Chilling stress is one of the main abiotic factors affecting rice growth and yield. In rice, chlorophyllide
a oxygenase encoded by
OsCAO1 is responsible for converting chlorophyllide
a to chlorophyllide
b, playing a crucial role in photosynthesis and thus rice growth. However,
[...] Read more.
Chilling stress is one of the main abiotic factors affecting rice growth and yield. In rice, chlorophyllide
a oxygenase encoded by
OsCAO1 is responsible for converting chlorophyllide
a to chlorophyllide
b, playing a crucial role in photosynthesis and thus rice growth. However, little is known about the function of
OsCAO1 in chilling stress responses. The presence of the
cis-acting element involved in low-temperature responsiveness (LTR) in the
OsCAO1 promoter implied that
OsCAO1 probably is a cold-responsive gene. The gene expression level of
OsCAO1 was usually inhibited by low temperatures during the day and promoted by low temperatures at night. The
OsCAO1 knockout mutants generated by the CRISPR-Cas9 technology in rice (
Oryza sativa L.) exhibited significantly weakened chilling tolerance at the seedling stage.
OsCAO1 dysfunction led to the accumulation of reactive oxygen species and malondialdehyde, an increase in relative electrolyte leakage, and a reduction in antioxidant gene expression under chilling stress. In addition, the functional deficiency of
OsCAO1 resulted in more severe damage to chloroplast morphology, such as abnormal grana thylakoid stacking, caused by low temperatures. Moreover, the rice yield was reduced in
OsCAO1 knockout mutants. Therefore, the elevated expression of
OsCAO1 probably has the potential to increase both rice yield and chilling tolerance simultaneously, providing a strategy to cultivate chilling-tolerant rice varieties with high yields.
Full article