Phenotypic effects of disruption of all four rice HK cytokinin receptors

In order to further characterize the role of cytokinin in a monocot, we used CRISPR-Cas9 to generate rice lines with frameshift alleles in the four putative cytokinin receptors (Histidine Kinases 3,4,5,6) in all single and multiple combinations. The transcriptome of the hk3,4,5,6 mutant is completely insensitive to cytokinin, suggesting that all cytokinin signaling regulating transcription acts through these four HKs, despite the presence of a CHASE-containing Serine-Threonine kinase in rice.