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Temporal association of potato tuber development with susceptibility to common scab and Streptomyces scabiei-induced responses in the potato periderm

journal contribution
posted on 06.12.2017, 00:00 authored by B Khatri, R Tegg, Philip BrownPhilip Brown, C Wilson
Using hydroponics and novel non-destructive pot culture systems which enable inoculation at specific tuber development stages, the dynamics of common scab infection patterns in potato were studied in order to provide more precise identification of tuber physiological factors associated with susceptibility. At the whole-tuber level, infection percentages were greatest when Streptomyces scabiei inoculation occurred early; at 2 weeks after tuberization (WAT) 68% of tubers became infected, contrasting with late inoculation (8 WAT), when only 4% infection occurred. The first-formed internodes were most susceptible to infection, whilst later-forming and slower-expanding internodes were less susceptible. Detailed tuber physiological examination of internode 2 showed that pathogen-induced changes, including increased phellem (periderm) thickness, cell layers and phellem suberization (key physiological features believed critical to S. scabiei infection) were promoted through S. scabiei inoculation. Sequential harvesting showed enhanced phellem suberization (28% greater than the control) within 7 days of pathogen exposure, while phellem thickness and layer responses were also initiated early in the infection process (10–14 days after pathogen exposure) and these responses were independent of symptom expression. Differences in cultivar response were observed, with greater phellem suberization observed 10 days after tuberization (DAT) in the common-scabtolerantcv. Russet Burbank than in the susceptible cv. Desiree. Likewise, Russet Burbank had thicker and more numerous cell layers in the phellem (up to eight cell layers) during early tuber growth (20–30 DAT) than Desiree (up to six cell layers).

History

Volume

60

Issue

4

Start Page

776

End Page

786

Number of Pages

11

eISSN

1365-3059

ISSN

0032-0862

Location

United Kingdom

Publisher

Wiley-Blackwell Publishing

Language

en-aus

Peer Reviewed

Yes

Open Access

No

Era Eligible

Yes

Journal

Plant pathology.