'Root of all success': Plasticity in root architecture of invasive wild radish for adaptive benefit.

Successful plant establishment in a particular environment depends on the root architecture of the seedlings and the extent of edaphic resource utilization. However, diverse habitats often pose a predicament on the suitability of the fundamental root structure of a species that evolved over a long period. We hypothesized that the plasticity in the genetically controlled root architecture in variable habitats provides an adaptive advantage to worldwide-distributed wild radish (, ) over its close relative (, ) that remained endemic to the East Mediterranean region. To test the hypothesis, we performed a reciprocal comparative analysis between the two species, growing in a common garden experiment on their native soils (Hamra/Sandy for , Terra Rossa for ) and complementary controlled experiments mimicking the major soil compositions. Additionally, we analyzed the root growth kinetics semi-automated digital profiling and compared the architecture between and . In both experiments, the primary roots of were significantly longer, developed fewer lateral roots, and showed slower growth kinetics than . Multivariate analyses of seven significant root architecture variables revealed that could successfully adapt to different surrogate growth conditions by only modulating their main root length and number of lateral roots. In contrast, needs to modify several other root parameters, which are very resource-intensive, to grow on non-native soil. Altogether the findings suggest an evo-devo adaptive advantage for as it can potentially establish in various habitats with the minimal tweak of key root parameters, hence allocating resources for other developmental requirements.