大豆根系应答重金属Cd胁迫的转录组分析

Transcriptome analysis of response to heavy metal Cd stress in soybean root

重金属镉(Cd)作为一种非生命活动所需的常见污染物,在土壤中以低浓度存在时,便可以对生物体产生极强的毒性,影响农作物的生长发育.为了解大豆对重金属Cd胁迫应答的分子机制,把发芽7 d的大豆苗在75μmol·L^(-1)Cd浓度中处理0、4、8、12和48 h,然后取根进行转录组表达分析.共得到2670个表达差异基因,其中4、8、12和48 h处理组中分别有244、1545、442和1401个基因显示了表达差异.这些基因通过GO分类,可分为56类;采用COG数据库进行比对,根据其功能大致可分为25类.KEGG通路富集分析表明,差异表达基因主要富集在苯丙氨酸代谢、泛醌和其他萜类醌生物合成,以及半胱氨酸和甲硫氨酸代谢等通路中.发现3个异黄酮2'-羟化酶基因、2个异黄酮还原酶基因和1个查尔酮合成酶基因在Cd胁迫下均表达上调.RT-PCR检测4个差异表达基因的表达模式与RNA-Seq分析结果一致,证实了RNA-Seq结果的可靠性.

Cadmium （Cd） is a common pollutant not required for life activities, which can have ex- tremely strong toxicity to organisms and affect the growth of crops at a low concentration in soil. To investigate the molecular mechanism of soybean root responding to Cd stress, 7-day old soybean seedlings were stressed by Cd （75 μmol · L-1 ） for 0 , 4 , 8, 12 and 48 h. Comparative transcrip- tome analysis showed 244, 1545, 442 and 1401 of genes responded to the four Cd treatments, re- spectively, and total 2670 differential expression genes were obtained. GO analysis classified these genes into 56 functional categories and COG analysis classified them into 25 functional categories. KEGG analysis showed that many genes involved in the phenylalanine metabolism, ubiquinone and other terpenoid-quinone biosynthesis and cysteine and methionine metabolism and so on. Further we found that expression of three isoflavones 2＇-hydroxylase genes, two isoflavonereductase genes and a chalcone synthase gene were evidently up-regulated in all Cd treatments. The results of RT-PCR analysis of four DEGs were consistent with those of RNA-Seq results. of RNA-Seq data, further confirming the reliability