Cytological and Gene Expression Analysis Reveal Salt Resistance in Common Wild Rice (Oryza rufipogon Griff.): A Case for Root Tissue Resistance.

Common wild rice (Oryza rufipogon Griff.) is an important germplasm resource harboring valuable genes. Our previous analysis identified a core collection of wild rice primarily originating from the common wild rice of Guangdong Province. However, there was no information on its salt-stress tolerance. In this study, we assessed 13 accessions of common wild rice collected in Gaozhou, Guangdong, China. Salt-stress treatments applied at the tillering and seedling stages revealed that CRW3 exhibited stronger salt tolerance than CRW13 under NaCl treatment. Cytological observations indicated that root tip elongation in CRW3 was less inhibited by NaCl treatment, accompanied by a lower percentage of abnormalities in cortical cells and layers, as well as reduced shrinkage of epidermal cells. Resequencing analysis identified 2390 genes with genetic variations between CRW3 and CRW13. Furthermore, RT-qPCR was conducted to examine the expression levels of salt-stress-related genes in these two accessions. Overall, our study demonstrates the strong salt tolerance of CRW3, providing a theoretical foundation for the selection of salt-tolerant germplasm in rice.