梭梭幼苗在高温胁迫适应性建立过程中的细胞死亡特征分析

Analysis of Cell Death Characteristics of Haloxylon ammodendron Seedlings During the Establishment of Adaptability to Heat Stress

为分析梭梭幼苗在高温胁迫中的细胞死亡特征,探究高温胁迫梭梭幼苗产生的“胁迫记忆”对二次高温胁迫的适应性作用。本研究以高温胁迫记忆处理过程中的梭梭幼苗同化枝为研究对象,通过吉姆萨染色、Hoechst33342和碘化丙碇(PI)双染法分析死亡细胞的形态,用荧光定量PCR分析相关基因表达模式,用比色法测定脯氨酸含量。结果显示,经过高温胁迫锻炼的同化枝在二次高温胁迫下细胞死亡率降低;BI-1基因表达仅受高温胁迫诱导,ATG12、ATG18D、PP2C、P5CS2、JMJ22基因在常温复原或二次高温胁迫下高表达,且脯氨酸含量提升。这些结果表明,梭梭幼苗受高温胁迫锻炼后,自噬、脯氨酸合成、ABA信号转导、组蛋白去甲基化等途径基因的增强表达,脯氨酸的积累可能有助于抑制二次高温胁迫下的细胞死亡。本研究结果为进一步分析梭梭幼苗的高温胁迫记忆对细胞死亡的抑制作用提供参考,对梭梭及其他荒漠植物高温胁迫适应性机制的研究具有一定的参考价值。

To analyze cell death characteristics of Haloxylon ammodendron seedlings during heat stress,the adaptive effects of stress memory produced by initial heat stress on secondary heat stress were explored in H.ammodendron seedlings.The assimilated branches of H.ammodendron seedlings subjected to heat stress memory treatments were applied as the research objects of this study which included:cell death morphological analysis with Giemsa staining and Hoechst33342/propidium iodide(PI)double staining;related genes expression analysis with fluorescence quantitative PCR(RT-qPCR);proline content detection with colorimetry method.The results showed that cell death of heat stress trained assimilated branches was repressed during secondary heat stress,and BI-1 gene was only induced by heat stress training,while genes including ATG12,ATG18D,PP2C,P5CS2 and JMJ22 were highly expressed during normal temperature recovery or secondary heat stress with proline content prompted.It indicated that increased expression of autophagy,proline synthesis,histone demethylation genes and accumulation of proline might help to repress cell death during secondary heat stress in H.ammodendron seedlings.This study provided a reference to further analysis of the inhibitory effect of heat stress memory on cell death of H.am-modendron seedlings,and had a certain reference value for the study of adaptability mechanism of heat stress of H.ammodendron and other desert plants.