Ecological divergence and evolutionary transition of resprouting types inBanksia attenuata

Abstract

Resprouting is a key functional trait that allows plants to survive diverse disturbances. The fitness benefits associated with resprouting include a rapid return to adult growth, early flowering, and setting seed. The resprouting responses observed following fire are varied, as are the ecological outcomes. Understanding the ecological divergence and evolutionary pathways of different resprouting types and how the environment and genetics interact to drive such morphological evolution represents an important, but under-studied, topic. In the present study, microsatellite markers and microevolutionary approaches were used to better understand: (1) whether genetic differentiation is related to morphological divergence among resprouting types and if so, whether there are any specific genetic variations associated with morphological divergence and (2) the evolutionary pathway of the transitions between two resprouting types in Banksia attenuata (epicormic resprouting from aerial stems or branch; resprouting from a underground lignotuber). The results revealed an association between population genetic differentiation and the morphological divergence of postfire resprouting types in B. attenuata. A microsatellite allele has been shown to be associated with epicormic populations. Approximate Bayesian Computation analysis revealed a likely evolutionary transition from epicormic to lignotuberous resprouting in B. attenuata. It is concluded that the postfire resprouting type in B. attenuata is likely determined by the fire's characteristics. The differentiated expression of postfire resprouting types in different environments is likely a consequence of local genetic adaptation. The capacity to shift the postfire resprouting type to adapt to diverse fire regimes is most likely the key factor explaining why B. attenuata is the most widespread member of the Banksia genus.

Epicormic Resprouting in Fire-Prone Ecosystems

“…In forest ecosystems Eucalyptus and some have limited capacity for resprouting and are considered post-fire obligate seeders [14,15]. There are other trees with post-fire epicormic resprouting in Australia as well as in South Africa (Table 1), including examples that exhibit within-species (amongpopulation) variability in epicormic and basal resprouting [16,17].…”

Degree of domestication influences susceptibility of Theobroma cacao to frosty pod rot: a severe disease devastating Mexican cacao

“…Cereals are the best example, with a longer domestication time. Throughout domestication, cereals have lost their capacity of seed dispersal and modified their plant architecture in order to increase yield and production (Gepts & Papa 2003, Pickersgill 2007, 2013, Mondolot et al 2008, Chacón-Sánchez 2009, Bautista-Lozada et al 2012, He 2014, but selection of specific traits has reduced the genetic diversity of the domesticated varieties (Chacón-Sánchez 2009, Rauf et al 2010, Bautista-Lozada et al 2012.…”

Environmental drivers and genomic architecture of trait differentiation in fire‐adapted Banksia attenuata ecotypes

“…Previous work has shown that Banksia attenuata has two distinctive growth forms: a tree form that resprouts epicormically, post‐fire, and a shrub form that resprouts from a lignotuber. The two growth forms display consistent morphological differences, and there are no records of the co‐occurrence of both forms within a population (Taylor and Hopper ; He ; Figure ). The morphological divergence patterns between tree and shrub populations show significant concordance with the divergence of neutral genetic markers, and the genetic populations are clustered into two groups (tree and shrub populations), with a minor genetic differentiation between the groups of F ST = 0.27 (He ).…”

“…The two growth forms display consistent morphological differences, and there are no records of the co‐occurrence of both forms within a population (Taylor and Hopper ; He ; Figure ). The morphological divergence patterns between tree and shrub populations show significant concordance with the divergence of neutral genetic markers, and the genetic populations are clustered into two groups (tree and shrub populations), with a minor genetic differentiation between the groups of F ST = 0.27 (He ). Despite the striking morphological divergence and absence of cross‐pollination studies between the groups, its taxonomic status as one species has been accepted without dispute (Taylor and Hopper ; Mast and Thiele ).…”

“…Given the clear morphological divergence between the B. attenuata tree and shrub forms (He ), in this study we addressed the following questions. What environmental factors (fire, climate) have driven the morphological divergence of the populations showing contrasting growth forms?…”