Two-component systems (TCSs) have been identified as participants in mediating plant response to water deficit. Nevertheless, insights of their contribution to plant drought responses and associated regulatory mechanisms remain limited. Herein, a soybean response regulator (RR) gene RR34, which is the potential drought-responsive downstream member of a TCS, was ectopically expressed in the model plant Arabidopsis for the analysis of its biological roles in drought stress response. Results from the survival test revealed outstanding recovery ratios of 52%–53% in the examined transgenic lines compared with 28% of the wild-type plants. Additionally, remarkedly lower water loss rates in detached leaves as well as enhanced antioxidant enzyme activities of catalase and superoxide dismutase were observed in the transgenic group. Further transcriptional analysis of a subset of drought-responsive genes demonstrated higher expression in GmRR34-transgenic plants upon exposure to drought, including abscisic acid (ABA)-related genes NCED3, OST1, ABI5, and RAB18. These ectopic expression lines also displayed hypersensitivity to ABA treatment at germination and post-germination stages. Collectively, these findings indicated the ABA-associated mode of action of GmRR34 in conferring better plant performance under the adverse drought conditions.

Tách dòng phân tử và thiết kế vector chuyển gen DAT 236 TÁCH DÒNG PHÂN TỬ VÀ THIẾT KẾ VECTOR CHUYỂN GENTrường Đại học sư phạm, Đại học Thái Nguyên, *chuhoangmau@tnu.edu.vn TÓM TẮT: Cây dừa cạn, Catharanthus roseus (L.) G. Don, là thực vật hai lá mầm, có khả năng sản xuất các alkaloid, trong đó có vincristine và vinblastine, chữa được các bệnh ung thư, đặc biệt là ung thư máu. Deacetylvindoline 4-O-acetyltransferase (DAT) là enzyme chìa khóa xúc tác cho phản ứng cuối cùng trong quá trình sinh tổng hợp vindoline ở cây dừa cạn. Nghiên cứu nâng cao hàm lượng alkaloid trong cây dừa cạn theo hướng tiếp cận ứng dụng công nghệ gen nhằm đáp ứng nguồn nguyên liệu phục vụ mục đích chữa bệnh được đặt ra trong chiến lược nghiên cứu cây dược liệu. Trong bài báo này, chúng tôi trình bày kết quả nhân bản, tách dòng cDNA và xác định trình tự nucleotide của gen DAT phân lập từ mRNA của giống cây dừa cạn có hoa hồng tím (TN1) và hoa trắng (TN2) thu tại Thái Nguyên. Gen DAT (cDNA) được phân lập từ hai mẫu dừa cạn TN1 và TN2 có kích thước 1320 bp, mã hóa deacetylvindoline 4-O-acetyltransferase gồm 439 amino acid. Trình tự nucleotide của cDNA ở mẫu dừa cạn TN1 (hoa hồng tím) và TN2 (hoa trắng) khác nhau ở 13 vị trí nucleotide, trình tự amino acid suy diễn của DAT của hai mẫu dừa cạn TN1, TN2 sai khác ở 10 vị trí amino acid. Vector chuyển gen mang gen DAT đã được thiết kế thành công và được sử dụng trong mục đích tạo dòng cây chuyển gen có hàm lượng alkaloid được cải thiện.

Catharanthus roseus (L.) G. Don contains about 130 types of alkaloids, including vincristine and vinblastine, which are outstanding drugs for cancer. The C. roseus deacetylvindoline-4-O-acetyl transferase (CrDAT) is a key enzyme which catalyzes the second to the final reactions in the vindoline way. The low content of indole alkaloid in C. roseus plants and the high cost of indole alkaloid production have promted many research to improve indole alkaloid yield in this plant. The aim of this work was to express recombinant CrDAT in tobacco, a model plant, to create the basis for the overexpression of the gene encoding CrDAT (GenBank LN809930) in C. Roseus plants. In this study, the 35S-DAT-cmyc structure was transferred to tobacco and the transgenic tobacco lines was generated. The T1 generation was then analyzed by Western blot method and ELISA analysis. Southern blot assays confirmed that the CrDAT gene was completely introduced into tobacco genome by Agrobacterium-mediated transformation. The recombinant CrDAT protein of 51.5 kDa in size was successfully expressed at the seven transgenic tobacco lines. The recombinant CrDAT protein content of transgenic tobacco lines were 2.75-5.35 (g. mg-1 of total protein) range and the recombinant CrDAT protein content of the T0-1 line was highest (5.35 g. mg-1 of total protein).

In this paper, the dispersion of Ag metal nanoparticles on SBA-15 mesoporous silica and its catalytic performance to oxidize glucose to gluconic acid were studied. Mesoporous silica SBA-15 materials were synthesized using the triblock copolymer Pluronic P123 as a template in acid condition. Ag nanoparticles were prepared using impregnation method inside the pores of the support by controlled reduction of AgNO3 with sodium borohydrate (NaBH4). The XRD, TEM, EDS, BET techniques were used for characterization of materials. Silver nanoparticle formation is confirmed by TEM. The efficiency of glucose oxidation to gluconic acid is determinated by HPLC-RID and LC-MS. Obtained results showed that it can prepare silver nanopartilces with particle diameter about 5 nm; and catalyst based on these particles has quite efficiency in glucose oxidation to gluconic acid.