TY - JOUR
T1 - Molecular evolution of phytochromes in Cardamine nipponica (Brassicaceae) suggests the involvement of PHYE in local adaptation
AU - Ikeda, Hajime
AU - Fujii, Noriyuki
AU - Setoguchi, Hiroaki
PY - 2009/6
Y1 - 2009/6
N2 - Given that plants are sessile organisms, traits involved in adapting to local environments and/or in monitoring the surrounding environment, such as having photoreceptors, are significant targets of natural selection in plant evolution. To assess the intraspecific adaptive evolution of photoreceptors, we investigated sequence variations in four phytochrome genes (PHYA-C and PHYE) of Cardamine nipponica (Brassicaceae), an endemic Japanese alpine plant. The genealogies of haplotypes and genetic differentiations showed inconsistent patterns of evolution across phytochromes, suggesting that evolutionary forces were distinct in phytochromes of C. nipponica. An overall low level of nucleotide diversity in phytochrome genes suggests that the evolution of phytochromes is constrained by purifying selection within C. nipponica, which is consistent with previous findings on phytochromes. However, PHYE alone exhibited a non-neutral pattern of polymorphisms (Tajima's D= 1.91, P<0.05) and an accumulation of nonsynonymous substitutions between central and northern Japan. In particular, the PHY domain, which plays an important role in stabilizing the active form (Pfr) of phytochromes, harbored a specific nonsynonymous fixation between regions. Thus, our finding indicates that local adaptation is involved in the evolution of PHYE in C. nipponica and is the first to suggest the involvement of PHYE in local adaptation.
AB - Given that plants are sessile organisms, traits involved in adapting to local environments and/or in monitoring the surrounding environment, such as having photoreceptors, are significant targets of natural selection in plant evolution. To assess the intraspecific adaptive evolution of photoreceptors, we investigated sequence variations in four phytochrome genes (PHYA-C and PHYE) of Cardamine nipponica (Brassicaceae), an endemic Japanese alpine plant. The genealogies of haplotypes and genetic differentiations showed inconsistent patterns of evolution across phytochromes, suggesting that evolutionary forces were distinct in phytochromes of C. nipponica. An overall low level of nucleotide diversity in phytochrome genes suggests that the evolution of phytochromes is constrained by purifying selection within C. nipponica, which is consistent with previous findings on phytochromes. However, PHYE alone exhibited a non-neutral pattern of polymorphisms (Tajima's D= 1.91, P<0.05) and an accumulation of nonsynonymous substitutions between central and northern Japan. In particular, the PHY domain, which plays an important role in stabilizing the active form (Pfr) of phytochromes, harbored a specific nonsynonymous fixation between regions. Thus, our finding indicates that local adaptation is involved in the evolution of PHYE in C. nipponica and is the first to suggest the involvement of PHYE in local adaptation.
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U2 - 10.1534/genetics.109.102152
DO - 10.1534/genetics.109.102152
M3 - Article
C2 - 19363127
AN - SCOPUS:68949217692
VL - 182
SP - 603
EP - 614
JO - Genetics
JF - Genetics
SN - 0016-6731
IS - 2
ER -