AUTHOR=Ueda Minoru , Matsui Akihiro , Watanabe Shunsuke , Kobayashi Makoto , Saito Kazuki , Tanaka Maho , Ishida Junko , Kusano Miyako , Seo Mitsunori , Seki Motoaki 

TITLE=Transcriptome Analysis of the Hierarchical Response of Histone Deacetylase Proteins That Respond in an Antagonistic Manner to Salinity Stress

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01323

DOI=10.3389/fpls.2019.01323

ISSN=1664-462X

ABSTRACT=<p>Acetylation in histone and non-histone proteins is balanced by histone acetyltransferase and histone deacetylase (HDAC) enzymatic activity, an essential aspect of fine-tuning plant response to environmental stresses. HDACs in <italic>Arabidopsis</italic> are composed of three families (RPD3-like, SIRT, and HD-tuins). A previous study indicated that class I (HDA19) and class II (HDA5/14/15/18) RPD3-like family HDACs control positive and negative responses to salinity stress, respectively. Furthermore, quintuple <italic>hda5/14/15/18/19</italic> mutants (<italic>quint</italic>) exhibit salinity stress tolerance, suggesting that <italic>hda19</italic> suppresses the sensitivity to salinity stress present in quadruple <italic>hda5/14/15/18</italic> mutants (<italic>quad</italic>). In the present study, transcriptome analysis of the <italic>quint</italic> mutant was conducted to elucidate the hierarchical control of salinity stress response operated by RPD3-like family HDACs (HDA5/14/15/18/19). The analysis identified 4,832 salt-responsive genes in wild-type (Col-0), <italic>hda19-3</italic>, <italic>quad</italic>, and <italic>quint</italic> plants and revealed that 56.7% of the salt-responsive genes exhibited a similar expression pattern in both the <italic>hda19-3</italic> and <italic>quint</italic> plants. These results indicate that deficiency in HDA19 has a bigger impact on salinity stress response than in class II HDACs. Furthermore, the expression pattern of genes encoding enzymes that metabolize phytohormones raises the possibility that a drastic change in the homeostasis of phytohormones, such as abscisic acid, brassinosteroid, and gibberellin, may contribute to increasing stress tolerance in <italic>hda19-3</italic> and <italic>quint</italic> plants. Among these phytohormones, abscisic acid accumulation actually increased in <italic>hda19-3</italic> and <italic>quint</italic> plants, and decreased in <italic>quad</italic>, compared with wild-type plants. Importantly, 7.8% of the salt-responsive genes in <italic>quint</italic> plants exhibited a similar expression pattern in <italic>quad</italic> plants, suggesting that some gene sets are regulated in an HDA5/14/15/18-dependent manner. The transcriptome analysis conducted in the present study revealed the hierarchical and independent regulation of salt stress response that is mediated through HDA19 and class II HDACs.</p>