LSSR1 Facilitates Seed Setting Rate By Promoting Fertilization in Rice

The seed set, which pertains to the number of seeds per pollinated flower, is one of the vital components that determine rice yield. Successful fertilization is important for normal seed setting, but there is limited knowledge about the molecular mechanisms controlling this process. Scientists from the National Rice Research Institute in China reported a novel rice gene, LOW SEED SETTING RATE1 (LSSR1), which controls the seed setting rate through rice fertilization. The results of their study are published in Rice.

According to the study, LSSR1 codes for a GH5 cellulase, which is highly conserved in plants. To investigate the physiological role of LSSR1 in rice, the CRISPR-Cas9 system was used to develope loss-of-function mutants of LSSR1. Results showed that the morphology of the vegetative and reproductive organs looks normal in the mutant lines. Analysis of the cells showed that the impediment of fertilization caused low seed setting rate in lssr1 mutant lines, probably due to abnormal pollen germination, failed pollen tube penetration, and retarded pollen tube elongation.

The results of the study suggest that LSSR1 has a vital role in rice fertilization, which leads to maintaining good rice seed setting rate.

Read the research article in Rice.