# BrDMC1-mediated tolerance during pollen meiosis under heat stress in Brassica rapa

## TL;DR

This study shows how a gene called BrDMC1 helps Brassica rapa tolerate heat during pollen development, improving fertility and reducing cell damage.

## Contribution

The study identifies BrDMC1 as a novel regulator of heat tolerance during pollen meiosis in Brassica rapa.

## Key findings

- OE-BrDMC1 plants showed increased pollen fertility and reduced chromosomal abnormalities under heat stress.
- Overexpression of BrDMC1 lowered ROS levels and increased antioxidant enzyme activity in heat-stressed plants.
- Heat stress upregulated genes related to DNA repair and meiotic cell cycle in OE-BrDMC1 plants.

## Abstract

High temperatures may have a substantial impact on cellular meiosis, and subsequently affects plant reproduction, development, and yield over time. In this study, using overexpressed transgenic lines, we show that BrDMC1, a gene involved in meiotic recombination, regulates heat tolerance during the early pollen development stage in Brassica rapa. According to the expression pattern analysis, BrDMC1.A03 was not discovered at the transcriptional level, whereas BrDMC1.A01 was highly expressed in young flower buds in B.rapa. The Cis-acting element prediction revealed that BrDMC1.A01 contains a low-temperature responsive element, and GUS histochemical analysis revealed an increased staining ability following temperature stress. Under normal conditions, there were no significant cytogenetic or molecular differences between wild-type (WT) and overexpressed-BrDMC1 (OE-BrDMC1).After 24 h of treatment at 38°C, compared with WT, OE-BrDMC1 demonstrated dramatically increased pollen fertility, reduced aberrant chromosomal behaviors during meiosis, lowered reactive oxygen species (ROS) concentration, and boosted antioxidant enzymes SOD, POD, and CAT. Furthermore, genes involved in repair of DNA double-strand breaks (DSBs), as well as those that govern meiotic cell cycle transition, were considerably increased in OE-BrDMC1 under high temperature stress. These findings suggest that BrDMC1 could probably mediate heat tolerance during pollen meiosis, revealing the genetic basis for meiotic adaptation to high temperatures in B.rapa.