Premium
COMPLEX EVOLUTIONARY TRANSITIONS AND THE SIGNIFICANCE OF C 3 –C 4 INTERMEDIATE FORMS OF PHOTOSYNTHESIS IN MOLLUGINACEAE
Author(s) -
Christin PascalAntoine,
Sage Tammy L.,
Edwards Erika J.,
Ogburn R. Matthew,
Khoshravesh Roxana,
Sage Rowan F.
Publication year - 2011
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2010.01168.x
Subject(s) - biology , evolutionary biology , photosynthesis , c4 photosynthesis , botany
C 4 photosynthesis is a series of biochemical and structural modifications to C 3 photosynthesis that has evolved numerous times in flowering plants, despite requiring modification of up to hundreds of genes. To study the origin of C 4 photosynthesis, we reconstructed and dated the phylogeny of Molluginaceae, and identified C 4 taxa in the family. Two C 4 species, and three clades with traits intermediate between C 3 and C 4 plants were observed in Molluginaceae. C 3 –C 4 intermediacy evolved at least twice, and in at least one lineage was maintained for several million years. Analyses of the genes for phosphoenolpyruvate carboxylase, a key C 4 enzyme, indicate two independent origins of fully developed C 4 photosynthesis in the past 10 million years, both within what was previously classified as a single species, Mollugo cerviana . The propensity of Molluginaceae to evolve C 3 –C 4 and C 4 photosynthesis is likely due to several traits that acted as developmental enablers. Enlarged bundle sheath cells predisposed some lineages for the evolution of C 3 –C 4 intermediacy and the C 4 biochemistry emerged via co‐option of photorespiratory recycling in C 3 –C 4 intermediates. These evolutionarily stable transitional stages likely increased the evolvability of C 4 photosynthesis under selection environments brought on by climate and atmospheric change in recent geological time.