Xác định và phân tích biểu hiện toàn bộ bộ gen của cây trạm (Medicago truncatula) và cỏ linh lăng (Medicago sativa L.) trong gia đình yếu tố phiên mã BHLH cơ bản dưới áp lực muối và hạn hán

Journal of Plant Growth Regulation - Tập 40 - Trang 2058-2078 - 2020
Boniface Ndayambaza1, Xiaoyu Jin1, Xueyang Min1, Xiaoshan Lin1, Xiaofan Yin1, Wenxian Liu1
1State Key Laboratory of Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Western China Technology Innovation Centre for Grassland Industry; Engineering Research Center of Grassland Industry, Ministry of Education; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, People’s Republic of China

Tóm tắt

Yếu tố phiên mã helix-loop-helix cơ bản (bHLH) gồm một trong những bộ điều chỉnh phiên mã lớn nhất đặc hữu cho thực vật trong sự phát triển và tăng trưởng của thực vật, phản ứng với các áp lực sinh học và không sinh học. Nhiều thành viên của bHLH đóng vai trò thiết yếu trong sự phát triển của sợi rễ và phản ứng với áp lực do hạn hán, muối và lạnh. Gia đình gen bHLH đã được tìm thấy ở nhiều loài; tuy nhiên, loài cỏ trạm và cỏ linh lăng vẫn còn một khoảng trống nhỏ về các thành viên bHLH mới đến nay. Nghiên cứu này nhằm xác định các thành viên của gia đình bHLH trong cây cỏ trạm và cỏ linh lăng, đồng thời làm rõ mức độ biểu hiện của chúng, phân tích mạng lưới, mô hình 3D dự đoán và mối quan hệ phát sinh loài. Tại đây, chúng tôi đã xác định và đặc trưng hóa gia đình gen bHLH ở cả hai loại cây cỏ trạm và cỏ linh lăng, đồng thời nghiên cứu phản ứng biểu hiện gen của chúng đối với các áp lực hạn hán, độ mặn và lạnh. Tổng cộng, 159 gen MtbHLH và 133 gen MsbHLH đã được xác định và đặc trưng, phân chia thành 18 nhóm phụ và 17 nhóm phụ, tương ứng. Như một phương pháp phổ biến và hiện diện rộng rãi, phân cụm theo hàng xóm được sử dụng. Dựa trên phân tích phát sinh loài, nhóm phụ VIII và IX cùng với nhóm phụ X được chọn là nhóm phụ liên quan đến áp lực trong hai loài này. 154 gen MtbHLH phân bố đồng đều trên 8 nhiễm sắc thể và 23 gen sao chép nối tiếp, cùng 44 đoạn gen sao chép được phát hiện trong gia đình MtbHLH. Phân tích chức năng gen phát hiện ra rằng bHLH chủ yếu hoạt động trong việc gắn kết protein và DNA trong hai loài này. Kết quả của Ka/Ks là < 1, cho thấy đa số giá trị gen đồng hình bHLH được tìm thấy giữa loài A. thaliana và M. truncatula. Đặc biệt, 7 gen MtbHLH và 10 gen MsbHLH được chọn và xác thực bằng qRT-PCR sau khi xử lý các mẫu dưới các điều kiện abiotic căng thẳng. Các mẫu biểu hiện tương tự giữa M. truncatula và M. sativa L đã cho thấy mẫu biểu hiện đồng nhất ở rễ, trong khi mẫu ở thân và lá lại rất khác nhau. Nghiên cứu nhấn mạnh rằng phân tích biểu hiện gen của 17 gen bHLH đã được điều chỉnh lên đối với áp lực, trong khi một số gen có xu hướng giảm tốc độ xuống so với đối chứng (0 giờ). Nghiên cứu này cung cấp một cái nhìn tổng quan về chức năng gen bHLH cụ thể theo mô ở cấp độ toàn bộ bộ gen dưới áp lực hạn hán, muối và lạnh. Phân tích của chúng tôi cung cấp những hiểu biết đầu tiên về sự tiến hóa của M. truncatula và M. sativa L, góp phần vào việc lai tạo ở cấp độ phân tử nhằm cải thiện năng suất cây trồng và khả năng chịu stress.

Từ khóa

#bHLH #Medicago truncatula #Medicago sativa #yếu tố phiên mã #áp lực hạn hán #áp lực muối

Tài liệu tham khảo

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