-Quick and accurate diagnosis possible by real-time PCR-
National Agriculture and Food Research Organization (NARO) has developed a new technology to detect and identify Diaporthe destruens causing foot rot disease of sweet potatoes. It is possible to distinguish and identify a related fungal species of the Diaporthe batatas that causes dry rot disease of sweet potatoes. In recent years, the outbreak of foot rot disease has been confirmed and caused widespread damage in Japan. This newly developed technology has provided a quick and accurate diagnosis of foot rot disease. This contributes to prevention of widespread of damage caused by disease by means of quick and accurate diagnosis of foot rot disease.
Sweet potatoes when infected by D. destruens, then the symptoms of foot rot disease appear from its base and then wither. Also, it causes rot of bulbs and serious damage to the production area of sweet potatoes. It is said that due to the movement of infected seedlings and plant residue, the outbreak region/area may spread widely. Outbreak of foot rot disease was first confirmed in Japan in 2018 and are currently confirmed in 19 prefectures (as of August 25, 2021). NARO is working on the development of countermeasure technology for foot rot disease in order to prevent the spread of outbreak areas and to suppress the damage in areas where the disease has already occurred. We have recently developed a new detection and identification technology that enables early diagnosis of this disease.
In Japan, D. batatas causing dry rot disease of sweet potatoes, which is a related species of the D. destruens causing foot rot disease, is also distributed in a wide area of the country already, and it has been known that the root tuber are mainly rotted during storage. On the other hand, foot rot disease still occurs only in a limited area of the country. Since it spreads in the field during the growing season and causes more serious damage to the production than the existing dry rot disease, in addition to controlling it in the field, it is also necessary to prevent the spread to unaffected areas through seedlings. If suspicious symptoms are found, they should be distinguished from dry rot disease and immediate action should be taken. However, the pathogens causing foot rot disease and dry rot disease are morphologically similar, and it took about two weeks to accurately determine the cause.
Meanwhile NARO has developed a technology to detect and identify foot rot and dry rot pathogens with high accuracy in a minimum time span of about one day by real-time PCR using each of specific primers that can specifically detect both species.
By utilizing this technology, it is possible to grasp the outbreak at an early stage and take appropriate control measures, which leads to the suppression of the spread of the outbreak area. In addition, it is expected to speed up the development of new control technology to restore the production of sweet potato in the areas where the outbreak has already occurred. This technology has already been used for confirmation of first disease outbreak in some prefecture by NARO and is expected to be used in other prefectures of Japan in the future.
Real-Time PCR Assay for the Diagnosis and Quantification of Co-infections by Diaporthe batatas and Diaporthe destruens in Sweet Potato. Front. Plant Sci.22 June 2021 URL: https://www.frontiersin.org/articles/10.3389/fpls.2021.694053/full