First Report of Anthracnose on Ctenanthe oppenheimiana Caused by Colletotrichum siamense in China

Pest categorisation of Colletotrichum aenigma, C. alienum, C. perseae, C. siamense and C. theobromicola

The EFSA Plant Health Panel performed a pest categorisation of Colletotrichum aenigma, C. alienum, C. perseae, C. siamense and C. theobromicola, five clearly defined fungi of the C. gloeosporioides complex causing anthracnose. The pathogens are widely distributed in at least three continents. C. aenigma and C. siamense are reported from Italy and C. alienum from Portugal, including the Madeira Islands, with a restricted distribution. C. perseae and C. theobromicola are not known to be present in the EU. However, there is uncertainty on the status of the pathogens worldwide and in the EU because of the taxonomic re-evaluation of the genus Colletotrichum and the lack of specific surveys. The pathogens are not included in Commission Implementing Regulation (EU) 2019/2072 and there are no reports of interceptions in the EU. With the exception of C. perseae, which has a very limited number of hosts, the other four Colletotrichum species have relatively wide host ranges. Therefore, this pest categorisation focused on those hosts for which there is robust evidence that the pathogens were formally identified by a combination of morphology, pathogenicity and multilocus sequence analysis. Host plants for planting and fresh fruits are the main entry pathways into the EU. Host availability and climate suitability factors occurring in some parts of the EU are favourable for the establishment of the pathogens. No yield losses have been reported so far in the EU but in non-EU areas of their current distribution, the pathogens have a direct impact on cultivated hosts that are also relevant for the EU. Phytosanitary measures are available to prevent the further introduction and spread of C. aenigma, C. alienum and C. siamense into the EU as well as the introduction and spread of C. perseae and C. theobromicola. C. aenigma, C. alienum, C. perseae, C. siamense and C. theobromicola satisfy the criteria that are within the remit of EFSA to assess for these species to be regarded as potential Union quarantine pests.

An Efficient Method for DNA Purification-Free PCR from Plant Tissue

Amplification of genomic DNA fragments by PCR is necessary for plant molecular biology approaches such as genotyping. While this is a routine molecular technique in a modern laboratory, there are still significant hurdles when analyzing a large number of samples or collecting and storing samples while in the field. Because PCR amplification directly from plant tissue is often unsuccessful due to various inhibitors, genomic DNA purification is usually required, which involves laborious and time-consuming procedures or costly materials, particularly when using commercial kits. These undermine scalability and use in less-equipped settings. In addition, plant tissues and purified DNA need to be stored under proper conditions to avoid degradation. Here, we describe a low-cost, high-throughput PCR method to amplify genomic DNA fragments from plant tissue pounded to cellulose-based filter paper without the need for DNA purification or special equipment for sample storage. In this protocol, a small punch of plant tissue is pounded to a commercially available or homemade DNA storage card and directly placed into a PCR mixture containing Tween-20, a non-ionic detergent, directly followed by PCR. We also describe the steps to prepare a homemade DNA storage card, which is easy to make and can be stored with plant tissue at room temperature for a long time without any special equipment, allowing us to test the same sample multiple times. We have used this method in at least eleven plant species, including arabidopsis, tomato, soybean, potato, cotton, and rice. Altogether, our method decreases labor and cost, thereby increasing throughput and making plant DNA-based molecular diagnostic assays accessible to resource-limited settings, including classrooms, and facilitating sample collection in the field. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Making a homemade cellulose-based DNA storage card Basic Protocol 2: Pounding plant tissue on a DNA storage card Basic Protocol 3: DNA-purification free PCR.