Draft Genome Resources of Two Strains (“ESVL” and “IVIA5901”) of Xylella fastidiosa Associated with Almond Leaf Scorch Disease in Alicante, Spain

Abstract

An outbreak of Xylella fastidiosa subsp. multiplex sequence type ST6 was discovered in 2017 in mainland Spain affecting almond trees. Two cultured almond strains, “ESVL” and “IVIA5901,” were subjected to high throughput sequencing and the draft genomes assembled. Phylogenetic analysis conclusively indicated they belong to the subspecies multiplex, and pairwise comparisons of the chromosomal genomes showed an average nucleotide identity higher than 99%. Interestingly, the two strains differ for the presence of the plasmids pXF64-Hb_ESVL and pUCLA-ESVL detected only in the ESVL strain. The availability of these draft genomes contribute to extend the European genomic sequence dataset, a first step toward setting new research to elucidate the pathway of introduction and spread of the numerous strains of this subspecies so far detected in Europe.

Phylogenetic inference enables reconstruction of a long-overlooked outbreak of almond leaf scorch disease (Xylella fastidiosa) in Europe

“…ALSD was first reported in California in the mid-1930's 9,30 , and more recently there have been confirmed outbreaks in Iran 11 , in Alicante in eastern Spain 29 and in the Hula Valley, Israel 33 . In California, ALSD is transmitted by xylem specialist insect species commonly known as sharpshooter leafhoppers (Hemiptera: Cicadellidae) and by the meadow spittlebug, P. spumarius, although the latter seems to play a secondary role in disease transmission 34 .…”

“…A new disease named 'olive quick decline syndrome' is caused by a strain of the subspecies pauca, mainly transmitted by the insect Philaenus spumarius (Hemiptera: Aphrophoridae) 20,21,23 . Since 2013, various Xf genotypes belonging to fastidiosa, pauca, multiplex and 'sandyi' subspecies have been intercepted in and/or introduced into Europe [24][25][26][27][28][29] .…”

“…multiplex belonging to ST6 and ST7, which form a clonal complex integrated into a monophyletic clade 31,35 . The phylogeny and likely origin of these strains have been reviewed by Nunney et al 36,37 , and the complete genomes of several representative ALSD strains have been sequenced 29,38,39 . ST1 strains infect grapevines and can cross-infect almonds as well, whereas almond strains of ST6/7 do not cause disease on grapevines 30 .…”

La dimensión geográfica de las invasiones biológicas en el Antropoceno: el caso de Xylella fastidiosa

“…Desde entonces se han producido daños gravísimos en los olivares de dicha región (Carlucci, et al, 2013;Mang, et al, 2016), lo cual ha llevado a las autoridades regionales a declarar el estado de emergencia fitosanitaria (http://www.emergenzaxylella.it). En noviembre 2016, se reporta el primer registro de presencia en las Islas Baleares ) y en 2017 se detectan los primeros brotes de X. fastidiosa en sureste de la península Ibérica (Giampetruzzi et al, 2018). Ya en 2018, se detectó la presencia del patógeno en otros enclaves puntuales del centro de la península Ibérica y en región italiana de la Toscana, al tiempo que prosigue su avance en el sureste (Alicante).…”

Tracking the outbreak. An optimized delimiting survey strategy for Xylella fastidiosa

“…So far, only Xf subsp. multiplex has been detected in the demarcated area (Giampetruzzi et al, 2018). With circa 2,000 orchards and 51,000 trees already destroyed (GVA, 2019), this outbreak represent one of the largest plant disease eradication campaigns ever attempted in Europe.…”