The banyan tree Ficus macrocarpa produces aerial roots that provide it its unique appearance. A brand-new research study exposes the genomic modifications that permit the tree to produce roots that derive from its branches. Credit: Photo by Gang Wang
The banyan fig tree Ficus microcarpa is popular for its aerial roots, which grow from branches and ultimately reach the soil. The tree likewise has actually a unique relationship with a wasp that has coevolved with it and is the only bug that can pollinate it.
In a brand-new research study, scientists recognize areas in the banyan fig’s genome that promote the advancement of its uncommon aerial roots and improve its capability to signify its wasp pollinator.
The research study, released in the journal Cell, likewise recognizes a sex-determining area in an associated fig tree, Ficus hispida. Unlike F. microcarpa, which produces aerial roots and bears male and female flowers on the exact same tree, F. hispida produces unique male and female trees and no aerial roots.
Understanding the evolutionary history of Ficus types and their wasp pollinators is very important due to the fact that their capability to produce big fruits in a range of environments makes them a keystone types in the majority of tropical forests, stated Ray Ming, a plant biology teacher at the University of Illinois, Urbana-Champaign who led the research study with Jin Chen, of the Chinese Academy of Sciences. Figs are understood to sustain a minimum of 1,200 bird and mammal types. Fig trees were amongst the earliest domesticated crops and look like spiritual signs in Hinduism, Buddhism and other spiritual customs.
Ray Ming, a teacher of plant biology at the University of Illinois Urbana-Champaign, led a genomic research study of the banyan tree, Ficus macrocarpa, and its essential pollinator, a wasp. Credit: Photo by L. Brian Stauffer
The relationship in between figs and wasps likewise provides an interesting clinical difficulty. The body shapes and sizes of the wasps correspond precisely to those of the fig fruits, and each types of fig produces a unique fragrance to attract its particular wasp pollinator.
To much better comprehend these evolutionary advancements, Ming and his associates examined the genomes of the 2 fig types, together with that of a wasp that pollinates the banyan tree.
“When we sequenced the trees’ genomes, we discovered more segmental duplications in the genome of the banyan tree than in F. hispida, the fig without the aerial roots,” Ming stated. “Those duplicated regions account for about 27% of the genome.”
The duplications increased the variety of genes associated with the synthesis and transportation of auxins, a class of hormonal agents that promote plant development. The duplicated areas likewise consisted of genes associated with plant resistance, nutrition and the production of unstable natural substances that signify pollinators.
“The levels of auxin in the aerial roots are five times higher than in the leaves of trees with or without aerial roots,” Ming stated. The raised auxin levels appear to have actually activated aerial root production. The duplicated areas likewise consist of genes that code for a light receptor that speeds up auxin production.
When they studied the genome of the fig wasp and compared it with those of other associated wasps, the scientists observed that the wasps were keeping and protecting genes for odorant receptors that discover the exact same foul-smelling substances the fig trees produce. These genomic signatures are a signal of coevolution in between the fig trees and the wasps, the scientists report.
Ming and his associates likewise found a Y chromosome-specific gene that is revealed just in male plants of F. hispida and 3 other fig types that produce different male and female plants, a condition called dioecy.
“This gene had actually been duplicated two times in the dioecious genomes, providing the plants 3 copies of the gene. But Ficus types that have male and female flowers together on one plant have just one copy of this gene,” Ming stated. “This strongly suggests that this gene is a dominant factor affecting sex determination.”
Reference: “Genomes of the Banyan Tree and Pollinator Wasp Provide Insights into Fig-Wasp Coevolution” by Xingtan Zhang, Gang Wang, Shengcheng Zhang, Shuai Chen, Yibin Wang, Ping Wen, Xiaokai Ma, Yan Shi, Rui Qi, Yang Yang, Zhenyang Liao, Jing Lin, Jishan Lin, Xiuming Xu, Xuequn Chen, Xindan Xu, Fang Deng, Lihua Zhao, Yi-lun Lee, Rong Wang, Xiao-Yong Chen, Yann-rong Lin, Jisen Zhang, Haibao Tang, Jin Chen and Ray Ming, 8 October 2020, Cell.
DOI: 10.1016/j.cell.2020.09.043
Ming is an affiliate of the Carl R. Woese Institute for Genomic Biology at the U. of I. The Fujian Agriculture and Forestry University, National Science Foundation and the National Natural Science Foundation of China supported this research study.
