Study On The Effect Of Gibberellin On Cold-induced Sweetening Of Potato Tubers

Cold-induced sweetening（CIS）of potato tubers troubled the potato industry for a long time,which is regulated by key enzymes of starch and sucrose metabolism pathway and phytohormones.At present,research on CIS mostly focus on the key enzymes of starch and sucrose metabolism pathway,while the effect of phytohormones such as Gibberellin on CIS is still at the physiological and biochemical level.In order to further clarify the specific molecular pathway of Gibberellin effect CIS,"Huashu No.3"and"Zhongshu No.5"tubers selected as materials,compared the CIS characteristics of two varieties and preliminary analysis of transcriptome sequencing and candidate gene mining were performed,discussed the effect of Uniconazole on CIS of potato tubers.The main results of the study are as follows:1.Under low temperature and room temperature storage conditions,the sugar content,enzyme activity and GA₃ content of"Huashu No.3"and"Zhongshu No.5"tubers all increased with the extension of storage time,that is,CIS happened in two varieties.In addition,the color index,sugar content and invertase activity of"Zhongshu No.5"tubers were significantly higher than those of"Huashu No.3"tubers,that is,the degree of CIS of the former is higher than that of the latter,the CIS characteristics of the two varieties tubers were verified from the physiological level.In addition,the transcriptome sequencing results showed that the expression level of the acid invertase gene of"Zhongshu No.5"tubers was significantly higher than that of"Huashu No.3",which was consistent with the trend that invertase activity in"Zhongshu No.5"tuber was higher than that in"Huazhuo3"tuber.The sensitivity of the two varieties to CIS has been further verified at the molecular level.2.RNA-Seq results of"Huashu No.3"and"Zhongshu No.5"tubers showed that the sequencing quality of each sample was good,gene expression levels are mostly distributed in the range of 0-1.Most DEGs are enriched in biological processes such as DNA template transcription,DNA template transcriptional regulation and defense response,and are mainly involved in KEGG pathways such as phytohormone signal transduction,glycolysis/gluconeogenesis,and starch and sucrose metabolism.The results of q RT-PCR confirmed the reliability of transcriptome data.A large number of DEGs related to phytohormone were identified,and the mechanism of KOox,GA3ox,AP2/ERF,BRI1 and BKI1 affecting CIS was preliminarily analyzed,which provides theoretical basis for understanding the relationship between phytohormones and CIS of potato tubers.3.The chip color index,reducing sugar content,amylase activity and GA₃content of"Huashu No.3"and"Zhongshu No.5"tubers storaged for 30 days at low temperature treated with Uniconazole were lower than those of the control group,which indicated that Uniconazole improved CIS of potato tubers.