In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 116, No. 1 ( 2019-01-02), p. 313-318
Abstract:
Acidic soils, where aluminum (Al) toxicity is a major agricultural constraint, are globally widespread and are prevalent in developing countries. In sorghum, the root citrate transporter SbMATE confers Al tolerance by protecting root apices from toxic Al 3+ , but can exhibit reduced expression when introgressed into different lines. We show that allele-specific SbMATE transactivation occurs and is caused by factors located away from SbMATE . Using expression-QTL mapping and expression genome-wide association mapping, we establish that SbMATE transcription is controlled in a bipartite fashion, primarily in cis but also in trans . Multiallelic promoter transactivation and ChIP analyses demonstrated that intermolecular effects on SbMATE expression arise from a WRKY and a zinc finger-DHHC transcription factor (TF) that bind to and trans -activate the SbMATE promoter. A haplotype analysis in sorghum RILs indicates that the TFs influence SbMATE expression and Al tolerance. Variation in SbMATE expression likely results from changes in tandemly repeated cis sequences flanking a transposable element (a miniature inverted repeat transposable element) insertion in the SbMATE promoter, which are recognized by the Al 3+ -responsive TFs. According to our model, repeat expansion in Al-tolerant genotypes increases TF recruitment and, hence, SbMATE expression, which is, in turn, lower in Al-sensitive genetic backgrounds as a result of lower TF expression and fewer binding sites. We thus show that even dominant cis regulation of an agronomically important gene can be subjected to precise intermolecular fine-tuning. These concerted c is / trans interactions, which allow the plant to sense and respond to environmental cues, such as Al 3+ toxicity, can now be used to increase yields and food security on acidic soils.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.1808400115
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2019
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
