IPentastiridius leporinus/I as a Vector of Phloem-Restricted Pathogens on Potatoes: ‘ICandidatus/I Arsenophonus Phytopathogenicus’ and ‘ICandidatus/I Phytoplasma Solani’

• Published in: Insects (Basel, Switzerland) Switzerland), 2024-03, Vol.15 (3)
• Main Authors: Therhaag, Eva, Schneider, Bernd, Zikeli, Kerstin, Maixner, Michael, Gross, Jürgen
• Format: Article
• Language: English
• Subjects: Analysis; Diseases and pests; Influence; Planthoppers; Potatoes; Sugar beet; Vector-borne diseases
• ISSN: 2075-4450; 2075-4450
• DOI: 10.3390/insects15030189

In Germany, the planthopper Pentastiridius leporinus currently represents the most important vector for the spread of two pathogens, ‘Candidatus Arsenophonus phytopathogenicus’ and ‘Candidatus Phytoplasma solani’, which are associated with the syndrome “Basses Richesses” in sugar beets. In 2022, this planthopper was also found in potato fields in Germany along with symptoms of yellowing, wilting and rubbery tubers. In this study, greenhouse experiments with adult P. leporinus were conducted showing that it is able to transmit both pathogens to potatoes. Furthermore, it was confirmed that this vector can complete its entire lifecycle on both crops. To enable an accurate assessment of the phytoplasma titer in the vector and host plant, real-time PCR assays were performed using a synthetic DNA standard. Our study results highlight that P. leporinus may play an increasingly important role in agricultural cropping systems being a vector for two bacterial pathogens in two crops. In Germany, the phloem-sucking planthopper Pentastiridius leporinus (Hemiptera: Cixiidae) currently represents the epidemiological driver for the spread of the syndrome “Basses Richesses” in sugar beets, which results in a reduced sugar content and an economic loss for the farmers. This disease is associated with the γ-proteobacterium ‘Candidatus Arsenophonus phytopathogenicus’ and the Stolbur phytoplasma ‘Candidatus Phytoplasma solani’. Recently, P. leporinus was found in potato fields in Germany and is associated with Stolbur-like symptoms in this crop. In this study, we confirmed that the vector completes its lifecycle on sugar beets as well as on potatoes when reared under controlled conditions. Transmission experiments with adults of this vector combined with molecular analyses showed, for the first time, that both pathogens are transmitted by this vector to potatoes. For an accurate assessment of the Ca. P. solani and Ca. A. phytopathogenicus titers in the vector and host plants, gBlocks derived from the hsp20- and 16S rRNA genes were employed, respectively. For Ca. P. solani, the limit of detection was determined in potato and sugar beet material. The results of this study will further the research on the epidemiology of the syndrome “Basses Richesses” and “Stolbur” diseases and the response of host plants and vector insects to both pathogens.