Premium
Germostatin resistance locus 1 encodes a PHD finger protein involved in auxin‐mediated seed dormancy and germination
Author(s) -
Ye Yajin,
Gong Ziying,
Lu Xiao,
Miao Deyan,
Shi Jianmin,
Lu Juan,
Zhao Yang
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.13086
Subject(s) - biology , auxin , germination , repressor , arabidopsis , seed dormancy , dormancy , mutant , microbiology and biotechnology , gene , botany , genetics , transcription factor
Summary Seed dormancy and germination are important physiological processes during the life cycle of a seed plant. Recently, auxin has been characterized as a positive regulator that functions during seed dormancy and as a negative regulator during germination. Through chemical genetic screenings, we have identified a small molecule, germostatin ( GS ), which effectively inhibits seed germination in Arabidopsis. GSR1 ( germostatin resistance locus 1 ) encodes a tandem plant homeodomain (PHD) finger protein, identified by screening GS ‐resistant mutants. Certain PHD fingers of GSR 1 are capable of binding unmethylated H3K4, which has been reported as an epigenetic mark of gene transcriptional repression. Biochemical studies show that GSR 1 physically interacts with the transcriptional repressor ARF 16 and attenuates the intensity of interaction of IAA 17/ ARF 16 by directly interacting with IAA 17 to release ARF 16. Further results show that axr3‐1 , arf10 arf16 are hyposensitive to GS , and gsr1 not only resists auxin‐mediated inhibition of seed germination but also displays decreased dormancy. We therefore propose that GSR 1 may form a co‐repressor with ARF 16 to regulate seed germination. Besides promoting auxin biosynthesis via upregulating expression of YUCCA1 , GS also enhances auxin responses by inducing degradation of DΙΙ‐ VENUS and upregulating expression of DR 5‐ GFP . In summary, we identified GSR1 as a member of the auxin‐mediated seed germination genetic network, and GS , a small non‐auxin molecule that specifically acts on auxin‐mediated seed germination.