Lavender Decline in France Is Associated with Chronic Infection by Lavender-Specific Strains of “Candidatus Phytoplasma solani”

Abstract

The etiology and main pathways for the spread of lavender decline, an infectious disease affecting French lavender production since the 1960s, have remained unclear, hampering the development of efficient control strategies. An extensive survey of lavender fields led to the conclusion that “Candidatus Phytoplasma solani” was chronically infecting declining lavenders and was associated with large infectious populations of Hyalesthes obsoletus planthoppers living on the crop itself. Lavender appeared to be the main reservoir host for lavender-specific phytoplasma strains, an unusual feature for this phytoplasma, which usually propagates from reservoir weeds to various economically important crops. These results point out the necessity to protect young lavender fields from the initial phytoplasma inoculum coming from surrounding lavender fields or from infected nurseries and to promote agricultural practices that reduce the development of H. obsoletus vector populations.

Proposal of A New Bois Noir Epidemiological Pattern Related to ‘Candidatus Phytoplasma Solani’ Strains Characterized by A Possible Moderate Virulence in Tuscany

“…Unique stamp and secY nucleotide sequences, identified in this study, were attributed to sequence variants by their comparison with sequences previously deposited in GenBank and listed in reference datasets previously published [13,14] and provided in the present study (Tables S1-S3). No correspondence was present between the names of sequence variants listed in the reference datasets here utilized and those submitted in the GenBank database in another study [33]. For each stamp and secY sequence variant never reported before this study, one representative nucleotide sequence was deposited in the NCBI GenBank.…”

Field-based metabolomic reveals alteration of the volatiles organic compounds produced by Lavandula species in the context of yellow decline disease

“…Over the last years, French lavender crops have suffered from the combined effect of the yellow decline disease and repeated severe drought (Sémétey et al 2018). Yellow decline is associated with the presence of Stolbur phytoplasma (Candidatus Phytoplasma solani), a cell wall-less bacterium, which causes a severe decline in lavender plantations.…”

“…Yellow decline is associated with the presence of Stolbur phytoplasma (Candidatus Phytoplasma solani), a cell wall-less bacterium, which causes a severe decline in lavender plantations. This pathogen is transmitted by an insect vector, the planthopper Hyalesthes obsoletus (Hemiptera: Cixiidae), during feeding on lavender phloem sap (S. Kessler et al 2011;Sémétey et al 2018). It is now well known that volatile organic compounds (VOCs) emitted by plants play a crucial role in plant-insect interactions (Becker et al 2015; A.…”

Quick and efficient approach to develop genomic resources in orphan species: Application in Lavandula angustifolia

“…Initially collected in its natural habitat, the best individuals and the best lavender populations were selected by mass selection and cultivated on plateaus and plains for their essential oil. Nowadays, the new environmental challenges: drought, biotic stresses (mainly lavender decline caused by Candidatus Phytoplasma solani [13]), underline the need to select new varieties adapted to these stresses, while keeping good essential oil yields and a quality corresponding to the standards of the market. Traditional breeding may not be sufficient to address those challenges so that it is critical to develop genomic tools helping to improve breeding programs efficiency.…”