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Article|01 Jan 2021|OPEN
Ecological adaptations influence the susceptibility of plants in the genus Zantedeschia to soft rot Pectobacterium spp.
Yelena Guttman1,2, Janak Raj Joshi1,3, Nofar Chriker1,2, Nirmal Khadka1,2, Maya Kleiman2, Noam Reznik2, Zunzheng Wei2, Zohar Kerem1 & Iris Yedidia2,
1The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
2Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Rishon Lezion, Israel
3Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, USA

Horticulture Research 8,
Article number: 13 (2021)
doi: 10.1038/hortres.2021.13
Views: 676

Received: 06 Sep 2020
Revised: 07 Nov 2020
Accepted: 13 Nov 2020
Published online: 01 Jan 2021

Abstract

Soft rot disease caused by Pectobacterium spp. is responsible for severe agricultural losses in potato, vegetables, and ornamentals. The genus Zantedeschia includes two botanical groups of tuberous ornamental flowers that are highly susceptible to the disease. Previous studies revealed that Z. aethiopica, a member of the section Zantedeschia, is significantly more resistant to Pectobacterium spp. than members of the same genus that belong to the section Aestivae. During early infection, we found different patterns of bacterial colonization on leaves of hosts belonging to the different sections. Similar patterns of bacterial colonization were observed on polydimethylsiloxane (PDMS) artificial inert replicas of leaf surfaces. The replicas confirmed the physical effect of leaf texture, in addition to a biochemical plant–bacterium interaction. The differential patterns may be associated with the greater roughness of the abaxial leaf surfaces of Aestivae group that have evolutionarily adapted to mountainous environments, as compared to Zantedeschia group species that have adapted to warm, marshy environments. Transverse leaf sections also revealed compact aerenchyma and reduced the total volume of leaf tissue air spaces in Aestivae members. Finally, an analysis of defense marker genes revealed differential expression patterns in response to infection, with significantly higher levels of lipoxygenase 2 (lox2) and phenylalanine ammonia lyase (pal) observed in the more resistant Z. aethiopica, suggesting greater activation of induced systemic resistance (ISR) mechanisms in this group. The use of Zantedeschia as a model plant sheds light on how natural ecological adaptations may underlay resistance to bacterial soft rot in cultivated agricultural environments.