Pentastiridius leporinus (Linnaeus, 1761) as a Vector of Phloem-Restricted Pathogens on Potatoes: ‘Candidatus Arsenophonus Phytopathogenicus’ and ‘Candidatus Phytoplasma Solani’

Abstract

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.

Prevalence in Potato of ‘Candidatus Arsenophonus Phytopathogenicus’ and ‘Candidatus Phytoplasma Solani’ and Their Transmission via Adult Pentastiridius leporinus

“…Systemic infection may promote the spreading of stolbur to healthy plants during seed potato distribution, which would necessitate the testing of seed tubers to maintain phytosanitary conditions. Arsenophonus and stolbur were recently shown to be transmitted to potato tubers by field-collected P. leporinus adults at rates of 48% and 12%, respectively [18]. By detection in the shoots, leaves, and roots, we observed higher transmission rates for both pathogens.…”

“…Furthermore, Arsenophonus was detected in potato tubers taken from that region, with plants showing symptoms like wilting, yellow leaves, and rubbery tubers, and are referred to as bacterial tuber wilt. Subsequent transmission assays demonstrated the ability of P. leporinus nymphs and adults to transmit Arsenophonus to potatoes [17,18]. Although Arsenophonus can infect potato tubers, its propagation through infected seed tubers has not been verified.…”