Abstract Detail

Molecular Ecology

Fradera-Soler, Marc [1], Leverett, Alistair [2], Mravec, Jozef [3], Jørgensen, Bodil [3], Grace, Olwen [4].

Exploring the succulent cell wall glycome: the link between cell wall biochemistry and succulence.

The expansion of aridity due to climate change is exacerbating the need to understand how plants cope with these conditions. It has been proposed that cell walls contribute to the mechanisms which allow succulent plants to withstand drought for relatively long periods, as they are able to fold regularly with fluctuating water status while preventing irreversible damage to the tissues. In this project, we sought to test whether cell wall compositional differences exist between succulent and non-succulent plants. With this aim, we used comprehensive microarray polymer profiling (CoMPP) to analyse cell wall glycomic profiles. Our data showed differences between succulents and non-succulents in relative content of several extracellular polymers, namely arabinogalactan proteins (AGPs), homogalacturonan, rhamnogalacturonan I and xylans. Such differences agree with higher cell wall elasticity in succulents, as well as the presence of specific components in muro with a role in stabilizing and/or plasticizing the wall during drought-induced folding. Therefore, these biochemical differences point towards the existence of a common ‘succulent cell wall glycome’ across distantly related succulent taxa, which can be linked to cell wall biomechanical properties. We also wanted to assess whether any cell wall biochemical differences would also exist at a greater phylogenetic resolution, within a specific succulent lineage. Crassula is a morphologically diverse leaf-succulent genus, which makes it a suitable case for the study of succulent plant evolution. The transition to highly succulent compact growth forms (i.e. reduced internodes and tightly arranged leaves) has played a crucial role in the diversification of the genus into arid habitats. We used CoMPP to analyse cell wall glycomic profiles across a wide sample of Crassula species. Our data showed cell wall biochemical differences between compact and non-compact Crassula species, mostly related to pectins and AGPs. These differences can also be linked to differences in cell wall biomechanics, which may be part of the set of co-adaptive traits that have facilitated the evolution of Crassula into arid habitats. Interestingly, some pectic polysaccharides, mannans and AGPs, most of which have been linked to drought response in previous studies, showed strong phylogenetic signal in Crassula, which may indicate that they are conserved traits that have indeed played an important role in the evolution of the genus. Our data suggest that cell wall biochemistry and the associated biomechanical properties differ between succulents and non-succulents, and also within succulent lineages in relation to other traits. We therefore propose that cell wall traits should be regarded as a core component of the succulent syndrome, which allows for acclimation to decreasing water content during drought.

1 - University Of Copenhagen, Department Of Plant And Environmental Sciences (PLEN), Thorvaldsensvej 40, Office B108, Frederiksberg, 147, DK-1871, Denmark
2 - Newcastle University, School of Natural and Environmental Sciences, Newcastle Upon Tyne, NE1 7RU, UK
3 - University of Copenhagen, Department of Plant and Environmental Sciences, Thorvaldsensvej 40, Frederiksberg, DK-1871, Denmark
4 - Royal Botanic Gardens Kew, Richmond, London, TW9 3AE, United Kingdom

cell walls
succulent plants
drought resistance.

Presentation Type: Oral Paper
Number: ME3005
Abstract ID:1029
Candidate for Awards:None

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