An extensin-like gene OsPEX1 plays key roles in temperature stress response in rice

Plant root growth is highly sensitive to temperature. Leucine-rich repeat extensins (LRXs) are crucial for root growth and development; however, their involvement in the temperature stress response remains unclear. Here, we demonstrate that the overexpression of OsPEX1 leads to reduced plant height and impaired root growth, resulting in a decreased survival rate under heat stress compared to the wild-type plants. Conversely, moderate low temperatures alleviate the phenotypic effects associated with OsPEX1 overexpression. GUS activity staining revealed variable expression levels of OsPEX1 in different root regions under varying temperatures. RNA-seq analysis indicated substantial transcriptomic changes in the pex1 mutant. Functional analysis of differentially expressed genes (DEGs) highlighted disruptions in pathways linked to phenylpropanoid biosynthesis and diterpenoid biosynthesis. Consistent with these disrupted pathways, we observed an upregulation of lignin metabolism related genes in the pex1 mutant, while genes involved in gibberellin (GA) biosynthesis were downregulated. Moreover, we investigated the temperature stress related genes and found that the transcript level of heat stress responsive NAC transcription factor (ONAC129) was significantly increased in pex1 mutant. These findings demonstrate that OsPEX1 plays key roles in the temperature stress response in rice.