Heterotrimeric G-protein complexes comprising Gα-, Gβ-, and Gγ-subunits and the regulator of G-protein signaling (RGS) are conserved across most eukaryotic lineages. Signaling pathways mediated by these proteins influence overall growth, development, and physiology. In plants, this protein complex has been characterized primarily from angiosperms with the exception of spreading-leaved earth moss (Physcomitrium patens) and Chara braunii (charophytic algae). Even within angiosperms, specific G-protein components are missing in certain species, whereas unique plant-specific variants—the extra-large Gα (XLGα) and the cysteine-rich Gγ proteins—also exist. The distribution and evolutionary history of G-proteins and their function in nonangiosperm lineages remain mostly unknown. We explored this using the wealth of available sequence data spanning algae to angiosperms representing extant species that diverged approximately 1,500 million years ago, using BLAST, synteny analysis, and custom-built Hidden Markov Model profile searches. We show that a minimal set of components forming the XLGαβγ trimer exists in the entire land plant lineage, but their presence is sporadic in algae. Additionally, individual components have distinct evolutionary histories. The XLGα exhibits many lineage-specific gene duplications, whereas Gα and RGS show several instances of gene loss. Similarly, Gβ remained constant in both number and structure, but Gγ diverged before the emergence of land plants and underwent changes in protein domains, which led to three distinct subtypes. These results highlight the evolutionary oddities and summarize the phyletic patterns of this conserved signaling pathway in plants. They also provide a framework to formulate pertinent questions on plant G-protein signaling within an evolutionary context.
The evolutionary modification of development was fundamental in generating extant plant diversity. Similarly, the modification of development is a path forward to engineering the plants of the future, provided we know enough about what to modify. Understanding how extant diversity was generated will reveal productive pathways forward for modifying development. Here, I discuss four examples of developmental pathways that have been remodeled by changes to protein–protein interactions. These are cases where changes to developmental pathways have been paralleled by recent changes, selected for or engineered by humans. Extant plant diversity represents a vast treasure trove of molecular solutions to ecological problems. Mining this treasure trove will allow for the intentional modification of plant development for solving future problems.more » « less
- Award ID(s):
- NSF-PAR ID:
- Publisher / Repository:
- Date Published:
- Journal Name:
- New Phytologist
- Page Range / eLocation ID:
- p. 1127-1133
- Medium: X
- Sponsoring Org:
- National Science Foundation
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