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 salt stress-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 OsBBS1 gene 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.



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