Isolation And Function Analysis Of GmSTOP1s Gene Family

Acid soils significantly limit plant growth and development because of the phosphorous(P) deficiency, proton(H+) toxicity and aluminum(Al3+) toxicity. Application of P fertilizer and limestone is commonly used to prevent crop production decrease, but those high-input farming practices are not applicable for the sustainable agriculture. Also, it could cause environmental problems because of the enrichment of P in water. Understanding the mechanisms of crop resistance to P deficiency, H+ toxicity and Al3+ toxicity, and molecular breeding of crops for enhanced tolerance to acid stress are of great importance. The transcription factor Sensitive to proton rhyzotoxicity 1(STOP1) plays important roles in plant adaption to acid soils. In this study, three STOP1-like genes were identified and isolated from soybean cultivar YC03-3. And their transcriptional activity, subcellular localization and expression pattern are analyzed. We further performed in planta complementation assays in the Atstop1 mutant, and overexpress Gm STOP1 s in the Arabidopsis wild type to analyze their regulatory mechanism of plant adaption to acid soils. The results were shown as follows:1, Three STOP1-like genes were cloned from the soybean cultivar YC03-3, and named as Gm STOP1-1, Gm STOP1-2 and Gm STOP1-3 respectively. All of those genes contained four Cys-2-His-2 zinc-finger domains. Subcellular localization verified that Gm STOP1 s are located in the nucleus. Yeast one-hybrid analysis showed that although all of them had transactivation activity, only Gm STOP1-3 could bind to the promoter of Gm ALMT1.2, The expression of all the Gm STOP1 s were increased by aluminum toxicity in root. No significant changes of Gm STOP1-1 and Gm STOP1-3 expression were observed under low p H treatment, while the expression of Gm STOP1-2 increased after 24 hour treatment. The genetic variation of the expression of Gm STOP1 s in response to low p H were investigated. However, no correlation between the transcriptional level of Gm STOP1 s and soybean low p H tolerance was found.3, Nutrient deficiency regulated Gm STOP1 s expression. In leaves, nitrogen, phosphorus and sulfur deficiency increased the expression of Gm STOP1s; while only Gm STOP1-1 and Gm STOP1-3 were up regulated by potassium deficiency in old leaves. Iron and calcium deficiency decreased Gm STOP1 s expression in young leaves, no significant difference were observed in old leaves. In root, the expression of Gm STOP1-1 increased under nitrogen deficiency, while sulfur deficiency significantly decreased its expression. Iron and calcium deficiency increased Gm STOP1-2 expression. Nitrogen, phosphorus and sulfur deficiency increased the expression of Gm STOP1-3, while iron deficiency decreased its expression.4, In planta complementation assays showed that Gm STOP1-1 and Gm STOP1-2 conferred H+ tolerance in stop1 mutant. Overexpression Gm STOP1 s in Arabidopsis wild type increased the biomass and root-shoot ratio of transgenic lines. However, only overexpression Gm STOP1-3 increased the root-shoot ratio under low phosphorus conditions.5, Further analysis showed that Overexpression Gm STOP1-3 increased the root surface area, total root length and lateral root length, and had no obvious effect on tap root length.Taken together, we cloned 3 Gm STOP1 s genes in soybean, and analyzed their transcriptional activity, subcellular localization and expression pattern. In addition, the function of Gm STOP1 s on plant adaptation to proton and aluminum toxicity and low phosphorus stress was also analyzed, which could provide theoretical basis and candidate genes for the breeding of adaptive soybean varieties to acid soils.