Plants transitioned from an aquatic to a terrestrial lifestyle during
their evolution. On land, fluctuations on water availability in the
environment became one of the major problems they encountered. The
appearance of morpho-physiological adaptations to cope with and tolerate
water loss from the cells was undeniably useful to survive on dry land.
Some of these adaptations, such as carbon concentrating mechanisms
(CCMs), desiccation tolerance (DT) and root impermeabilization, appeared
in multiple plant lineages. Despite being crucial for evolution on land,
it has been unclear how these adaptations convergently evolved in the
various plant lineages. Recent advances on whole genome and
transcriptome sequencing are revealing that co-option of genes and gene
regulatory networks (GRNs) is a common feature underlying the convergent
evolution of these adaptations. In this review we address how the study
of CCMs and DT have provided insight into convergent evolution of GRNs
underlying plant adaptation to dry environments, and how these insights
could be applied to currently emerging understanding of evolution of
root impermeabilization through different barrier cell types. We discuss
examples of co-option, conservation, and innovation of genes and GRNs at
the cell, tissue and organ levels revealed by recent phylogenomic
(comparative genomic) and comparative transcriptomic studies.
Convergent evolution of gene regulatory networks underlying plant adaptations to dry environments