The HOS1-PIF4/5 module controls callus formation in Arabidopsis leaf explants

ABSTRACT

A two-step plant regeneration has been widely exploited to genetic manipulation and genome engineering in plants. Despite technical importance, understanding of molecular mechanism underlying in vitro plant regeneration remains to be fully elucidated. Here, we found that the HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1)-PHYTOCHROME INTERACTING FACTOR 4/5 (PIF4/5) module participates in callus formation. Consistent with the repressive role of HOS1 in PIF transcriptional activation activity, hos1–3 mutant leaf explants exhibited enhanced callus formation, whereas pif4–101 pif5–3 mutant leaf explants showed reduced callus size. The HOS1-PIF4/5 function would be largely dependent on auxin biosynthesis and signaling, which are essential for callus initiation and proliferation. Our findings suggest that the HOS1-PIF4/5 module plays a pivotal role in auxin-dependent callus formation in Arabidopsis.

KEYWORDS:

• Callus formation
• HOS1
• PIF4/5
• auxin signaling
• plant regeneration

Acknowledgments

We thank Dr. Jae-Hoon Jung (Sungkyunkwan University, South Korea) for kindly providing pif4-101 pif5-3, hos1-3 pif4-101 pif5-3, and pHOS1:HOS1-eGFP seeds.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15592324.2023.2261744

Additional information

Funding

This work was supported by the Basic Science Research (NRF-2022R1A2B5B02001266) and Basic Research Laboratory (NRF-2022R1A4A3024451) programs funded by the National Research Foundation of Korea and by the New Breeding Technologies Development Program (PJ01653002) provided by the Rural Development Administration.