Research Projects

Chloroplasts are essential for life on Earth, enabling photosynthesis and the development of chloroplasts from proplastids. The process involves DNA replication, gene expression, division, and thylakoid development, which relies on translocon machinery at the outer and inner membranes to import nucleus-encoded proteins. Genetic defects in these components can lead to embryo or seedling lethality. The Arabidopsis cue8 mutant exhibits slow greening due to a genetic defect that delays proplastid to chloroplast development. The CUE8 gene locus is TIC100, which encodes the TIC100 protein, an essential component of the TIC 1MDa complex at the inner chloroplast envelope. A partial loss of function in the tic100/cue8 mutant results in reduced accumulation of TIC 1MDa proteins, leading to slow greening. A forward genetic screen was conducted to search for suppressors of tic100/cue8, identifying a novel potential suppressor named suppressor of tic hundred 2 (soh2). The leaves of the soh2 tic100/cue8 double mutant show enhanced greening and robust plant growth, suggesting a role for soh2 in correcting the chloroplast development defect in the tic100/cue8 mutant. The proposed study aims to identify the soh2 gene using next-generation sequencing and confirm the candidate gene through complementation. It will also examine the role of soh2 in enhanced greening by examining both mesophyll cellular chloroplast compartment and grana thylakoids. Additionally, immunoblotting will be used to investigate the levels of TIC complex components. This study aims to uncover the role of SOH2 in chloroplast development and its role in chloroplast protein import.