AI Insight
Researchers discovered that climate adaptation in Arabidopsis thaliana involves epigenetic regulation of the sucrose transporter gene SUC2 through small interfering RNAs (siRNAs). These siRNAs, originating from related genes SUC5 and SUC8, guide DNA methylation of SUC2's exon 2, which controls the gene's expression level and correlates with summer temperature in different plant populations. The methylation-based regulation adjusts how efficiently plants export photosynthetically-produced sugars from leaves, providing a molecular mechanism for plants to optimize carbon transport under different climatic conditions.
Why it matters
This discovery reveals a novel epigenetic mechanism that plants use to adapt to different climates, which could inform crop breeding strategies for climate resilience. Understanding how siRNA-guided DNA methylation regulates carbon transport may help develop agricultural varieties better suited to specific environmental conditions or changing climates.
Understand the Science
by Jianqiu Li, Min Song, Qiyu Xu, Yunjia Tang, Johannes Liesche
Climatic adaptation of plants involves the adjustment of carbon transport to achieve an optimal balance between carbon assimilation and carbon utilization. This study describes a potential molecular mechanism of this adjustment by investigating the climate-dependent regulation of SUCROSE TRANSPORTER 2 (SUC2) in the model plant Arabidopsis thaliana. SUC2 is responsible for loading photosynthetically-produced sucrose into the leaf vascular system. Its protein and mRNA abundance in A. thaliana natural accessions were found to correlate with leaf sucrose export and summer temperature. Exploration of methylome data and epigenome editing experiments suggested that epigenetic marks on SUC2’s exon 2 contributed to the climate-dependent expression of SUC2. Two siRNAs were identified as mediators of SUC2 methylations and their respective origins localized to the SUC5 and SUC8 genes. The analysis of plants with reduced or enhanced SUC5 or SUC8 transcriptional activity corroborated the link to SUC2 methylation. Besides illustrating a novel regulatory strategy of carbon export from leaves, our results establish exon methylation mediated by gene-derived siRNAs as yet another potential mechanism for plant adaptation.