BABA诱导烟草抵御高锌胁迫的初步研究

A preliminary research on BABA induced resistance to high Zn^(2+) stress of tobacco

通过测定抗氧化体系、离子含量及基因表达探讨了β-氨基丁酸(BABA)诱导烟草抵御高锌胁迫作用机理。结果表明:0.2 mmol/L BABA能够诱导烟草缓解高锌胁迫,相比对照组增加了幼苗叶片中脯氨酸、还原性谷胱甘肽及可溶性蛋白含量且使丙二醛含量恢复到几乎正常水平;APX、POD、CAT酶活性略有下降但SOD酶活性增加最终使信号分子H_2O_2含量上升;等离子体发射光谱仪测试表明BABA处理使叶片中Zn^(2+)含量下降,而对根部Zn^(2+)含量影响不大;基因表达得出0.2 mmol/L BABA处理后PR1、PR2、Nt MTP1A、Nt MTP1B、Nt C477及Nt YSL基因表达上调。综合来看0.2 mmol/L BABA缓解烟草高锌胁迫是通过激发植物体抗氧化系统、限制Zn^(2+)向上运输以及抗病蛋白和离子转运蛋白相关基因表达量上调的综合结果。

Excess amount of Zinc is toxic and has negative effects on inhibition of growth, root development and may cause leaf chlorosis. The role of BABA in protecting tobacco seedling from high Zn2＋ stress was studied and its working mechanism was explored through measuring antioxidative molecular content, antioxidative enzyme activities, concentration of Zn2＋ in leaf and root and related gene expression. Results showed that 0.2 mmol/L BABA protected tobacco seedling from high-Zn2＋ stress via increasing content of proline, GSH, total soluble protein and keeping MDA content at nearly normal level. Activities of CAT, POD and APX were reduced while SOD activity was increased, which raised signal molecule H2O2 content. BABA lowered Zn2＋ concentration in leaf, but no obvious difference was found in root under high-Zn2＋ stress by ICP-7300DV. In addition, gene expression indicated that the transcript level of PR1, PR2, NtMTP 1 A, NtMTP 1 B, NTC477 and NtYSL was higher than that of BABA untreated samples. It was suggested that the 0.2 mmol/L BABA was beneficial in alleviating high-Zn2＋ stress in tobacco seedling by stimulating antioxidant system, restricting Zn2＋ upper transportation and over expression genes of related ion transporters and pathogenesis-related proteins.