Early leaf senescence can cause negative effects on rice yield, but the underlying molecular regulation is not fully understood. The bilateral blade senescence 1 (bbs1), an early leaf senescence and saltstress-sensitive mutant, was isolated from a population generated via ethylmethane sulfonate (EMS) treatment. The team of Dong-Dong Zeng of Zhejiang University in China studied the mutant to determine the gene responsible for the mutation.
The team found an insertion on the OsBBS1gene that caused the mutation. This gene encodes a receptor-like cytoplasmic kinase. To validate their result, the team used CRISPR-Cas9 OsBBS1-knockout plants. The generated mutants exhibited similar early leaf senescence and salt stress sensitivity as the bbs1 mutant.
OsBBS1 was found to be expressed in all tissues and its expression could be greatly induced by salt stress. These results suggest that OsBBS1 participates in leaf senescence and could be critical in the salt stress response in rice.