Seed Embryo Development Is Regulated via an AN3-MINI3 Gene Cascade

Abstract

In agriculture, seed mass is one of the most important components related to seed yield. MINISEED3 (MINI3) which encodes the transcriptional activator WRKY10, is thought to be a pivotal regulator of seed mass. In Arabidopsis SHORT HYPOCOTYL UNDER BLUE1 (SHB1) associates with the promoter of MINI3, regulating embryo cell proliferation (both cell division and elongation), which, in turn, modulates seed mass. Furthermore, the recruitment of SHB1 via MINI3 to both its cognate promoter and that of IKU2 implies a two-step amplification for countering the low expression level of IKU2, which is thought to function as a molecular switch for seed cavity enlargement. However, it is largely unknown how embryo cell proliferation, which encompasses both cell division and elongation, is regulated by SHB1 and MINI3 function. Here, we show that a loss of function mutation within the transcriptional coactivator ANGUSTIFOLIA3 (AN3), increases seed mass. Further, AN3 associates with the MINI3 promoter in vivo. Genetic evidence indicates that the absence of MINI3 function suppresses the decrease of cell number observed in an3-4 mutants by regulating cell division and in turn inhibits increased cell size of the an3-4 line by controlling cell elongation. Thus, seed embryo development is modulated via an AN3-MINI3 gene cascade. This regulatory model provides a deeper understanding of seed mass regulation, which may in turn lead to increased crop yields.

Transcriptional repression of GIF1 by the KIX-PPD-MYC repressor complex controls seed size in Arabidopsis

“…In addition, GIF1 was reported to play significant roles in leaf, flower, and root development in Arabidopsis [8][9][10][11][12][13][14] , indicating that GIF1 is required for normal plant organ growth. Surprisingly, a previous study showed that one mutant allele of GIF1 (an3) promotes seed growth 48 . In this study, we have sufficient evidence to support that GIF1 is a positive regulator of seed size in Arabidopsis.…”

The Arabidopsis ANGUSTIFOLIA3-YODA Gene Cascade Induces Anthocyanin Accumulation by Regulating Sucrose Levels

“…Condition of Arabidopsis plant growth was described by Meng and Yao (2015) and Meng L. et al (2016).…”

Arabidopsis ANGUSTIFOLIA3 (AN3) is associated with the promoter of CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) to regulate light‐mediated stomatal development

“…The seedlings grown on agar were maintained in a growth room under 16 hr/8 hr light/dark cycles with 21°C ± 2°C. Plants grown in soil less media were maintained in a controlled environment growth room under 16 hr/8 hr light/dark cycles with 21°C ± 2°C (Meng, Li, Liu, & Jiang, 2016;Meng, Wang, et al, 2016;Meng, Wang, Yao, & Liu, 2015a, Meng, Wang, Yao & Liu, 2015b.…”

“…Besides the delay of an3 stomatal development, an3 mutants present many developmental delays, for example, narrower and smaller leaf blades (Horiguchi et al, 2005), smaller cell number in leaf blades (Meng, Wang, et al, 2016). However, an3 mutants have longer primary roots, more lateral roots, and larger seed mass than does wild type (Meng, Xu, et al, 2017;Meng & Yao, 2015).…”

“…AN3 is a homolog of the human transcription co‐activator, known as GRF‐INTERACTING FACTOR1 (AtGIF1; Horiguchi, Kim, & Tsukaya, ). AN3 is a member of a small gene family in the Arabidopsis genome (Horiguchi et al, ) and is implicated in regulating cell proliferation, drought tolerance, root growth and development, anthocyanin biosynthesis, and seed size (Horiguchi et al, ; Meng, ; Meng & Yao, ; Meng, Wang, Loake, & Jiang, , Meng, Wang, Yao, & Liu, ; Meng, Xu, Li, & Jiang, ). Here, we find that AN3 mediates light‐induced stomatal development and is itself light‐regulated.…”