Transcriptome data from silica-preserved leaf tissue reveal gene flow patterns in a Caribbean bromeliad.

BACKGROUND AND AIMS: Transcriptome sequencing is a cost-effective approach that allows researchers to study a broad range of questions. However, to preserve RNA for transcriptome sequencing, tissue is often kept in special conditions, such as immediate ultracold freezing. Here, we demonstrate that RNA can be obtained from 6-month-old, field-collected samples stored in silica gel at room temperature. Using these transcriptomes, we explore the evolutionary relationships of the genus Pitcairnia (Bromeliaceae) in the Dominican Republic and infer barriers to gene flow. METHODS: We extracted RNA from silica-dried leaf tissue from 19 Pitcairnia individuals collected across the Dominican Republic. We used a series of macro- and micro-evolutionary approaches to examine the relationships and patterns of gene flow among individuals. KEY RESULTS: We produced high-quality transcriptomes from silica-dried material and demonstrated that evolutionary relationships on the island match geography more closely than species delimitation methods. A population genetic examination indicates that a combination of ecological and geographical features presents barriers to gene flow in Pitcairnia. CONCLUSIONS: Transcriptomes can be obtained from silica-preserved tissue. The genetic diversity among Pitcairnia populations does not warrant classification as separate species, but the Dominican Republic contains several barriers to gene flow, notably the Cordillera Central mountain range.

Eco-Evo-Devo of petal pigmentation patterning.

Colourful spots, stripes and rings decorate the corolla of most flowering plants and fulfil important biotic and abiotic functions. Spatial differences in the pigmentation of epidermal cells can create these patterns. The last few years have yielded new data that have started to illuminate the mechanisms controlling the function, formation and evolution of petal patterns. These advances have broad impacts beyond the immediate field as pigmentation patterns are wonderful systems to explore multiscale biological problems: from understanding how cells make decisions at the microscale to examining the roots of biodiversity at the macroscale. These new results also reveal there is more to petal patterning than meets the eye, opening up a brand new area of investigation. In this mini-review, we summarise our current knowledge on the Eco-Evo-Devo of petal pigmentation patterns and discuss some of the most exciting yet unanswered questions that represent avenues for future research.