Researchers Study the Function of FRUCTOKINASE-LIKE PROTEIN 1 in Rice Using CRISPR-Cas9

FRUCTOKINASE-LIKE PROTEINS (FLNs) are phosphofructokinase-B (PfkB)-type carbohydrate kinases that act as part of the PEP complex, which are known to transcribe chloroplast genes. However, the mechanisms underlying FLNs activity in rice remain elusive. Previously, the team of Lei He from China National Rice Research Institute studied a heat-stress sensitive albino mutant in rice, hsa1. Analysis of this mutant revealed that HSA1 gene encodes an OsFLN2 protein.

Using CRISPR-Cas9 technology, the team aimed to prove that knockdown or knockout of the OsFLN1, a homolog of HSA1/OsFLN2, will inhibit chloroplast biogenesis. The fln1 knockout mutants exhibited severe albino phenotype and seedling lethality. Analysis found that OsFLN1 localizes in the chloroplast and that the OsFLN1 and HSA1/OsFLN2 proteins interact with THIOREDOXINZ (OsTRXz) to regulate chloroplast development.

To prove this, OsTRXz knockout plants were developed and it resulted in similar albino and seedling lethal phenotype as the fln1 mutants.

These results show that OsFLN1 and HSA1/OsFLN2 contribute to chloroplast biogenesis and plant growth.

For more on this study, read the article in Journal of Integrative Plant Biology.