Screening potential insect vectors in a museum biorepository reveals undiscovered diversity of plant pathogens in natural areas

Abstract

Phytoplasmas (Mollicutes, Acholeplasmatales, Acholeplasmataceae) are a large group of phloem-restricted, cell wall-less, vector-borne bacteria that infect hundreds of plant species and cause serious economic loss worldwide (Rao et al., 2018). In plants, phytoplasma infection may induce a variety of typical symptoms including virescence, phyllody, and witches'-broom, thereby altering plant morphology, growth patterns,

Comparison of Traditional and Next-Generation Approaches for Uncovering Phytoplasma Diversity, with Discovery of New Groups, Subgroups and Potential Vectors

“…We provide a new methodological protocol to analyze the diversity of phytoplasmas and also report the discovery of new strains. Our findings build on recent work suggesting that natural areas worldwide harbor a highly diverse assemblage of undocumented phytoplasmas [3].…”

“…Graminella sonora (from USA, Arizona), a widespread grass-feeding species, tested positive for phytoplasma here for the first time; its congener, Graminella nigrifrons is a known vector of aster yellows phytoplasmas in the USA [36]. Doratura homophyla (from France), a grass-feeding species, is recorded in association with phytoplasmas for the first time and [3] (points in yellow, 2021) . Map created QGIS 3.8 and was modified with Adobe Photoshop CC 2019.…”

“…However, as has already been well documented for other groups of organisms, natural habitats worldwide continue to harbor large numbers of undiscovered taxa [ 2 ]. Recent discoveries of new phytoplasmas in natural areas worldwide suggest that the diversity and ecology of this ancient lineage of highly specialized bacteria remain poorly known [ 3 , 4 ]. Broader knowledge of phytoplasma diversity and phylogeny will be crucial to uncovering the evolutionary mechanisms that drive host shifts and evolution in this system, and for providing a framework to understand the potential of previously undiscovered phytoplasmas as future threats to agriculture [ 5 ].…”

“…Recently, we used quantitative PCR (qPCR) to screen a large sample of phloem-feeding leafhoppers (227 species) collected in natural areas worldwide. We detected phytoplasmas in 3% of the samples and the phytoplasmas detected represented 6 previously unknown phytoplasma subgroups [ 3 , 4 ]. These results not only indicate that natural areas worldwide harbor a large diversity of undocumented phytoplasmas but also suggest that screening DNA extracted from phloem-feeding leafhoppers is an efficient method for discovering new phytoplasmas.…”

Metatranscriptomic Assessment of the Microbial Community Associated With the Flavescence dorée Phytoplasma Insect Vector Scaphoideus titanus

“…The past decade has also witnessed a rise in the studies describing microbiome dynamics in insect vectors of plant pathogens, such as whiteflies (Himler et al, 2011 ; Su et al, 2015 ), psyllids (Fagen, 2012 ; Meng et al, 2019 ), sharpshooters (Hail et al, 2011 ; Rogers and Backus, 2014 ) and aphids (McLean et al, 2019 ; He et al, 2021 ). Likewise, unraveling the diversity of microorganisms associated with phytoplasma insect vectors is gaining increasing importance due to the devastating impact of phytoplasmas on agricultural production worldwide (Kumari et al, 2019 ) and the recent finding that their diversity and potential insect host range have been so far largely underestimated (Trivellone et al, 2021 ). Insect vectors of these bacterial plant pathogens are phloem feeders of the order Hemiptera , mainly leafhoppers, planthoppers, and psyllids.…”