Molecular characterization and functional analysis of “fruit-weight2.2-like” gene family in rice

Abstract

Tomato fruit-weight 2.2 (FW2.2) was reported to control up to 30 % fruit weight. Recent studies demonstrated that FW2.2-like (FWL) genes also play important roles in plant growth and development. For instance, a maize homolog of FW2.2, named cell number regulator 1 (CNR1), negatively regulates plant and organ size. However, FWL genes in rice have not been characterized yet. In this study, eight FWL genes were identified in rice genome and designated as OsFWL1-8. The chromosome location, gene structure, protein motif, and phylogenetic relationship of OsFWL genes were analyzed. RT-PCR result and microarray data revealed that OsFWL genes exhibited diverse expression patterns and the detailed expression patterns of OsFWL5, 6, and 7 negatively correlated with leaf growth activity. Rice protoplast transient transformation experiment showed that most OsFWL proteins locate at cell membrane but OsFWL8 is present in the nucleus. In addition, the functions of OsFWL genes were investigated by analyzing two T-DNA insertion lines for OsFWL3 and 5. Compared with wild type, the grain weight of osfwl3 mutant and the plant height of osfwl5 mutant were increased by 5.3 and 12.5 %, respectively. We also found that the increase in grain length of osfwl3 mutant was due chiefly to incremental cell number, not cell size and the expression of OsFWL3 negatively correlated with glume growth activity. These results provide a comprehensive foundation for further study of OsFWL functions in rice.

The GmFWL1 (FW2‐2‐like) nodulation gene encodes a plasma membrane microdomain‐associated protein

“…; Supporting Information Movies S1 and S2; green channel). This same punctate localization has been shown to be characteristic of other known FWL proteins, such as the rice FWL proteins (Xu et al ). In addition, similarly to M. truncatula SYMREM1 (Lefebvre et al ), GmFWL1 localization upon tobacco cell plasmolysis remains between the PM and cell wall (Libault et al ), which is compatible with plasmodesmata and membrane microdomain localization.…”

“…Subsequently, the Zea mays homolog cell number regulator1 ( CNR1 ) was found to have a role in cell division, impacting plant development (Guo et al ). More recently, several groups have highlighted the critical role of FW2‐2‐like genes as negative regulators of cell division and fruit development in Oryza sativa [ FWL3; (Xu et al )], Physalis floridana [ CNR1; (Li & He )], Prunus avium [ CNR12 and CNR20 (De Franceschi et al )] and Persea americana (Dahan et al . ).…”

“…Subsequently, the Zea mays homolog cell number regulator1 (CNR1) was found to have a role in cell division, impacting plant development (Guo et al 2010). More recently, several groups have highlighted the critical role of FW2-2-like genes as negative regulators of cell division and fruit development in Oryza sativa [FWL3; (Xu et al 2013)], Physalis floridana [CNR1; (Li & He 2015)], Prunus avium [CNR12 and CNR20 (De Franceschi et al 2013)] and Persea americana (Dahan et al 2010). In soybean, GmFWL1 gene expression is strongly induced during the nodulation process and silencing of this gene reduced nodule cell size and the number of symbionts per nodule (Libault et al 2010b), suggesting its importance in nodulation.…”

Expression of mammalian Onzin and Fungal Cadmium Resistance 1 in S. cerevisiae suggests ancestral functions of PLAC8 proteins in regulating mitochondrial metabolism and DNA damage repair

“…In this work, we showed that Onzin, the reference for PLAC8 cell growth regulators [2], could induce cadmium resistance in S. cerevisiae , demonstrating that these two functions are not mutually exclusive in PLAC8 proteins. Another example of how the same PLAC8 protein can display both functions is the rice OsPCR1 that, even though with different acronyms, has been reported as cell growth regulator [16] and able to confer cadmium-resistance [65].…”

Biological and Cellular Functions of the Microdomain-Associated FWL/CNR Protein Family in Plants

“…This gene acts as a major negative regulator of tomato fruit size compared to other tomato fruit weight QTLs (i.e., up to 30% of the tomato fruit weight [33][34][35]). The FW2.2 gene encodes a small protein (22 kDa) enriched in cysteine residues and characterized by one transmembrane domain [31,[36][37][38]. The functional characterization of the protein suggests that FW2.2 acts as a negative regulator of cell division supporting the repressive role of FW2.2 in controlling tomato fruit size [34,39].…”