FUSCA3-induced AINTEGUMENTA-like 6 manages seed dormancy and lipid metabolism

Abstract

FUSCA 3 (FUS3), a seed master regulator, plays critical roles in seed dormancy and oil accumulation. However, its downstream regulation mechanisms remain poorly understood. Here, we explored the roles of AINTEGUMENTA-like 6 (AIL6), a seed transcription factor, in these processes. The activation of AIL6 by FUS3 was demonstrated by dual-LUC assay. Seeds of ail6 mutants showed alterations of fatty acid compositions, and both AtAIL6 (AIL6 from Arabidopsis thaliana) and BnaAIL6 (AIL6 from Brassica napus) rescued the phenotype. Over-expression (OE) of AIL6s reversed changes in seed fatty acid composition. Notably, OE lines showed low seed germination rates down to 12% compared to 100% of wild-type Col-0. Transcriptome analysis of the mutant and an OE line indicated widespread expression changes of genes involved in lipid metabolism and phytohormone pathways. In OE mature seeds, GA4 content decreased more than 15-fold, while ABA and IAA contents clearly increased. Exogenous GA3 treatments did not effectively rescue the low germination rate. Nicking seed coats increased germination rates from 25% to nearly 80% while the wild-type rdr6-11 is 100% and 98% respectively, and elongation of storage time also improved seed germination. Furthermore, dormancy imposed by AIL6 was fully released in the della quintuple mutant. Together, our results indicate AIL6 acts as a manager downstream of FUS3 in seed dormancy and lipid metabolism.

Intergrative metabolomic and transcriptomic analyses reveal the potential regulatory mechanism of unique dihydroxy fatty acid biosynthesis in the seeds of an industrial oilseed crop Orychophragmus violaceus

“…The remaining KCS18 gene of O. violaceus from clade I did not express in any tissues we sequenced, and the other two copies of KCS18 from clade II mainly expressed during seed development stages in O. violaceus . In the two expressed FAE1 sub-network, we found a WGD paired TFs from B3 family named FUS3 (Ov_B3_50 and Ov_B3_45), which have been certified to impact seed oil content in many other oilseed crops [ 73 , 74 ]. Both copies of FUS3 have high correlation with the expression of FAE1-2 and therefore may be highly related to the regulation of the diOH-FA contents in seed oil of O. violaceus (Fig.…”

Functions of the AP2/ERF family transcription factor AIL7 in immunity against soilborne clubroot pathogen in Arabidopsis

“…Such interactions might explain the synergistic accumulation of SA and JA that occurs in both inoculated and non-inoculated plants. Moreover, AIL7 was shown previously to influence lipid biosynthesis and metabolism, impacting both storage and membrane lipid biosynthesis (Singer et al, 2021), and its close relative, AIL6 , has also been demonstrated to be involved in storage and membrane lipid biosynthesis and metabolism (Kim et al, 2024; Liu et al, 2023; Zhang et al, 2016). This hints at the possibility that alterations in the expression of AIL7 could feasibly lead to membrane lipid remodeling, which could trigger defense pathways such as the MAPK cascade, and phospholipid-based signaling cascade further activating phytohormone signaling (Mehta et al, 2021; Takasato et al, 2023).…”

Genome-Wide Identification and Expression Analysis Reveals the B3 Superfamily Involved in Embryogenesis and Hormone Responses in Dimocarpus longan Lour.

“…FUS3 was expressed in the embryonic tissues and stimulated viviparous germination through an interaction with ABA, GA, BR, and auxin, indicating that it played an important role in the occurrence of the viviparous process [ 28 ]. Furthermore, FUS3 regulated the downstream gene AIL6 to play a role in seed dormancy and lipid metabolism [ 29 ]. The LEC2 gene regulates the meristem and participates in the biosynthesis of plant hormones [ 7 ], and the increase in ABA inhibitors in the fus3 mutant showed an intolerance to high temperature [ 27 ].…”