OsCRY2 and OsFBO10 co-regulate photomorphogenesis and photoperiodic flowering in indica rice

Shipra Singh; Satyam Vergish; Nitin Jain; Arun Kumar Sharma; Paramjit Khurana; Jitendra P Khurana

doi:10.1016/j.plantsci.2023.111631

OsCRY2 and OsFBO10 co-regulate photomorphogenesis and photoperiodic flowering in indica rice

Plant Sci. 2023 May:330:111631. doi: 10.1016/j.plantsci.2023.111631. Epub 2023 Feb 10.

Authors

Shipra Singh¹, Satyam Vergish¹, Nitin Jain¹, Arun Kumar Sharma¹, Paramjit Khurana², Jitendra P Khurana¹

Affiliations

¹ Interdisciplinary Centre for Plant Genomics & Department of Plant Molecular Biology, University of Delhi, South Campus, New Delhi 110021, India.
² Interdisciplinary Centre for Plant Genomics & Department of Plant Molecular Biology, University of Delhi, South Campus, New Delhi 110021, India. Electronic address: param@genomeindia.org.

PMID: 36773757
DOI: 10.1016/j.plantsci.2023.111631

Abstract

Cryptochromes (CRYs) are a class of photoreceptors that perceive blue/ultraviolet-A light of the visible spectrum to mediate a vast number of physiological responses in bacteria, fungi, animals and plants. In the present study, we have characterized OsCRY2 in a photoperiod sensitive indica variety, Basmati 370, by generating and analyzing overexpression (OE) and knock-down (KD) transgenic lines. The OsCRY2^OE lines displayed dwarfism as shown in their reduced plant height and leaf length, attributed largely by an overall reduction in their cell size. The OsCRY2^OE lines flowered significantly earlier and showed shorter and broader seeds with an overall reduced seed weight. The OsCRY2^KD lines showed contrasting phenotypes, such as increased plant height and delayed flowering, however, decreased seed size and weight were also observed in the KD lines, along with reduced spikelet fertility and high seed shattering rate in mature panicles. Novel interactions were confirmed between OsCRY2 and members of ZEITLUPE family of blue/ultraviolet-A light photoreceptors, encoded by OsFBO8, OsFBO9 and OsFBO10 which are orthologous to ZEITLUPE (ZTL), LOV KELCH PROTEIN2 (LKP2) and FLAVIN BINDING, KELCH REPEAT F-BOX1 (FKF1), respectively, of Arabidopsis thaliana. Since FKF1 is known to play a role in regulating photoperiodic flowering, OsFBO10 was chosen for further studies. OsCRY2 and OsFBO10 interacted in the nucleus and cytoplasm of the cell and cross-regulated the expression of each other. They were also found to regulate the expression of several genes involved in photoperiodic flowering in rice. Both OsCRY2 and OsFBO10 played a positive role in photomorphogenic responses in different light conditions. The physical interaction of OsCRY2 with OsFBO10, their involvement in common physiological and developmental pathways and their cross-regulation of each other suggest that the two photoreceptors may regulate common developmental pathways in plants, either jointly or redundantly.

Keywords: Light signaling; OsCRY2; OsFBO10; Photomorphogenesis; Photoperiodic flowering; Rice.

MeSH terms

Arabidopsis Proteins* / metabolism
Arabidopsis* / genetics
Flowers / metabolism
Gene Expression Regulation, Plant
Light
Oryza* / genetics
Oryza* / metabolism
Photoperiod
Plants / metabolism

Substances

Arabidopsis Proteins
ZTL protein, Arabidopsis
FKF1 protein, Arabidopsis
LKP2 protein, Arabidopsis