A group of nuclear factor Y transcription factors are sub-functionalized during endosperm development in monocots

Abstract

A group of phylogenetically conserved nuclear factor Y transcription factors are preferentially expressed in the endosperm and probably play essential roles in endosperm development for rice and other monocots.

NF‐YB1‐YC12‐bHLH144 complex directly activates Wx to regulate grain quality in rice (Oryza sativa L.)

“…mRNA in situ hybridization result showed that NF‐YB1 majorly accumulated in embryo and alueron layer, but not in the endosperm of the 7 DAP seeds (Figure c). As shown in Figure S1a‐c, NF‐YB1 protein accumulated in nuclear and cytoplasm, which is consistent with the previous reports (E et al ., ; Xu et al ., ).…”

“…However, the function of each NF‐Y subunit may not be strictly conserved in plants. A recent publication reported a systematical analysis of the transactivation activity of rice NF‐Y subunits, and found that NF‐YB1, NF‐YB9, NF‐YC11 and NF‐YC12 showed no transcriptional activation, whereas NF‐YC8, NF‐YC9 and NF‐YC10 did (E et al ., ). In the case of NF‐YB1, a controversial case also reported that it directly attached to the CCAAT box of several sucrose transporter gene promoters and activated their transcription in vivo , suggesting the functional overlapping of NF‐YB and NF‐YA in rice (Bai et al ., ).…”

“…During the process of our NF‐YB1 project, at least four independent labs reported their works on NF‐YB1 with similar biological functions (Bai et al ., ; E et al ., ; Sun et al ., ; Xu et al ., ). In consistence with this study, RNAi or CRISPR/Cas9 knock‐out lines of NF‐YB1 had smaller seeds and chalky endosperms, when compared with the WT.…”

Central role of the LEAFY COTYLEDON1 transcription factor in seed development

“…Despite their difference from non‐LEC1 subunits, both Arabidopsis LEC1 and L1L form functional NF‐Y complexes, as diagramed in Figure (Calvenzani et al ; Gnesutta et al ). Assembly of the LEC1 NF‐Y complex appears to occur similarly with non‐LEC1 NF‐Y complexes in that rice LEC1 preferentially localizes to tobacco epidermal cells nuclei only when a rice NF‐YC subunit is coexpressed, suggesting that LEC1 lacks a nuclear localization sequence (E et al ). Protein crystallography studies predict that the structure of the NF‐Y complex containing L1L is very similar to NF‐Y complexes from animals, and NF‐Y complexes containing LEC1 or L1L bind CCAAT DNA motifs (Calvenzani et al ; Nardini et al ; Gnesutta et al ).…”

“…LEC1 is expressed in the endosperm of many plant species, including Arabidopsis , maize, rapeseed, rice, and soybean (Figure A) (Lotan et al ; Huang et al ; Belmonte et al ; Zhan et al ; Pelletier et al ; E et al ). Moreover, Arabidopsis LEC1 directly activates genes that act both in the embryo and endosperm in processes related to the morphogenesis and maturation phases, suggesting the LEC1 regulates aspects of endosperm development, although the lec1 mutant does not display obvious morphological defects in endosperm (Meinke ; Meinke et al ; Lotan et al ).…”