# Research on Cold Resistance of Kandelia obovata Transplanted to Zhoushan Area at the mRNA Level

## TL;DR

This study explores how a mangrove species, Kandelia obovata, resists cold stress at the mRNA level by analyzing gene expression and antioxidant activity in cold-tolerant and sensitive populations.

## Contribution

The study identifies specific molecular mechanisms, including transcription factors and metabolic pathways, that contribute to cold tolerance in Kandelia obovata.

## Key findings

- Cold-tolerant Kandelia obovata showed elevated catalase activity and efficient hydrogen peroxide scavenging.
- Transcription factors like WRKY, NAC, MYB, and ERF were differentially expressed in the cold-tolerant population.
- Phenylpropanoid biosynthesis and plant hormone signal transduction pathways were enriched in response to cold stress.

## Abstract

To elucidate the physiological and molecular mechanisms underlying cold tolerance in the mangrove species Kandelia obovata Sheue & al, this study measured the antioxidant enzyme activities and photosynthetic pigment contents of two populations—cold-tolerant and -sensitive—under natural overwintering conditions. In addition, transcriptome sequencing was performed to analyze differentially expressed genes (DEGs), transcription factor families, single nucleotide polymorphisms (SNPs), and alternative splicing events. The results showed that catalase activity was significantly elevated in the cold-tolerant population, which enhanced the efficiency of hydrogen peroxide scavenging. In contrast, although the superoxide dismutase activity was relatively high in the cold-sensitive population, its downstream scavenging capacity was insufficient, resulting in an overall lower antioxidant efficiency. The KEGG enrichment analysis indicated that pathways such as phenylpropanoid biosynthesis, amino sugar metabolism, and plant hormone signal transduction might be involved in the response to low-temperature stress. Further analysis revealed that transcription factors such as WRKY, NAC, MYB, and ERF were differentially expressed at significant levels in the cold-tolerant population, suggesting that they may play important roles in low-temperature adaptation. In addition, the diversity of SNPs and alternative splicing events may enhance protein function and contribute to improved cold tolerance. In summary, the cold-tolerant K. obovata population achieves low-temperature tolerance through multiple mechanisms, including antioxidant defense, metabolic regulation, and transcriptional as well as post-transcriptional regulation. This study provides a theoretical basis for elucidating the molecular foundations of cold tolerance in K. obovata.