J Integr Plant Biol. ›› 2022, Vol. 64 ›› Issue (12): 2327-2343.DOI: 10.1111/jipb.13379

• Research Articles • Previous Articles     Next Articles

CHH methylation of genes associated with fatty acid and jasmonate biosynthesis contributes to cold tolerance in autotetraploids of Poncirus trifoliata

Yue  Wang1,  Lanlan  Zuo1,  Tonglu  Wei1,  Yu  Zhang1,  Yang  Zhang1,  Ruhong Ming1, Daharo  Bachar1, Wei  Xiao1, Khan  Madiha1, Chuanwu  Chen2,  Qijun Fan2, Chunlong Li1, Ji-Hong Liu1*   

  1. 1 Key Laboratory of Horticultural Plant Biology(MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
    2 Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin 541004, China

    *Correspondence: Ji-Hong Liu (liujihong@mail.hzau.edu.cn)
  • Received:2022-07-06 Accepted:2022-10-08 Online:2022-10-11 Published:2022-12-01


Polyploids have elevated stress tolerance, but the underlying mechanisms remain largely elusive. In this study, we showed that naturally occurring tetraploid plants of trifoliate orange (Poncirus trifoliata (L.) Raf.) exhibited enhanced cold tolerance relative to their diploid progenitors. Transcriptome analysis revealed that whole-genome duplication was associated with higher expression levels of a range of well-characterized cold stress-responsive genes. Global DNA methylation profiling demonstrated that the tetraploids underwent more extensive DNA demethylation in comparison with the diploids under cold stress. CHH methylation in the promoters was associated with up-regulation of related genes, whereas CG, CHG, and CHH methylation in the 3'-regions was relevant to gene down-regulation. Of note, genes involved in unsaturated fatty acids (UFAs) and jasmonate (JA) biosynthesis in the tetraploids displayed different CHH methylation in the gene flanking regions and were prominently up-regulated, consistent with greater accumulation of UFAs and JA when exposed to the cold stress. Collectively, our findings explored the difference in cold stress response between diploids and tetraploids at both transcriptional and epigenetic levels, and gained new insight into the molecular mechanisms underlying enhanced cold tolerance of the tetraploid. These results contribute to uncovering a novel regulatory role of DNA methylation in better cold tolerance of polyploids.

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