The CAM lineages of planet Earth.
C3 photosynthesis
C3+CAM
C4+CAM
crassulacean acid metabolism
nocturnal acidification
photosynthetic pathway evolution
strong CAM
vascular plants
Journal
Annals of botany
ISSN: 1095-8290
Titre abrégé: Ann Bot
Pays: England
ID NLM: 0372347
Informations de publication
Date de publication:
12 Sep 2023
12 Sep 2023
Historique:
received:
22
09
2022
medline:
12
9
2023
pubmed:
12
9
2023
entrez:
12
9
2023
Statut:
aheadofprint
Résumé
The growth of experimental studies of crassulacean acid metabolism (CAM) in diverse plant clades, coupled with recent advances in molecular systematics, presents an opportunity to re-assess the phylogenetic distribution and diversity of species capable of CAM. It has been more than two decades since the last comprehensive lists of CAM taxa were published, and an updated survey of the occurrence and distribution of CAM taxa is needed to facilitate and guide future CAM research. We aimed to survey the phylogenetic distribution of these taxa, their diverse morphology, physiology, and ecology, and the likely number of evolutionary origins of CAM based on currently known lineages. We found direct evidence - in the form of experimental or field observations of gas exchange, day-night fluctuations in organic acids, carbon isotope ratios, and enzymatic activity - for CAM in 370 genera of vascular plants, representing 38 families. Further assumptions about the frequency of CAM species in CAM clades, and the distribution of CAM in the Cactaceae and Crassulaceae, bring the currently estimated number of CAM-capable species to nearly 7% of all vascular plants. The phylogenetic distribution of these taxa suggests a minimum of 66 independent origins of CAM in vascular plants, with possibly dozens more. To achieve further insight into CAM origins, there is a need for more extensive and systematic surveys of previously unstudied lineages, particularly in living material to identify low-level CAM activity, and for denser sampling to increase phylogenetic resolution in CAM-evolving clades. This should allow further progress in understanding the functional significance of this pathway by integration with studies on the evolution and genomics of CAM in its many forms.
Sections du résumé
BACKGROUND AND SCOPE
OBJECTIVE
The growth of experimental studies of crassulacean acid metabolism (CAM) in diverse plant clades, coupled with recent advances in molecular systematics, presents an opportunity to re-assess the phylogenetic distribution and diversity of species capable of CAM. It has been more than two decades since the last comprehensive lists of CAM taxa were published, and an updated survey of the occurrence and distribution of CAM taxa is needed to facilitate and guide future CAM research. We aimed to survey the phylogenetic distribution of these taxa, their diverse morphology, physiology, and ecology, and the likely number of evolutionary origins of CAM based on currently known lineages.
RESULTS AND CONCLUSIONS
CONCLUSIONS
We found direct evidence - in the form of experimental or field observations of gas exchange, day-night fluctuations in organic acids, carbon isotope ratios, and enzymatic activity - for CAM in 370 genera of vascular plants, representing 38 families. Further assumptions about the frequency of CAM species in CAM clades, and the distribution of CAM in the Cactaceae and Crassulaceae, bring the currently estimated number of CAM-capable species to nearly 7% of all vascular plants. The phylogenetic distribution of these taxa suggests a minimum of 66 independent origins of CAM in vascular plants, with possibly dozens more. To achieve further insight into CAM origins, there is a need for more extensive and systematic surveys of previously unstudied lineages, particularly in living material to identify low-level CAM activity, and for denser sampling to increase phylogenetic resolution in CAM-evolving clades. This should allow further progress in understanding the functional significance of this pathway by integration with studies on the evolution and genomics of CAM in its many forms.
Identifiants
pubmed: 37698538
pii: 7271350
doi: 10.1093/aob/mcad135
pii:
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Informations de copyright
© The Author(s) 2023. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.