《植物生理学报》 2017, 53(10): 1859-1866

转酮醇酶基因沉默对高温胁迫下黄瓜幼苗光合作用的影响

毕焕改, 李福德, 董绪兵, 艾希珍^∗

山东农业大学园艺科学与工程学院, 作物生物学国家重点实验室, 农业部黄淮地区园艺作物生物学与种质创制重点开放实验室, 山东泰安271018

通信作者：艾希珍；E-mail: axz@sdau.edu.cn

摘　要：

以2个反义转酮醇酶基因(CsTK)黄瓜株系T2′-2和T2′-4以及野生型黄瓜‘08-1’为试材, 研究CsTK沉默对高温(40°C)下黄瓜幼苗净光合速率(P_n)、核酮糖-1,5-二磷酸羧化/加氧酶(Rubisco)活性及其mRNA表达量和叶绿素荧光参数的影响。结果表明, 与野生型相比, 2个反义株系的转酮醇酶(TK)活性和CsTK mRNA的表达量显著降低。高温胁迫2 h后, 黄瓜幼苗叶片的P_n、气孔导度(G_s)以及以吸收光能为基础的光化学性能指数(PI_ABS)、Rubisco活性及其mRNA表达量和光系统(PSII)活性均显著降低, 而CsTK的mRNA表达量和TK活性及胞间CO₂ (C_i)浓度明显升高, 但2个反义株系各指标始终低于野生型植株, 尤其‘T2′-4’最低。CsTK沉默加剧了高温条件下黄瓜幼苗Rubisco和PSII活性的降低, 从而导致转反义CsTK黄瓜幼苗的光合作用降低幅度较大, 对高温耐性下降。

关键词：CsTK; 反义植株; 高温; 光合速率; 黄瓜

收稿：2017-03-06   修定：2017-09-22

资助：山东省自然科学基金(BS2015NY011)、国家自然科学基金(31701909)、山东省现代农业产业技术体系建设专项资金(SDAIT-05-10)和“双一流”奖补资金(SYL2017YSTD06)。 * 通讯作者(E-mail: axz@sdau.edu.cn)。

Effects of transketolase gene silencing on photosynthesis in cucumber seedlings under high temperature stress

BI Huan-Gai, LI Fu-De, DONG Xu-Bing, AI Xi-Zhen^*

College of Horticulture Science and Engineering, State Key Laboratory of Crop Biology, Key Laboratory of Horticultural Crop Biology and Germplasm Innovation of Agriculture Ministry, Shandong Agricultural University, Tai’an, Shandong 271018, China

Corresponding author: AI Xi-Zhen; E-mail: axz@sdau.edu.cn

Abstract:

The two anti-sense transketolase gene (CsTK) transgenic lines T2′-2 and T2′-4 as well as the wild type (WT) ‘08-1’ cucumber seedlings were used as test materials to study the effect of CsTK silence on net photosynthetic rate (P_n), the mRNA abundance and activity of ribulose bisphosphate carboxylic enzyme (Rubisco) as well as the chlorophyll fluorescence parameters of cucumber (Cucumis sativa) seedlings under high temperature (40°C) stress. The results showed that the mRNA abundance of CsTK and TK (transketolase) activity were significantly lower in CsTK suppress-expressing cucumber seedlings than those in WT. Following 2-h exposure to high temperature, we assayed a lower P_n, stomatal conductance (G_s), photochemical performance index based on the absorption of light energy (PI_ABS), the mRNA abundance and activity of Rubisco as well as the activity of photosystem (PSII), while a higher CsTK mRNA abundance and TK activity and intercellular CO₂ concentration (C_i) in both antisense and WT plants. However, these parameters of the two anti-sense transgenic lines were always lower compared to the WT, especially, the parameters of T2′-4 was the lowest. In general, the data suggested that CsTK silence exacerbated the reduction of the activity of Rubisco and PSII which led to the decrease of photosynthesis and high temperature tolerance in anti-sense CsTK transgenic cucumber seedlings.

Key words: CsTK; antisense transgenic plant; high temperature; photosynthetic rate; Cucumis sativa