毛竹ICE基因家族的全基因组鉴定及低温胁迫下的表达模式分析

Genome-wide identification of the ICE gene family in moso bamboo and its expression pattern under low temperature stress

【目的】对毛竹Phyllostachys edulis ICE基因家族进行鉴定及分析,找出响应毛竹抗寒关键家族成员,研究毛竹ICE基因的生物学功能、响应低温胁迫的分子机制及遗传转化,为提高毛竹抗寒性奠定理论基础。【方法】利用生物信息学方法分析毛竹ICE基因家族成员,并对4、0、−2℃低温处理0(对照)、0.5、1.0、24.0、48.0 h的毛竹生理指标和ICE基因的表达模式进行分析。【结果】共鉴定了4个毛竹ICE基因。保守结构域和多重序列比对分析表明:PeICE基因结构高度相似。系统发育关系及启动子顺式作用元件分析显示:PeICE基因与水稻Oryza sativa亲缘关系更近,同时存在大量与非生物胁迫相关的顺式作用元件。活性氧自由基(ROS)染色发现随着处理时间增长,ROS染色逐渐加深,但是其0℃处理24.0 h、−2℃处理1.0 h后染色逐渐减弱。脯氨酸(Pro)质量摩尔浓度、超氧化物歧化酶(SOD)活性显示:4和0℃条件下,Pro质量摩尔浓度和SOD活性整体增加,但−2℃时低于对照。过氧化物酶(POD)活性显示:在3个低温处理下均增加。ICE基因表达模式分析发现:4、0℃处理时PeICE表达量整体增加,且都以PeICE3增量最明显;而−2℃处理下PeICE整体表达量水平低于对照。【结论】随着温度降低和处理时间增强,毛竹受到的损伤不断增强,其内酶活系统以及ICE基因积极响应低温胁迫,其中,PeICE3对低温胁迫最为敏感,但在−2℃时,ICE基因表达量并未增加,推测该基因家族响应了寒冷胁迫而非冷冻胁迫。

[Objective]The ICE gene family of Phyllostachys edulis(moso bamboo)was identified and analyzed to find out the key family members responding to cold resistance of moso bamboo,and to lay a theoretical foundation for further research on the biological functions of moso bamboo ICE genes,the molecular mechanisms responding to low-temperature stress,and the genetic transformation to improve the cold resistance of moso bamboo.[Method]Bioinformatics methods were used to identify and analyze the ICE gene family members of moso bamboo,and to analyze the physiological indexes and the expression patterns of ICE genes in moso bamboo at 0,0.5,1.0,24.0,and 48.0 h of low-temperature treatments at 4,0 and−2℃.[Result]A total of four mosaic bamboo ICE genes were identified.Conserved structural domains and multiple sequence comparison analyses showed that their structures were highly similar. Phylogenetic relationships and promoter cis-acting element analyses showed that the PeICE gene was more closely related to rice, and a large number of cis-acting elements associated with abiotic stresses were also present. Reactive oxygen radical (superoxide anion) staining revealed that the ROS staining gradually deepened with the increase in treatment time, but its staining gradually weakened after 24.0 h of 0 ℃ treatment and 1.0 h of −2 ℃ treatment. Proline content and superoxide dismutase activity assays revealed an overall increase in Pro and SOD content at 4 ℃ and 0 ℃, but their expression was lower than the control at −2 ℃, and peroxidase activity assays revealed an increase at all three temperatures. Analysis of ICE gene expression pattern revealed that the overall expression of PeICE increased in 4 ℃ and 0 ℃ treatment, and the most obvious increase was in PeICE3. The overall expression level of PeICE was lower than that of the control at −2 ℃. [Conclusion] With the decrease of cold treatment temperature and the enhancement of treatment time, moso bamboo was subjected to increasing damage, and its in vivo enzyme activity system as well as ICE genes responded positively to cold stress, and PeICE3 was the most sensitive to cold stress, whereas the expression of ICE genes did not increase at −2 ℃, and this gene family maybe respond to low-temperature stress instead of freezing stress.