Roles of plant cell wall modifications and nutrient signalling in plant-plant interactions : insights on plant parasitism and grafting

Abstract

Parasitic plants and grafting are examples of plant-plant interactions and plant regeneration. In plant parasitism, one plant connects to another to steal its resources, while during grafting the reconnection allows the survival of both individuals as part of a new individual. Plant regeneration is linked to the availability of nutrients in the environment and involves the modification of the cell wall. In this thesis, we studied the roles of sucrose and nitrogen signalling and of cell wall modifications during Arabidopsis thaliana grafting and plant parasitism by the facultative parasite Phtheirospermum japonicum. We found that applying sucrose or nitrogen inhibited both plant parasitism and graft reconnection (papers I and IV). We showed that the inhibition of plant parasitism by nitrogen is mediated by abscisic acid signalling in P. japonicum (paper I). We also discovered a long-distance signalling mechanism in P. japonicum to balance the availability of nutrients with the number of parasitic organs (haustoria) (paper II). We termed this phenomenon “autoregulation of haustoria”, and discovered it is mediated by cytokinin signalling. In paper III, we found that pectin methylesterification is modified during the development of P. japonicum haustoria in a tissue-specific manner, to allow host penetration and vascular connection to the host xylem. Finally, in paper IV we discovered that sucrose inhibits graft reconnection by activating cellulose biosynthesis, and that this phenotype can be rescued by applying abscisic acid. Overall, our results contribute to the understanding of the mechanisms regulating plant grafting and parasitism, and suggest interplay between cell wall, nutrients and hormone signalling.

Keywords

parasitic plants; grafting; cell wall; pectin; cellulose; sucrose signalling; nitrogen signalling; cytokinin; abscisic acid

Published in

Acta Universitatis Agriculturae Sueciae
2024, number: 2024:87ISBN: 978-91-8046-378-2, eISBN: 978-91-8046-414-7Publisher: Swedish University of Agricultural Sciences

SLU Authors

• Leso, Martina

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Botany


Publication identifier

DOI: https://doi.org/10.54612/a.4hh88nrii2

Permanent link to this page (URI)

https://res.slu.se/id/publ/130482