# Promising New Methods Based on the SOD Enzyme and SAUR36 Gene to Screen for Canola Materials with Heavy Metal Resistance

## TL;DR

This study identifies SOD enzyme and SAUR36 gene as potential tools to screen canola plants resistant to heavy metal stress, improving breeding efforts.

## Contribution

The study introduces SOD and SAUR36 as novel indicators for screening canola materials with heavy metal resistance.

## Key findings

- F335 showed higher SOD and POD activities than F338 under heavy metal stress.
- SAUR36 and SAUR32 were identified as key differential genes in heavy metal tolerance.
- SAUR36 expression was significantly higher in field-grown canola, with FY958 showing the largest increase.

## Abstract

Canola is the largest self-produced vegetable oil source in China; however, excessive levels of cadmium, lead, and arsenic seriously affect its yield. In this study, canola near-isogenic lines with different oil contents (F338 (40.62%) and F335 (46.68%) as the control) were used as the experimental materials, and heavy metal stress experiments and omics analysis were carried out. The results show that superoxide dismutase and SAUR36 were closely related to heavy metal stress tolerance. Therefore, they may be used to screen for new canola materials with good heavy metal stress tolerance for canola breeding.

Canola is the largest self-produced vegetable oil source in China, although excessive levels of cadmium, lead, and arsenic seriously affect its yield. Therefore, developing methods to identify canola materials with good heavy metal tolerance is a hot topic for canola breeding. In this study, canola near-isogenic lines with different oil contents (F338 (40.62%) and F335 (46.68%) as the control) and heavy metal tolerances were used as raw materials. In an experiment with 100 times the safe standard values, the superoxide dismutase (SOD) and peroxidase (POD) activities of F335 were 32.02 mmol/mg and 71.84 mmol/mg, while the activities of F338 were 24.85 mmol/mg and 63.86 mmol/mg, exhibiting significant differences. The DEGs and DAPs in the MAPK signaling pathway of the plant hormone signal transduction pathway and other related pathways were analyzed and verified using RT-qPCR. SAUR36 and SAUR32 were identified as the key differential genes. The expression of the SAUR36 gene in canola materials planted in the experimental field was significantly higher than in the control, and FY958 exhibited the largest difference (27.82 times). In this study, SOD and SAUR36 were found to be closely related to heavy metal stress tolerance. Therefore, they may be used to screen for new canola materials with good heavy metal stress tolerance for canola breeding.