Transgenerational Genetic Effects Help Explain Latitudinal Variation in Seed Mass and Germination Timing in Plantago lanceolata.

Elizabeth P Lacey,Marc Bucciarelli,Scott J Richter,Matthew M Marshall

doi:10.3390/plants11040522

Elizabeth P Lacey, Marc Bucciarelli + Show 2 more

Open Access

https://doi.org/10.3390/plants11040522

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Abstract

We know little about the underlying genetic control of phenotypic patterns of seed traits across large-scale geographic and environmental gradients. Such knowledge is important for understanding the evolution of populations within species and for improving species conservation. Therefore, to test for genetic variation in Plantago lanceolata, we made reciprocal crosses between northern and southern genotypes that span the species’ range in Europe. The results provide evidence of transgenerational genetic effects on seed mass and germination timing. Northern mothers produced larger seeds with delayed germination, in contrast to southern mothers, which produced smaller seeds with accelerated germination. A maternal latitude affected both the seed coat, solely maternal tissue, and embryo/endosperm tissues. Thus, latitudinal variation in seed size and germination timing can be explained, in part, by the direct influence of maternal genotype, independent of zygotic genes that parents pass directly to the embryo and endosperm. Data suggest that researchers exploring the existence and evolution of large-scale geographic variation within species test for transgenerational genetic effects. In addition, data suggest that transgenerational control of seed traits should be considered when developing procedures designed to facilitate species conservation and restoration.

Highlights

Large-scale geographic variation has long been a focus of plant research [1,2,3,4,5], and much of that research has focused on seed traits because of their large contributions to a species’ fitness
We have found seven studies that have tested for genetic differences in seeds produced by plants that were derived from wild populations along a latitudinal gradient but had been grown in a common environment [3,31,44,47,67,68,81]
We present our results based on maternal latitude because many controlled experiments have demonstrated that seed traits are more often determined by the mother than the father

Summary

Introduction

Germination timing, including dormancy, can strongly influence seedling establishment, survivorship, and reproduction, which contribute to lifetime fitness [9,12,14,15,16,17,18,19,20,21]. For all these reasons, seed traits are key determinants of agronomic success [22]. These contributions to fitness have motivated many evolutionary biologists to explore how seed traits vary systematically along latitudinal/altitudinal/longitudinal gradients. Conservation biologists studying the effects of large-scale environmental change (e.g., via climate change, urbanization, agriculture, and deforestation) have increased efforts to sample and preserve seeds from multiple populations along these gradients

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