<i>Xylella fastidiosa</i> subsp. <i>pauca</i><scp>ST53</scp> exploits pit membranes of susceptible olive cultivars to spread systemically in the xylem

Montilon, Vito; Stradis, A. De; Saponari, María; Kubaa, Raied Abou; Giampetruzzi, Annalisa; D’Attoma, Giusy; Saldarelli, P.

doi:10.1111/ppa.13646

Cited by 19 publications

(32 citation statements)

References 37 publications

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“…Samples of this diameter were chosen to select for approximately 1-year-old semihardwood stems. Both molecular and cytopathological evidence show that X. fastidiosa replicates and damages the xylem in vessels of 1-year-old stems (Montilon et al, 2022). The age of the stem is a developmental parameter that makes the comparison between cultivars uniform.…”

Section: Sample Selection and Preparationmentioning

confidence: 99%

The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa: An image‐based study

et al. 2022

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Xylella fastidiosa is a xylem-limited plant pathogen infecting many crops globally and is the cause of the recent olive disease epidemic in Italy. One strategy proposed to mitigate losses is to replant susceptible crops with resistant varieties. Several genetic, biochemical and biophysical traits are associated to X. fastidiosa disease resistance.However, mechanisms underpinning resistance are poorly understood. We hypothesize that the susceptibility of olive cultivars to infection will correlate to xylem vessel diameters, with narrower vessels being resistant to air embolisms and having slower flow rates limiting pathogen spread. To test this, we scanned stems from four olive cultivars of varying susceptibility to X. fastidiosa using X-ray computed tomography.Scans were processed by a bespoke methodology that segmented vessels, facilitating diameter measurements. Though significant differences were not found comparing stem-average vessel section diameters among cultivars, they were found when comparing diameter distributions. Moreover, the measurements indicated that although vessel diameter distributions may play a role regarding the resistance of Leccino, it is unlikely they do for FS17. Considering Young-Laplace and Hagen-Poiseuille equations, we inferred differences in embolism susceptibility and hydraulic conductivity of the vasculature. Our results suggest susceptible cultivars, having a greater proportion of larger vessels, are more vulnerable to air embolisms. In addition, results suggest that under certain pressure conditions, functional vasculature in susceptible cultivars could be subject to greater stresses than in resistant cultivars. These results support investigation into xylem morphological screening to help inform olive replanting. Furthermore, our framework could test the relevance of xylem geometry to disease resistance in other crops.

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Section: Sample Selection and Preparationmentioning

confidence: 99%

The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa: An image‐based study

et al. 2022

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“…In addition, molecular mechanisms entailing the plant cell wall receptors have been described in transcriptome studies (Giampetruzzi et al, 2016). The cell wall involvement is also supported by recent electron microscopy observations showing a higher pit membranes degradation in susceptible Cellina di Nardò compared to Leccino (Giampetruzzi et al, 2021;Montilon et al, 2022).…”

Section: Introductionmentioning

confidence: 74%

“…In addition, changes in the stem hydraulic conductivity and consequently in the water transport occur in the infected plants as a direct impact of the bacterial dynamics and spread in the xylem tissues; more specifically as documented in grapevine, the degradation of Pit Membrane-middle lamellas by the bacterium cell wall degrading enzymes (Fanton and Brodersen, 2021 ) is one of the mechanisms underlining the loss of hydraulic conductivity. Similarly, a severe degradation of the pit membranes occurs in the susceptible cultivar Cellina di Nardò compared to the resistant cultivar Leccino (Giampetruzzi et al, 2021 ; Montilon et al, 2022 ). All together, these studies and the results herein reveal that Xfp infection determines physiological alterations in olives resembling a water stress, and that these changes are less pronounced in resistant cultivars.…”

Section: Discussionmentioning

confidence: 99%

Susceptible and resistant olive cultivars show differential physiological response to Xylella fastidiosa infections

Surano

Kubaa²,

Nigro³

et al. 2022

Front. Plant Sci.

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Olive quick decline syndrome (OQDS) is a severe disease, first described in Italy in late 2013, caused by strains of Xylella fastidiosa subsp. pauca (Xfp) in susceptible olive cultivars. Conversely, resistant olive cultivars do not develop OQDS but present scattered branch dieback, which generally does not evolve to severe canopy decline. In the present study, we assessed the physiological responses of Xfp-infected olive trees of susceptible and resistant cultivars. Periodic measurements of stomatal conductance (gs) and stem water potential (Ψstem) were performed using a set of healthy and Xfp-infected plants of the susceptible “Cellina di Nardò” and resistant “Leccino” and “FS17” cultivars. Strong differences in Δgs and ΔΨstem among Xfp-infected trees of these cultivars were found, with higher values in Cellina di Nardò than in Leccino and FS17, while no differences were found among healthy plants of the different cultivars. Both resistant olive cultivars showed lower water stress upon Xfp infections, compared to the susceptible one, suggesting that measurements of gs and Ψstem may represent discriminating parameters to be exploited in screening programs of olive genotypes for resistance to X. fastidiosa.

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“…fastidiosa infection (Chatelet et al, 2011;Ingel et al, 2019;Montilon et al, 2022;Sun et al, 2011). Previous studies have analysed pit structure in relation to X. fastidiosa disease resistance (Montilon et al, 2022;Niza et al, 2015); however, studies have not yet examined differences in the distributions of these pits, which could equally have significant implications for pathogen virulence.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

A high‐throughput analysis of high‐resolution X‐ray CT images of stems of olive and citrus plants resistant and susceptible to Xylella fastidiosa

Walker,

Ruiz,

Ferreira

et al. 2023

Plant Pathology

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The bacterial plant pathogen Xylella fastidiosa causes disease in several globally important crops. However, some cultivars harbour reduced bacterial loads and express few symptoms. Evidence considering plant species in isolation suggests xylem structure influences cultivar susceptibility to X. fastidiosa. We test this theory more broadly by analysing high‐resolution synchrotron X‐ray computed tomography of healthy and infected plant vasculature from two taxonomic groups containing susceptible and resistant varieties: two citrus cultivars (sweet orange cv. Pera, tangor cv. Murcott) and two olive cultivars (Koroneiki, Leccino). Results found the susceptible plants had more vessels than resistant ones, which could promote within‐host pathogen spread. However, features associated with resistance were not shared by citrus and olive. While xylem vessels in resistant citrus stems had comparable diameters to those in susceptible plants, resistant olives had narrower vessels that could limit biofilm spread. And while differences among olive cultivars were not detected, results suggest greater vascular connectivity in resistant compared to susceptible citrus plants. We hypothesize that this provides alternate flow paths for sustaining hydraulic functionality under infection. In summary, this work elucidates different physiological resistance mechanisms between two taxonomic groups, while supporting the existence of an intertaxonomical metric that could speed up the identification of candidate‐resistant plants.

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Xylella fastidiosa subsp. paucaST53 exploits pit membranes of susceptible olive cultivars to spread systemically in the xylem

Cited by 19 publications

References 37 publications

The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa: An image‐based study

The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa: An image‐based study

Susceptible and resistant olive cultivars show differential physiological response to Xylella fastidiosa infections

A high‐throughput analysis of high‐resolution X‐ray CT images of stems of olive and citrus plants resistant and susceptible to Xylella fastidiosa

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