甘蔗应答乙烯调控的转录组差异分析

Ethephon, an effective plant growth regulater, has been extensively used in sugarcane to improve cane yield and sugar content.Suitable concentration of ethephon can effectively promote the sprouting, tillering and stalk elongation, enhance the photosynthesis, and improve the cane yield and drought resistance of sugarcane. In order to illustrate the molecular mechanism of ethephon on sugarcane, the differentially expressional genes in sugarcane induced by ethephon have been analyzed by cDNA-AFLP in our previous research. Some genes relevant to photosynthesis and resistance have been identified, such as chitinase I genes, glutathione S shift enzyme gene, auxin induced protein gene,light harvesting chlorophyll a/b binding protein, etc., and the ethylene receptor gene (Sc-ERS) in sugarcane has been cloned and sequenced. Base on the previous research results, the differentially expressional genes would be continuously cloned, sequenced,expressed in the present proposal and the functions would be further identified by the methods of molecular crossing, gene silencing and bioinformatics. The relationships between the differentially expressional genes induced by ethylene and sugarcane growth stimulation, including of tillering and yield improvement, would be analyzed, which could provide evidences for illustrating the molecular mechanism of plant growth regulation with ethephon in sugarcane.

适宜浓度的乙烯利能有效促进甘蔗早期的萌芽、分蘖和蔗茎伸长，增强光合作用，提高甘蔗产量和抗旱性，是调控甘蔗高产高糖生产中普遍使用的有效化学调控物质。为进一步了解乙烯利调控甘蔗生长的分子作用机理，本项目组已利用cDNA-AFLP技术分析了乙烯利诱导甘蔗基因的差异表达，获得了一些与甘蔗光合作用及抗逆性相关的差异表达基因，如几丁质酶Ⅰ基因、谷胱甘肽S转移酶基因、生长素诱导蛋白基因、捕光叶绿素a/b结合蛋白基因等，并对甘蔗乙烯受体Sc-ERS基因进行了克隆和序列分析。本申请项目拟在此基础上，运用基因沉默技术和生物信息学技术，对差异表达基因进行克隆、序列分析、表达分析和功能验证，探讨在乙烯诱导下甘蔗差异表达的基因与乙烯利促进甘蔗分蘖、提高甘蔗产量的关系，为解析乙烯调控甘蔗生长的分子作用机理提供理论依据。

适宜浓度的乙烯利能有效促进甘蔗早期的萌芽、分蘖和蔗茎伸长，增强光合作用，提高甘蔗产量和抗旱性，是调控甘蔗高产高糖生产中普遍使用的有效化学调控物质。本项目在前期研究基础上对已获得的阳性差异片段进行序列分析，利用生物信息学软件和在线分析对差异表达基因的功能进行分析，筛选获得与乙烯调控甘蔗生长相关的候选基因12个，分别为赤霉素受体基因gibberellin receptor GID1L2 、生长素诱导蛋白PCNT115（auxin-induced protein,AIP）基因、生长素结合蛋白（auxin binding protein,ABP）基因、捕光叶绿素a/b结合蛋白(Light harvesting chlorophyll a/b-binding protein)基因、甘蔗乙烯受体基因Sc-ERS、纤维素合成酶(cellulose synthase)基因、伸长因子2 (elongation factor 2 )基因、 ATPase基因、Ca2+-ATPase基因 、丙酮酸激酶（pyruvate kinase,PK）基因、ethylene-responsive transcription factor 3基因 、ethylene responsive element基因等。项目建立并优化了甘露糖筛选的甘蔗遗传转化体系，构建了AIP基因、Ca2+-ATPase基因和PK基因的超量表达载体p3301-AIP、p3301-PK、p3301-Ca2+-ATPase和RANi干扰载体pART27-pHAN-AIP、pART27-pHAN- Ca2+-ATPase、pART27-pHAN-PK，并通过根癌农杆菌介导法导入到甘蔗中去，获得了转基因甘蔗植株，为分析差异表达基因在甘蔗生长中的作用提供了研究材料。