中文摘要：

甜菜碱醛脱氢酶（betaine aldehyde dehydrogenase，BADH）是甜菜碱（glycine betaine，GB）合成过程中的关键酶。为检测BADH基因在木薯（Manihotesculenta）不同组织中的表达差异，探究干旱与NaCl胁迫下其表达谱变化规律，本研究利用生物信息学方法分析和鉴定木薯BADH基因，定位MeBADHs在染色体上的位置以及确定5’端上游序列顺式作用元件；采用qRT-PCR测定BADH基因在木薯品种SC5根、块根、茎和叶中的表达差异，同时检测在PEG．6000模拟脱水胁迫、NaCl胁迫及自然干旱胁迫下MeBADHs基因的转录水平变化，采用相关试剂盒测定木薯中GB含量的变化。结果显示，MeBADHs两个基因在各组织之中均有表达，在块根中表达量显著高于根（P〈0．05）。PEG-6000模拟干旱条件下，与0h相比，1～2h时MeBADHl和MeBADH2在叶、茎、根以及块根中的表达量变化不大；NaCl处理条件下，叶中MeBADHl在8h表达量极显著高于（P〈0．01），而MeBADH2则在不同处理时间下的表达量水平相差不大，在茎和根中，MeBADHs在处理发生1h时表达量水平极显著高于0h伊〈0．01）；自然缺水干旱条件下，茎和根中MeBADHl和MeBADH2分别在6和18d时的表达量极显著高于0d（P〈0．01）。PEG．6000处理下，GB含量出现了波动并呈现略增趋势；NaCl处理条件下GB含量在前期表达较稳定，8h时剧烈响应，即出现下调趋势，24h时GB含量显著低于0h（P〈0．05）。在自然干旱胁迫下，GB含量逐渐呈现上调趋势，并在9和15d达到高峰，显著高于0d（P〈0．05）。研究结果为进一步研究木薯分子抗旱机制及新品种的选育提供了理论依据。

英文摘要：

Betaine aldehyde dehydrogenase （BADH） is the key enzyme in the synthesis process of glycine betaine （GB）. To explore the expression difference of BADH gene in different tissues of cassava （Manihot esculenta） and the expression under drought and salt stress, bioinformatics approaches were used to identify and characterize MeBADH genes. Using computational methods, these genes were localized on cassava genome chromosome and stress-responsive cis-elements within their 5＇ upstream regions were identified. Expression profiles of these genes in different tissues were detected by qRT-PCR, at the same time, the differential expression of MeBADH genes under PEG-6000 stress, salt stress and natural drought stress were investigated in cassava. The GB content in cassava was determined by ELISA. The results showed that MeBADHs genes expressed in all tissues （root, root tuber, stem, leaf）. The expression in root tuber was significantly higher than that in root （P〈0.05）. The expression of MeBADttl and MeBADH2 in leaves, stems, root and root tuber in 1-2 h changed a little compared with 0 h under PEG- 6000 treatment. Under NaCl treatment, the expression of MeBADH1 in leaf at 8 h was the highest, and was extremely significantly higher than that at 0 h （P〈0.01）; the expression of MeBADH2 did not change much at different times. In stems and roots, the expressions of MeBADHI and MeBADH2 at l h were significantly higher than that at 0 h （P〈0.01）. Under natural drought treatment, the expressions of MeBADH1 and MeBADH2 in stem and root at 6 and 18 d were significantly higher than that at 0 d （P〈0.01）, respectively. Under PEG-6000 treatment, the GB content was fluctuant and slightly increased. The GB content under NaCl treatment showed stable expression in the early stage, and then occurred intense response at 8 h （appeared downward trend）, and the GB content at 24 h was significantly lower than that at 0 h （P〈0.05）. Under natrual drought stress, the GB content gradually increased at b