Cloning And Characterization Of GmPRP2p And GmTIPp, Two Root-specific Promoters In Soybean

Promoters are important components in transgenic engineering and regulate the gene expression pattern. Root-specific promoters can direct pest-and disease-resistance genes in root expression, which can enhance the root resistance and tolerance. According to some root-specific genes reported, two root-specific genes from soybean were selected by RT-PCR, named GmPRP2and GmTIP, respectively. For deeply study the function of root-specific promoter, GmPRP2and GmTIP promoters were cloned from soybean, and also got the5’deletion fragments from each promoter. All of these promoter and fragments were fused to the GUS reporter gene. The constructs were introduced into Arabidopsis and soybean cotylodens. The transgenic plants were used to examine the expression pattern and promoter activity. The results were as follows:1. According to the GmPRP2sequence, a1,062bp5’flanking sequence of GmPRP2was cloned by two round PCR. A2,054bp5’flanking sequence of GmTIP was also got with the same method above. The two promoters named GmPRP2p-1062and GmTIPp-2054, respectively.5’deletion fragments were got to research the core regions of specification. The5’deletion fragments of GmPRP2promoter were defined as:GmPRP2p-852, GmPRP2p-471, and GmPRP2p-369; the5’deletion fragments of GmTIP promoter were defined as:GmTIPp-1546, GmTTPp-1201, GmTIPp-253.2. The histochemical staining showed that GmPRP2p-1062driven GUS expression was mainly detected in hypocotyls and roots, and GUS staining appeared in the petiole during the reproductive growth stage, and emerged in the split margins besides the abscission in siliques, but the expression levels were quite weak. GUS staining was not detected in cotyledon、leaf、flower and seed. The expression patterns of GmPRP2p-852and GmPRP2p-369were similar to that of GmPRP2p-1062, but the expression level was difference. GUS staining was not visible in any organs of plants containing the GmPRP2p-471construct. It is speculated that-1062to-852and-471to-369may exist silence elements;-852to-471may exist enhance elements. Its core fragment for root-specific expression lies between-369and+1. 3. GmTIPp-2054-driven GUS expression was mainly in roots, weak expression was detected in other organs like petiole, hypocotyls, flower, out shell of silique. GmTIPp-1546、GmTIPp-1201and GmTIPp-253driven root-specific expression. GUS staining was not visible in leaf、flower and seed. Its core fragment that is beneficial for root-specific expression lies between-1546and+1.4. GmPRP2p-1062, GmPRP2p-852and GmPRP2p-369also drove GUS staining in soybean hairy roots, but GUS staining was not detected in transgenic GmPRP2p-471hairy roots. The expression level of GmPRP2promoter is weak. All of GmTIP promoter and5’deletion fragments drive strong gene expression in the soybean hairy roots.