TY - JOUR

T1 - Transmission of Bacterial Symbionts With and Without Genome Erosion Between a Beetle Host and the Plant Environment

AU - Wierz, Jürgen C.

AU - Gaube, Paul

AU - Klebsch, Dagmar

AU - Kaltenpoth, Martin

AU - Flórez, Laura V.

N1 - Publisher Copyright: © Copyright © 2021 Wierz, Gaube, Klebsch, Kaltenpoth and Flórez.

PY - 2021

Y1 - 2021

N2 - Many phytophagous insects harbor symbiotic bacteria that can be transmitted vertically from parents to offspring, or acquired horizontally from unrelated hosts or the environment. In the latter case, plants are a potential route for symbiont transfer and can thus foster a tripartite interaction between microbe, insect, and plant. Here, we focus on two bacterial symbionts of the darkling beetle Lagria villosa that belong to the genus Burkholderia; the culturable strain B. gladioli Lv-StA and the reduced-genome strain Burkholderia Lv-StB. The strains can be transmitted vertically and confer protection to the beetle’s eggs, but Lv-StA can also proliferate in plants, and both symbiont strains have presumably evolved from plant pathogens. Notably, little is known about the role of the environment for the transmission dynamics and the maintenance of the symbionts. Through manipulative assays, we demonstrate the transfer of the symbionts from the beetle to wheat, rice and soybean plants, as well as leaf litter. In addition, we confirm that aposymbiotic larvae can pick up Lv-StA from dry leaves and the symbiont can successfully establish in the beetle’s symbiotic organs. Also, we show that the presence of plants and soil in the environment improves symbiont maintenance. These results indicate that the symbionts of L. villosa beetles are still capable of interacting with plants despite signatures of genome erosion and suggest that a mixed-mode of bacterial transmission is likely key for the persistence of the symbiosis.

AB - Many phytophagous insects harbor symbiotic bacteria that can be transmitted vertically from parents to offspring, or acquired horizontally from unrelated hosts or the environment. In the latter case, plants are a potential route for symbiont transfer and can thus foster a tripartite interaction between microbe, insect, and plant. Here, we focus on two bacterial symbionts of the darkling beetle Lagria villosa that belong to the genus Burkholderia; the culturable strain B. gladioli Lv-StA and the reduced-genome strain Burkholderia Lv-StB. The strains can be transmitted vertically and confer protection to the beetle’s eggs, but Lv-StA can also proliferate in plants, and both symbiont strains have presumably evolved from plant pathogens. Notably, little is known about the role of the environment for the transmission dynamics and the maintenance of the symbionts. Through manipulative assays, we demonstrate the transfer of the symbionts from the beetle to wheat, rice and soybean plants, as well as leaf litter. In addition, we confirm that aposymbiotic larvae can pick up Lv-StA from dry leaves and the symbiont can successfully establish in the beetle’s symbiotic organs. Also, we show that the presence of plants and soil in the environment improves symbiont maintenance. These results indicate that the symbionts of L. villosa beetles are still capable of interacting with plants despite signatures of genome erosion and suggest that a mixed-mode of bacterial transmission is likely key for the persistence of the symbiosis.

KW - Burkholderia

KW - Coleoptera

KW - environmental symbiont acquisition

KW - insect symbiosis

KW - insect-plant-microbe

KW - Lagriinae

KW - mixed-mode transmission

KW - reduced genome

U2 - 10.3389/fmicb.2021.715601

DO - 10.3389/fmicb.2021.715601

M3 - Journal article

C2 - 34630349

AN - SCOPUS:85116544654

VL - 12

JO - Frontiers in Microbiology

JF - Frontiers in Microbiology

SN - 1664-302X

M1 - 715601

ER -