乙烯利对苦瓜幼苗内源激素代谢及相关调控基因表达的影响

Effect of Ethephon on Endogenous Hormone Metabolism and Related Genes Expression in Bitter Melon Seedlings

以苦瓜常规品种“绿爵士”为试材,在日光温室内于幼苗3-4叶期叶面喷施乙烯利溶液,通过高效液相色谱串联质谱(HPLC-MS/MS)仪测定了相关内源激素的含量,并结合高通量测序技术对相关调控基因表达进行分析,探究外源乙烯利对苦瓜幼苗激素代谢的影响,获得苦瓜应对外源乙烯诱导的内源激素代谢靶点,初步明确相关调控基因的作用特点,为深入开展苦瓜类作物外源乙烯调控机制的研究奠定基础。结果表明:(1)在外源乙烯利作用下,苦瓜幼苗植株内源乙烯合成直接前体物质1-氨基环丙基-1-羧酸(ACC)含量和主要限速酶ACC合成酶(ACS)活性均表现为显著升高的趋势;内源生长素(IAA)和细胞分裂素(tZR)的含量同样显著升高,而其赤霉素(GA_(3))的含量则显著降低。(2)经过Hi-seq测序,共获得1234个差异表达基因(DEGs),功能富集分析显示有570个DEGs富集于118条代谢通路中。(3)对所有DEGs进行功能注释,鉴定了多个参与内源激素合成及信号转导的基因,包括乙烯代谢相关的ACS、ACO、HMT3、EIN3、ERFs基因,IAA代谢相关的ALDH、TAA1、UGT74B1、AUX/IAA、ARF等基因,细胞分裂素代谢相关的CYP735A、CKX、A-ARR基因,以及GA_(3)代谢相关的KAO1、CYP736A12-like、GID1、PIF3基因。(4)qRT-PCR分析表明,所挑选的8个基因的表达趋势与转录组log_(2)FC值变化趋势一致,其中4个基因为上调表达,另外4个基因下调表达。

In this study,ethephon solution was sprayed on the leaves of Green-J(Momordica charantia L.)seedlings at 3-4 leaf stage in solar greenhouse.The contents of related endogenous hormones were determined by HPLC-MS/MS,and the expression of related regulatory genes was analyzed by high-throughput sequencing technology.The present studies are helpful to explore the effect of exogenous ethephon on hormone metabolism of bitter melon seedlings,obtain endogenous hormone metabolism targets of bitter melon dealing with exogenous ethylene induction,and preliminarily identify the function characteristics of related regulatory genes.These findings lay a foundation for further research on the regulation mechanism of exogenous ethylene in bitter melon crops.The results showed that:(1)the contents of 1-aminocyclopropyl 1-carboxylic acid(ACC)and the activity of ACC synthase(ACS)significantly increased under ethephon treatment in bitter melon seedlings.The contents of auxin(IAA)and trans-zeatin nucleoside(tZR)also significantly increased.The content of gibberellin(GA_(3))showed marked decreased.(2)A total of 1234 differentially expressed genes(DEGs)were obtained by Hi-seq sequencing.Functional enrichment analysis showed that 570 DEGs were enriched in 118 metabolic pathways.(3)All DEGs were functional annotated and a series of genes involved in endogenous hormone synthesis and signal transduction were identified,including ethylene metabolism related genes of ACS,ACO,HMT3,EIN3,ERFs;IAA metabolism related genes of ALDH,TAA1,UGT74B1,AUX/IAA,ARF;cytokinin metabolism related genes of CYP735A,CKX and A-ARR;GA_(3) related genes of KAO1,CYP736A12-like,GID1 and PIF3.(4)qRT-PCR analysis showed that the expression trend of 4 selected genes was consistent with the log_(2)FC value of the transcriptome data.Among them,4 genes were up-regulated and the other 4 genes were down-regulated.