In this news, we discuss the Genomic study brings to light hidden secrets of banyan tree.
Aerial roots are roots above the ground found in various plant species such as mangroves, banyan figs, and orchids.
The banyan tree Ficus microcarpa is famous for its aerial roots, which grow from branches and eventually reach the ground. The tree also has a unique relationship with a wasp that co-evolved with it and is the only insect capable of pollinating it. Figs are known to be home to at least 1,200 species of birds and mammals.
Fig trees were among the earliest domesticated cultures and appear as sacred symbols in Hinduism, Buddhism, and other spiritual traditions.
In a new study, researchers are identifying regions of the banyan fig genome that promote the development of its unusual aerial roots and improve its ability to signal its wasp pollinator.
The study, published in the journal Cell, also identifies a sex-determining region in a related fig tree, Ficus hispida. Unlike F. microcarpa, which produces aerial roots and bears male and female flowers on the same tree, F. hispida produces separate male and female trees and no aerial roots.
Understanding the evolutionary history of Ficus species and their wasp pollinators is important because their ability to produce large fruits in a variety of habitats makes them a keystone species in most rainforests, said Ray Ming, professor of plant biology at the University of Illinois at Urbana. -Champagne who conducted the study with Jin Chen from the Chinese Academy of Sciences.
The relationship between figs and wasps also presents an intriguing scientific challenge. Wasps’ body shapes and sizes match exactly those of figs, and each species of fig produces a unique scent to attract its specific wasp pollinator.
To better understand these evolutionary developments, Ming and his colleagues analyzed the genomes of both species of figs, as well as that of a wasp that pollinates banyan trees.
“When we sequenced the tree genomes, we found more segmental duplications in the banyan genome than in F. hispida, the fig without aerial roots,” Ming said. “These duplicated regions represent about 27% of the genome.”
Duplications increased the number of genes involved in the synthesis and transport of auxins, a class of hormones that promote plant growth. The duplicated regions also contained genes involved in plant immunity, nutrition, and the production of volatile organic compounds that signal pollinators.
“The auxin levels in aerial roots are five times higher than in leaves of trees with or without aerial roots,” Ming said. The high levels of auxin appear to have triggered the production of aerial roots. The duplicated regions also include genes that encode a light receptor that accelerates the production of auxin.
When they studied the genome of the fig wasp and compared it to those of other related wasps, the researchers observed that wasps kept and preserved genes for scent receptors that detect the same scent compounds that fig trees produce. These genomic signatures are a signal for coevolution between fig trees and wasps, the researchers report.
Ming and his colleagues also discovered a specific gene for the Y chromosome that is expressed only in male plants of F. hispida and three other fig species that produce separate male and female plants, a condition known as dioecium, which means “two households” in Greek.
“This gene had been duplicated twice in dioecious genomes, giving plants three copies of the gene. But Ficus species that have male and female flowers united on a single plant only have one copy of this gene, ”Ming said. “This strongly suggests that this gene is a dominant factor affecting sex determination.”
Genomic study reveals hidden secrets of banyan
Banyan Fig’s genome promotes development of its unusual aerial roots