The BoEMB1923-BoPORBs module regulates chlorophyll biosynthesis in cabbage

Area of Science:

• Plant Biology
• Molecular Genetics
• Biochemistry

Background:

• Embryo defective 1923 (EMB1923) is crucial for plant embryo development, but its roles in other processes are largely unknown.
• Leaf color variations in plants are often linked to chlorophyll levels and chloroplast structure, impacting photosynthesis.

Purpose of the Study:

• To investigate the function of Brassica oleracea EMBRYO DEFECTIVE 1923 (BoEMB1923) in leaf development and chlorophyll biosynthesis.
• To elucidate the molecular mechanisms by which BoEMB1923 influences leaf color and chloroplasts.

Main Methods:

• Map-based cloning was used to identify the gene responsible for the yellow-green leaf (ygl) phenotype.
• Functional analyses, including subcellular localization, yeast two-hybrid, BiFC, and Co-IP assays, were performed.
• Enzyme activity and chlorophyllide a production were quantified in wild-type and mutant plants.

Main Results:

• A mutation in BoEMB1923 caused a yellow-green leaf phenotype with abnormal chloroplasts in Brassica oleracea.
• BoEMB1923 was found to localize in chloroplasts and positively regulate chlorophyll biosynthesis.
• BoEMB1923 interacts with BoPORB1 and BoPORB2, and the mutation reduced BoPORB activity and chlorophyllide a production.

Conclusions:

• BoEMB1923 plays a vital role in regulating chlorophyll biosynthesis through its interaction with BoPORB proteins.
• These findings provide new insights into the molecular mechanisms controlling leaf color formation in cabbage.