ICE1 demethylation drives the range expansion of a plant invader through cold tolerance divergence. Issue 4 (4th February 2015)

• Record Type: Journal Article
• Authors: Xie, H. J.; Li, H.; Liu, D.; Dai, W. M.; He, J. Y.; Lin, S.; Duan, H.; Liu, L. L.; Chen, S. G.; Song, X. L.; Valverde, B. E.; Qiang, S.
• Is Part Of: Molecular ecology. Volume 24:Issue 4(2015)
• Page Start: 835
• Page End: 850
• Publication Date: 2015-02-04
• Subjects: Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.13067
• Languages: English
• ISSNs: 0962-1083

Abstract

<abstract abstract-type="main" id="mec13067-abs-0001"> <title>Abstract</title> <p>Cold tolerance adaption is a crucial determinant for the establishment and expansion of invasive alien plants into new cold environments; however, its evolutionary mechanism is poorly understood. Crofton weed (<italic>Ageratina adenophora</italic>), a highly invasive alien plant, is continuously spreading across subtropical areas in China, north‐eastward from the first colonized south‐western tropical regions, through cold tolerance evolution. Close relations between the cold tolerance levels of 34 populations, represented by 147 accessions, and the latitude, extreme lowest temperature, coldest month average temperature, and invasion period have provided direct insight into its cold tolerance divergence. A comparative study of the <italic>CBF</italic> pathway, associated with the cold tolerance enhancement of cold‐susceptible <italic>CBF1</italic>‐transgenic plant, among four geographically distinct crofton weed populations revealed that the <italic>CBF</italic> pathway plays a key role in the observed cold tolerance divergence. Four epialleles of the cold response regulator <italic>ICE1</italic> ranged from 66 to 50 methylated cytosines, representing a 4.4% to 3.3% methylation rate and significantly corresponding to the lowest to highest cold tolerance levels among these different populations. The significant negative relation between the transcription levels of the primary <italic>CBF</italic> pathway members, except for <italic>CBF2</italic>, and the methylation levels among the four populations firstly demonstrates that the demethylation‐upregulated transcription level of <italic>CBF</italic> pathway is responsible for this evolution. These facts, combined with the cold tolerance variation and methylation found among three native and two other introduced populations, indicate that the <italic>ICE1‐</italic>demethylated upregulation of cold tolerance may be the underlying evolutionary mechanism allowing crofton weed to expand northward in China.</p> </abstract>