Climate change is expected to challenge plant populations and potentially impact their reproductive strategies. A better understanding of the factors affecting plant mating modes and the transitions between them should aid in minimizing their harmful effects on plant populations.

This mixed mode is long-lived and does not decay to either of the pure strategies even after long time. Mixtures of self-compatible and self-incompatible were found in natural population but previously considered a transitory state.

Besides the two pure strategies, where the entire population is either capable or not of self-fertilization, we find a third ‘volatile mixed’ regime. This mixed mode, which we describe for the first time, exhibits a mixture of both self-compatible and incompatible plants, in fluctuating proportions

we focus on ‘self-incompatibility,’ a widespread genetic mechanism that disables self-fertilization in bisexual plants and only allows cross-fertilization. This mechanism is vulnerable and often breaks down via various mutations, yielding plants capable of self-fertilization (‘self-compatible’).

🧵The plant’s reproductive mode has far-reaching implications for its fitness and survival. Self-fertilization plants do not depend on finding mating partners, which is advantageous when colonizing new territories. In contrast, cross-fertilizing plants are more genetically diverse and more adaptable

We found that these proteins combine two strategies: a ‘global’ strategy where proteins are broadly repulsive regardless of the partner, and a ‘local’ strategy where proteins specifically attract or repel only particular partners.

This system is based on molecular recognition (or lack of) between highly diverse proteins of two families, that are expressed in the plant reproductive organs. We studied how the molecular recognition domains of these proteins evolve, under pressures to match some partners and mismatch others.

In this picture you can see self-compatible (left) vs. self-incompatible (right) flowers of a wild tomato S. habrochaites.
The plants were grown by Ben Stescovich from my lab with the help of Menachem Moshelion, and thanks to Dani Zamir for providing us the seeds! @huji-pes.bsky.social

As self-compatible plants are guaranteed to be pollinated, they do not need to attract pollinating insects to visit the flowers. One of the changes known follow the transition to self-compatibility is the decrease of flower size relative to self-incompatible plants.

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