Biological complexity: how parasitic plants attack (Introduction)

by David Turell , Wednesday, November 04, 2020, 19:04 (1480 days ago) @ David Turell

The molecule ethylene is driven genetically:

https://phys.org/news/2020-11-parasitic-ethylene-host-invasion.html

"Researchers at Nara Institute of Science and Technology in Japan report in a new study in Science Advances that parasitic plants use the plant hormone ethylene as a signal to invade the roots of host plants.

"To develop a successful parasitic relationship, parasitic plants form a specialized structure, the haustorium which attaches to and invades the host plant. The formation of haustoria is regulated by signal molecules derived from the host plant and allows the parasitic plant to absorb water, nutrients, and small materials from the host plant.

"'To understand the genetic programs for haustorium development, we identified mutants that displayed haustorial defects on host invasion," says lead author of the study Songkui Cui. "Genome sequencing showed that these mutants have defective ethylene signaling, and it turned out that ethylene signaling genes are crucial for the parasitic plant to infect its host plant."

"Ethylene is a gaseous plant hormone that is involved in fruit ripening, aging of leaves, and the formation of root nodules. Ethylene is also widely involved in plant interactions with viruses and numerous organisms, such as insects and bacteria, lending either resistance or susceptibility to plants depending on the types of pathogens.

"'Our results indicate that ethylene mediates host recognition in parasitic plants for host invasion," explains project leader Satoko Yoshida. "This is the first time that the mediation of host invasion by parasitic plant genes has been identified via forward genetics. Our findings offer a new understanding of how a parasitic plant uses the ethylene molecule to tweak haustorium development and host invasion."

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"'Our results suggest that parasitic plants have taken over ethylene signaling for parasitism at multiple stages of their life cycle, such as germination, haustorium growth termination, and host invasion."

Comment: Another very complex mechanism that must be considered as designed.