Biomolecule interactions and macromolecular rearrangement participate in numerous cellular functions in plants, and resolving the dynamics of plasma membrane proteins represents a central goal in current plant biology. Compared to yeast and mammalian systems, the quantification of heterogeneous distribution and dynamics of membrane proteins in cellular processes remains sparse in plant cells. In this study, we introduce the application of fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS) in measuring membrane protein diffusion, concentration and interactions in living plant cell. The review showed FCS/FCCS as a tool for imaging the membrane proteins fused with a fluorescent tag, quantifying the density fluctuation and interactions of membrane proteins in the living cells of plants. Owing to the single-molecular level sensitivity and minimally invasive of FCS/FCCS, their application provides an ideal approach to understanding plant cell membrane lateral organization.
Rice (Oryza sativa L.) is a major dietary source of cadmium (Cd). Developing rice varieties with reduced Cd levels in the grain is a cost-effective and practical approach to enhance food safety, particularly in regions with high Cd contamination. However, the genetic mechanisms underlying Cd accumulation in rice grains are not fully understood. In this study, we identified eight quantitative trait loci (QTLs) associated with Cd accumulation in rice grains through substitution mapping using single segment substitution lines (SSSLs). These QTLs, named qCd‐2‐1, qCd‐3‐1, qCd‐3‐2, qCd‐5‐1, qCd‐6‐1, qCd‐7‐1, qCd‐8‐1, and qCd‐11‐1, are distributed across seven chromosomes. Notably, the qCd‐5‐1 and qCd‐6‐1 loci are reported for the first time. We performed a detailed haplotype analysis of candidate genes related to heavy metal metabolism, specifically focusing on Cd accumulation. All SSSLs carrying alleles from donor parents exhibited a significant reduction in Cd accumulation, with additive effects ranging from −0.061 to −0.105. To further develop rice varieties with lower Cd accumulation in the grain, we developed six pyramided lines through crossing and marker-assisted selection. These pyramided lines showed significantly reduced Cd content in the grain compared to the elite indica recurrent parent, Huajingxian74 (HJX74). Importantly, most agronomic characteristics of the pyramided lines were similar to those of HJX74. In conclusion, this study demonstrates that identifying and pyramiding QTLs associated with reduced Cd accumulation is an effective strategy for developing rice varieties with lower Cd content in the grain.

