or loss due to viral disease even before any symptoms appear.
Dr. Emmanuel Tiongco, PhilRice research fellow, said that recent advances in biotechnology have led to the development of the loop-mediated isothermal amplification (LAMP) assay in Japan which has been proven successful in diagnosing pathogens in animals and humans.
“If it was successful in humans and animal, we believe that we could also use LAMP in plants,” the head of the study group said.
The procedure for LAMP is known to be user-friendly and relatively faster compared to previous biotechnological methods employed to detect rice viruses.
Tiongco’s team has been focusing 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 in 1 day after inoculation (DAI),” Tiongco said.
He said that 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 said.
“This proves that LAMP can detect the virus even before disease actually happens,” Tiongco said.
With the successful RRSV detection by LAMP in the BPH vector, an operational virus detection system in insects 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
This early, 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.
Tiongco noted that conventional assessment is not very reliable because symptoms are, in some cases, due to other factors such as nutrient or water deficiency.
Likewise, 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.
The PhilRice scientist said that with the very promising results in LAMP assay studies his group had painstakingly undertaken, it is already 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. (PNA)