Functional analysis of the HD-Zip transcription factor genes Oshox12 and Oshox14 in rice

Abstract

The homeodomain-leucine zipper (HD-Zip) transcription factor family plays vital roles in plant development and morphogenesis as well as responses to biotic and abiotic stresses. In barley, a recessive mutation in Vrs1 (HvHox1) changes two-rowed barley to six-rowed barley, which improves yield considerably. The Vrs1 gene encodes an HD-Zip subfamily I transcription factor. Phylogenetic analysis has shown that the rice HD-Zip I genes Oshox12 and Oshox14 are the closest homologues of Vrs1. Here, we show that Oshox12 and Oshox14 are ubiquitously expressed with higher levels in developing panicles. Trans-activation assays in yeast and rice protoplasts demonstrated that Oshox12 and Oshox14 can bind to a specific DNA sequence, AH1 (CAAT(A/T)ATTG), and activate reporter gene expression. Overexpression of Oshox12 and Oshox14 in rice resulted in reduced panicle length and a dwarf phenotype. In addition, Oshox14 overexpression lines showed a deficiency in panicle exsertion. Our findings suggest that Oshox12 and Oshox14 may be involved in the regulation of panicle development. This study provides a significant advancement in understanding the functions of HD-Zip transcription factors in rice.

A novel gene, CaATHB-12, negatively regulates fruit carotenoid content under cold stress in Capsicum annuum

“…In the current study, we characterized contribution of a novel transcription factor gene, CaATHB-12, in response to cold stress. As the subcellular localization of proteins is closely related to their function, most of the previously obtained HD-Zip family members are located in the nucleus (58), for example, Athb-12 in Arabidopsis in the nucleus (59), and then Oshox12, Oshox14, Oshox22, and ZmHDZ1 are nuclear-localized proteins (60)(61)(62)(63). Consistent with the known function of TFs, the GFP-tagged fusion constructs indicated that CaATHB-12 has nuclear-localized proteins (Fig.…”

Genome-Wide Identification and Expression Analysis of HD-ZIP I Gene Subfamily in Nicotiana tabacum

“…Ariel et al demonstrated that Medicago truncatula HD-Zip I TF HB1 was required for the adaptive developmental response of lateral roots [24]. Overexpression of rice HD-Zip I genes, Oshox12 , and Oshox14 , led to reduced panicle length and a dwarf phenotype [25]. In addition to function in plant growth and development, HD-Zip I proteins were shown to play important roles in abiotic stress responses.…”

Heterotrimeric G-protein α subunit (RGA1) regulates tiller development, yield, cell wall, nitrogen response and biotic stress in rice

“…This is also consistent with the literature on the role of G-protein signaling in regulating grain size in rice 80 . Over-expression of a homeobox domain containing protein (LOC_Os03g10210) has been shown to reduce the plant height and panicle development 81 . The up-regulation of this gene as we found in the rga1 mutant (Fig.…”