The zinc-finger protein STOP1 （sensitive to proton rhizotoxicity 1） regulates transcription of multiple genescritical for tolerance to aluminum （AI） and low pH in Arabidopsis. We evaluated the contributions of gen...The zinc-finger protein STOP1 （sensitive to proton rhizotoxicity 1） regulates transcription of multiple genescritical for tolerance to aluminum （AI） and low pH in Arabidopsis. We evaluated the contributions of genes that are sup-pressed in the stop1 mutant to AI- and low pH-tolerance using T-DNA-inserted disruptants, and transgenic stop1 mutantsexpressing each of the suppressed genes. STOP2, a STOP1 homolog, partially recovered AI- and low pH-tolerance byrecovering the expression of genes regulated by STOP1. Growth and root tip viability under proton stress were partiallyrescued in the STOP2-complemented line. STOP2 localized in the nucleus and regulated transcription of two genes （PGIP1and PGIP2） associated with cell wall stabilization at low pH. GUS assays revealed that STOP1 and STOP2 showed similarcellular expression in the root. However, the expression level of STOP2 was much lower than that of STOP1. In a STOP1promoter：：STOP2-complemented line, AI tolerance was slightly recovered, concomitant with the recovery of expressionof ALS3 （aluminum sensitive 3） and AtMATE （Arabidopsis thaliana multidrug and toxic compound extrusion）, while theexpression of AtALMT1 （aluminum-activated malate transporter 1） was not recovered. These analyses indicated thatSTOP2 is a physiologically minor isoform of STOP1, but it can activate expression of some genes regulated by STOP1.展开更多
文摘The zinc-finger protein STOP1 （sensitive to proton rhizotoxicity 1） regulates transcription of multiple genescritical for tolerance to aluminum （AI） and low pH in Arabidopsis. We evaluated the contributions of genes that are sup-pressed in the stop1 mutant to AI- and low pH-tolerance using T-DNA-inserted disruptants, and transgenic stop1 mutantsexpressing each of the suppressed genes. STOP2, a STOP1 homolog, partially recovered AI- and low pH-tolerance byrecovering the expression of genes regulated by STOP1. Growth and root tip viability under proton stress were partiallyrescued in the STOP2-complemented line. STOP2 localized in the nucleus and regulated transcription of two genes （PGIP1and PGIP2） associated with cell wall stabilization at low pH. GUS assays revealed that STOP1 and STOP2 showed similarcellular expression in the root. However, the expression level of STOP2 was much lower than that of STOP1. In a STOP1promoter：：STOP2-complemented line, AI tolerance was slightly recovered, concomitant with the recovery of expressionof ALS3 （aluminum sensitive 3） and AtMATE （Arabidopsis thaliana multidrug and toxic compound extrusion）, while theexpression of AtALMT1 （aluminum-activated malate transporter 1） was not recovered. These analyses indicated thatSTOP2 is a physiologically minor isoform of STOP1, but it can activate expression of some genes regulated by STOP1.
