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Summary Cuscuta campestris, a stem parasitic plant, has served as a valuable model plant for the exploration of plant–plant interactions and molecular trafficking. However, a major barrier toC. campestrisresearch is that a method to generate stable transgenic plants has not yet been developed.Here, we describe the development of aCuscutatransformation protocol using various reporter genes (GFP, GUS, or RUBY) and morphogenic genes (CcWUS2andCcGRF/GIF), leading to a robust protocol forAgrobacterium‐mediatedC. campestristransformation.The stably transformed and regenerated RUBYC. campestrisplants produced haustoria, the signature organ of parasitic plants, and these were functional in forming host attachments. The locations of T‐DNA integration in the parasite genome were confirmed through TAIL‐PCR. TransformedC. campestrisalso produced flowers and viable transgenic seeds exhibiting betalain pigment, providing proof of germline transmission of the RUBY transgene. Furthermore, RUBY is not only a useful selectable marker for theAgrobacterium‐mediated transformation, but may also provide insight into the movement of molecules fromC. campestristo the host during parasitism.Thus, the protocol for transformation ofC. campestrisreported here overcomes a major obstacle toCuscutaresearch and opens new possibilities for studying parasitic plants and their interactions with hosts.
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The seed transcriptome of Rafflesia reveals horizontal gene transfer and convergent evolution: Implications for conserving the world's largest flower
Societal Impact Statement Rafflesiais a genus of parasitic plants with the largest flowers in the world, unique to the threatened forest habitats of tropical Asia. Here, we report on genes that are active (the transcriptome) inRafflesiaseeds as part of a larger effort to understandRafflesia.Rafflesiahas never been grown successfully outside of its native range. Consequently, seed banking is not yet possible, precluding a critical management strategy for conservation. The study ofRafflesiaseed biology is a critical step to improve its cultivation, which will educate the public about unique species and the importance of conserving their habitats. SummaryRafflesiais of great interest as one of the only two plants known to have completely lost its chloroplast genome.Rafflesiais a holoparasite and an endophyte that lives inside the tissues of its host, a tropical grape vine (Tetrastigma), emerging only to bloom—with the largest flower of any plant. Here, we report the firstRafflesiaseed transcriptome and compare it with those of other plants to deepen our understanding of its extraordinary life history.We assembled a transcriptome from RNA extracted from seeds of the Philippine endemicRafflesia speciosaand compared this with those of other plants, includingArabidopsis, parasitic plantsStrigaandCuscuta, and the mycoheterotrophic orchidAnoectochilus.Genetic and metabolic seed pathways inRafflesiawere generally similar to the other plant species. However, there were some notable exceptions. We found evidence of horizontal transfer of a gene potentially involved in circumventing host defenses. Moreover, we identified a possible convergence among parasitic plants becauseRafflesia,Striga, andCuscutashared important similarities. We were unable to find evidence of genes involved in mycorrhizal symbiosis, suggesting that mycoheterotrophy is unlikely to play a role inRafflesiaparasitism.To date, ex situ propagation ofRafflesiaby seed has been mostly unsuccessful. Our research is a bold step forward in understanding the fundamentals ofRafflesiaseed biology that will inform the continued propagation and seed‐banking efforts concerning this recalcitrant plant. We discuss our findings in the broader context of the conservation of a genus in peril.
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- Award ID(s):
- 2204938
- PAR ID:
- 10406693
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- PLANTS, PEOPLE, PLANET
- Volume:
- 7
- Issue:
- 2
- ISSN:
- 2572-2611
- Format(s):
- Medium: X Size: p. 448-466
- Size(s):
- p. 448-466
- Sponsoring Org:
- National Science Foundation
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