异源过表达Atvip1基因增强转基因高粱对盐碱胁迫的抗性

Heterologous Overexpression of Atvip1 Gene Enhances the Resistance of Transgenic Sorghum to Saline-alkali Stress

为了研究异源过表达Atvip1基因的高粱对盐碱胁迫的耐受性及相应生长情况,采用NaHCO_(3)∶Na_(2)CO_(3)为5∶1,75 mmol/L,pH值9.63的盐碱胁迫液在高粱三叶一心期处理,在胁迫0,4,12,24,72,120 h对根系的生长指标、叶绿素含量、抗氧化酶活性以及MDA含量进行测定。结果表明:异源过表达Atvip1基因能缓解盐碱胁迫对高粱幼苗生长的伤害,可使幼苗根表面积和根体积增大,根尖数和分叉数增多,高粱主根褐化出现较晚且症状轻,侧根发生早且数量多,在72 h后仍能保证新叶正常伸展,对地上部生长影响较轻。过表达Atvip1基因可提高转基因高粱根系抗O_(2)^(-·)活力,降低MDA的含量,抗氧化酶活性增强;胁迫早期(4~12 h),SOD、CAT和GR作用明显;胁迫中期(24~72 h),所有酶均发挥作用;胁迫后期(120 h),CAT和GSH-PX起重要作用。盐碱胁迫差异转录组分析中,差异表达基因COG分析表明,防御机制在不同时间段中占比较大,获得抗氧化酶相关差异表达基因42个。异源过表达Atvip1基因可通过缓解盐碱胁迫对光合作用和生长发育的影响,降低活性氧破坏及膜损伤来提高转基因高粱对盐碱胁迫的抗性。

In order to study the tolerance of heterologously overexpressed Atvip1 gene in sorghum to defense saline-alkali stress and the corresponding growth,NaHCO_(3)∶Na_(2)CO_(3) of 5∶1 solution with 75 mmol/L and pH 9.63 was used in sorghum at the stage of three leaves and one heart.The root growth index,chlorophyll content,antioxidant enzyme activity and MDA content were measured at 0,4,12,24,72,and 120 h of stress.The results indicated that the heterologous overexpression of Atvip1 gene could alleviate the damage of saline-alkali stress on the growth of sorghum seedlings,increase the root surface area and root volume,the number of root tips and branches,and also cause the browning of sorghum main roots to appear later and mild symphonys,and the earlier and more lateral roots occurrence.The new leaves could still be normally extended at 72 h and present little effect on the growth of aboveground.Overexpression of Atvip1 gene could increase the activity of O_(2)^(-·)resistance,decrease the content of MDA and enhance the activities of antioxidant enzymes in transgenic sorghum roots.SOD,CAT and GR had obvious effects at 4-12 h during the early stage of stress,respectively.All enzymes played roles during the middle of stress at 24-72 h.CAT and GSH-PX played important roles at the later stage of stress at 120 h.On the base of differential transcriptome analysis of saline-alkali stress,COG analysis of differentially expressed genes(DEGs)showed that defense mechanisms accounted for a relatively large proportion during various periods,and 42 DEGs related to antioxidant enzymes were obtained.Heterologous overexpression of Atvip1 gene can improve the resistance of transgenic sorghum to saline-alkali stress by alleviating the effects on photosynthesis,growth and development,reducing the damages of reactive oxygen species and membrane damage.