Abstract Detail

Systematics Section/ASPT

Chen, Shichao [1], Shi, Fei [1], Zhang, Li [1].

Molecular Adaptation of rbcL in Liliaceae.

Plants in Liliaceae show marked phenotypic plasticity. Morphological data of Liliaceae documented that a pattern of concerted convergence in leaf form, flower size, fruit type, and storage organs associated with the transition from closed to open habitats. They environmental changed by producing different phenotypes under selective pressure modifying the optima for photosynthesis. But little is known about the evolutionary outcome of habit in molecular level of this family. Rubisco is responsible for the fixation of CO₂ into organic compounds through photosynthesis. Recent evolutionary analyses suggested that rbcL, a chloroplast gene that encodes a catalytic subunit of RuBisCO, evolves under positive selection in most land plant lineages. We used the timescale and phylogenetic analyses to investigate and search for processes of adaptive evolution in rbcL gene of Liliaceae. Six positively selected sites (11A, 142T, 143S, 225L, 281A, 328A) were identified in all the tests. This amino acid replacement might increase the thermal stability of rbcL in the open habitats lineages. Our results showed that the ancestor of Liliaceae s.s (Clade A) diverged from Lilioideae around 16Mya; and its descendants diverged from about 13 Mya; and most of the positive sites happened at the last 10 million years. These changes may be associated with the adaptation of the protein into the environment of open, sunny, seasonal conditions. The increased amino acid replacement in rbcL may reflect the continuous fine-tuning of RuBisCO under varying ecological conditions.

Broader Impacts:

1 - Tongji University, College of Life Science and Technology, 1239 Siping Road Medical Building, Shanghai, 200092, China

Keywords:
ecological niche
natural selection
Liliaceae
RuBisCO.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PSY065
Abstract ID:606
Candidate for Awards:None