Histological and anatomical responses in avocado, Persea americana, induced by the vascular wilt pathogen, Raffaelea lauricola

Sharon Inch, Randy Ploetz, Benjamin W Held, Robert A Blanchette

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Raffaelea lauricola causes laurel wilt of avocado, Persea americana. Host × pathogen interactions were examined with light and scanning electron microscopy. The susceptible avocado cultivar 'Simmonds' was inoculated and examined 5 cm above the inoculation site 3, 7, 14, 21, and 42 days after inoculation (dai). No external symptoms were observed at 3 and 7 dai, and there were no anatomical differences when compared with the mock-inoculated plants. By 14 dai, external symptoms were present and dark discoloration had developed in sapwood. Tylose development increased significantly by 14 dai, and was positivity correlated with disease severity (P < 0.05). By 14 dai, gels formed in xylem vessels, fibers, and adjacent parenchyma cells; they were associated with xylem blockage and composed of phenols, pectin, and lipids, as suggested by, respectively, toluidine blue O, ruthenium red, and Sudan III stains. With a chitin-specific stain, fluorescein-conjugated wheat germ agglutinin, infrequent mycelia, and conidia of R. lauricola were visualized within xylem lumena and fibers, regardless of sample date. Understanding how avocado responds to the presence of this pathogen could assist the development of laurel wilt-resistant avocado genotypes and inform efforts to manage this disease with other measures.

Original languageEnglish (US)
Pages (from-to)627-635
Number of pages9
JournalBotany
Volume90
Issue number7
DOIs
StatePublished - Jul 1 2012

Fingerprint

vascular wilt
Persea americana
wilt
avocados
inoculation
pathogen
pathogens
xylem
signs and symptoms (plants)
dyes
tyloses
toluidine blue
wheat germ
host-pathogen relationships
agglutinins
xylem vessels
sapwood
Sudan
fluorescein
discoloration

Keywords

  • Ambrosia beetle
  • Avocado
  • Laurel wilt
  • Raffaelea lauricola
  • Xyleborus glabratus

Cite this

Histological and anatomical responses in avocado, Persea americana, induced by the vascular wilt pathogen, Raffaelea lauricola. / Inch, Sharon; Ploetz, Randy; Held, Benjamin W; Blanchette, Robert A.

In: Botany, Vol. 90, No. 7, 01.07.2012, p. 627-635.

Research output: Contribution to journalArticle

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