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Potential targets of VIVIPAROUS 1/ ABI 3‐ LIKE 1 ( VAL 1) repression in developing Arabidopsis thaliana embryos
Author(s) -
Schneider Andrew,
Aghamirzaie Delasa,
Elmarakeby Haitham,
Poudel Arati N.,
Koo Abraham J.,
Heath Lenwood S.,
Grene Ruth,
Collakova Eva
Publication year - 2016
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13106
Subject(s) - repressor , arabidopsis , psychological repression , regulon , mutant , biology , genetics , wild type , transcription factor , gene , arabidopsis thaliana , epigenetics , gene expression
Summary Developing Arabidopsis seeds accumulate oils and seed storage proteins synthesized by the pathways of primary metabolism. Seed development and metabolism are positively regulated by transcription factors belonging to the LAFL ( LEC 1, AB 13, FUSCA 3 and LEC 2) regulatory network. The VAL gene family encodes repressors of the seed maturation program in germinating seeds, although they are also expressed during seed maturation. The possible regulatory role of VAL 1 in seed development has not been studied to date. Reverse genetics revealed that val1 mutant seeds accumulated elevated levels of proteins compared with the wild type, suggesting that VAL 1 functions as a repressor of seed metabolism; however, in the absence of VAL 1, the levels of metabolites, ABA , auxin and jasmonate derivatives did not change significantly in developing embryos. Two VAL 1 splice variants were identified through RNA sequencing analysis: a full‐length form and a truncated form lacking the plant homeodomain‐like domain associated with epigenetic repression. None of the transcripts encoding the core LAFL network transcription factors were affected in val1 embryos. Instead, activation of VAL 1 by FUSCA 3 appears to result in the repression of a subset of seed maturation genes downstream of core LAFL regulators, as 39% of transcripts in the FUSCA 3 regulon were derepressed in the val1 mutant. The LEC 1 and LEC 2 regulons also responded, but to a lesser extent. Additional 832 transcripts that were not LAFL targets were derepressed in val1 mutant embryos. These transcripts are candidate targets of VAL 1, acting through epigenetic and/or transcriptional repression.