Abstract Detail

Population Genetics/Genomics

McKain, Michael [1], Jones, Sydney [1], Risman, Daniel [1], Lewis, Michelle [1], Thia, Yada [2], Studer, Anthony [2].

Population variation of C4 syndrome in the C3-C4 intermediate Steinchisma hians.

alone and demonstrates the capacity for plant lineages to develop more efficient photosynthetic syndromes from existing cellular machinery. The increased efficiency of the C4 photosynthetic syndrome comes from the modification of leaf anatomy, physiology, and biochemical pathways such that carbon dioxide is sequestered in bundle-sheath cells creating a higher carbon dioxide to oxygen ratio than is found in the mesophyll cells of C3 plants. This skewed ratio helps to counteract the tendency of RuBisCO to fix oxygen as well as carbon in photorespiration. There exist a few taxa that are characterized as C3-C4 intermediates, where they are in evolutionary transition between the two syndromes. One such taxon, Steinchisma hians is a native to the southeastern United States and exhibits a wide distribution from the US to Argentina. Steinchisma hians has potential as a useful model for C4 evolution due to its ease of propagation and tendency to hybridize with close relatives of varying photosynthetic syndromes. The species Alloteropsis semialata has been shown to vary between C3 and C4 in different populations. We wanted to determine if the same could be said of S. hians growing in the Southeast. We combined 18 herbarium specimens with 29 wild collected individuals from eight populations and characterized leaf anatomy, δ13C, and stomata number to identify potential variation in C4-like characteristics of these populations. We also sequenced whole chloroplast genomes for each of these individuals to determine the relationships of these populations and trends of potentially shared unique C4 character. We discuss the noted variation anatomy and physiology across these populations in the context of their evolutionary relationships and explore the potential utility of Steinchisma hians for research into the origins of C4 photosynthesis.

1 - The University of Alabama, Biological Sciences, 500 Hackberry Lane, Box 870344, Tuscaloosa, AL, 35487, USA
2 - University of Illinois, Crop Science, 289 E R Madigan Laboratory , 1201 W. Gregory Dr., Urbana,, IL, 61801, USA

C3-C4 intermediate
Steinchisma hians
Whole Chloroplast.

Presentation Type: Oral Paper
Number: 0015
Abstract ID:993
Candidate for Awards:Margaret Menzel Award

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