New Organ Found in Arabidopsis Thaliana

Microscopes for decades may seem unlikely to keep secrets. But in widely studied Arabidopsis thaliana, scientists have identified the “cantil” — a newly reported plant organ named for its cantilever-like way of branching off of the main stem. The structure appears in only some A. thaliana and only under certain conditions, researchers report.

Scientists first suspected contamination or a mutation when they noticed some A. thaliana with odd stalks jutting out from the stem, like half-finished bridges. It took 12 years of experiments at Penn State to show that the rare stalks are a new type of plant part and to explain their trigger: delayed flowering.

Like many other plants, short days prompt A. thaliana, which is in the same family as cabbage and mustard greens, to shore up resources; long days tell it to churn out flowers. Cantils form when that transition from stockpiling to blooming is postponed, as the plant keeps growing while waiting for the flowering signal, the researchers found.

A newly described cantilever-like organ (arrow) depends on both genetics and circumstance to appear. It develops only in some Arabidopsis thaliana varieties, and only when flowering is postponed. Scientists’ preference for using long growing days and fast-flowering conditions have helped keep cantils hidden in hundreds of labs worldwide. The organs can develop in the wild, though some favorite, fast-growing A. thaliana varieties have lost the genetic ability to produce cantils. It’s unclear how the plants use the organs.

Cantils are, so far, known to occur only in A. thaliana. The plant parts may not rewrite biology textbooks just yet, but after being found in a lab-plant that’s scrutinized so widely, it’s a reminder to keep observing closely

Sources:

T.E. Gookin and S.M. Assmann. Cantil: a previously unreported organ in wild-type Arabidopsis regulated by FT, ERECTA and heterotrimeric G proteins. Development. Published online June 15, 2021. doi:10.1242/dev.195545.