Lodiculeless Spikelet is a Mutation of MicroRNA172b Controlling Cleistogamy in Rice

Previously, we isolated a natural cleistogamous rice mutant, lodiculeless spikelet (ld). Map-based cloning approach identified about 4 kb deletion spanning two microRNAs, the entire MIR806a precursor and upstream of MIR172b precursor, in the ld locus.

CRISPR/Cas9-mediated transgenic approach validated that mutations of MIR172b, not MIR806a, was responsible for the cleistogamy phenotype. Small RNA sequencing revealed that the expression of miR172b was almost completely reduced in the ld mutants. Quantitative RT-PCR analysis indicated that expression of AP2 target genes of miR172b was not changed in the ld mutants.