title: New insights into aluminum tolerance in rice: the ASR5 protein binds the STAR1 promoter and other aluminum-responsive genes.
abstract: Aluminum (Al) toxicity in plants is one of the primary constraints in crop production. Al³⁺, the most toxic form of Al, is released into soil under acidic conditions and causes extensive damage to plants, especially in the roots. In rice, Al tolerance requires the ASR5 gene, but the molecular function of ASR5 has remained unknown. Here, we perform genome-wide analyses to identify ASR5-dependent Al-responsive genes in rice. Based on ASR5_RNAi silencing in plants, a global transcriptome analysis identified a total of 961 genes that were responsive to Al treatment in wild-type rice roots. Of these genes, 909 did not respond to Al in the ASR5_RNAi plants, indicating a central role for ASR5 in Al-responsive gene expression. Under normal conditions, without Al treatment, the ASR5_RNAi plants expressed 1.756 genes differentially compared to the wild-type plants, and 446 of these genes responded to Al treatment in the wild-type plants. Chromatin immunoprecipitation followed by deep sequencing identified 104 putative target genes that were directly regulated by ASR5 binding to their promoters, including the STAR1 gene, which encodes an ABC transporter required for Al tolerance. Motif analysis of the binding peak sequences revealed the binding motif for ASR5, which was confirmed via in vitro DNA-binding assays using the STAR1 promoter. These results demonstrate that ASR5 acts as a key transcription factor that is essential for Al-responsive gene expression and Al tolerance in rice.
authors.affiliation: Programa de Pós-Graduação em Genética e Biologia Molecular Avenida Bento Gonçalves 9500, Departamento de Genética, sala 207, prédio 43312, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, Brasil.
authors.forename: Rafael Augusto
authors.initials: RA
authors.lastname: Arenhart
authors.forename: Yang
authors.initials: Y
authors.lastname: Bai
authors.forename: Luiz Felipe Valter
authors.initials: LF
authors.lastname: de Oliveira
authors.forename: Lauro Bucker
authors.initials: LB
authors.lastname: Neto
authors.forename: Mariana
authors.initials: M
authors.lastname: Schunemann
authors.forename: Felipe dos Santos
authors.initials: Fdos S
authors.lastname: Maraschin
authors.forename: Jorge
authors.initials: J
authors.lastname: Mariath
authors.forename: Adriano
authors.initials: A
authors.lastname: Silverio
authors.forename: Gilberto
authors.initials: G
authors.lastname: Sachetto-Martins
authors.forename: Rogerio
authors.initials: R
authors.lastname: Margis
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Wang
authors.forename: Marcia
authors.initials: M
authors.lastname: Margis-Pinheiro
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D012275:Oryza / Q000187:drug effects* / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics
chemical_list: D010940:Plant Proteins; D000535:Aluminum
keywords: ASR.; Aluminum; ChIP-Seq; RNA-Seq; rice