β–氨基丁酸对Cd胁迫下菊花生理特性的影响

为探究β–氨基丁酸(BABA)能否缓解Cd胁迫对菊花生长和生理代谢的毒害作用,以耐Cd型菊花品种‘钟山金葵’和Cd敏感型菊花品种‘钟山丹桂’为试验材料,用1/2Hogland营养液培养,研究了200μmol·L-1 Cd单独处理和200μmol·L-1 Cd+0.2 mmol·L-1 BABA处理下两个品种的生长、生物量、Cd积累和转运、根尖Cd流量以及叶片MDA含量、相对电导率、叶绿素含量、脯氨酸含量的变化。结果表明:Cd胁迫抑制菊花的生长和叶绿素的合成,破坏细胞膜结构的完整性,引起膜脂过氧化伤害。耐Cd品种‘钟山金葵’的膜脂过氧化程度较低,细胞膜的完整性较好,能快速、大量地合成渗透调节物质(脯氨酸)来减轻Cd胁迫的毒害作用。BABA能改善Cd胁迫下菊花的生长,缓解Cd胁迫对株高、根长和生物量的抑制作用。BABA还可减缓Cd胁迫下叶片MDA含量的增加和相对电导率的升高,但并不增加脯氨酸的含量。耐Cd品种‘钟山金葵’根尖Cd离子流量大于Cd敏感型品种‘钟山丹桂’,能积累较多的Cd,并可以利用老叶贮存Cd,且受害程度较低。BABA能促进Cd胁迫下根系对Cd的吸收及其向地上部的转运,但对Cd在地上部不同叶位中的分布无影响。BABA处理可以促进菊花对Cd污染土壤的修复。

Effects of β-Amino Butyric Acid Induced Rice Blast Resistance on Reactive Oxygen Metabolism

[Objective] This study was to understand the effects of β-Amino butyric acid(abbreviated as BABA) induced rice blast resistance on reactive oxygen metabolism. [Method] Using the cultivar Chaochan 2 that is highly susceptible to disease as experimental material, the changes of catalase(CAT), and superoxide dismutase(SOD) and MDA activities in rice treated by BABA were investigated. [Result] In rice plants treated by BABA, the activities of CAT and SOD increased, meanwhile the MDA content also rose to some extent, resulting in the disease resistance to rice blast. [Conclusion] By influencing reactive oxygen metabolism, BABA endows rice plants with resistance to rice blast. BABA is safe to environment and has highly resistance-inducing capacity, it could be generalized in production.

桃TGA家族鉴定及BABA诱导的抗病表达分析

以高度保守的BRLZ(PF07716)和DOG1(PF14144)结构域为种子序列,通过生物信息分析共鉴定得到15个桃TGA(TGACG motif-binding factor)家族基因,这些基因分布于桃的4条染色体上,其编码蛋白大小介于333~546 aa,分子量介于37.07~61.47 kD,等电点介于6.01~8.59,均定位于细胞核上。根据系统进化关系,拟南芥、大豆、番茄、水稻和桃的TGA家族分为5个亚族,其中桃TGA家族成员主要分布于第Ⅰ、Ⅱ和Ⅳ亚族。对桃TGA家族成员启动子区域的顺式调控元件进行预测分析,其启动子区含有至少1个激素或逆境胁迫响应元件。经RNA-seq数据分析可知,β–氨基丁酸(β-aminobutyric acid,BABA)处理和匍枝根霉(Rhizopus stolonifer)侵染能诱导桃TGA成员表达,其中PpTGA1-1在处理后12h内上调最为显著;显著表达的Pp TGA1-1通过与PpNPR1蛋白相互作用赋予PpNPR1蛋白DNA结合功能,启动一系列病程相关(pathogenesis-related,PR)基因的表达,从而诱导果实敏化(priming)抗性。桃TGA家族成员(尤其PpTGA1-1)可直接响应激发子诱导和病原菌侵染,并通过修饰PpNPR1蛋白从而在防卫反应中发挥重要调控作用。