Os05g0119000
Os05g0119000 is the gene STAR2 which is responsible for Al tolerance in rice, and it encodes a transmembrane domain, of a bacterial-type ATP binding cassette (ABC) transporter.
Contents
Annotated Information
Function
Aluminum (Al) toxicity is a major factor limiting crop production in acidic soil, but the molecular mechanisms of Al tolerance are poorly understood. The gene STAR2 is responsible for Al tolerance in rice. Proteins encoded by STAR1 form a complex that functions as a unique ATP binding cassette (ABC) transporter, which is required for detoxification of Al in rice. The results described that STAR1 is translated to TMD, respectively, and then functions as an ABC transporter protein complex[1]. However, the function of most ABC transporters is still unknown.
Expression
STAR2 is mainly expressed in the roots, and mRNA accumulation of STAR2 is significantly enhanced when seedlings were exposed to aluminum. A time-course experiment showed that the expression of STAR2 was similarly induced by aluminum as early as 2h after the exposure. Furthermore, an aluminum concentration as low as 5μM triggered the expression of STAR2, and the expression level increased with increasing external aluminum concentration. The mRNA accumulation of STAR2 does not respond to low pH and other metals, indicating that STAR2 is specifically induced by aluminum[1]. Expression of STAR2 alone also resulted in current change, but it lost the specificity for the preloaded substrates (UDP-Glc, UDPGlcA, and water) probably due to increased membrane permeability for all substrates.
Evolution
STAR2 is a homolog of ALS3, which is involved in Al tolerance in Arabidopsis[2]. However, STAR2 and ALS3 differ in expression pattern and cellular localization. STAR2 is only expressed in the roots, whereas ALS3 is expressed in all organs, including roots, leaves, stems, and flowers [2].The expression of both STAR2 and ALS3 is induced by Al[2]. In the roots exposed to Al, ALS3 is localized in the phloem and root tips. By contrast, STAR2 is localized in all cells excepting epidermal cells in the mature root zone.
Labs working on this gene
·Research Institute for Bioresources, Okayama University, Kurashiki 710-0046, Japan. ·QTL Genomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan. ·Genome Resource Center, Division of Genome and Biodiversity Research, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
References
- ↑ 1.0 1.1 Chao Feng Huang, Naoki Yamaji, Namiki Mitani, et.al. (2009) A Bacterial-Type ABC Transporter Is Involved in Aluminum Tolerance in Rice. The Plant Cell, Vol. 21: 655-667.
- ↑ 2.0 2.1 2.2 Larsen, P.B., Geisler, M.J.B., Jones, C.A., Williams, K.M., and Cancel, J.D.(2005). ALS3encodes a phloem-localized ABC transporter-like protein that is required for aluminum tolerance inArabidopsis.Plant J.41:353–363.
