Physiochemical responses of Ailanthus altissima under the challenge of Verticillium dahliae: elucidating the decline of one of the world’s worst invasive alien plant species

Abstract

Natural infections of Verticillium spp. (Fungi, Ascomycota) on Ailanthus altissima have suggested to consider the biological control as a promising strategy to counteract this invasive plant, which is otherwise difficult to control by traditional mechanical and chemical treatments. Verticillium wilt is able to lead plants to death, throughout a pathogenic mechanism including vessel occlusions and production of degrading enzymes and phytotoxins. In this study, a 10 weeks open air pot experiment was set to investigate the ecophysiological and biochemical responses of Ailanthus trees artificially inoculated in the trunk with the V. dahliae strain VdGL16, previously isolated in Central Italy from the same host. Inoculated plants showed visible injuries starting from 2 weeks post inoculation (wpi), that progressively developed until a final severe defoliation. The fungal infection rapidly compromised the plant water status, and photosynthesis was impaired due to both stomatal and mesophyll limitations from 4 wpi, with subsequent detrimental effects also on PSII activity. Moreover, the disease altered the translocations of nutrients, as confirmed by cation and carbohydrate contents, probably due to a consumption of simple sugars and starch reserves without replacement of new photosynthesized. An accumulation of osmolytes (abscisic acid and proline) and phenylalanine (a precursor of phenylpropanoids) was also reported at 8 wpi, this being a response mechanism that needs to be further elucidated. However, the activation delay of such defence strategy inevitably did not avoid the premature defoliation of plants and the decline of physiochemical parameters, confirming the key role of Verticillium in Ailanthus decay.

Signalling responses in the bark and foliage of canker‐susceptible and ‐resistant cypress clones inoculated with Seiridium cardinale

“…Abscisic acid content was determined after extracting lyophilized samples (50 mg) in 1 mL of distilled water for bark and 1 mL of 80% (v/v) methanol for foliage (Bianco et al, 1999), according to Pisuttu et al (2023). The determination of ABA was performed at 415 nm by using a fluorescence/absorbance microplate reader (Victor3 1420 Multilabel Counter, Perkin Elmer), after following the protocol of the Phytodetek ® Immunoassay Kit (Agdia).…”

Verticillium Species as an Ecofriendly Alternative to Manage the Invasive Tree Ailanthus altissima (Mill.) Swingle

“…Verticillium dahliae can be easily and rapidly grown on agar m (e.g., on potato dextrose agar it needs 15 days) and conidia (Figure 3) can be resus in sucrose-based broth, being stable and vital for a few days. Spore suspensions, prepared at high concentration (1 × 10 7 conidia mL −1 ) we for inoculation protocols tested in controlled environment through typical rootoculation on A. altissima seedlings and stem-inoculation on pot-grown mature tr Spore suspensions, prepared at high concentration (1 × 10 7 conidia mL −1 ) were used for inoculation protocols tested in controlled environment through typical root-deep inoculation on A. altissima seedlings and stem-inoculation on pot-grown mature trees [59] (Figure 4), in urban environment [60] and open field (data unpublished). In general, macroscopic responses are those characteristic of a wilt disease, including defoliation, abundant production of epicormic sprouts along the stem and vigorous sprouting.…”

“…In general, macroscopic responses are those characteristic of a wilt disease, including defoliation, abundant production of epicormic sprouts along the stem and vigorous sprouting. Leaves wilt, turn yellow and fall in a short time after inoculation, even if the visual detection of the disease is difficultly recognizable since the absence of pathognomonic symptoms [59]. In cross sections of branches, a continuous discolored ring or arc is present in the outermost sapwood.…”

Features of Seed Propagation of Ailanthus Altissima (Mill.) Swingle in the Mykolaiv Region

“…Наукові доповіді НУБіП України ISSN 2223-1609 [13,14], а в ряді країн застосовується інвентаризація, картування, різноплановий моніторинг з метою обмеження насаджень [15][16][17][18] та побудови моделей поширення цього виду [19] [30]. Середнє значення маси крилатки -0,03 г. Насінина 0,3-0,5 см завдовжки (середнє значення 0,42±0,01 см), 0,1-0,3 см завширшки (середнє значення 0,23±0,01 см Висновки і перспективи подальших досліджень.…”