Abstract Detail

Reproductive Processes

Pretz, Chelsea [1], Smith, Stacey [2].

Intraspecific breakdown of self-incompatibility in Physalis acutifolia (Solanaceae).

Variation in mating systems is prevalent throughout angiosperms. Comparative studies of related self-incompatible (SI) and self-compatible (SC) taxa imply many instances of the breakdown of self-incompatibility. However, there are few studies of intraspecific variation in compatibility; thus, we do not know much about the frequency with which SC arises and the factors that drive fixation. This study investigates the breakdown of self-incompatibility within a wild tomatillo, Physalis acutifolia. We took a multifaceted approach by first conducting controlled greenhouse crosses to identify SI and SC individuals. Next, we measured flowers and fruits to characterize the differences between SI and SC plants. Finally, we measured pollen tube growth in vivo and tested for the presence of the S-RNases proteins in style tissue to better understand the possible mechanisms of breakdown. We found one SC P. acutifolia population with typical selfing syndromes traits such as smaller corolla, reduced stigma-anther, and a smaller pollen-ovule ratio. However, there was no difference in fruit size between SI and SC individuals. SC individuals lack S-RNase protein expression in styles, and self-pollen can grow to reach the ovules. We also found plasticity as SI individuals became SC and lost S-RNase expression after six months in the greenhouse. This is the first study in Physalis that shows the intraspecific breakdown of self-incompatibility with the loss of S-RNase expression in the style. Our results indicate that even such within population variation can be tied to a large suite of morphological changes, suggesting many generations of self-fertilization.

1 - University Of Colorado-Boulder, 1900 Pleasant St, Boulder, CO, 80302, United States
2 - University Of Colorado-Boulder, EBIO Department, Campus Box 0334, Boulder, CO, 80309, United States

Keywords:
selfing
Solanaceae
physalis
mating system
reproductive strategy
self-incompatibility.

Presentation Type: Oral Paper
Session: RP2, Reproductive Processes 2
Location: /
Date: Thursday, July 22nd, 2021
Time: 1:45 PM(EDT)
Number: RP2006
Abstract ID:132
Candidate for Awards:None