CsMIKC1 regulates inflorescence development and grain production in Cannabis sativa plants

Abstract

Female inflorescence is the primary output of medical Cannabis. It contains hundreds of cannabinoids that accumulate in the glandular trichomes. However, little is known about the genetic mechanisms governing Cannabis inflorescence development. In this study, we reported the map-based cloning of a gene determining the number of inflorescences per branch. We named this gene CsMIKC1 since it encodes a transcription factor that belongs to the MIKC-type MADS subfamily. Constitutive overexpression of CsMIKC1 increases inflorescence number per branch, thereby promoting flower production as well as grain yield in transgenic Cannabis plants. We further identified a plant-specific transcription factor, CsBPC2, promoting the expression of CsMIKC1. CsBPC2 mutants and CsMIKC1 mutants were successfully created using the CRISPR-Cas9 system; they exhibited similar inflorescence degeneration and grain reduction. We also validated the interaction of CsMIKC1 with CsVIP3, which suppressed expression of four inflorescence development-related genes in Cannabis. Our findings establish important roles for CsMIKC1 in Cannabis, which could represent a previously unrecognized mechanism of inflorescence development regulated by ethylene.

Acknowledgements

We appreciate Dr Pu Yan (ITBB, CATAS, China) for providing the pA7-GFP plasmid. This research was supported by the Natural Science Foundation of Hunan Province China (grants 2021JJ40649 and 2023JJ60211), the National Natural Science Foundation of China (32200219), the Central Public-interest Scientific Institution Basal Research Fund (Y2023QC25), the Basic Research Foundation of IBFC (1610242021006), IBFC-YLQN-202101, the Science and Technology Project of Hebei Education Department (ZD2021049), and the S&T Program of Hebei (21372902D).

Author contributions

J.S., S.Y., C.L., and X.Z. designed the research; X.Z., S.Y. and K.T.wrote original draft; G.X., D.K., and Y.L. performed the experiments and analyzed the data; C.C., C.D., Z.D., Z.Y., and Q.T. reviewed the manuscript; Y.L., D.K., and X.Z. funded acquisition.

Data availability statement

The data supporting this article are accessible within both the article itself and its online supplementary material.

Conflict of interest

The authors declare no competing interests.

Supplementary information

Supplementary data are available at Horticulture Research online.

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