导　　师： 邹琦

学科专业： 071001

授予学位： 博士

作　　者： ;

机构地区： 山东农业大学

摘　　要： 在干旱、低温等胁迫环境中，植物细胞内通常会积累一些相容性物质（也叫渗调物质），从而减轻环境胁迫对植物造成的伤害，甜菜碱是主要的相容性物质之一。编码甜菜碱醛脱氢酶（BADH，催化甜菜碱醛合成甜菜碱）的基因在甜菜碱的生物合成过程中处于关键地位。本研究首先对抗旱性强的小麦品系旱丰9703与抗旱性弱的品种山农215953干旱胁迫下的渗透调节能力和光合作用进行了比较，分析了不同生育期叶片中BADH基因表达特性、BADH活性与甜菜碱含量，从生理与分子机制两方面对甜菜碱的生理功能进行了初步探讨。其次，研究测定了转菠菜BADH基因小麦低温及干旱胁迫下，不同生育期BADH活性、甜菜碱含量与光合作用等生理参数的变化，进一步研究了小麦胁迫耐性与甜菜碱含量、BADH活性之间的关系。考虑到菠菜与小麦BADH基因的保守性，我们从抗旱小麦新品系旱丰9703叶片中克隆了BADH cDNA序列，并构建了表达载体，对模式植物烟草进行了转化，旨在进一步研究小麦BADH基因在抗逆性中的作用，为其今后在小麦育种中的应用打下基础。主要结论如下： 1. 长期大田干旱胁迫下，旱丰9703表现出了较强抗性；三个生育期中旱丰9703的叶片相对含水量与渗透调节能力均高于山农215953，灌浆期的渗透调节能力最强，比乳熟期高0.284MPa；干旱胁迫下旱丰9703仍具有较高的净光合速率（Pn）、最大光化学效率（Fv//Fm）和实际光化学效率（φPSII），耐光抑制能力较强。Northern印迹杂交结果表明：灌浆期中度水分胁迫时BADH的表达水平显著增加，旱丰9703略高于山农215953；乳熟期较严重的土壤水分胁迫下抗旱性强的品种叶片中BADH表达量明显高于抗旱性弱的品种；三个生育期中，BADH活性和甜菜碱含量的变化与BADH基因的表达呈现相同的趋势，均是先增加后 Under environmental stress, plant cells usually accumulates some compatible solutes/(also regarded as osmotin/) in order to alleviate the injury derived from environmental stress. Glycine betaine /(GB/) is regarded as an extremely effective compatible solute, therefore researchers pay much attention to the bio-engineering of GB. The BADH encoding BADH which catalyzes betaine aldehyde /(BA/) into GB stands the essential position in the synthesis of GB. Firstly, we determined the OA and photosynthesis of flag leaves in strong and weak drought resistant wheat varieties, and then analyzed the expression level of BADH, BADH activity and GB content of flag leaves in two wheat varieties at different stage under drought stress and dissertated the physiological function of GB in molecular biology. Secondly, some physiological parameters such as the BADH activity, GB content and photosynthesis of transformed wheat plants with BADH from spinach under drought stress were studied; Finally, we cloned complete sequence of the BADH cDNA from the leaves of strong drought resistant cultivar Hanfeng9703, constructed the expression vector and acquired transgenic tobacco plants. The results are followed: 1. Two winter wheat/(Triticum aestivum L./)varieties/( Drought-resistant cultivar Hanfeng 9703 and Drought-sensitive cultivar Shannong 215953/) were used to study the OA, Pn and photochemical activity of PSII complex as well as the expression level of BADH and GB content in flag leaves at different stage under long-term field drought stress. OA and RWC of Hanfeng 9703 were higher than those of Shannong 215953 at three stages, OA at seed filling stage was the highest which increased 0.058and 0.284MPa comparing to that of flowering stage and milk ripening stage respectively. Drought stress resulted in the decrease of Pn, Fv//Fm and φPSII of two wheat varieties at three different stage; But Pn, Fv//Fm, φPSII of Hanfeng 9703 were higher than those of Shannong 215953 under drought

关 键 词： 小麦 甜菜碱醛脱氢酶 基因克隆 转化 表达调控 光合作用

领　　域： [农业科学]