Abstract
Rice is the most aluminum (Al)-tolerant species among the small grain cereals, but there are great variations in the Al tolerance between subspecies, with higher tolerance in japonica subspecies than indica subspecies. Here, we performed a screening of Al tolerance using 65 indica cultivars and found that there was also a large genotypic difference in Al tolerance among indica subspecies. Further characterization of two cultivars contrasting in Al tolerance showed that the expression level of ART1 (ALUMINUM RESISTANCE TRANSCRIPTION FACTOR 1) encoding a C2H2-type Zn-finger transcription factor, was higher in an Al-tolerant indica cultivar, Jinguoyin, than in an Al-sensitive indica cultivar, Kasalath. Furthermore, a dose-response experiment showed that ART1 expression was not induced by Al in both cultivars, but Jinguoyin always showed 5.9 to 11.4-fold higher expression compared with Kasalath, irrespectively of Al concentrations. Among genes regulated by ART1, 19 genes showed higher expression in Jinguoyin than in Kasalath. This is associated with less Al accumulation in the root tip cell wall in Jinguoyin. Sequence comparison of the 2-kb promoter region of ART1 revealed the extensive sequence polymorphism between two cultivars. Whole transcriptome analysis with RNA-seq revealed that more genes were up- and downregulated by Al in Kasalath than in Jinguoyin. Taken together, our results suggest that there is a large genotypic variation in Al tolerance in indica rice and that the different expression level of ART1 is responsible for the genotypic difference in the Al tolerance.
Highlights
The toxicity of aluminum ion is a major limiting factor of crop production in acid soils, which comprises around 30–40% of arable land in the world [1]
The root root elongation (RRE) ranged from 15.9% to 74.6%, indicating that there was a genotypic difference in Al tolerance in indica subspecies
Indica rice is usually cultivated in tropics and subtropics, where acid soils are widely distributed
Summary
The toxicity of aluminum ion (mainly Al3+ ) is a major limiting factor of crop production in acid soils, which comprises around 30–40% of arable land in the world [1]. Studies mainly on japonica cultivars showed that high Al tolerance in rice is achieved by the pyramiding of multiple mechanisms conferred by multiple genes [4,5]. These genes are involved in both the external and internal detoxification of Al and are regulated by ART1 (ALUMINUM RESISTANCE TRANSCRIPTION FACTOR 1). ART1 is a C2H2-type zinc finger transcription factor [7], which regulates at least 32 genes by binding to the core cis-acting element [GGN(T/g/a/C)V(C/A/g)S(C/G)] in the promoter region of these genes [8].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
