Scientists have found a gene that gives the parasitic plant Cuscuta campestris, a powerful sense of touch. The gene CcMCA1 helps the plant create mechanosensitive ion channels, that allow it to recognise when it has coiled around a victim, and start producing tools to rob other plants.
Cuscuta campestris, also known as dodder, lacks chlorophyll and so cannot make its own food. Instead it survives by stabbing inserting specialised organs called haustoria. These allow dodder to suck water and nutrients from its victims, rather like a vampire plant.
This lifestyle doesn’t come for free. By taking food from other plants dodder weakens its victims. When the victim is a crop, this reduces yield. Dodder causes tens of millions of dollars worth of damage to crops like tomatoes, alfalfa and soy beans.
Jihwan Park and colleagues have taken a step towards de-fanging dodder by examining its genes. When they silenced the MID1-COMPLEMENTING ACTIVITY 1 (CcMCA1) gene, the plant’s ability to form haustoria dramatically decreased, potentially offering a new way to control this pest.
How does dodder “feel” its victims? When the vine coils around a host stem, it creates pressure on the plant’s cell membranes. This activates the CcMCA1 channels, allowing calcium ions to flood into the cell—triggering a chemical cascade that ultimately leads to haustorium formation.
Using a technique called host-induced gene silencing, researchers confirmed CcMCA1‘s crucial role. When silenced, dodder produced fewer haustoria with greater spacing between them. This significantly hampered its ability to effectively parasitize host plants.
“For the first time, the genes involved in sensing mechanical stimuli that lead to the climbing of vines, such as morning glories and bindweed, have been discovered,” said Professor Koh Aoki, who led the study, in a press release.
These findings help explain how plants can sense touch. By revealing how parasitic plants detect hosts, researchers open new possibilities for protecting crops. Targeted approaches disrupting this touch-sensing pathway could limit dodder’s spread without harming beneficial plants.
Park, J., Morinaga, K., Houki, Y., Tsushima, A., & Aoki, K. (2025). Involvement of MID1-COMPLEMENTING ACTIVITY 1 encoding a mechanosensitive ion channel in prehaustorium development of the stem parasitic plant Cuscuta campestris. Plant and Cell Physiology, pcaf009. https://doi.org/pdxm (FREE)
Cross-posted to Bluesky & Mastodon.
Image: Starr Environmental / Wikimedia Commons. CC BY 2.0
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